Gitlab run a pipeline job when a merge request is merged - gitlab

Question

I have a gitlab pipeline where there are two stages, one is build and the other one is deploy. The build stage is run when a commit is made. I want a way to run the deploy job when the merge request is merged to master. I tried several things but no luck. Can anyone help?
stages:
- build
- deploy
dotnet:
script: "echo This builds!"
stage: build
production:
script: "echo This deploys!"
stage: deploy
only:
refs:
- master

Answer 1

Try using the gitlab-ci.yml "rules" feature to check for the merge request event.
Your current gitlab-ci.yml will run your "dotnet" job every commit, merge request, schedule, and manually triggered pipeline.
https://docs.gitlab.com/ee/ci/yaml/#workflowrules
dotnet:
script: "echo This builds!"
stage: build
rules:
- if: '$CI_COMMIT_REF_NAME != "master" && $CI_PIPELINE_SOURCE == "push" || $CI_PIPELINE_SOURCE == "merge_request_event"'
production:
script: "echo This deploys!"
stage: deploy
rules:
- if: '$CI_PIPELINE_SOURCE == "push" && $CI_COMMIT_REF_NAME == "master"'

Answer 2

If you want your job run on only after merging the merge request, then you can trigger a job based on the commit message, as shown below.
rules:
- if: '$CI_COMMIT_MESSAGE =~ /See merge request/'
Basically, all the merge request comes with a "See merge request" commit message so you can depend on that message to trigger your job.

Answer 3

You can run the pipeline after merge by using Gitlab ci predefined variable $CI_MERGE_REQUEST_APPROVED this will return true after merge and available from gitlab v14.1.
If you want to run the pipeline when merge request is created to main branch you can use $CI_MERGE_REQUEST_TARGET_BRANCH_NAME with $CI_MERGE_REQUEST_APPROVED.
you can add the rule like this in your job.
rules:
- if: $CI_MERGE_REQUEST_APPROVED && $CI_MERGE_REQUEST_TARGET_BRANCH_NAME == "main"

Answer 4

CI_MERGE_REQUEST_APPROVED variable seems to be designed for check approve status, not for triggering pipeline. (Issue, https://gitlab.com/gitlab-org/gitlab/-/issues/375908)
When you use merge request predefined variables, gitlab creates pipeline at merge request created, not at merge request approved.
Instead, use CI_COMMIT_BRANCH predefined variables with regular expression and restrict commit at master branch using branch access rights.
stages:
- build
- deploy
dotnet:
stage: build
rules:
- if: $CI_PIPELINE_SOURCE == "push" && $CI_COMMIT_BRANCH == "master"
script: "echo This builds!"
production:
stage: deploy
rules:
- if: $CI_PIPELINE_SOURCE == "push" && $CI_COMMIT_BRANCH == "master"
script: "echo This deploys!"
Edit answer for incorrect example. (edited at 2023. 01. 26)
Assume that we have rc and master branch.
We can configure master branch as protected, and use only for merge request.
In this case, we can define gitlab-ci file like below.
stages:
- build
- deploy
dotnet:
stage: build
rules:
- if: $CI_PIPELINE_SOURCE == "push" && $CI_COMMIT_BRANCH == "rc"
script: "echo This builds!"
production:
stage: deploy
rules:
- if: $CI_PIPELINE_SOURCE == "push" && $CI_COMMIT_BRANCH == "master"
script: "echo This deploys!"
Thanks for notification #Kappacake