Add GitLab CI job to pipeline based on script command result

user_1808052 0
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I have a GitLab CI pipeline with a 'migration' job which I want to be added only if certain files changed between current commit and master branch, but in my current project I'm forced to use GitLab CI pipelines for push event which complicates things.

Docs on rules:changes clearly states that it will glitch and will not work properly without MR (my case of push event), so that's out of question.

Docs on rules:if states that it only works with env variables. But docs on passing CI/CD variables to another job clearly states that

These variables cannot be used as CI/CD variables to configure a pipeline, but they can be used in job scripts.

So, now I'm stuck. I can just skip running the job in question overriding the script and checking for file changes, but what I want is not adding the job in question to pipeline in first place.

gitlab gitlab-ci
2 Answers

While you can't add a job alone to a pipeline based on the output of a script, you can add a child pipeline dynamically based on the script output. The method of using rules: with dynamic variables won't work because rules: are evaluated at the time the pipeline is created, as you found in the docs.

However, you can achieve the same effect using dynamic child-pipelines feature. The idea is you dynamically create the YAML for the desired pipeline in a job. That YAML created by your job will be used to create a child pipeline, which your pipeline can depend on.

user_57479440

Sadly, to add/remove a Gitlab job based on variables created from a previous job is not possible for a given pipeline

A way to achieve this is if your break your current pipeline to an upstream and downstream

The upstream will have 2 jobs

  1. The first one will use your script to define a variable
  2. This job will trigger the downstream, passing this variable

Upstream

check_val:
 ...
 script:
   ... Script imposes the logic with the needed checks
   ... If true
   - echo "MY_CONDITIONAL_VAR=true" >> var.env
   ... If false 
   - echo "MY_CONDITIONAL_VAR=false" >> var.env
 artifacts:
  reports:
    dotenv: var.env

trigger_your_original_pipeline:
    ...
    variables:
      MY_CONDITIONAL_VAR: "$MY_CONDITIONAL_VAR"
    trigger:
        project: "project_namespance/project"

The downstream would be your original pipeline

Downstream

... 
migration:
...
  rules:
   - if: '$MY_CONDITIONAL_VAR == "true"'

Now the MY_CONDITIONAL_VAR will be available at the start of the pipeline, so you can impose rules to add or not the migration job

user_104632110
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