feat: config file as option

Fix https://github.com/lampajr/backporting/issues/37

This enhancement required a huge refactoring where all arguments
defaults have been centralized in one single place ArgsParser#parse

README.md

@@ -75,8 +75,9 @@ This tool comes with some inputs that allow users to override the default behavi
 |---------------|----------------------|--------------|--------------------------------------------------------------------------------------------------------------------------------------------------------|-------------|
 | Version       | -V, --version        | -            | Current version of the tool                                                                                                                            |             |
 | Help          | -h, --help           | -            | Display the help message                                                                                                                               |             |
-| Target Branch | -tb, --target-branch | Y            | Branch where the changes must be backported to                                                                                                         |             |
+| Target Branch | -tb, --target-branch | N            | Branch where the changes must be backported to                                                                                                         |             |
-| Pull Request  | -pr, --pull-request  | Y            | Original pull request url, the one that must be backported, e.g., https://github.com/lampajr/backporting/pull/1                                        |             |
+| Pull Request  | -pr, --pull-request  | N            | Original pull request url, the one that must be backported, e.g., https://github.com/lampajr/backporting/pull/1                                        |             |
+| Configuration File  | -cf, --config-file  | N            | Configuration file, in JSON format, containing all options to be overridded, note that if provided all other CLI options will be ignored                                        |             |
 | Auth          | -a, --auth           | N            | `GITHUB_TOKEN`, `GITLAB_TOKEN` or a `repo` scoped [Personal Access Token](https://docs.github.com/en/github/authenticating-to-github/creating-a-personal-access-token) | ""          |
 | Folder        | -f, --folder         | N            | Local folder full name of the repository that will be checked out, e.g., /tmp/folder                                                                                     | {cwd}/bp    |
 | Git User       | -gu, --git-user        | N            | Local git user name                                                       | "GitHub"       |
@@ -90,6 +91,22 @@ This tool comes with some inputs that allow users to override the default behavi
 | Backport Branch Name       | --bp-branch-name        | N            | Name of the backporting pull request branch                                                           | bp-{target-branch}-{sha}       |
 | Dry Run       | -d, --dry-run        | N            | If enabled the tool does not push nor create anything remotely, use this to skip PR creation                                                           | false       |
 
+> **NOTE**: `pull request` and `target branch` are *mandatory*, they must be provided as CLI options or as part of the configuration file (if used).
+
+#### Configuration file example
+
+This is an example of a configuration file that can be used.
+```json
+{
+  "pullRequest": "https://gitlab.com/<namespace>/<repo>/-/merge_requests/1",
+  "targetBranch": "old",
+  "folder": "/tmp/my-folder",
+  "title": "Override Title",
+  "auth": "*****"
+}
+```
+Keep in mind that its structue MUST match the [Args](src/service/args/args.types.ts) interface, which is actually a camel-case version of the CLI options.
+
 ## Supported git services
 
 Right now **bper** supports the following git management services:

action.yml

@@ -1,6 +1,15 @@
 name: "Backporting GitHub Action"
 description: "GitHub action providing an automated way to backport pull requests from one branch to another"
 inputs:
+  pull-request:
+    description: "URL of the pull request to backport, e.g., https://github.com/lampajr/backporting/pull/1"
+    required: false
+  target-branch:
+    description: "Branch where the pull request must be backported to"
+    required: false
+  config-file:
+    description: "Path to a file containing the json configuration for this tool, the object must match the Args interface"
+    required: false
   dry-run:
     description: "If enabled the tool does not create any pull request nor push anything remotely"
     required: false
@@ -17,12 +26,6 @@ inputs:
     description: "Local git user email"
     default: "noreply@github.com"
     required: false
-  pull-request:
-    description: "URL of the pull request to backport, e.g., https://github.com/lampajr/backporting/pull/1"
-    required: true
-  target-branch:
-    description: "Branch where the pull request must be backported to"
-    required: true
   title:
     description: "Backporting PR title. Default is the original PR title prefixed by the target branch"
     required: false

dist/cli/index.js

@@ -22,44 +22,155 @@ runner.run();
 
 /***/ }),
 
-/***/ 7938:
+/***/ 3025:
-/***/ ((__unused_webpack_module, exports, __nccwpck_require__) => {
+/***/ ((__unused_webpack_module, exports) => {
 
 "use strict";
 
 Object.defineProperty(exports, "__esModule", ({ value: true }));
+/**
+ * Abstract arguments parser interface in charge to parse inputs and
+ * produce a common Args object
+ */
+class ArgsParser {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    getOrDefault(parsedValue, defaultValue) {
+        return parsedValue === undefined ? defaultValue : parsedValue;
+    }
+    parse() {
+        const args = this.readArgs();
+        // validate and fill with defaults
+        if (!args.pullRequest || !args.targetBranch) {
+            throw new Error("Missing option: pull request and target branch must be provided");
+        }
+        return {
+            pullRequest: args.pullRequest,
+            targetBranch: args.targetBranch,
+            dryRun: this.getOrDefault(args.dryRun, false),
+            auth: this.getOrDefault(args.auth),
+            folder: this.getOrDefault(args.folder),
+            gitUser: this.getOrDefault(args.gitUser),
+            gitEmail: this.getOrDefault(args.gitEmail),
+            title: this.getOrDefault(args.title),
+            body: this.getOrDefault(args.body),
+            bodyPrefix: this.getOrDefault(args.bodyPrefix),
+            bpBranchName: this.getOrDefault(args.bpBranchName),
+            reviewers: this.getOrDefault(args.reviewers, []),
+            assignees: this.getOrDefault(args.assignees, []),
+            inheritReviewers: this.getOrDefault(args.inheritReviewers, true),
+        };
+    }
+}
+exports["default"] = ArgsParser;
+
+
+/***/ }),
+
+/***/ 8048:
+/***/ (function(__unused_webpack_module, exports, __nccwpck_require__) {
+
+"use strict";
+
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    var desc = Object.getOwnPropertyDescriptor(m, k);
+    if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
+      desc = { enumerable: true, get: function() { return m[k]; } };
+    }
+    Object.defineProperty(o, k2, desc);
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
+    Object.defineProperty(o, "default", { enumerable: true, value: v });
+}) : function(o, v) {
+    o["default"] = v;
+});
+var __importStar = (this && this.__importStar) || function (mod) {
+    if (mod && mod.__esModule) return mod;
+    var result = {};
+    if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
+    __setModuleDefault(result, mod);
+    return result;
+};
+Object.defineProperty(exports, "__esModule", ({ value: true }));
+exports.readConfigFile = exports.parseArgs = void 0;
+const fs = __importStar(__nccwpck_require__(7147));
+/**
+ * Parse the input configuation string as json object and
+ * return it as Args
+ * @param configFileContent
+ * @returns {Args}
+ */
+function parseArgs(configFileContent) {
+    return JSON.parse(configFileContent);
+}
+exports.parseArgs = parseArgs;
+/**
+ * Read a configuration file in json format anf parse it as {Args}
+ * @param pathToFile Full path name of the config file, e.g., /tmp/dir/config-file.json
+ * @returns {Args}
+ */
+function readConfigFile(pathToFile) {
+    const asString = fs.readFileSync(pathToFile, "utf-8");
+    return parseArgs(asString);
+}
+exports.readConfigFile = readConfigFile;
+
+
+/***/ }),
+
+/***/ 7938:
+/***/ (function(__unused_webpack_module, exports, __nccwpck_require__) {
+
+"use strict";
+
+var __importDefault = (this && this.__importDefault) || function (mod) {
+    return (mod && mod.__esModule) ? mod : { "default": mod };
+};
+Object.defineProperty(exports, "__esModule", ({ value: true }));
+const args_parser_1 = __importDefault(__nccwpck_require__(3025));
 const commander_1 = __nccwpck_require__(4379);
 const package_json_1 = __nccwpck_require__(6625);
+const args_utils_1 = __nccwpck_require__(8048);
 function commaSeparatedList(value, _prev) {
     // remove all whitespaces
     const cleanedValue = value.trim();
     return cleanedValue !== "" ? cleanedValue.replace(/\s/g, "").split(",") : [];
 }
-class CLIArgsParser {
+class CLIArgsParser extends args_parser_1.default {
     getCommand() {
         return new commander_1.Command(package_json_1.name)
             .version(package_json_1.version)
             .description(package_json_1.description)
-            .requiredOption("-tb, --target-branch <branch>", "branch where changes must be backported to.")
+            .option("-tb, --target-branch <branch>", "branch where changes must be backported to.")
-            .requiredOption("-pr, --pull-request <pr-url>", "pull request url, e.g., https://github.com/lampajr/backporting/pull/1.")
+            .option("-pr, --pull-request <pr-url>", "pull request url, e.g., https://github.com/lampajr/backporting/pull/1.")
-            .option("-d, --dry-run", "if enabled the tool does not create any pull request nor push anything remotely", false)
+            .option("-d, --dry-run", "if enabled the tool does not create any pull request nor push anything remotely")
-            .option("-a, --auth <auth>", "git service authentication string, e.g., github token.", "")
+            .option("-a, --auth <auth>", "git service authentication string, e.g., github token.")
-            .option("-gu, --git-user <git-user>", "local git user name, default is 'GitHub'.", "GitHub")
+            .option("-gu, --git-user <git-user>", "local git user name, default is 'GitHub'.")
-            .option("-ge, --git-email <git-email>", "local git user email, default is 'noreply@github.com'.", "noreply@github.com")
+            .option("-ge, --git-email <git-email>", "local git user email, default is 'noreply@github.com'.")
-            .option("-f, --folder <folder>", "local folder where the repo will be checked out, e.g., /tmp/folder.", undefined)
+            .option("-f, --folder <folder>", "local folder where the repo will be checked out, e.g., /tmp/folder.")
-            .option("--title <bp-title>", "backport pr title, default original pr title prefixed by target branch.", undefined)
+            .option("--title <bp-title>", "backport pr title, default original pr title prefixed by target branch.")
-            .option("--body <bp-body>", "backport pr title, default original pr body prefixed by bodyPrefix.", undefined)
+            .option("--body <bp-body>", "backport pr title, default original pr body prefixed by bodyPrefix.")
-            .option("--body-prefix <bp-body-prefix>", "backport pr body prefix, default `backport <original-pr-link>`.", undefined)
+            .option("--body-prefix <bp-body-prefix>", "backport pr body prefix, default `backport <original-pr-link>`.")
-            .option("--bp-branch-name <bp-branch-name>", "backport pr branch name, default auto-generated by the commit.", undefined)
+            .option("--bp-branch-name <bp-branch-name>", "backport pr branch name, default auto-generated by the commit.")
-            .option("--reviewers <reviewers>", "comma separated list of reviewers for the backporting pull request.", commaSeparatedList, [])
+            .option("--reviewers <reviewers>", "comma separated list of reviewers for the backporting pull request.", commaSeparatedList)
-            .option("--assignees <assignees>", "comma separated list of assignees for the backporting pull request.", commaSeparatedList, [])
+            .option("--assignees <assignees>", "comma separated list of assignees for the backporting pull request.", commaSeparatedList)
-            .option("--no-inherit-reviewers", "if provided and reviewers option is empty then inherit them from original pull request", true);
+            .option("--no-inherit-reviewers", "if provided and reviewers option is empty then inherit them from original pull request")
+            .option("-cf, --config-file <config-file>", "configuration file containing all valid options, the json must match Args interface.");
     }
-    parse() {
+    readArgs() {
         const opts = this.getCommand()
             .parse()
             .opts();
-        return {
+        let args;
+        if (opts.configFile) {
+            // if config file is set ignore all other options
+            args = (0, args_utils_1.readConfigFile)(opts.configFile);
+        }
+        else {
+            args = {
                 dryRun: opts.dryRun,
                 auth: opts.auth,
                 pullRequest: opts.pullRequest,
@@ -76,6 +187,8 @@ class CLIArgsParser {
                 inheritReviewers: opts.inheritReviewers,
             };
         }
+        return args;
+    }
 }
 exports["default"] = CLIArgsParser;
 
@@ -133,12 +246,12 @@ const git_client_factory_1 = __importDefault(__nccwpck_require__(8550));
 class PullRequestConfigsParser extends configs_parser_1.default {
     constructor() {
         super();
-        this.gitService = git_client_factory_1.default.getClient();
+        this.gitClient = git_client_factory_1.default.getClient();
     }
     async parse(args) {
         let pr;
         try {
-            pr = await this.gitService.getPullRequestFromUrl(args.pullRequest);
+            pr = await this.gitClient.getPullRequestFromUrl(args.pullRequest);
         }
         catch (error) {
             this.logger.error("Something went wrong retrieving pull request");
@@ -153,8 +266,8 @@ class PullRequestConfigsParser extends configs_parser_1.default {
             originalPullRequest: pr,
             backportPullRequest: this.getDefaultBackportPullRequest(pr, args),
             git: {
-                user: args.gitUser,
+                user: args.gitUser ?? this.gitClient.getDefaultGitUser(),
-                email: args.gitEmail,
+                email: args.gitEmail ?? this.gitClient.getDefaultGitEmail(),
             }
         };
     }
@@ -180,7 +293,7 @@ class PullRequestConfigsParser extends configs_parser_1.default {
         const bodyPrefix = args.bodyPrefix ?? `**Backport:** ${originalPullRequest.htmlUrl}\r\n\r\n`;
         const body = args.body ?? `${originalPullRequest.body}`;
         return {
-            author: args.gitUser,
+            author: args.gitUser ?? this.gitClient.getDefaultGitUser(),
             title: args.title ?? `[${args.targetBranch}] ${originalPullRequest.title}`,
             body: `${bodyPrefix}${body}`,
             reviewers: [...new Set(reviewers)],
@@ -466,6 +579,12 @@ class GitHubClient {
         this.mapper = new github_mapper_1.default();
     }
     // READ
+    getDefaultGitUser() {
+        return "GitHub";
+    }
+    getDefaultGitEmail() {
+        return "noreply@github.com";
+    }
     async getPullRequest(owner, repo, prNumber) {
         this.logger.info(`Getting pull request ${owner}/${repo}/${prNumber}.`);
         const { data } = await this.octokit.rest.pulls.get({
@@ -651,7 +770,7 @@ class GitLabClient {
         this.client = axios_1.default.create({
             baseURL: this.apiUrl,
             headers: {
-                Authorization: `Bearer ${token}`,
+                Authorization: token ? `Bearer ${token}` : "",
                 "User-Agent": "lampajr/backporting",
             },
             httpsAgent: new https_1.default.Agent({
@@ -660,6 +779,12 @@ class GitLabClient {
         });
         this.mapper = new gitlab_mapper_1.default(this.client);
     }
+    getDefaultGitUser() {
+        return "Gitlab";
+    }
+    getDefaultGitEmail() {
+        return "noreply@gitlab.com";
+    }
     // READ
     // example: <host>/api/v4/projects/alampare%2Fbackporting-example/merge_requests/1
     async getPullRequest(namespace, repo, mrNumber) {

dist/gha/index.js

@@ -22,14 +22,118 @@ runner.run();
 
 /***/ }),
 
-/***/ 7283:
+/***/ 3025:
-/***/ ((__unused_webpack_module, exports, __nccwpck_require__) => {
+/***/ ((__unused_webpack_module, exports) => {
 
 "use strict";
 
 Object.defineProperty(exports, "__esModule", ({ value: true }));
+/**
+ * Abstract arguments parser interface in charge to parse inputs and
+ * produce a common Args object
+ */
+class ArgsParser {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    getOrDefault(parsedValue, defaultValue) {
+        return parsedValue === undefined ? defaultValue : parsedValue;
+    }
+    parse() {
+        const args = this.readArgs();
+        // validate and fill with defaults
+        if (!args.pullRequest || !args.targetBranch) {
+            throw new Error("Missing option: pull request and target branch must be provided");
+        }
+        return {
+            pullRequest: args.pullRequest,
+            targetBranch: args.targetBranch,
+            dryRun: this.getOrDefault(args.dryRun, false),
+            auth: this.getOrDefault(args.auth),
+            folder: this.getOrDefault(args.folder),
+            gitUser: this.getOrDefault(args.gitUser),
+            gitEmail: this.getOrDefault(args.gitEmail),
+            title: this.getOrDefault(args.title),
+            body: this.getOrDefault(args.body),
+            bodyPrefix: this.getOrDefault(args.bodyPrefix),
+            bpBranchName: this.getOrDefault(args.bpBranchName),
+            reviewers: this.getOrDefault(args.reviewers, []),
+            assignees: this.getOrDefault(args.assignees, []),
+            inheritReviewers: this.getOrDefault(args.inheritReviewers, true),
+        };
+    }
+}
+exports["default"] = ArgsParser;
+
+
+/***/ }),
+
+/***/ 8048:
+/***/ (function(__unused_webpack_module, exports, __nccwpck_require__) {
+
+"use strict";
+
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    var desc = Object.getOwnPropertyDescriptor(m, k);
+    if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
+      desc = { enumerable: true, get: function() { return m[k]; } };
+    }
+    Object.defineProperty(o, k2, desc);
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
+    Object.defineProperty(o, "default", { enumerable: true, value: v });
+}) : function(o, v) {
+    o["default"] = v;
+});
+var __importStar = (this && this.__importStar) || function (mod) {
+    if (mod && mod.__esModule) return mod;
+    var result = {};
+    if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
+    __setModuleDefault(result, mod);
+    return result;
+};
+Object.defineProperty(exports, "__esModule", ({ value: true }));
+exports.readConfigFile = exports.parseArgs = void 0;
+const fs = __importStar(__nccwpck_require__(7147));
+/**
+ * Parse the input configuation string as json object and
+ * return it as Args
+ * @param configFileContent
+ * @returns {Args}
+ */
+function parseArgs(configFileContent) {
+    return JSON.parse(configFileContent);
+}
+exports.parseArgs = parseArgs;
+/**
+ * Read a configuration file in json format anf parse it as {Args}
+ * @param pathToFile Full path name of the config file, e.g., /tmp/dir/config-file.json
+ * @returns {Args}
+ */
+function readConfigFile(pathToFile) {
+    const asString = fs.readFileSync(pathToFile, "utf-8");
+    return parseArgs(asString);
+}
+exports.readConfigFile = readConfigFile;
+
+
+/***/ }),
+
+/***/ 7283:
+/***/ (function(__unused_webpack_module, exports, __nccwpck_require__) {
+
+"use strict";
+
+var __importDefault = (this && this.__importDefault) || function (mod) {
+    return (mod && mod.__esModule) ? mod : { "default": mod };
+};
+Object.defineProperty(exports, "__esModule", ({ value: true }));
+const args_parser_1 = __importDefault(__nccwpck_require__(3025));
 const core_1 = __nccwpck_require__(2186);
-class GHAArgsParser {
+const args_utils_1 = __nccwpck_require__(8048);
+class GHAArgsParser extends args_parser_1.default {
     /**
      * Return the input only if it is not a blank or null string, otherwise returns undefined
      * @param key input key
@@ -39,37 +143,41 @@ class GHAArgsParser {
         const value = (0, core_1.getInput)(key);
         return value !== "" ? value : undefined;
     }
-    getOrDefault(key, defaultValue) {
-        const value = (0, core_1.getInput)(key);
-        return value !== "" ? value : defaultValue;
-    }
     getAsCommaSeparatedList(key) {
         // trim the value
         const value = ((0, core_1.getInput)(key) ?? "").trim();
-        return value !== "" ? value.replace(/\s/g, "").split(",") : [];
+        return value !== "" ? value.replace(/\s/g, "").split(",") : undefined;
     }
-    getAsBooleanOrDefault(key, defaultValue) {
+    getAsBooleanOrDefault(key) {
         const value = (0, core_1.getInput)(key).trim();
-        return value !== "" ? value.toLowerCase() === "true" : defaultValue;
+        return value !== "" ? value.toLowerCase() === "true" : undefined;
     }
-    parse() {
+    readArgs() {
-        return {
+        const configFile = this.getOrUndefined("config-file");
-            dryRun: this.getAsBooleanOrDefault("dry-run", false),
+        let args;
-            auth: (0, core_1.getInput)("auth"),
+        if (configFile) {
+            args = (0, args_utils_1.readConfigFile)(configFile);
+        }
+        else {
+            args = {
+                dryRun: this.getAsBooleanOrDefault("dry-run"),
+                auth: this.getOrUndefined("auth"),
                 pullRequest: (0, core_1.getInput)("pull-request"),
                 targetBranch: (0, core_1.getInput)("target-branch"),
                 folder: this.getOrUndefined("folder"),
-            gitUser: this.getOrDefault("git-user", "GitHub"),
+                gitUser: this.getOrUndefined("git-user"),
-            gitEmail: this.getOrDefault("git-email", "noreply@github.com"),
+                gitEmail: this.getOrUndefined("git-email"),
                 title: this.getOrUndefined("title"),
                 body: this.getOrUndefined("body"),
                 bodyPrefix: this.getOrUndefined("body-prefix"),
                 bpBranchName: this.getOrUndefined("bp-branch-name"),
                 reviewers: this.getAsCommaSeparatedList("reviewers"),
                 assignees: this.getAsCommaSeparatedList("assignees"),
-            inheritReviewers: !this.getAsBooleanOrDefault("no-inherit-reviewers", false),
+                inheritReviewers: !this.getAsBooleanOrDefault("no-inherit-reviewers"),
             };
         }
+        return args;
+    }
 }
 exports["default"] = GHAArgsParser;
 
@@ -127,12 +235,12 @@ const git_client_factory_1 = __importDefault(__nccwpck_require__(8550));
 class PullRequestConfigsParser extends configs_parser_1.default {
     constructor() {
         super();
-        this.gitService = git_client_factory_1.default.getClient();
+        this.gitClient = git_client_factory_1.default.getClient();
     }
     async parse(args) {
         let pr;
         try {
-            pr = await this.gitService.getPullRequestFromUrl(args.pullRequest);
+            pr = await this.gitClient.getPullRequestFromUrl(args.pullRequest);
         }
         catch (error) {
             this.logger.error("Something went wrong retrieving pull request");
@@ -147,8 +255,8 @@ class PullRequestConfigsParser extends configs_parser_1.default {
             originalPullRequest: pr,
             backportPullRequest: this.getDefaultBackportPullRequest(pr, args),
             git: {
-                user: args.gitUser,
+                user: args.gitUser ?? this.gitClient.getDefaultGitUser(),
-                email: args.gitEmail,
+                email: args.gitEmail ?? this.gitClient.getDefaultGitEmail(),
             }
         };
     }
@@ -174,7 +282,7 @@ class PullRequestConfigsParser extends configs_parser_1.default {
         const bodyPrefix = args.bodyPrefix ?? `**Backport:** ${originalPullRequest.htmlUrl}\r\n\r\n`;
         const body = args.body ?? `${originalPullRequest.body}`;
         return {
-            author: args.gitUser,
+            author: args.gitUser ?? this.gitClient.getDefaultGitUser(),
             title: args.title ?? `[${args.targetBranch}] ${originalPullRequest.title}`,
             body: `${bodyPrefix}${body}`,
             reviewers: [...new Set(reviewers)],
@@ -460,6 +568,12 @@ class GitHubClient {
         this.mapper = new github_mapper_1.default();
     }
     // READ
+    getDefaultGitUser() {
+        return "GitHub";
+    }
+    getDefaultGitEmail() {
+        return "noreply@github.com";
+    }
     async getPullRequest(owner, repo, prNumber) {
         this.logger.info(`Getting pull request ${owner}/${repo}/${prNumber}.`);
         const { data } = await this.octokit.rest.pulls.get({
@@ -645,7 +759,7 @@ class GitLabClient {
         this.client = axios_1.default.create({
             baseURL: this.apiUrl,
             headers: {
-                Authorization: `Bearer ${token}`,
+                Authorization: token ? `Bearer ${token}` : "",
                 "User-Agent": "lampajr/backporting",
             },
             httpsAgent: new https_1.default.Agent({
@@ -654,6 +768,12 @@ class GitLabClient {
         });
         this.mapper = new gitlab_mapper_1.default(this.client);
     }
+    getDefaultGitUser() {
+        return "Gitlab";
+    }
+    getDefaultGitEmail() {
+        return "noreply@gitlab.com";
+    }
     // READ
     // example: <host>/api/v4/projects/alampare%2Fbackporting-example/merge_requests/1
     async getPullRequest(namespace, repo, mrNumber) {

src/service/args/args-parser.ts

@@ -4,7 +4,38 @@ import { Args } from "@bp/service/args/args.types";
  * Abstract arguments parser interface in charge to parse inputs and 
  * produce a common Args object
  */
-export default interface ArgsParser {
+export default abstract class ArgsParser {
 
-  parse(): Args;
+  abstract readArgs(): Args;
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  private getOrDefault(parsedValue: any, defaultValue?: any) {
+    return parsedValue === undefined ? defaultValue : parsedValue;
+  }
+
+  public parse(): Args {
+    const args = this.readArgs();
+
+    // validate and fill with defaults
+    if (!args.pullRequest || !args.targetBranch) {
+      throw new Error("Missing option: pull request and target branch must be provided");
+    }
+    
+    return {
+      pullRequest: args.pullRequest,
+      targetBranch: args.targetBranch,
+      dryRun: this.getOrDefault(args.dryRun, false),
+      auth: this.getOrDefault(args.auth),
+      folder: this.getOrDefault(args.folder),
+      gitUser: this.getOrDefault(args.gitUser),
+      gitEmail: this.getOrDefault(args.gitEmail),
+      title: this.getOrDefault(args.title),
+      body: this.getOrDefault(args.body),
+      bodyPrefix: this.getOrDefault(args.bodyPrefix),
+      bpBranchName: this.getOrDefault(args.bpBranchName),
+      reviewers: this.getOrDefault(args.reviewers, []),
+      assignees: this.getOrDefault(args.assignees, []),
+      inheritReviewers: this.getOrDefault(args.inheritReviewers, true),
+    };
+  }
 }

src/service/args/args-utils.ts

@@ -0,0 +1,22 @@
+import { Args } from "@bp/service/args/args.types";
+import * as fs from "fs";
+
+/**
+ * Parse the input configuation string as json object and 
+ * return it as Args
+ * @param configFileContent 
+ * @returns {Args}
+ */
+export function parseArgs(configFileContent: string): Args {
+  return JSON.parse(configFileContent) as Args;
+}
+
+/**
+ * Read a configuration file in json format anf parse it as {Args}
+ * @param pathToFile Full path name of the config file, e.g., /tmp/dir/config-file.json
+ * @returns {Args}
+ */
+export function readConfigFile(pathToFile: string): Args {
+  const asString: string = fs.readFileSync(pathToFile, "utf-8");
+  return parseArgs(asString);
+}

src/service/args/args.types.ts

@@ -2,18 +2,18 @@
  * Input arguments
  */
 export interface Args {
-  dryRun: boolean, // if enabled do not push anything remotely
-  auth: string, // git service auth, like github token
   targetBranch: string,  // branch on the target repo where the change should be backported to
   pullRequest: string, // url of the pull request to backport
+  dryRun?: boolean, // if enabled do not push anything remotely
+  auth?: string, // git service auth, like github token
   folder?: string, // local folder where the repositories should be cloned
-  gitUser: string, // local git user, default 'GitHub'
+  gitUser?: string, // local git user, default 'GitHub'
-  gitEmail: string, // local git email, default 'noreply@github.com'
+  gitEmail?: string, // local git email, default 'noreply@github.com'
   title?: string, // backport pr title, default original pr title prefixed by target branch
   body?: string, // backport pr title, default original pr body prefixed by bodyPrefix
   bodyPrefix?: string, // backport pr body prefix, default `backport <original-pr-link>`
   bpBranchName?: string, // backport pr branch name, default computed from commit
   reviewers?: string[], // backport pr reviewers
   assignees?: string[], // backport pr assignees
-  inheritReviewers: boolean, // if true and reviewers == [] then inherit reviewers from original pr
+  inheritReviewers?: boolean, // if true and reviewers == [] then inherit reviewers from original pr
 }

src/service/args/cli/cli-args-parser.ts

@@ -2,6 +2,7 @@ import ArgsParser from "@bp/service/args/args-parser";
 import { Args } from "@bp/service/args/args.types";
 import { Command } from "commander";
 import { name, version, description } from "@bp/../package.json";
+import { readConfigFile } from "@bp/service/args/args-utils";
 
 function commaSeparatedList(value: string, _prev: unknown): string[] {
   // remove all whitespaces
@@ -9,34 +10,40 @@ function commaSeparatedList(value: string, _prev: unknown): string[] {
   return cleanedValue !== "" ? cleanedValue.replace(/\s/g, "").split(",") : [];
 }
 
-export default class CLIArgsParser implements ArgsParser {
+export default class CLIArgsParser extends ArgsParser {
 
   private getCommand(): Command {
     return new Command(name)
       .version(version)
       .description(description)
-      .requiredOption("-tb, --target-branch <branch>", "branch where changes must be backported to.")
+      .option("-tb, --target-branch <branch>", "branch where changes must be backported to.")
-      .requiredOption("-pr, --pull-request <pr-url>", "pull request url, e.g., https://github.com/lampajr/backporting/pull/1.")
+      .option("-pr, --pull-request <pr-url>", "pull request url, e.g., https://github.com/lampajr/backporting/pull/1.")
-      .option("-d, --dry-run", "if enabled the tool does not create any pull request nor push anything remotely", false)
+      .option("-d, --dry-run", "if enabled the tool does not create any pull request nor push anything remotely")
-      .option("-a, --auth <auth>", "git service authentication string, e.g., github token.", "")
+      .option("-a, --auth <auth>", "git service authentication string, e.g., github token.")
-      .option("-gu, --git-user <git-user>", "local git user name, default is 'GitHub'.", "GitHub")
+      .option("-gu, --git-user <git-user>", "local git user name, default is 'GitHub'.")
-      .option("-ge, --git-email <git-email>", "local git user email, default is 'noreply@github.com'.", "noreply@github.com")
+      .option("-ge, --git-email <git-email>", "local git user email, default is 'noreply@github.com'.")
-      .option("-f, --folder <folder>", "local folder where the repo will be checked out, e.g., /tmp/folder.", undefined)
+      .option("-f, --folder <folder>", "local folder where the repo will be checked out, e.g., /tmp/folder.")
-      .option("--title <bp-title>", "backport pr title, default original pr title prefixed by target branch.", undefined)
+      .option("--title <bp-title>", "backport pr title, default original pr title prefixed by target branch.")
-      .option("--body <bp-body>", "backport pr title, default original pr body prefixed by bodyPrefix.", undefined)
+      .option("--body <bp-body>", "backport pr title, default original pr body prefixed by bodyPrefix.")
-      .option("--body-prefix <bp-body-prefix>", "backport pr body prefix, default `backport <original-pr-link>`.", undefined)
+      .option("--body-prefix <bp-body-prefix>", "backport pr body prefix, default `backport <original-pr-link>`.")
-      .option("--bp-branch-name <bp-branch-name>", "backport pr branch name, default auto-generated by the commit.", undefined)
+      .option("--bp-branch-name <bp-branch-name>", "backport pr branch name, default auto-generated by the commit.")
-      .option("--reviewers <reviewers>", "comma separated list of reviewers for the backporting pull request.", commaSeparatedList, [])
+      .option("--reviewers <reviewers>", "comma separated list of reviewers for the backporting pull request.", commaSeparatedList)
-      .option("--assignees <assignees>", "comma separated list of assignees for the backporting pull request.", commaSeparatedList, [])
+      .option("--assignees <assignees>", "comma separated list of assignees for the backporting pull request.", commaSeparatedList)
-      .option("--no-inherit-reviewers", "if provided and reviewers option is empty then inherit them from original pull request", true);
+      .option("--no-inherit-reviewers", "if provided and reviewers option is empty then inherit them from original pull request")
+      .option("-cf, --config-file <config-file>", "configuration file containing all valid options, the json must match Args interface.");
   }
 
-  parse(): Args {
+  readArgs(): Args {
     const opts = this.getCommand()
       .parse()
       .opts();
     
-    return {
+    let args: Args; 
+    if (opts.configFile) {
+      // if config file is set ignore all other options
+      args = readConfigFile(opts.configFile);
+    } else {
+      args = {
         dryRun: opts.dryRun,
         auth: opts.auth,
         pullRequest: opts.pullRequest,
@@ -54,4 +61,7 @@ export default class CLIArgsParser implements ArgsParser {
       };
     }
 
+    return args;
+  }
+
 }

src/service/args/gha/gha-args-parser.ts

@@ -1,8 +1,9 @@
 import ArgsParser from "@bp/service/args/args-parser";
 import { Args } from "@bp/service/args/args.types";
 import { getInput } from "@actions/core";
+import { readConfigFile } from "@bp/service/args/args-utils";
 
-export default class GHAArgsParser implements ArgsParser {
+export default class GHAArgsParser extends ArgsParser {
 
   /**
    * Return the input only if it is not a blank or null string, otherwise returns undefined
@@ -14,39 +15,43 @@ export default class GHAArgsParser implements ArgsParser {
     return value !== "" ? value : undefined;
   }
 
-  public getOrDefault(key: string, defaultValue: string): string {
+  public getAsCommaSeparatedList(key: string): string[] | undefined {
-    const value = getInput(key);
-    return value !== "" ? value : defaultValue;
-  }
-
-  public getAsCommaSeparatedList(key: string): string[] {
     // trim the value
     const value: string = (getInput(key) ?? "").trim();
-    return value !== "" ? value.replace(/\s/g, "").split(",") : []; 
+    return value !== "" ? value.replace(/\s/g, "").split(",") : undefined; 
   }
 
-  public getAsBooleanOrDefault(key: string, defaultValue: boolean): boolean {
+  private getAsBooleanOrDefault(key: string): boolean | undefined {
     const value = getInput(key).trim();
-    return value !== "" ? value.toLowerCase() === "true" : defaultValue;
+    return value !== "" ? value.toLowerCase() === "true" : undefined;
   }
 
-  parse(): Args {
+  readArgs(): Args {
-    return {
+    const configFile = this.getOrUndefined("config-file");
-      dryRun: this.getAsBooleanOrDefault("dry-run", false),
+
-      auth: getInput("auth"),
+    let args: Args; 
+    if (configFile) {
+      args = readConfigFile(configFile);
+    } else {
+      args = {
+        dryRun: this.getAsBooleanOrDefault("dry-run"),
+        auth: this.getOrUndefined("auth"),
         pullRequest: getInput("pull-request"),
         targetBranch: getInput("target-branch"),
         folder: this.getOrUndefined("folder"),
-      gitUser: this.getOrDefault("git-user", "GitHub"),
+        gitUser: this.getOrUndefined("git-user"),
-      gitEmail: this.getOrDefault("git-email", "noreply@github.com"),
+        gitEmail: this.getOrUndefined("git-email"),
         title: this.getOrUndefined("title"),
         body: this.getOrUndefined("body"),
         bodyPrefix: this.getOrUndefined("body-prefix"),
         bpBranchName: this.getOrUndefined("bp-branch-name"),
         reviewers: this.getAsCommaSeparatedList("reviewers"),
         assignees: this.getAsCommaSeparatedList("assignees"),
-      inheritReviewers: !this.getAsBooleanOrDefault("no-inherit-reviewers", false),
+        inheritReviewers: !this.getAsBooleanOrDefault("no-inherit-reviewers"),
       };
     }
 
+    return args;
+  }
+
 }

src/service/configs/configs.types.ts

@@ -12,7 +12,7 @@ export interface LocalGit {
  */
 export interface Configs {
   dryRun: boolean,
-  auth: string,
+  auth?: string,
   git: LocalGit,
   folder: string,
   targetBranch: string,

src/service/configs/pullrequest/pr-configs-parser.ts

@@ -7,17 +7,17 @@ import { GitPullRequest } from "@bp/service/git/git.types";
 
 export default class PullRequestConfigsParser extends ConfigsParser {
 
-  private gitService: GitClient;
+  private gitClient: GitClient;
 
   constructor() {
     super();
-    this.gitService = GitClientFactory.getClient();
+    this.gitClient = GitClientFactory.getClient();
   }
   
   public async parse(args: Args): Promise<Configs> {
     let pr: GitPullRequest; 
     try {
-      pr = await this.gitService.getPullRequestFromUrl(args.pullRequest);
+      pr = await this.gitClient.getPullRequestFromUrl(args.pullRequest);
     } catch(error) {
       this.logger.error("Something went wrong retrieving pull request");
       throw error;
@@ -26,15 +26,15 @@ export default class PullRequestConfigsParser extends ConfigsParser {
     const folder: string = args.folder ?? this.getDefaultFolder();
 
     return {
-      dryRun: args.dryRun,
+      dryRun: args.dryRun!,
       auth: args.auth,
       folder: `${folder.startsWith("/") ? "" : process.cwd() + "/"}${args.folder ?? this.getDefaultFolder()}`,
       targetBranch: args.targetBranch,
       originalPullRequest: pr,
       backportPullRequest: this.getDefaultBackportPullRequest(pr, args),
       git: {
-        user: args.gitUser,
+        user: args.gitUser ?? this.gitClient.getDefaultGitUser(),
-        email: args.gitEmail,
+        email: args.gitEmail ?? this.gitClient.getDefaultGitEmail(),
       }
     };
   }
@@ -64,7 +64,7 @@ export default class PullRequestConfigsParser extends ConfigsParser {
     const body = args.body ?? `${originalPullRequest.body}`;
     
     return {
-      author: args.gitUser,
+      author: args.gitUser ?? this.gitClient.getDefaultGitUser(),
       title: args.title ?? `[${args.targetBranch}] ${originalPullRequest.title}`, 
       body: `${bodyPrefix}${body}`,
       reviewers: [...new Set(reviewers)],

src/service/git/git-cli.ts

@@ -10,10 +10,10 @@ import { LocalGit } from "@bp/service/configs/configs.types";
 export default class GitCLIService {
 
   private readonly logger: LoggerService;
-  private readonly auth: string;
+  private readonly auth: string | undefined;
   private readonly gitData: LocalGit;
 
-  constructor(auth: string, gitData: LocalGit) {
+  constructor(auth: string | undefined, gitData: LocalGit) {
     this.logger = LoggerServiceFactory.getLogger();
     this.auth  = auth;
     this.gitData = gitData;

src/service/git/git-client-factory.ts

@@ -26,7 +26,7 @@ export default class GitClientFactory {
    * @param type git management service type
    * @param authToken authentication token, like github/gitlab token
    */
-  public static getOrCreate(type: GitClientType, authToken: string, apiUrl: string): GitClient {
+  public static getOrCreate(type: GitClientType, authToken: string | undefined, apiUrl: string): GitClient {
 
     if (GitClientFactory.instance) {
       GitClientFactory.logger.warn("Git service already initialized!");

src/service/git/git-client.ts

@@ -8,6 +8,10 @@ import { BackportPullRequest, GitPullRequest } from "@bp/service/git/git.types";
 
   // READ
   
+  getDefaultGitUser(): string;
+
+  getDefaultGitEmail(): string;
+
   /**
    * Get a pull request object from the underneath git service
    * @param owner repository's owner

src/service/git/github/github-client.ts

@@ -14,7 +14,7 @@ export default class GitHubClient implements GitClient {
   private octokit: Octokit;
   private mapper: GitHubMapper;
 
-  constructor(token: string, apiUrl: string) {
+  constructor(token: string | undefined, apiUrl: string) {
     this.apiUrl = apiUrl;
     this.logger = LoggerServiceFactory.getLogger();
     this.octokit = OctokitFactory.getOctokit(token, this.apiUrl);
@@ -23,6 +23,14 @@ export default class GitHubClient implements GitClient {
 
   // READ
 
+  getDefaultGitUser(): string {
+    return "GitHub";
+  }
+  
+  getDefaultGitEmail(): string {
+    return "noreply@github.com";
+  }
+
   async getPullRequest(owner: string, repo: string, prNumber: number): Promise<GitPullRequest> {
     this.logger.info(`Getting pull request ${owner}/${repo}/${prNumber}.`);
     const { data } = await this.octokit.rest.pulls.get({

src/service/git/github/octokit-factory.ts

@@ -10,7 +10,7 @@ export default class OctokitFactory {
   private static logger: LoggerService = LoggerServiceFactory.getLogger();
   private static octokit?: Octokit;
 
-  public static getOctokit(token: string, apiUrl: string): Octokit {
+  public static getOctokit(token: string | undefined, apiUrl: string): Octokit {
     if (!OctokitFactory.octokit) {
       OctokitFactory.logger.info("Creating octokit instance.");
       OctokitFactory.octokit = new Octokit({

src/service/git/gitlab/gitlab-client.ts

@@ -14,13 +14,13 @@ export default class GitLabClient implements GitClient {
   private readonly mapper: GitLabMapper;
   private readonly client: Axios;
 
-  constructor(token: string, apiUrl: string, rejectUnauthorized = false) {
+  constructor(token: string | undefined, apiUrl: string, rejectUnauthorized = false) {
     this.logger = LoggerServiceFactory.getLogger();
     this.apiUrl = apiUrl;
     this.client = axios.create({
       baseURL: this.apiUrl,
       headers: {
-        Authorization: `Bearer ${token}`,
+        Authorization: token ? `Bearer ${token}` : "",
         "User-Agent": "lampajr/backporting",
       },
       httpsAgent: new https.Agent({  
@@ -30,6 +30,14 @@ export default class GitLabClient implements GitClient {
     this.mapper = new GitLabMapper(this.client);
   }
 
+  getDefaultGitUser(): string {
+    return "Gitlab";
+  }
+  
+  getDefaultGitEmail(): string {
+    return "noreply@gitlab.com";
+  }
+
   // READ
 
   // example: <host>/api/v4/projects/alampare%2Fbackporting-example/merge_requests/1

test/service/args/args-utils.test.ts

@@ -0,0 +1,42 @@
+import { parseArgs, readConfigFile } from "@bp/service/args/args-utils";
+import { createTestFile, removeTestFile } from "../../support/utils";
+
+const RANDOM_CONFIG_FILE_CONTENT_PATHNAME = "./args-utils-test-random-config-file.json";
+const RANDOM_CONFIG_FILE_CONTENT = {
+  "dryRun": true,
+  "auth": "your-git-service-auth-token",
+  "targetBranch": "target-branch-name",
+  "pullRequest": "https://github.com/user/repo/pull/123",
+  "folder": "/path/to/local/folder",
+  "gitUser": "YourGitUser",
+  "gitEmail": "your-email@example.com",
+  "title": "Backport: Original PR Title",
+  "body": "Backport: Original PR Body",
+  "bodyPrefix": "backport <original-pr-link>",
+  "bpBranchName": "backport-branch-name",
+  "reviewers": ["reviewer1", "reviewer2"],
+  "assignees": ["assignee1", "assignee2"],
+  "inheritReviewers": true,
+};
+
+
+describe("args utils test suite", () => {
+  beforeAll(() => {
+    // create a temporary file
+    createTestFile(RANDOM_CONFIG_FILE_CONTENT_PATHNAME, JSON.stringify(RANDOM_CONFIG_FILE_CONTENT));
+  });
+
+  afterAll(() => {
+    // clean up all temporary files
+    removeTestFile(RANDOM_CONFIG_FILE_CONTENT_PATHNAME);
+  });
+
+  test("check parseArgs function", () => {
+    const asString = JSON.stringify(RANDOM_CONFIG_FILE_CONTENT);
+    expect(parseArgs(asString)).toStrictEqual(RANDOM_CONFIG_FILE_CONTENT);
+  });
+
+  test("check readConfigFile function", () => {
+    expect(readConfigFile(RANDOM_CONFIG_FILE_CONTENT_PATHNAME)).toStrictEqual(RANDOM_CONFIG_FILE_CONTENT);
+  });
+});

test/service/args/cli/cli-args-parser.test.ts

@@ -1,10 +1,46 @@
 import { Args } from "@bp/service/args/args.types";
 import CLIArgsParser from "@bp/service/args/cli/cli-args-parser";
-import { addProcessArgs, resetProcessArgs, expectArrayEqual } from "../../../support/utils";
+import { addProcessArgs, resetProcessArgs, expectArrayEqual, createTestFile, removeTestFile } from "../../../support/utils";
+
+export const SIMPLE_CONFIG_FILE_CONTENT_PATHNAME = "./cli-args-parser-test-simple-config-file-pulls-1.json";
+export const SIMPLE_CONFIG_FILE_CONTENT = {
+  "targetBranch": "target",
+  "pullRequest": "https://localhost/whatever/pulls/1",
+};
+
+const RANDOM_CONFIG_FILE_CONTENT_PATHNAME = "./cli-args-parser-test-random-config-file.json";
+const RANDOM_CONFIG_FILE_CONTENT = {
+  "dryRun": true,
+  "auth": "your-git-service-auth-token",
+  "targetBranch": "target-branch-name",
+  "pullRequest": "https://github.com/user/repo/pull/123",
+  "folder": "/path/to/local/folder",
+  "gitUser": "YourGitUser",
+  "gitEmail": "your-email@example.com",
+  "title": "Backport: Original PR Title",
+  "body": "Backport: Original PR Body",
+  "bodyPrefix": "backport <original-pr-link>",
+  "bpBranchName": "backport-branch-name",
+  "reviewers": ["reviewer1", "reviewer2"],
+  "assignees": ["assignee1", "assignee2"],
+  "inheritReviewers": true,
+};
 
 describe("cli args parser", () => {
   let parser: CLIArgsParser;
   
+  beforeAll(() => {
+    // create a temporary file
+    createTestFile(SIMPLE_CONFIG_FILE_CONTENT_PATHNAME, JSON.stringify(SIMPLE_CONFIG_FILE_CONTENT));
+    createTestFile(RANDOM_CONFIG_FILE_CONTENT_PATHNAME, JSON.stringify(RANDOM_CONFIG_FILE_CONTENT));
+  });
+
+  afterAll(() => {
+    // clean up all temporary files
+    removeTestFile(SIMPLE_CONFIG_FILE_CONTENT_PATHNAME);
+    removeTestFile(RANDOM_CONFIG_FILE_CONTENT_PATHNAME);
+  });
+
   beforeEach(() => {
     // create a fresh new instance every time
     parser = new CLIArgsParser();
@@ -23,9 +59,32 @@ describe("cli args parser", () => {
 
     const args: Args = parser.parse();
     expect(args.dryRun).toEqual(false);
-    expect(args.auth).toEqual("");
+    expect(args.auth).toEqual(undefined);
-    expect(args.gitUser).toEqual("GitHub");
+    expect(args.gitUser).toEqual(undefined);
-    expect(args.gitEmail).toEqual("noreply@github.com");
+    expect(args.gitEmail).toEqual(undefined);
+    expect(args.folder).toEqual(undefined);
+    expect(args.targetBranch).toEqual("target");
+    expect(args.pullRequest).toEqual("https://localhost/whatever/pulls/1");
+    expect(args.title).toEqual(undefined);
+    expect(args.body).toEqual(undefined);
+    expect(args.bodyPrefix).toEqual(undefined);
+    expect(args.bpBranchName).toEqual(undefined);
+    expect(args.reviewers).toEqual([]);
+    expect(args.assignees).toEqual([]);
+    expect(args.inheritReviewers).toEqual(true);
+  });
+
+  test("with config file [default, short]", () => {
+    addProcessArgs([
+      "-cf",
+      SIMPLE_CONFIG_FILE_CONTENT_PATHNAME,
+    ]);
+
+    const args: Args = parser.parse();
+    expect(args.dryRun).toEqual(false);
+    expect(args.auth).toEqual(undefined);
+    expect(args.gitUser).toEqual(undefined);
+    expect(args.gitEmail).toEqual(undefined);
     expect(args.folder).toEqual(undefined);
     expect(args.targetBranch).toEqual("target");
     expect(args.pullRequest).toEqual("https://localhost/whatever/pulls/1");
@@ -48,9 +107,32 @@ describe("cli args parser", () => {
 
     const args: Args = parser.parse();
     expect(args.dryRun).toEqual(false);
-    expect(args.auth).toEqual("");
+    expect(args.auth).toEqual(undefined);
-    expect(args.gitUser).toEqual("GitHub");
+    expect(args.gitUser).toEqual(undefined);
-    expect(args.gitEmail).toEqual("noreply@github.com");
+    expect(args.gitEmail).toEqual(undefined);
+    expect(args.folder).toEqual(undefined);
+    expect(args.targetBranch).toEqual("target");
+    expect(args.pullRequest).toEqual("https://localhost/whatever/pulls/1");
+    expect(args.title).toEqual(undefined);
+    expect(args.body).toEqual(undefined);
+    expect(args.bodyPrefix).toEqual(undefined);
+    expect(args.bpBranchName).toEqual(undefined);
+    expect(args.reviewers).toEqual([]);
+    expect(args.assignees).toEqual([]);
+    expect(args.inheritReviewers).toEqual(true);
+  });
+
+  test("with config file [default, long]", () => {
+    addProcessArgs([
+      "--config-file",
+      SIMPLE_CONFIG_FILE_CONTENT_PATHNAME,
+    ]);
+
+    const args: Args = parser.parse();
+    expect(args.dryRun).toEqual(false);
+    expect(args.auth).toEqual(undefined);
+    expect(args.gitUser).toEqual(undefined);
+    expect(args.gitEmail).toEqual(undefined);
     expect(args.folder).toEqual(undefined);
     expect(args.targetBranch).toEqual("target");
     expect(args.pullRequest).toEqual("https://localhost/whatever/pulls/1");
@@ -135,9 +217,78 @@ describe("cli args parser", () => {
     expect(args.body).toEqual("New Body");
     expect(args.bodyPrefix).toEqual("New Body Prefix");
     expect(args.bpBranchName).toEqual("bp_branch_name");
-    expectArrayEqual(["al", "john", "jack"], args.reviewers!);
+    expectArrayEqual(args.reviewers!, ["al", "john", "jack"]);
-    expectArrayEqual(["pippo", "pluto", "paperino"], args.assignees!);
+    expectArrayEqual(args.assignees!, ["pippo", "pluto", "paperino"]);
     expect(args.inheritReviewers).toEqual(false);
   });
 
+  test("override using config file", () => {
+    addProcessArgs([
+      "--config-file",
+      RANDOM_CONFIG_FILE_CONTENT_PATHNAME,
+    ]);
+
+    const args: Args = parser.parse();
+    expect(args.dryRun).toEqual(true);
+    expect(args.auth).toEqual("your-git-service-auth-token");
+    expect(args.gitUser).toEqual("YourGitUser");
+    expect(args.gitEmail).toEqual("your-email@example.com");
+    expect(args.folder).toEqual("/path/to/local/folder");
+    expect(args.targetBranch).toEqual("target-branch-name");
+    expect(args.pullRequest).toEqual("https://github.com/user/repo/pull/123");
+    expect(args.title).toEqual("Backport: Original PR Title");
+    expect(args.body).toEqual("Backport: Original PR Body");
+    expect(args.bodyPrefix).toEqual("backport <original-pr-link>");
+    expect(args.bpBranchName).toEqual("backport-branch-name");
+    expectArrayEqual(args.reviewers!, ["reviewer1", "reviewer2"]);
+    expectArrayEqual(args.assignees!,["assignee1", "assignee2"]);
+    expect(args.inheritReviewers).toEqual(true);
+  });
+
+  test("ignore custom option when config file is set", () => {
+    addProcessArgs([
+      "--config-file",
+      RANDOM_CONFIG_FILE_CONTENT_PATHNAME,
+      "--dry-run",
+      "--auth",
+      "bearer-token",
+      "--target-branch",
+      "target",
+      "--pull-request",
+      "https://localhost/whatever/pulls/1",
+      "--git-user",
+      "Me",
+      "--git-email",
+      "me@email.com",
+      "--title",
+      "New Title",
+      "--body",
+      "New Body",
+      "--body-prefix",
+      "New Body Prefix",
+      "--bp-branch-name",
+      "bp_branch_name",
+      "--reviewers",
+      "al , john,  jack",
+      "--assignees",
+      " pippo,pluto, paperino",
+      "--no-inherit-reviewers",
+    ]);
+
+    const args: Args = parser.parse();
+    expect(args.dryRun).toEqual(true);
+    expect(args.auth).toEqual("your-git-service-auth-token");
+    expect(args.gitUser).toEqual("YourGitUser");
+    expect(args.gitEmail).toEqual("your-email@example.com");
+    expect(args.folder).toEqual("/path/to/local/folder");
+    expect(args.targetBranch).toEqual("target-branch-name");
+    expect(args.pullRequest).toEqual("https://github.com/user/repo/pull/123");
+    expect(args.title).toEqual("Backport: Original PR Title");
+    expect(args.body).toEqual("Backport: Original PR Body");
+    expect(args.bodyPrefix).toEqual("backport <original-pr-link>");
+    expect(args.bpBranchName).toEqual("backport-branch-name");
+    expectArrayEqual(args.reviewers!, ["reviewer1", "reviewer2"]);
+    expectArrayEqual(args.assignees!,["assignee1", "assignee2"]);
+    expect(args.inheritReviewers).toEqual(true);
+  });
 });

test/service/args/gha/gha-args-parser.test.ts

@@ -1,10 +1,46 @@
 import { Args } from "@bp/service/args/args.types";
 import GHAArgsParser from "@bp/service/args/gha/gha-args-parser";
-import { spyGetInput, expectArrayEqual } from "../../../support/utils";
+import { spyGetInput, expectArrayEqual, removeTestFile, createTestFile } from "../../../support/utils";
+
+const SIMPLE_CONFIG_FILE_CONTENT_PATHNAME = "./gha-args-parser-test-simple-config-file-pulls-1.json";
+const SIMPLE_CONFIG_FILE_CONTENT = {
+  "targetBranch": "target",
+  "pullRequest": "https://localhost/whatever/pulls/1",
+};
+
+const RANDOM_CONFIG_FILE_CONTENT_PATHNAME = "./gha-args-parser-test-random-config-file.json";
+const RANDOM_CONFIG_FILE_CONTENT = {
+  "dryRun": true,
+  "auth": "your-git-service-auth-token",
+  "targetBranch": "target-branch-name",
+  "pullRequest": "https://github.com/user/repo/pull/123",
+  "folder": "/path/to/local/folder",
+  "gitUser": "YourGitUser",
+  "gitEmail": "your-email@example.com",
+  "title": "Backport: Original PR Title",
+  "body": "Backport: Original PR Body",
+  "bodyPrefix": "backport <original-pr-link>",
+  "bpBranchName": "backport-branch-name",
+  "reviewers": ["reviewer1", "reviewer2"],
+  "assignees": ["assignee1", "assignee2"],
+  "inheritReviewers": true,
+};
 
 describe("gha args parser", () => {
   let parser: GHAArgsParser;
 
+  beforeAll(() => {
+    // create a temporary file
+    createTestFile(SIMPLE_CONFIG_FILE_CONTENT_PATHNAME, JSON.stringify(SIMPLE_CONFIG_FILE_CONTENT));
+    createTestFile(RANDOM_CONFIG_FILE_CONTENT_PATHNAME, JSON.stringify(RANDOM_CONFIG_FILE_CONTENT));
+  });
+
+  afterAll(() => {
+    // clean up all temporary files
+    removeTestFile(SIMPLE_CONFIG_FILE_CONTENT_PATHNAME);
+    removeTestFile(RANDOM_CONFIG_FILE_CONTENT_PATHNAME);
+  });
+
   beforeEach(() => {
     // create a fresh new instance every time
     parser = new GHAArgsParser();
@@ -14,14 +50,6 @@ describe("gha args parser", () => {
     jest.clearAllMocks();
   });
 
-  test("getOrDefault", () => {
-    spyGetInput({
-      "present": "value"
-    });
-    expect(parser.getOrDefault("not-present", "default")).toStrictEqual("default");
-    expect(parser.getOrDefault("present", "default")).toStrictEqual("value");
-  });
-
   test("getOrUndefined", () => {
     spyGetInput({
       "present": "value",
@@ -38,8 +66,8 @@ describe("gha args parser", () => {
       "blank": "   ",
     });
     expectArrayEqual(parser.getAsCommaSeparatedList("present")!, ["value1", "value2", "value3"]);
-    expect(parser.getAsCommaSeparatedList("empty")).toStrictEqual([]);
+    expect(parser.getAsCommaSeparatedList("empty")).toStrictEqual(undefined);
-    expect(parser.getAsCommaSeparatedList("blank")).toStrictEqual([]);
+    expect(parser.getAsCommaSeparatedList("blank")).toStrictEqual(undefined);
   });
 
   test("valid execution [default]", () => {
@@ -50,9 +78,9 @@ describe("gha args parser", () => {
 
     const args: Args = parser.parse();
     expect(args.dryRun).toEqual(false);
-    expect(args.auth).toEqual("");
+    expect(args.auth).toEqual(undefined);
-    expect(args.gitUser).toEqual("GitHub");
+    expect(args.gitUser).toEqual(undefined);
-    expect(args.gitEmail).toEqual("noreply@github.com");
+    expect(args.gitEmail).toEqual(undefined);
     expect(args.folder).toEqual(undefined);
     expect(args.targetBranch).toEqual("target");
     expect(args.pullRequest).toEqual("https://localhost/whatever/pulls/1");
@@ -92,9 +120,65 @@ describe("gha args parser", () => {
     expect(args.body).toEqual("New Body");
     expect(args.bodyPrefix).toEqual("New Body Prefix");
     expect(args.bpBranchName).toEqual("bp_branch_name");
-    expectArrayEqual(["al", "john", "jack"], args.reviewers!);
+    expectArrayEqual(args.reviewers!, ["al", "john", "jack"]);
-    expectArrayEqual(["pippo", "pluto", "paperino"], args.assignees!);
+    expectArrayEqual(args.assignees!, ["pippo", "pluto", "paperino"]);
     expect(args.inheritReviewers).toEqual(false);
   });
 
+  test("using config file", () => {
+    spyGetInput({
+      "config-file": SIMPLE_CONFIG_FILE_CONTENT_PATHNAME,
+    });
+
+    const args: Args = parser.parse();
+    expect(args.dryRun).toEqual(false);
+    expect(args.auth).toEqual(undefined);
+    expect(args.gitUser).toEqual(undefined);
+    expect(args.gitEmail).toEqual(undefined);
+    expect(args.folder).toEqual(undefined);
+    expect(args.targetBranch).toEqual("target");
+    expect(args.pullRequest).toEqual("https://localhost/whatever/pulls/1");
+    expect(args.title).toEqual(undefined);
+    expect(args.body).toEqual(undefined);
+    expect(args.bodyPrefix).toEqual(undefined);
+    expect(args.bpBranchName).toEqual(undefined);
+    expect(args.reviewers).toEqual([]);
+    expect(args.assignees).toEqual([]);
+    expect(args.inheritReviewers).toEqual(true);
+  });
+
+  test("ignore custom options when using config file", () => {
+    spyGetInput({
+      "config-file": RANDOM_CONFIG_FILE_CONTENT_PATHNAME,
+      "dry-run": "true",
+      "auth": "bearer-token",
+      "target-branch": "target",
+      "pull-request": "https://localhost/whatever/pulls/1",
+      "git-user": "Me",
+      "git-email": "me@email.com",
+      "title": "New Title",
+      "body": "New Body",
+      "body-prefix": "New Body Prefix",
+      "bp-branch-name": "bp_branch_name",
+      "reviewers": "al , john,  jack",
+      "assignees": " pippo,pluto, paperino",
+      "no-inherit-reviewers": "true",
+    });
+
+    const args: Args = parser.parse();
+    expect(args.dryRun).toEqual(true);
+    expect(args.auth).toEqual("your-git-service-auth-token");
+    expect(args.gitUser).toEqual("YourGitUser");
+    expect(args.gitEmail).toEqual("your-email@example.com");
+    expect(args.folder).toEqual("/path/to/local/folder");
+    expect(args.targetBranch).toEqual("target-branch-name");
+    expect(args.pullRequest).toEqual("https://github.com/user/repo/pull/123");
+    expect(args.title).toEqual("Backport: Original PR Title");
+    expect(args.body).toEqual("Backport: Original PR Body");
+    expect(args.bodyPrefix).toEqual("backport <original-pr-link>");
+    expect(args.bpBranchName).toEqual("backport-branch-name");
+    expectArrayEqual(args.reviewers!, ["reviewer1", "reviewer2"]);
+    expectArrayEqual(args.assignees!,["assignee1", "assignee2"]);
+    expect(args.inheritReviewers).toEqual(true);
+  });
 });

test/service/configs/pullrequest/github-pr-configs-parser.test.ts

@@ -4,7 +4,31 @@ import PullRequestConfigsParser from "@bp/service/configs/pullrequest/pr-configs
 import GitClientFactory from "@bp/service/git/git-client-factory";
 import { GitClientType } from "@bp/service/git/git.types";
 import { mockGitHubClient } from "../../../support/mock/git-client-mock-support";
+import { addProcessArgs, createTestFile, removeTestFile, resetProcessArgs } from "../../../support/utils";
 import { mergedPullRequestFixture, openPullRequestFixture, notMergedPullRequestFixture, repo, targetOwner } from "../../../support/mock/github-data";
+import CLIArgsParser from "@bp/service/args/cli/cli-args-parser";
+
+const GITHUB_MERGED_PR_SIMPLE_CONFIG_FILE_CONTENT_PATHNAME = "./github-pr-configs-parser-simple-pr-merged.json";
+const GITHUB_MERGED_PR_SIMPLE_CONFIG_FILE_CONTENT = {
+  "targetBranch": "prod",
+  "pullRequest": `https://github.com/${targetOwner}/${repo}/pull/${mergedPullRequestFixture.number}`,
+};
+
+const GITHUB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT_PATHNAME = "./github-pr-configs-parser-complex-pr-merged.json";
+const GITHUB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT = {
+  "dryRun": false,
+  "auth": "my-auth-token",
+  "pullRequest": `https://github.com/${targetOwner}/${repo}/pull/${mergedPullRequestFixture.number}`,
+  "targetBranch": "prod",
+  "gitUser": "Me",
+  "gitEmail": "me@email.com",
+  "title": "New Title",
+  "body": "New Body",
+  "bodyPrefix": "New Body Prefix -",
+  "reviewers": ["user1", "user2"],
+  "assignees": ["user3", "user4"],
+  "inheritReviewers": true, // not taken into account
+};
 
 describe("github pull request config parser", () => {
 
@@ -12,17 +36,33 @@ describe("github pull request config parser", () => {
   const openPRUrl = `https://github.com/${targetOwner}/${repo}/pull/${openPullRequestFixture.number}`;
   const notMergedPRUrl = `https://github.com/${targetOwner}/${repo}/pull/${notMergedPullRequestFixture.number}`;
   
-  let parser: PullRequestConfigsParser;
+  let argsParser: CLIArgsParser;
+  let configParser: PullRequestConfigsParser;
 
   beforeAll(() => {
+    // create a temporary file
+    createTestFile(GITHUB_MERGED_PR_SIMPLE_CONFIG_FILE_CONTENT_PATHNAME, JSON.stringify(GITHUB_MERGED_PR_SIMPLE_CONFIG_FILE_CONTENT));
+    createTestFile(GITHUB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT_PATHNAME, JSON.stringify(GITHUB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT));
+
     GitClientFactory.reset();
     GitClientFactory.getOrCreate(GitClientType.GITHUB, "whatever", "http://localhost/api/v3");
   });
 
+  afterAll(() => {
+    // clean up all temporary files
+    removeTestFile(GITHUB_MERGED_PR_SIMPLE_CONFIG_FILE_CONTENT_PATHNAME);
+    removeTestFile(GITHUB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT_PATHNAME);
+  });
+
   beforeEach(() => {
     mockGitHubClient("http://localhost/api/v3");
 
-    parser = new PullRequestConfigsParser();
+    // reset process.env variables
+    resetProcessArgs();
+
+    // create a fresh new instance every time
+    argsParser = new CLIArgsParser();
+    configParser = new PullRequestConfigsParser();
   });
 
   afterEach(() => {
@@ -42,7 +82,7 @@ describe("github pull request config parser", () => {
       inheritReviewers: true,
     };
 
-    const configs: Configs = await parser.parseAndValidate(args);
+    const configs: Configs = await configParser.parseAndValidate(args);
 
     expect(configs.dryRun).toEqual(false);
     expect(configs.git).toEqual({
@@ -113,7 +153,7 @@ describe("github pull request config parser", () => {
       inheritReviewers: true,
     };
 
-    const configs: Configs = await parser.parseAndValidate(args);
+    const configs: Configs = await configParser.parseAndValidate(args);
 
     expect(configs.dryRun).toEqual(true);
     expect(configs.auth).toEqual("whatever");
@@ -138,7 +178,7 @@ describe("github pull request config parser", () => {
       inheritReviewers: true,
     };
 
-    const configs: Configs = await parser.parseAndValidate(args);
+    const configs: Configs = await configParser.parseAndValidate(args);
 
     expect(configs.dryRun).toEqual(true);
     expect(configs.auth).toEqual("whatever");
@@ -189,7 +229,7 @@ describe("github pull request config parser", () => {
       inheritReviewers: true,
     };
 
-    expect(async () => await parser.parseAndValidate(args)).rejects.toThrow("Provided pull request is closed and not merged!");
+    expect(async () => await configParser.parseAndValidate(args)).rejects.toThrow("Provided pull request is closed and not merged!");
   });
 
   
@@ -209,7 +249,7 @@ describe("github pull request config parser", () => {
       inheritReviewers: true,
     };
 
-    const configs: Configs = await parser.parseAndValidate(args);
+    const configs: Configs = await configParser.parseAndValidate(args);
 
     expect(configs.dryRun).toEqual(false);
     expect(configs.git).toEqual({
@@ -283,7 +323,7 @@ describe("github pull request config parser", () => {
       inheritReviewers: true, // not taken into account
     };
 
-    const configs: Configs = await parser.parseAndValidate(args);
+    const configs: Configs = await configParser.parseAndValidate(args);
 
     expect(configs.dryRun).toEqual(false);
     expect(configs.git).toEqual({
@@ -357,7 +397,7 @@ describe("github pull request config parser", () => {
       inheritReviewers: false,
     };
 
-    const configs: Configs = await parser.parseAndValidate(args);
+    const configs: Configs = await configParser.parseAndValidate(args);
 
     expect(configs.dryRun).toEqual(false);
     expect(configs.git).toEqual({
@@ -414,4 +454,133 @@ describe("github pull request config parser", () => {
       bpBranchName: undefined,
     });
   });
+  
+  test("using simple config file", async () => {
+    addProcessArgs([
+      "-cf",
+      GITHUB_MERGED_PR_SIMPLE_CONFIG_FILE_CONTENT_PATHNAME,
+    ]);
+
+    const args: Args = argsParser.parse();
+    const configs: Configs = await configParser.parseAndValidate(args);
+
+    expect(configs.dryRun).toEqual(false);
+    expect(configs.git).toEqual({
+      user: "GitHub",
+      email: "noreply@github.com"
+    });
+    expect(configs.auth).toEqual(undefined);
+    expect(configs.targetBranch).toEqual("prod");
+    expect(configs.folder).toEqual(process.cwd() + "/bp");
+    expect(configs.originalPullRequest).toEqual({
+      number: 2368,
+      author: "gh-user",
+      url: "https://api.github.com/repos/owner/reponame/pulls/2368",
+      htmlUrl: "https://github.com/owner/reponame/pull/2368",
+      state: "closed",
+      merged: true,
+      mergedBy: "that-s-a-user",
+      title: "PR Title",
+      body: "Please review and merge",
+      reviewers: ["requested-gh-user", "gh-user"],
+      assignees: [],
+      targetRepo: {
+        owner: "owner",
+        project: "reponame",
+        cloneUrl: "https://github.com/owner/reponame.git"
+      },
+      sourceRepo: {
+        owner: "fork",
+        project: "reponame",
+        cloneUrl: "https://github.com/fork/reponame.git"
+      },
+      nCommits: 2,
+      commits: ["28f63db774185f4ec4b57cd9aaeb12dbfb4c9ecc"]
+    });
+    expect(configs.backportPullRequest).toEqual({
+      author: "GitHub",
+      url: undefined,
+      htmlUrl: undefined,
+      title: "[prod] PR Title",
+      body: "**Backport:** https://github.com/owner/reponame/pull/2368\r\n\r\nPlease review and merge",
+      reviewers: ["gh-user", "that-s-a-user"],
+      assignees: [],
+      targetRepo: {
+        owner: "owner",
+        project: "reponame",
+        cloneUrl: "https://github.com/owner/reponame.git"
+      },
+      sourceRepo: {
+        owner: "owner",
+        project: "reponame",
+        cloneUrl: "https://github.com/owner/reponame.git"
+      },
+      bpBranchName: undefined,
+    });
+  });
+
+  test("using complex config file", async () => {
+    addProcessArgs([
+      "-cf",
+      GITHUB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT_PATHNAME,
+    ]);
+
+    const args: Args = argsParser.parse();
+    const configs: Configs = await configParser.parseAndValidate(args);
+
+    expect(configs.dryRun).toEqual(false);
+    expect(configs.git).toEqual({
+      user: "Me",
+      email: "me@email.com"
+    });
+    expect(configs.auth).toEqual("my-auth-token");
+    expect(configs.targetBranch).toEqual("prod");
+    expect(configs.folder).toEqual(process.cwd() + "/bp");
+    expect(configs.originalPullRequest).toEqual({
+      number: 2368,
+      author: "gh-user",
+      url: "https://api.github.com/repos/owner/reponame/pulls/2368",
+      htmlUrl: "https://github.com/owner/reponame/pull/2368",
+      state: "closed",
+      merged: true,
+      mergedBy: "that-s-a-user",
+      title: "PR Title",
+      body: "Please review and merge",
+      reviewers: ["requested-gh-user", "gh-user"],
+      assignees: [],
+      targetRepo: {
+        owner: "owner",
+        project: "reponame",
+        cloneUrl: "https://github.com/owner/reponame.git"
+      },
+      sourceRepo: {
+        owner: "fork",
+        project: "reponame",
+        cloneUrl: "https://github.com/fork/reponame.git"
+      },
+      bpBranchName: undefined,
+      nCommits: 2,
+      commits: ["28f63db774185f4ec4b57cd9aaeb12dbfb4c9ecc"],
+    });
+    expect(configs.backportPullRequest).toEqual({
+      author: "Me",
+      url: undefined,
+      htmlUrl: undefined,
+      title: "New Title",
+      body: "New Body Prefix -New Body",
+      reviewers: ["user1", "user2"],
+      assignees: ["user3", "user4"],
+      targetRepo: {
+        owner: "owner",
+        project: "reponame",
+        cloneUrl: "https://github.com/owner/reponame.git"
+      },
+      sourceRepo: {
+        owner: "owner",
+        project: "reponame",
+        cloneUrl: "https://github.com/owner/reponame.git"
+      },
+      bpBranchName: undefined,
+    });
+  });
 });

test/service/configs/pullrequest/gitlab-pr-configs-parser.test.ts

@@ -5,6 +5,31 @@ import GitClientFactory from "@bp/service/git/git-client-factory";
 import { GitClientType } from "@bp/service/git/git.types";
 import { getAxiosMocked } from "../../../support/mock/git-client-mock-support";
 import { CLOSED_NOT_MERGED_MR, MERGED_SQUASHED_MR, OPEN_MR } from "../../../support/mock/gitlab-data";
+import GHAArgsParser from "@bp/service/args/gha/gha-args-parser";
+import { createTestFile, removeTestFile, spyGetInput } from "../../../support/utils";
+
+const GITLAB_MERGED_PR_SIMPLE_CONFIG_FILE_CONTENT_PATHNAME = "./gitlab-pr-configs-parser-simple-pr-merged.json";
+const GITLAB_MERGED_PR_SIMPLE_CONFIG_FILE_CONTENT = {
+  "targetBranch": "prod",
+  "pullRequest": `https://my.gitlab.host.com/superuser/backporting-example/-/merge_requests/${MERGED_SQUASHED_MR.iid}`,
+};
+
+const GITLAB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT_PATHNAME = "./gitlab-pr-configs-parser-complex-pr-merged.json";
+const GITLAB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT = {
+  "dryRun": false,
+  "auth": "my-token",
+  "pullRequest": `https://my.gitlab.host.com/superuser/backporting-example/-/merge_requests/${MERGED_SQUASHED_MR.iid}`,
+  "targetBranch": "prod",
+  "gitUser": "Me",
+  "gitEmail": "me@email.com",
+  "title": "New Title",
+  "body": "New Body",
+  "bodyPrefix": "New Body Prefix -",
+  "reviewers": [],
+  "assignees": ["user3", "user4"],
+  "inheritReviewers": false,
+};
+
 
 jest.mock("axios", () => {
   return {
@@ -20,15 +45,27 @@ describe("gitlab merge request config parser", () => {
   const openPRUrl = `https://my.gitlab.host.com/superuser/backporting-example/-/merge_requests/${OPEN_MR.iid}`;
   const notMergedPRUrl = `https://my.gitlab.host.com/superuser/backporting-example/-/merge_requests/${CLOSED_NOT_MERGED_MR.iid}`;
   
-  let parser: PullRequestConfigsParser;
+  let argsParser: GHAArgsParser;
+  let configParser: PullRequestConfigsParser;
 
   beforeAll(() => {
+    // create a temporary file
+    createTestFile(GITLAB_MERGED_PR_SIMPLE_CONFIG_FILE_CONTENT_PATHNAME, JSON.stringify(GITLAB_MERGED_PR_SIMPLE_CONFIG_FILE_CONTENT));
+    createTestFile(GITLAB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT_PATHNAME, JSON.stringify(GITLAB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT));
+
     GitClientFactory.reset();
     GitClientFactory.getOrCreate(GitClientType.GITLAB, "whatever", "my.gitlab.host.com");
   });
   
+  afterAll(() => {
+    // clean up all temporary files
+    removeTestFile(GITLAB_MERGED_PR_SIMPLE_CONFIG_FILE_CONTENT_PATHNAME);
+    removeTestFile(GITLAB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT_PATHNAME);
+  });
+
   beforeEach(() => {
-    parser = new PullRequestConfigsParser();
+    argsParser = new GHAArgsParser();
+    configParser = new PullRequestConfigsParser();
   });
 
   afterEach(() => {
@@ -38,24 +75,24 @@ describe("gitlab merge request config parser", () => {
   test("parse configs from merge request", async () => {
     const args: Args = {
       dryRun: false,
-      auth: "",
+      auth: undefined,
       pullRequest: mergedPRUrl,
       targetBranch: "prod",
-      gitUser: "GitLab",
+      gitUser: "Gitlab",
       gitEmail: "noreply@gitlab.com",
       reviewers: [],
       assignees: [],
       inheritReviewers: true,
     };
 
-    const configs: Configs = await parser.parseAndValidate(args);
+    const configs: Configs = await configParser.parseAndValidate(args);
 
     expect(configs.dryRun).toEqual(false);
     expect(configs.git).toEqual({
-      user: "GitLab",
+      user: "Gitlab",
       email: "noreply@gitlab.com"
     });
-    expect(configs.auth).toEqual("");
+    expect(configs.auth).toEqual(undefined);
     expect(configs.targetBranch).toEqual("prod");
     expect(configs.folder).toEqual(process.cwd() + "/bp");
     expect(configs.originalPullRequest).toEqual({
@@ -84,7 +121,7 @@ describe("gitlab merge request config parser", () => {
       commits: ["ebb1eca696c42fd067658bd9b5267709f78ef38e"]
     });
     expect(configs.backportPullRequest).toEqual({
-      author: "GitLab",
+      author: "Gitlab",
       url: undefined,
       htmlUrl: undefined,
       title: "[prod] Update test.txt",
@@ -113,21 +150,21 @@ describe("gitlab merge request config parser", () => {
       pullRequest: mergedPRUrl,
       targetBranch: "prod",
       folder: "/tmp/test",
-      gitUser: "GitLab",
+      gitUser: "Gitlab",
       gitEmail: "noreply@gitlab.com",
       reviewers: [],
       assignees: [],
       inheritReviewers: true,
     };
 
-    const configs: Configs = await parser.parseAndValidate(args);
+    const configs: Configs = await configParser.parseAndValidate(args);
 
     expect(configs.dryRun).toEqual(true);
     expect(configs.auth).toEqual("whatever");
     expect(configs.targetBranch).toEqual("prod");
     expect(configs.folder).toEqual("/tmp/test");
     expect(configs.git).toEqual({
-      user: "GitLab",
+      user: "Gitlab",
       email: "noreply@gitlab.com"
     });
   });
@@ -138,20 +175,20 @@ describe("gitlab merge request config parser", () => {
       auth: "whatever",
       pullRequest: openPRUrl,
       targetBranch: "prod",
-      gitUser: "GitLab",
+      gitUser: "Gitlab",
       gitEmail: "noreply@gitlab.com",
       reviewers: [],
       assignees: [],
       inheritReviewers: true,
     };
 
-    const configs: Configs = await parser.parseAndValidate(args);
+    const configs: Configs = await configParser.parseAndValidate(args);
 
     expect(configs.dryRun).toEqual(true);
     expect(configs.auth).toEqual("whatever");
     expect(configs.targetBranch).toEqual("prod");
     expect(configs.git).toEqual({
-      user: "GitLab",
+      user: "Gitlab",
       email: "noreply@gitlab.com"
     });
     expect(configs.originalPullRequest).toEqual({
@@ -189,14 +226,14 @@ describe("gitlab merge request config parser", () => {
       auth: "whatever",
       pullRequest: notMergedPRUrl,
       targetBranch: "prod",
-      gitUser: "GitLab",
+      gitUser: "Gitlab",
       gitEmail: "noreply@gitlab.com",
       reviewers: [],
       assignees: [],
       inheritReviewers: true,
     };
 
-    expect(async () => await parser.parseAndValidate(args)).rejects.toThrow("Provided pull request is closed and not merged!");
+    expect(async () => await configParser.parseAndValidate(args)).rejects.toThrow("Provided pull request is closed and not merged!");
   });
 
   test("override backport pr data inherting reviewers", async () => {
@@ -215,7 +252,7 @@ describe("gitlab merge request config parser", () => {
       inheritReviewers: true,
     };
 
-    const configs: Configs = await parser.parseAndValidate(args);
+    const configs: Configs = await configParser.parseAndValidate(args);
 
     expect(configs.dryRun).toEqual(false);
     expect(configs.git).toEqual({
@@ -288,7 +325,7 @@ describe("gitlab merge request config parser", () => {
       inheritReviewers: true, // not taken into account
     };
 
-    const configs: Configs = await parser.parseAndValidate(args);
+    const configs: Configs = await configParser.parseAndValidate(args);
 
     expect(configs.dryRun).toEqual(false);
     expect(configs.git).toEqual({
@@ -361,7 +398,7 @@ describe("gitlab merge request config parser", () => {
       inheritReviewers: false,
     };
 
-    const configs: Configs = await parser.parseAndValidate(args);
+    const configs: Configs = await configParser.parseAndValidate(args);
 
     expect(configs.dryRun).toEqual(false);
     expect(configs.git).toEqual({
@@ -417,4 +454,131 @@ describe("gitlab merge request config parser", () => {
       bpBranchName: undefined,
     });
   });
+
+    
+  test("using simple config file", async () => {
+    spyGetInput({
+      "config-file": GITLAB_MERGED_PR_SIMPLE_CONFIG_FILE_CONTENT_PATHNAME,
+    });
+
+    const args: Args = argsParser.parse();
+    const configs: Configs = await configParser.parseAndValidate(args);
+
+    expect(configs.dryRun).toEqual(false);
+    expect(configs.git).toEqual({
+      user: "Gitlab",
+      email: "noreply@gitlab.com"
+    });
+    expect(configs.auth).toEqual(undefined);
+    expect(configs.targetBranch).toEqual("prod");
+    expect(configs.folder).toEqual(process.cwd() + "/bp");
+    expect(configs.originalPullRequest).toEqual({
+      number: 1,
+      author: "superuser",
+      url: "https://my.gitlab.host.com/superuser/backporting-example/-/merge_requests/1",
+      htmlUrl: "https://my.gitlab.host.com/superuser/backporting-example/-/merge_requests/1",
+      state: "merged",
+      merged: true,
+      mergedBy: "superuser",
+      title: "Update test.txt",
+      body: "This is the body",
+      reviewers: ["superuser1", "superuser2"],
+      assignees: ["superuser"],
+      targetRepo: {
+        owner: "superuser",
+        project: "backporting-example",
+        cloneUrl: "https://my.gitlab.host.com/superuser/backporting-example.git"
+      },
+      sourceRepo: {
+        owner: "superuser",
+        project: "backporting-example",
+        cloneUrl: "https://my.gitlab.host.com/superuser/backporting-example.git"
+      },
+      nCommits: 1,
+      commits: ["ebb1eca696c42fd067658bd9b5267709f78ef38e"]
+    });
+    expect(configs.backportPullRequest).toEqual({
+      author: "Gitlab",
+      url: undefined,
+      htmlUrl: undefined,
+      title: "[prod] Update test.txt",
+      body: "**Backport:** https://my.gitlab.host.com/superuser/backporting-example/-/merge_requests/1\r\n\r\nThis is the body",
+      reviewers: ["superuser"],
+      assignees: [],
+      targetRepo: {
+        owner: "superuser",
+        project: "backporting-example",
+        cloneUrl: "https://my.gitlab.host.com/superuser/backporting-example.git"
+      },
+      sourceRepo: {
+        owner: "superuser",
+        project: "backporting-example",
+        cloneUrl: "https://my.gitlab.host.com/superuser/backporting-example.git"
+      },
+      bpBranchName: undefined,
+    });
+  });
+
+  test("using complex config file", async () => {
+    spyGetInput({
+      "config-file": GITLAB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT_PATHNAME,
+    });
+
+    const args: Args = argsParser.parse();
+    const configs: Configs = await configParser.parseAndValidate(args);
+
+    expect(configs.dryRun).toEqual(false);
+    expect(configs.git).toEqual({
+      user: "Me",
+      email: "me@email.com"
+    });
+    expect(configs.auth).toEqual("my-token");
+    expect(configs.targetBranch).toEqual("prod");
+    expect(configs.folder).toEqual(process.cwd() + "/bp");
+    expect(configs.originalPullRequest).toEqual({
+      number: 1,
+      author: "superuser",
+      url: "https://my.gitlab.host.com/superuser/backporting-example/-/merge_requests/1",
+      htmlUrl: "https://my.gitlab.host.com/superuser/backporting-example/-/merge_requests/1",
+      state: "merged",
+      merged: true,
+      mergedBy: "superuser",
+      title: "Update test.txt",
+      body: "This is the body",
+      reviewers: ["superuser1", "superuser2"],
+      assignees: ["superuser"],
+      targetRepo: {
+        owner: "superuser",
+        project: "backporting-example",
+        cloneUrl: "https://my.gitlab.host.com/superuser/backporting-example.git"
+      },
+      sourceRepo: {
+        owner: "superuser",
+        project: "backporting-example",
+        cloneUrl: "https://my.gitlab.host.com/superuser/backporting-example.git"
+      },
+      nCommits: 1,
+      commits: ["ebb1eca696c42fd067658bd9b5267709f78ef38e"]
+    });
+    expect(configs.backportPullRequest).toEqual({
+      author: "Me",
+      url: undefined,
+      htmlUrl: undefined,
+      title: "New Title",
+      body: "New Body Prefix -New Body",
+      reviewers: [],
+      assignees: ["user3", "user4"],
+      targetRepo: {
+        owner: "superuser",
+        project: "backporting-example",
+        cloneUrl: "https://my.gitlab.host.com/superuser/backporting-example.git"
+      },
+      sourceRepo: {
+        owner: "superuser",
+        project: "backporting-example",
+        cloneUrl: "https://my.gitlab.host.com/superuser/backporting-example.git"
+      },
+      bpBranchName: undefined,
+    });
+  });
 });

test/service/runner/cli-github-runner.test.ts

@@ -3,15 +3,42 @@ import Runner from "@bp/service/runner/runner";
 import GitCLIService from "@bp/service/git/git-cli";
 import GitHubClient from "@bp/service/git/github/github-client";
 import CLIArgsParser from "@bp/service/args/cli/cli-args-parser";
-import { addProcessArgs, resetProcessArgs } from "../../support/utils";
+import { addProcessArgs, createTestFile, removeTestFile, resetProcessArgs } from "../../support/utils";
 import { mockGitHubClient } from "../../support/mock/git-client-mock-support";
 
+const GITHUB_MERGED_PR_W_OVERRIDES_CONFIG_FILE_CONTENT_PATHNAME = "./cli-github-runner-pr-merged-with-overrides.json";
+const GITHUB_MERGED_PR_W_OVERRIDES_CONFIG_FILE_CONTENT = {
+  "dryRun": false,
+  "auth": "my-auth-token",
+  "pullRequest": "https://github.com/owner/reponame/pull/2368",
+  "targetBranch": "target",
+  "gitUser": "Me",
+  "gitEmail": "me@email.com",
+  "title": "New Title",
+  "body": "New Body",
+  "bodyPrefix": "New Body Prefix - ",
+  "bpBranchName": "bp_branch_name",
+  "reviewers": [],
+  "assignees": ["user3", "user4"],
+  "inheritReviewers": false,
+};
+
 jest.mock("@bp/service/git/git-cli");
 jest.spyOn(GitHubClient.prototype, "createPullRequest");
 
 let parser: ArgsParser;
 let runner: Runner;
 
+beforeAll(() => {
+  // create a temporary file
+  createTestFile(GITHUB_MERGED_PR_W_OVERRIDES_CONFIG_FILE_CONTENT_PATHNAME, JSON.stringify(GITHUB_MERGED_PR_W_OVERRIDES_CONFIG_FILE_CONTENT));
+});
+
+afterAll(() => {
+  // clean up all temporary files
+  removeTestFile(GITHUB_MERGED_PR_W_OVERRIDES_CONFIG_FILE_CONTENT_PATHNAME);
+});
+
 beforeEach(() => {
   mockGitHubClient();
 
@@ -391,4 +418,43 @@ describe("cli runner", () => {
       }
     );
   });
+
+  test("using config file with overrides", async () => {
+    addProcessArgs([
+      "--config-file",
+      GITHUB_MERGED_PR_W_OVERRIDES_CONFIG_FILE_CONTENT_PATHNAME,
+    ]);
+    
+    await runner.execute();
+
+    const cwd = process.cwd() + "/bp";
+
+    expect(GitCLIService.prototype.clone).toBeCalledTimes(1);
+    expect(GitCLIService.prototype.clone).toBeCalledWith("https://github.com/owner/reponame.git", cwd, "target");
+
+    expect(GitCLIService.prototype.createLocalBranch).toBeCalledTimes(1);
+    expect(GitCLIService.prototype.createLocalBranch).toBeCalledWith(cwd, "bp_branch_name");
+    
+    expect(GitCLIService.prototype.fetch).toBeCalledTimes(1);
+    expect(GitCLIService.prototype.fetch).toBeCalledWith(cwd, "pull/2368/head:pr/2368");
+
+    expect(GitCLIService.prototype.cherryPick).toBeCalledTimes(1);
+    expect(GitCLIService.prototype.cherryPick).toBeCalledWith(cwd, "28f63db774185f4ec4b57cd9aaeb12dbfb4c9ecc");
+
+    expect(GitCLIService.prototype.push).toBeCalledTimes(1);
+    expect(GitCLIService.prototype.push).toBeCalledWith(cwd, "bp_branch_name");
+
+    expect(GitHubClient.prototype.createPullRequest).toBeCalledTimes(1);
+    expect(GitHubClient.prototype.createPullRequest).toBeCalledWith({
+        owner: "owner", 
+        repo: "reponame", 
+        head: "bp_branch_name", 
+        base: "target", 
+        title: "New Title", 
+        body: "New Body Prefix - New Body",
+        reviewers: [],
+        assignees: ["user3", "user4"],
+      }
+    );
+  });
 });

test/service/runner/cli-gitlab-runner.test.ts

@@ -3,8 +3,25 @@ import Runner from "@bp/service/runner/runner";
 import GitCLIService from "@bp/service/git/git-cli";
 import GitLabClient from "@bp/service/git/gitlab/gitlab-client";
 import CLIArgsParser from "@bp/service/args/cli/cli-args-parser";
-import { addProcessArgs, resetProcessArgs } from "../../support/utils";
+import { addProcessArgs, createTestFile, removeTestFile, resetProcessArgs } from "../../support/utils";
 import { getAxiosMocked } from "../../support/mock/git-client-mock-support";
+import { MERGED_SQUASHED_MR } from "../../support/mock/gitlab-data";
+
+const GITLAB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT_PATHNAME = "./cli-gitlab-runner-pr-merged-with-overrides.json";
+const GITLAB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT = {
+  "dryRun": false,
+  "auth": "my-token",
+  "pullRequest": `https://my.gitlab.host.com/superuser/backporting-example/-/merge_requests/${MERGED_SQUASHED_MR.iid}`,
+  "targetBranch": "prod",
+  "gitUser": "Me",
+  "gitEmail": "me@email.com",
+  "title": "New Title",
+  "body": "New Body",
+  "bodyPrefix": `**This is a backport:** https://my.gitlab.host.com/superuser/backporting-example/-/merge_requests/${MERGED_SQUASHED_MR.iid}`,
+  "reviewers": [],
+  "assignees": ["user3", "user4"],
+  "inheritReviewers": false,
+};
 
 jest.mock("axios", () => {
   return {
@@ -27,6 +44,16 @@ jest.spyOn(GitLabClient.prototype, "createPullRequest");
 let parser: ArgsParser;
 let runner: Runner;
 
+beforeAll(() => {
+  // create a temporary file
+  createTestFile(GITLAB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT_PATHNAME, JSON.stringify(GITLAB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT));
+});
+
+afterAll(() => {
+  // clean up all temporary files
+  removeTestFile(GITLAB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT_PATHNAME);
+});
+
 beforeEach(() => {
   // create CLI arguments parser
   parser = new CLIArgsParser();
@@ -306,4 +333,44 @@ describe("cli runner", () => {
       }
     );
   });
+
+  test("using config file with overrides", async () => {
+    addProcessArgs([
+      "--config-file",
+      GITLAB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT_PATHNAME,
+    ]);
+    
+    await runner.execute();
+
+    const cwd = process.cwd() + "/bp";
+
+    expect(GitCLIService.prototype.clone).toBeCalledTimes(1);
+    expect(GitCLIService.prototype.clone).toBeCalledWith("https://my.gitlab.host.com/superuser/backporting-example.git", cwd, "prod");
+
+    expect(GitCLIService.prototype.createLocalBranch).toBeCalledTimes(1);
+    expect(GitCLIService.prototype.createLocalBranch).toBeCalledWith(cwd, "bp-prod-ebb1eca696c42fd067658bd9b5267709f78ef38e");
+    
+    // 0 occurrences as the mr is already merged and the owner is the same for
+    // both source and target repositories
+    expect(GitCLIService.prototype.fetch).toBeCalledTimes(0);
+
+    expect(GitCLIService.prototype.cherryPick).toBeCalledTimes(1);
+    expect(GitCLIService.prototype.cherryPick).toBeCalledWith(cwd, "ebb1eca696c42fd067658bd9b5267709f78ef38e");
+
+    expect(GitCLIService.prototype.push).toBeCalledTimes(1);
+    expect(GitCLIService.prototype.push).toBeCalledWith(cwd, "bp-prod-ebb1eca696c42fd067658bd9b5267709f78ef38e");
+
+    expect(GitLabClient.prototype.createPullRequest).toBeCalledTimes(1);
+    expect(GitLabClient.prototype.createPullRequest).toBeCalledWith({
+        owner: "superuser", 
+        repo: "backporting-example", 
+        head: "bp-prod-ebb1eca696c42fd067658bd9b5267709f78ef38e", 
+        base: "prod", 
+        title: "New Title", 
+        body: expect.stringContaining("**This is a backport:** https://my.gitlab.host.com/superuser/backporting-example/-/merge_requests/1"),
+        reviewers: [],
+        assignees: ["user3", "user4"],
+      }
+    );
+  });
 });

test/service/runner/gha-github-runner.test.ts

@@ -3,15 +3,43 @@ import Runner from "@bp/service/runner/runner";
 import GitCLIService from "@bp/service/git/git-cli";
 import GitHubClient from "@bp/service/git/github/github-client";
 import GHAArgsParser from "@bp/service/args/gha/gha-args-parser";
-import { spyGetInput } from "../../support/utils";
+import { createTestFile, removeTestFile, spyGetInput } from "../../support/utils";
 import { mockGitHubClient } from "../../support/mock/git-client-mock-support";
 
+const GITHUB_MERGED_PR_W_OVERRIDES_CONFIG_FILE_CONTENT_PATHNAME = "./gha-github-runner-pr-merged-with-overrides.json";
+const GITHUB_MERGED_PR_W_OVERRIDES_CONFIG_FILE_CONTENT = {
+  "dryRun": false,
+  "auth": "my-auth-token",
+  "pullRequest": "https://github.com/owner/reponame/pull/2368",
+  "targetBranch": "target",
+  "gitUser": "Me",
+  "gitEmail": "me@email.com",
+  "title": "New Title",
+  "body": "New Body",
+  "bodyPrefix": "New Body Prefix - ",
+  "bpBranchName": "bp_branch_name",
+  "reviewers": [],
+  "assignees": ["user3", "user4"],
+  "inheritReviewers": false,
+};
+
+
 jest.mock("@bp/service/git/git-cli");
 jest.spyOn(GitHubClient.prototype, "createPullRequest");
 
 let parser: ArgsParser;
 let runner: Runner;
 
+beforeAll(() => {
+  // create a temporary file
+  createTestFile(GITHUB_MERGED_PR_W_OVERRIDES_CONFIG_FILE_CONTENT_PATHNAME, JSON.stringify(GITHUB_MERGED_PR_W_OVERRIDES_CONFIG_FILE_CONTENT));
+});
+
+afterAll(() => {
+  // clean up all temporary files
+  removeTestFile(GITHUB_MERGED_PR_W_OVERRIDES_CONFIG_FILE_CONTENT_PATHNAME);
+});
+
 beforeEach(() => {
   mockGitHubClient();
 
@@ -231,4 +259,42 @@ describe("gha runner", () => {
       }
     );
   });
+
+  test("using config file with overrides", async () => {
+    spyGetInput({
+      "config-file": GITHUB_MERGED_PR_W_OVERRIDES_CONFIG_FILE_CONTENT_PATHNAME,
+    });
+    
+    await runner.execute();
+
+    const cwd = process.cwd() + "/bp";
+
+    expect(GitCLIService.prototype.clone).toBeCalledTimes(1);
+    expect(GitCLIService.prototype.clone).toBeCalledWith("https://github.com/owner/reponame.git", cwd, "target");
+
+    expect(GitCLIService.prototype.createLocalBranch).toBeCalledTimes(1);
+    expect(GitCLIService.prototype.createLocalBranch).toBeCalledWith(cwd, "bp_branch_name");
+    
+    expect(GitCLIService.prototype.fetch).toBeCalledTimes(1);
+    expect(GitCLIService.prototype.fetch).toBeCalledWith(cwd, "pull/2368/head:pr/2368");
+
+    expect(GitCLIService.prototype.cherryPick).toBeCalledTimes(1);
+    expect(GitCLIService.prototype.cherryPick).toBeCalledWith(cwd, "28f63db774185f4ec4b57cd9aaeb12dbfb4c9ecc");
+
+    expect(GitCLIService.prototype.push).toBeCalledTimes(1);
+    expect(GitCLIService.prototype.push).toBeCalledWith(cwd, "bp_branch_name");
+
+    expect(GitHubClient.prototype.createPullRequest).toBeCalledTimes(1);
+    expect(GitHubClient.prototype.createPullRequest).toBeCalledWith({
+        owner: "owner", 
+        repo: "reponame", 
+        head: "bp_branch_name", 
+        base: "target", 
+        title: "New Title", 
+        body: "New Body Prefix - New Body",
+        reviewers: [],
+        assignees: ["user3", "user4"],
+      }
+    );
+  });
 });

test/service/runner/gha-gitlab-runner.test.ts

@@ -3,8 +3,25 @@ import Runner from "@bp/service/runner/runner";
 import GitCLIService from "@bp/service/git/git-cli";
 import GitLabClient from "@bp/service/git/gitlab/gitlab-client";
 import GHAArgsParser from "@bp/service/args/gha/gha-args-parser";
-import { spyGetInput } from "../../support/utils";
+import { createTestFile, removeTestFile, spyGetInput } from "../../support/utils";
 import { getAxiosMocked } from "../../support/mock/git-client-mock-support";
+import { MERGED_SQUASHED_MR } from "../../support/mock/gitlab-data";
+
+const GITLAB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT_PATHNAME = "./gha-gitlab-runner-pr-merged-with-overrides.json";
+const GITLAB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT = {
+  "dryRun": false,
+  "auth": "my-token",
+  "pullRequest": `https://my.gitlab.host.com/superuser/backporting-example/-/merge_requests/${MERGED_SQUASHED_MR.iid}`,
+  "targetBranch": "prod",
+  "gitUser": "Me",
+  "gitEmail": "me@email.com",
+  "title": "New Title",
+  "body": "New Body",
+  "bodyPrefix": `**This is a backport:** https://my.gitlab.host.com/superuser/backporting-example/-/merge_requests/${MERGED_SQUASHED_MR.iid}`,
+  "reviewers": [],
+  "assignees": ["user3", "user4"],
+  "inheritReviewers": false,
+};
 
 jest.mock("axios", () => {
   return {
@@ -26,6 +43,16 @@ jest.spyOn(GitLabClient.prototype, "createPullRequest");
 let parser: ArgsParser;
 let runner: Runner;
 
+beforeAll(() => {
+  // create a temporary file
+  createTestFile(GITLAB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT_PATHNAME, JSON.stringify(GITLAB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT));
+});
+
+afterAll(() => {
+  // clean up all temporary files
+  removeTestFile(GITLAB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT_PATHNAME);
+});
+
 beforeEach(() => {
   // create GHA arguments parser
   parser = new GHAArgsParser();
@@ -242,4 +269,43 @@ describe("gha runner", () => {
       }
     );
   });
+
+  test("using config file with overrides", async () => {
+    spyGetInput({
+      "config-file": GITLAB_MERGED_PR_COMPLEX_CONFIG_FILE_CONTENT_PATHNAME,
+    });
+    
+    await runner.execute();
+
+    const cwd = process.cwd() + "/bp";
+
+    expect(GitCLIService.prototype.clone).toBeCalledTimes(1);
+    expect(GitCLIService.prototype.clone).toBeCalledWith("https://my.gitlab.host.com/superuser/backporting-example.git", cwd, "prod");
+
+    expect(GitCLIService.prototype.createLocalBranch).toBeCalledTimes(1);
+    expect(GitCLIService.prototype.createLocalBranch).toBeCalledWith(cwd, "bp-prod-ebb1eca696c42fd067658bd9b5267709f78ef38e");
+    
+    // 0 occurrences as the mr is already merged and the owner is the same for
+    // both source and target repositories
+    expect(GitCLIService.prototype.fetch).toBeCalledTimes(0);
+
+    expect(GitCLIService.prototype.cherryPick).toBeCalledTimes(1);
+    expect(GitCLIService.prototype.cherryPick).toBeCalledWith(cwd, "ebb1eca696c42fd067658bd9b5267709f78ef38e");
+
+    expect(GitCLIService.prototype.push).toBeCalledTimes(1);
+    expect(GitCLIService.prototype.push).toBeCalledWith(cwd, "bp-prod-ebb1eca696c42fd067658bd9b5267709f78ef38e");
+
+    expect(GitLabClient.prototype.createPullRequest).toBeCalledTimes(1);
+    expect(GitLabClient.prototype.createPullRequest).toBeCalledWith({
+        owner: "superuser", 
+        repo: "backporting-example", 
+        head: "bp-prod-ebb1eca696c42fd067658bd9b5267709f78ef38e", 
+        base: "prod", 
+        title: "New Title", 
+        body: expect.stringContaining("**This is a backport:** https://my.gitlab.host.com/superuser/backporting-example/-/merge_requests/1"),
+        reviewers: [],
+        assignees: ["user3", "user4"],
+      }
+    );
+  });
 });

test/support/utils.ts

@@ -1,4 +1,5 @@
 import * as core from "@actions/core";
+import * as fs from "fs";
 
 export const addProcessArgs = (args: string[]) => {
   process.argv = [...process.argv, ...args];
@@ -25,3 +26,20 @@ export const spyGetInput = (obj: any) => {
 export const expectArrayEqual = (actual: unknown[], expected: unknown[]) => {
   expect(actual.sort()).toEqual(expected.sort());
 };
+
+/**
+ * Create a test file given the full pathname
+ * @param pathname full file pathname e.g, /tmp/dir/filename.json
+ * @param content what must be written in the file
+ */
+export const createTestFile = (pathname: string, content: string) => {
+  fs.writeFileSync(pathname, content);
+};
+
+/**
+ * Remove a file located at pathname
+ * @param pathname full file pathname e.g, /tmp/dir/filename.json
+ */
+export const removeTestFile = (pathname: string) => {
+  fs.rmSync(pathname);
+};