How to trigger a job when specific files have changed at any commit in the branch

GitLab CI/CD
,
1

I have a CI pipeline that uses a template for the build job and a couple of other jobs that utilize that. Something similar to this:

.build_job:
  stage: build
  script:
    - echo "Build $APP"

build-one:
  extends: .build_job
  before_script:
    - APP=one
  rules:
    - changes:
      - src/one/**/*

build-two:
  extends: .build_job
  before_script:
    - APP=two
  rules:
    - changes:
      - src/two/**/*

The intention is to only build the components of our software that have changed.

The problem is that job will only trigger if a file in the specified directory has changed for the current commit. I would like to have that job run if a file in the specified directory has changed at any commit in the branch. So if I change something in src/one/* and push that commit, it would run the build-one job. But if, for the next push, I change something outside that I would like that job to still run. For example, I might change the top level CMakeLists.txt file and push that change. I would like that build-one job to still run.

Is this possible?

2

Pipelines are triggered per-commit and don’t know what happened in the past. But you can have multiple conditions which are evaluated with “OR”, so you can do

rules:
  - changes:
    - src/one/**/*
    - ./*

I don’t know if it helps.

3

Thanks, but it does not. I tried using a bash conditional in the script, but the problem is that there’s no way of determining the source branch of the current branch. There’s no $CI_... variable for that and git does not store that info anywhere. If I had that info, I could do something like

if git diff --quiet $CI_COMMIT_BRANCH <SOURCE_BRANCH> -- "src/one/**"; then
...
fi

I might just have to settle for checking each commit and building everything on a merge request.

4

If you need some really complex logic which files are changed you need to use Merge Requests where you can compare diff between branches:

- if [ "${CI_MERGE_REQUEST_TARGET_BRANCH_NAME}x" != "x" ]; then git fetch origin "${CI_MERGE_REQUEST_TARGET_BRANCH_NAME}"; export FILES=$(git diff --name-only origin/${CI_MERGE_REQUEST_TARGET_BRANCH_NAME}...); fi
- if [ "${CI_COMMIT_REF_NAME}" = "${CI_DEFAULT_BRANCH}" ]; then git fetch origin "${CI_COMMIT_REF_NAME}"; export FILES=$(git diff --name-only "${CI_COMMIT_BEFORE_SHA}" HEAD); fi

to get list of changed files.
The first line is for MR, the second for branch commits comparing against previous commit.

5

In case you’re not tied to GitLab’s own pipelines feature and want more control you could consider CircleCI’s dynamic configuration feature (disclaimer - I work for CircleCI)

It essentially splits the pipeline into two parts, where in the first part you can evaluate special conditions like paths that have diverged from a specific branch, and then either toggle parameters in the continuation of the pipeline, or even generate your own config on the fly.

I found it particularly useful for monorepo-style projects where you might have a frontend, API, or backend in the same repo.

6

I am tied to it for now. But thank you.