feat: integrate tool with gitlab service (#39)

* feat: integrate tool with gitlab service

Fix https://github.com/lampajr/backporting/issues/30

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

@@ -0,0 +1,157 @@
+import LoggerService from "@bp/service/logger/logger-service";
+import GitClient from "@bp/service/git/git-client";
+import { GitPullRequest, BackportPullRequest } from "@bp/service/git/git.types";
+import LoggerServiceFactory from "@bp/service/logger/logger-service-factory";
+import { MergeRequestSchema, UserSchema } from "@gitbeaker/rest";
+import GitLabMapper from "@bp/service/git/gitlab/gitlab-mapper";
+import axios, { Axios } from "axios";
+import https from "https";
+
+export default class GitLabClient implements GitClient {
+  
+  private readonly logger: LoggerService;
+  private readonly apiUrl: string;
+  private readonly mapper: GitLabMapper;
+  private readonly client: Axios;
+
+  constructor(token: string, apiUrl: string, rejectUnauthorized = false) {
+    this.logger = LoggerServiceFactory.getLogger();
+    this.apiUrl = apiUrl;
+    this.client = axios.create({
+      baseURL: this.apiUrl,
+      headers: {
+        Authorization: `Bearer ${token}`,
+        "User-Agent": "lampajr/backporting",
+      },
+      httpsAgent: new https.Agent({  
+        rejectUnauthorized
+      })
+    });
+    this.mapper = new GitLabMapper(this.client);
+  }
+
+  // READ
+
+  // example: <host>/api/v4/projects/alampare%2Fbackporting-example/merge_requests/1
+  async getPullRequest(namespace: string, repo: string, mrNumber: number): Promise<GitPullRequest> {
+    const projectId = this.getProjectId(namespace, repo);
+    const { data } = await this.client.get(`/projects/${projectId}/merge_requests/${mrNumber}`);
+
+    return this.mapper.mapPullRequest(data as MergeRequestSchema);
+  }
+
+  getPullRequestFromUrl(mrUrl: string): Promise<GitPullRequest> {
+    const { namespace, project, id } = this.extractMergeRequestData(mrUrl);
+    return this.getPullRequest(namespace, project, id);
+  }
+  
+  // WRITE
+  
+  async createPullRequest(backport: BackportPullRequest): Promise<string> {
+    this.logger.info(`Creating pull request ${backport.head} -> ${backport.base}.`);
+    this.logger.info(`${JSON.stringify(backport, null, 2)}`);
+
+    const projectId = this.getProjectId(backport.owner, backport.repo);
+
+    const { data } = await this.client.post(`/projects/${projectId}/merge_requests`, {
+      source_branch: backport.head,
+      target_branch: backport.base,
+      title: backport.title,
+      description: backport.body,
+      reviewer_ids: [],
+      assignee_ids: [],
+    });
+    
+    const mr = data as MergeRequestSchema;
+
+    // reviewers
+    const reviewerIds: number[] = [];
+    for(const r of backport.reviewers) {
+      try {
+        this.logger.debug("Retrieving user: " + r);
+        const user = await this.getUser(r);
+        reviewerIds.push(user.id);
+      } catch(error) {
+        this.logger.warn(`Failed to retrieve reviewer ${r}`);
+      }
+    }
+
+    if (reviewerIds.length > 0) {
+      try {
+        this.logger.info("Setting reviewers: " + reviewerIds);
+        await this.client.put(`/projects/${projectId}/merge_requests/${mr.iid}`, {
+          reviewer_ids: reviewerIds.filter(r => r !== undefined),
+        });
+      } catch(error) {
+        this.logger.warn("Failure trying to update reviewers. " + error);
+      }
+    }
+
+    // assignees
+    const assigneeIds: number[] = [];
+    for(const a of backport.assignees) {
+      try {
+        this.logger.debug("Retrieving user: " + a);
+        const user = await this.getUser(a);
+        assigneeIds.push(user.id);
+      } catch(error) {
+        this.logger.warn(`Failed to retrieve assignee ${a}`);
+      }
+    }
+    
+    if (assigneeIds.length > 0) {
+      try {
+        this.logger.info("Setting assignees: " + assigneeIds);
+        await this.client.put(`/projects/${projectId}/merge_requests/${mr.iid}`, {
+          assignee_ids: assigneeIds.filter(a => a !== undefined),
+        });
+      } catch(error) {
+        this.logger.warn("Failure trying to update assignees. " + error);
+      }
+    }
+
+    return mr.web_url;
+  }
+
+
+  /**
+   * Retrieve a gitlab user given its username
+   * @param username 
+   * @returns UserSchema
+   */
+  private async getUser(username: string): Promise<UserSchema> {
+    const { data } = await this.client.get(`/users?username=${username}`);
+    const users = data as UserSchema[];
+    
+    if (users.length > 1) {
+      throw new Error("Too many users found with username=" + username);
+    }
+    
+    if (users.length == 0) {
+      throw new Error("User " + username + " not found");
+    }
+    
+    return users[0];
+  }
+
+  /**
+   * Extract repository namespace, project and mr number from the merge request url
+   * example: <host>/alampare/backporting-example/-/merge_requests/1
+   * note: "-/" could be omitted
+   * @param mrUrl merge request url
+   * @returns {{owner: string, project: string}}
+   */
+  private extractMergeRequestData(mrUrl: string): {namespace: string, project: string, id: number} {
+    const elems: string[] = mrUrl.replace("/-/", "/").split("/");
+    return {
+      namespace: elems[elems.length - 4],
+      project: elems[elems.length - 3],
+      id: parseInt(mrUrl.substring(mrUrl.lastIndexOf("/") + 1, mrUrl.length)),
+    };
+  }
+
+  private getProjectId(namespace: string, repo: string) {
+    // e.g., <namespace>%2F<repo>
+    return encodeURIComponent(`${namespace}/${repo}`);
+  }
+}