Kicking off Jenkins build triggered by comment

README.md

@@ -18,6 +18,17 @@ See [CONTRIBUTING.md](CONTRIBUTING.md).
   The webhook secret that GitHub signs the POSTed payloads with. This is created when the webhook is defined. The default is `hush-hush`.
 - **`TRAVIS_CI_TOKEN`**<br>
   For scripts that communicate with Travis CI. Your Travis token is visible on [yourprofile](https://travis-ci.org/profile) page, by clicking the "show token" link. Also See: https://blog.travis-ci.com/2013-01-28-token-token-token
+- **`JENKINS_API_CREDENTIALS`** (optional)<br>
+  For scripts that communicate with Jenkins on http://ci.nodejs.org. The Jenkins API token is visible on
+  your own profile page `https://ci.nodejs.org/user/<YOUR_GITHUB_USERNAME>/configure`, by clicking the
+  "show API token" button. Also See: https://wiki.jenkins-ci.org/display/JENKINS/Authenticating+scripted+clients
+- **`JENKINS_JOB_URL_<REPO_NAME>`** (optional)<br>
+  Only required for the trigger Jenkins build script, to know which job to trigger a build for when
+  repository collaborator posts a comment to the bot. E.g. `JENKINS_JOB_URL_NODE=https://ci.nodejs.org/job/node-test-pull-request`
+- **`JENKINS_BUILD_TOKEN_<REPO_NAME>`** (optional)<br>
+  Only required for the trigger Jenkins build script. The authentication token configured for a particular
+  Jenkins job, for remote scripts to trigger builds remotely. Found on the job configuration page in
+  `Build Triggers -> Trigger builds remotely (e.g., from scripts)`.
 - **`LOGIN_CREDENTIALS`**<br>
   Username and password used to protected the log files exposed in /logs. Expected format: `username:password`.
 - **`KEEP_LOGS`**<br>

lib/bot-username.js

@@ -0,0 +1,14 @@
+const memoize = require('async').memoize
+
+const githubClient = require('./github-client')
+
+function requestGitHubForUsername (cb) {
+  githubClient.users.get({}, (err, currentUser) => {
+    if (err) {
+      return cb(err)
+    }
+    cb(null, currentUser.login)
+  })
+}
+
+exports.resolve = memoize(requestGitHubForUsername)

lib/github-events.js

@@ -27,6 +27,14 @@ module.exports = (app) => {
   app.emitGhEvent = function emitGhEvent (data, logger) {
     const repo = data.repository.name
     const org = data.repository.owner.login || data.organization.login
+
+    // Normalize how to fetch the PR / issue number for simpler retrieval in the
+    // rest of the bot's code. For PRs the number is present in data.number,
+    // but for webhook events raised for comments it's present in data.issue.number
+    if (!data.number && data.issue) {
+      data.number = data.issue.number
+    }
+
     const pr = data.number
 
     // create unique logger which is easily traceable throughout the entire app

scripts/trigger-jenkins-build.js

@@ -0,0 +1,127 @@
+'use strict'
+
+const request = require('request')
+
+const githubClient = require('../lib/github-client')
+const botUsername = require('../lib/bot-username')
+
+const jenkinsApiCredentials = process.env.JENKINS_API_CREDENTIALS || ''
+
+function ifBotWasMentionedInCiComment (commentBody, cb) {
+  botUsername.resolve((err, username) => {
+    if (err) {
+      return cb(err)
+    }
+
+    const atBotName = new RegExp(`^@${username} run CI`, 'mi')
+    const wasMentioned = commentBody.match(atBotName) !== null
+
+    cb(null, wasMentioned)
+  })
+}
+
+// URL to the Jenkins job should be triggered for a given repository
+function buildUrlForRepo (repo) {
+  // e.g. JENKINS_JOB_URL_CITGM = https://ci.nodejs.org/job/citgm-continuous-integration-pipeline
+  const jobUrl = process.env[`JENKINS_JOB_URL_${repo.toUpperCase()}`] || ''
+  return jobUrl ? `${jobUrl}/build` : ''
+}
+
+// Authentication token configured per Jenkins job needed when triggering a build,
+// this is set per job in Configure -> Build Triggers -> Trigger builds remotely
+function buildTokenForRepo (repo) {
+  // e.g. JENKINS_BUILD_TOKEN_CITGM
+  return process.env[`JENKINS_BUILD_TOKEN_${repo.toUpperCase()}`] || ''
+}
+
+function triggerBuild (options, cb) {
+  const { repo } = options
+  const base64Credentials = new Buffer(jenkinsApiCredentials).toString('base64')
+  const authorization = `Basic ${base64Credentials}`
+  const buildParameters = [{
+    name: 'GIT_REMOTE_REF',
+    value: `refs/pull/${options.number}/head`
+  }]
+  const payload = JSON.stringify({ parameter: buildParameters })
+  const uri = buildUrlForRepo(repo)
+  const buildAuthToken = buildTokenForRepo(repo)
+
+  if (!uri) {
+    return cb(new TypeError(`Will not trigger Jenkins build because $JENKINS_JOB_URL_${repo.toUpperCase()} is not set`))
+  }
+
+  if (!buildAuthToken) {
+    return cb(new TypeError(`Will not trigger Jenkins build because $JENKINS_BUILD_TOKEN_${repo.toUpperCase()} is not set`))
+  }
+
+  options.logger.debug('Triggering Jenkins build')
+
+  request.post({
+    uri,
+    headers: { authorization },
+    qs: { token: buildAuthToken },
+    form: { json: payload }
+  }, (err, response) => {
+    if (err) {
+      return cb(err)
+    } else if (response.statusCode !== 201) {
+      return cb(new Error(`Expected 201 from Jenkins, got ${response.statusCode}`))
+    }
+
+    cb(null, response.headers.location)
+  })
+}
+
+function createPrComment ({ owner, repo, number, logger }, body) {
+  githubClient.issues.createComment({
+    owner,
+    repo,
+    number,
+    body
+  }, (err) => {
+    if (err) {
+      logger.error(err, 'Error while creating comment to reply on CI run comment')
+    }
+  })
+}
+
+module.exports = (app) => {
+  app.on('issue_comment.created', function handleCommentCreated (event, owner, repo) {
+    const { number, logger, comment } = event
+    const commentAuthor = comment.user.login
+    const options = {
+      owner,
+      repo,
+      number,
+      logger
+    }
+
+    function replyToCollabWithBuildStarted (err, buildUrl) {
+      if (err) {
+        logger.error(err, 'Error while triggering Jenkins build')
+        return createPrComment(options, `@${commentAuthor} sadly an error occured when I tried to trigger a build :(`)
+      }
+
+      createPrComment(options, `@${commentAuthor} build started: ${buildUrl}`)
+      logger.info({ buildUrl }, 'Jenkins build started')
+    }
+
+    function triggerBuildWhenCollaborator (err) {
+      if (err) {
+        return logger.debug(`Ignoring comment to me by @${commentAuthor} because they are not a repo collaborator`)
+      }
+
+      triggerBuild(options, replyToCollabWithBuildStarted)
+    }
+
+    ifBotWasMentionedInCiComment(comment.body, (err, wasMentioned) => {
+      if (err) {
+        return logger.error(err, 'Error while checking if the bot username was mentioned in a comment')
+      }
+
+      if (!wasMentioned) return
+
+      githubClient.repos.checkCollaborator({ owner, repo, username: commentAuthor }, triggerBuildWhenCollaborator)
+    })
+  })
+}