A tiny serverless plugin to check the current branch before deploy

check-git-branch-before-deploy.js

const exec = require('child_process').exec;


class CheckGitBranchBeforeDeploy {
  constructor (serverless, options) {
    this.commands = {
      deploy: {
        lifecycleEvents: [
          'resources',
        ]
      },
    };

    this.hooks = {
      'before:deploy:resources': () => checkGitBranch(serverless),
    }
  }
}

const checkGitBranch = serverless => {
  const stage = serverless.service.provider.stage;
  const requiredBranch = serverless.service.custom.checkGitBranchBeforeDeploy[stage];

  if (!requiredBranch) {
    serverless.cli.log(`[CheckGitBranchBeforeDeploy] No branch requirement for stage "${stage}"`)
    return;
  }

  serverless.cli.log(`[CheckGitBranchBeforeDeploy] Checking branch requirement "${requiredBranch}" for stage "${stage}"`)

  return promiseExec('git rev-parse --abbrev-ref HEAD')
    .then(({stdout}) => {
      const currentBranch = stdout.split('\n')[0];

      if (currentBranch !== requiredBranch) {
        throw `[CheckGitBranchBeforeDeploy]\n\n\
  Current branch "${currentBranch}" and required branch "${requiredBranch}" mismatch.\n\
  Do a "git fetch --all && git checkout ${requiredBranch}" before deploy :)`
      }
    });
}


const promiseExec = cmd => (
  new Promise((resolve, reject) => (
    exec(cmd, (err, stdout, stderr) => {
      if (err) {
        reject(err);
      } else {
        resolve({stdout, stderr});
      }
    })
  ))
);

module.exports = CheckGitBranchBeforeDeploy;

This is not working for me. I tried with serverless v2.7 and now with v3.17.

What I did so far.

To print it nicer in v3:

.serverless_plugins/check-git-branch-before-deploy.js

    if (currentBranch !== requiredBranch) {
      serverless.cli.log(`[CheckGitBranchBeforeDeploy]\n\n\
  Current branch "${currentBranch}" and required branch "${requiredBranch}" mismatch.\n\
  Do a "git fetch --all && git checkout ${requiredBranch}" before deploy :)`);
      throw "";
    }

Also, in the serverless.yml, checkGitBranchBeforeDeploy should go under custom: (this is not right here) and stage: ${opt:stage} will throw an error in sls v3, so I did this for the yaml and in the JS code:

serverless.yml

custom:
  myStage: ${sls:stage}
  checkGitBranchBeforeDeploy:
    beta-live: beta-live
    dev-live: dev-live
    prod-live: prod-live

.serverless_plugins/check-git-branch-before-deploy.js

const stage = serverless.service.custom.myStage;

What's happing now:

# on main branch
$ sls deploy -s beta-live
Running "serverless" from node_modules

Deploying private-eye-converter to stage beta-live (eu-west-2, "mep" provider)
[CheckGitBranchBeforeDeploy] Checking branch requirement "beta-live" for stage "beta-live"
[CheckGitBranchBeforeDeploy]

  Current branch "main" and required branch "beta-live" mismatch.
  Do a "git fetch --all && git checkout beta-live" before deploy :)

✖ Stack private-eye-converter-beta-live failed to deploy (0s)

Good!

# on beta-live branch
$ sls deploy -s beta-live
Running "serverless" from node_modules

Deploying private-eye-converter to stage beta-live (eu-west-2, "mep" provider)
[CheckGitBranchBeforeDeploy] Checking branch requirement "beta-live" for stage "beta-live"

✔ Service deployed to stack private-eye-converter-beta-live (0s)

Hmmm... not good :-(, nothing's happening.

# on beta-live branch
$ sls deploy -s test
Running "serverless" from node_modules

Deploying private-eye-converter to stage test (eu-west-2, "mep" provider)
[CheckGitBranchBeforeDeploy] No branch requirement for stage "test"

✔ Service deployed to stack private-eye-converter-test (0s)

Neither :-(

If I disable the CheckGitBranchBeforeDeploy plugin, all works fine.