lambot-snippets

index.js

const yaml = require('js-yaml');
const tasks = require('./tasks'); // An object of supported tasks (functions)

// Helper function that attempts to run a task
function runTask(name, taskData) {
  // Ensure valid task provided
  if (!tasks[name]) return Promise.reject(`Invalid task name of '${name}' provided.`);
  return tasks[name].call(null, taskData);
}

// This is our lambda function
module.exports = async (event, context, callback) => {
  const response = JSON.parse(event.body);
  const repoOwner = response.repository.owner.login;
  const repoName = response.repository.name;

  // Retrieve lambot.yml
  // If missing, hook failure (lambot.yml is required)
  // Else, load and execute tasks
  const pendingTasks = await githubClient.get('config', { repoOwner, repoName })
    .then((res) => yaml.safeLoad(Buffer.from(res.data.content, 'base64')))
    .then((config) =>
      Object.keys(config.hooks).reduce((acc, hook) => {
        // If hook is enabled, attempt to run it and push to pending task queue
        if (config.hooks[hook]) {
          acc.push(runTask(hook, { githubEvent, response, config: config.hooks[hook] }));
        }
        return acc;
      }, []))
    .catch(() => {
      callback(null, respond(500, 'Missing or invalid lambot.yml.'));
      process.exit(0);
    })

  // Wait for all tasks to run
  await Promise.all(pendingTasks);

  return callback(null, respond(200, 'Success'));
}

labelTask.js

// Newly opened pull-requests without labels will receive a friendly notice
async function labelTask({ githubEvent, response }) {
  if (githubEvent === 'pull_request' && response.action === 'opened' && response.pull_request.labels.length === 0) {
    const repoName = response.repository.name;
    const repoOwner = response.repository.owner.login;
    const prNumber = response.number;

    // Post comment using the GitHub API
    await githubClient.post('comment', {
      repoOwner,
      repoName,
      prNumber,
      message: '_Hi :wave:, it\'s Lambot!_\n\n' +
        'I noticed this pull request has no assigned labels. :cry:\n\n' +
        'Please remember to label your pull requests. That helps keep things organized around here. :slightly_smiling_face:'
    })
  }

  return Promise.resolve();
};

lambot.yml

hooks:
  # Automatic versioning & publishing
  semver: true
  # Prefer labels on pull requests; notify if missing.
  labels: true
  # Run commands on each push and sends a Github status
  codereview:
    commands:
      - echo Installing node modules...
      - npm i
      - echo Running tests...
      - npm test

semverTask.js

const BOT_NAME = 'lambot';

// Automatically version and publish repositories that are npm packages
async function semverTask({ githubEvent, response }) {
  // Only listen to push events on master (we don't want to version + publish every branch!),
  // ignore commits from our bot (to avoid an infinite loop of versioning + publishing)
  // ignore [ci skip] commits
  if (githubEvent !== 'push' ||
    response.head_commit.author.username === BOT_NAME ||
    response.head_commit.message.includes('[ci skip]') ||
    response.ref !== 'refs/heads/master'
  ) {
    return Promise.resolve();
  }

  // get_version and push_changes are helper functions baked into our Docker image
  const commands = [
    'echo "Installing node modules..."',
    'npm ci',
    // Determine next version
    'increment=$(get_version)',
    // Create versioned commit; publish package; push versioned commit & tag
    'echo "Bumping version (type: $increment), publishing, and pushing..."',
    'npm version $increment',
    'npm publish',
    'push_changes'
  ];

  // Run the semver utility in our custom docker image
  return spawnDockerTask({
    GIT_REPO: response.repository.clone_url,
    GIT_BRANCH: response.ref,
    DOCKER_COMMANDS: commands.join('&&')
  });
};