NX Orb

✨ A CircleCI Orb which includes helpful commands for running Nx commands in the CI

Usage

version: 2.1

orbs:
  nx: nrwl/nx@1.6.2

jobs:
  checks:
    docker:
      - image: cimg/node:lts-browsers
    steps:
      - checkout
      - run:
          name: Install dependencies
          command: yarn install --frozen-lockfile
      - nx/set-shas
      - run:
          name: Run Builds
          command: yarn nx affected --target=build --base=$NX_BASE --parallel
      - run:
          name: Run Unit Tests
          command: yarn nx affected --target=test --base=$NX_BASE --parallel

Background

When we run affected command on Nx, we can specify 2 git history positions - base and head, and it calculates which projects in your repository changed between those 2 commits. We can then run a set of tasks (like building or linting) only on those affected projects.

This makes it easy to set-up a CI system that scales well with the continous growth of your repository, as you add more and more projects.

Problem

Figuring out what these two git commits are might not be as simple as it seems.

On a CI system that runs on submitted PRs, we determine what commits to include in the affected calculation by comparing our HEAD-commit-of-PR-branch to the commit in main branch (master or main usually) from which the PR branch originated. This will ensure the entirety of our PR is always being tested.

But what if we want to set up a continuous deployment system that, as changes get pushed to master, it builds and deploys only the affected projects?

What are the FROM and TO commits in that case?

Conceptually, what we want is to use the absolute latest commit on the master branch as the HEAD, and the previous successful commit on master as the BASE. Note, we want the previous successful one because it is still possible for commits on the master branch to fail for a variety of reasons.

The commits therefore can't just be HEAD and HEAD~1. If a few deployments fail one after another, that means that we're accumulating a list of affected projects that are not getting deployed. Anytime we retry the deployment, we want to include every commit since the last time we deployed successfully. That way we ensure we don't accidentally skip deploying a project that has changed.

This action enables you to find:

Commit SHA from which PR originated (in the case of pull_request)
Commit SHA of the last successful CI run

Private repositories

To use this orb with a private repository on your main branch, you need to grant the orb access to your CircleCI API. You can do this by creating an environment variable called CIRCLE_API_TOKEN in the context or the project.

Note: It should be a user token, not project token.

License