CircleCi and Heroku Orb

Recently I’ve had some pain trying to use the Heroku Orb in Circle CI config.

My goal was simple. Send the build number from Circle CI as part of the heroku deployment.

There are two ways to use this orb:

• Commands
• Jobs

The problem I was facing was that I had my blinkers on the Jobs and originally the config.yml looked like this:

version: 2.1
orbs:
  node: circleci/node@2.1.1
  heroku: circleci/heroku@1.0.1

workflows:
  build-test-deploy:
    jobs:
      - node/test
      - heroku/deploy-via-git:
          app-name: application-name
          requires:
            - node/test
          filters:
            branches:
              only: master

This is very simple right? However, where is the build number? How do we set that environment variable in Heroku so that the application can load it at runtime?

To set the environment variable, we’d need access to the heroku command line and call `heroku config:set …`. Then, I came across the pre-deploy step/hook for that job and that seemed to work!

workflows:
  build-test-deploy:
    jobs:
      - node/test
      - heroku/deploy-via-git:
          app-name: application-name
          pre-deploy:
            - run: heroku config:set BUILD_NUMBER=$CIRCLE_BUILD_NUM -a application-name

Nice :) But then I came across this error on the subsequent builds :(

#!/bin/bash -eo pipefail
if false;then
  force="-f"
fi
git push $force https://heroku:$HEROKU\_API\_KEY@git.heroku.com/xxxxx.git $CIRCLE\_BRANCH:master
To https://git.heroku.com/\*\*\*\*\*\*\*\*\*\*\*\*.git
 ! \[rejected\]        master -> master (fetch first)
error: failed to push some refs to 'https://heroku:\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*@git.heroku.com/\*\*\*\*\*\*\*\*\*\*\*\*.git'
hint: Updates were rejected because the remote contains work that you do
hint: not have locally. This is usually caused by another repository pushing
hint: to the same ref. You may want to first integrate the remote changes
hint: (e.g., 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.

The Fix!

The above error was happening probably because the container had cached git files and needed to do a force push. i.e. `git push -f …` which happens inside this job. But guess what? The job didn’t have that parameter available so we have to use the heroku commands instead!

The final working outcome is this (notice the `force:true`):

version: 2.1
orbs:
  node: circleci/node@2.1.1
  heroku: circleci/heroku@1.0.1

jobs:
  deploy:
    executor: heroku/default
    steps:
      - checkout
      - heroku/install
      - run: heroku config:set BUILD_NUMBER=$CIRCLE_BUILD_NUM -a application-name
      - heroku/deploy-via-git:
          app-name: application-name
          force: true

workflows:
  build-test-deploy:
    jobs:
      - node/test
      - deploy:
          requires:
            - node/test
          filters:
            branches:
              only: master