Passing branch names between pipelines

So far I was using the below pipeline which triggers the main pipeline. It tracks the pushed tags by developer to the master branch, and if so, starts running.

first_pipeline.yml

trigger:
  tags:
    include:
      - '*'
  paths:
    include:
      - master

variables:
  agent_pool: 'DEVAGENT'

pool:
  name: $(dev_pool)

The above pipeline triggers that one:

main_pipeline.yml

trigger: none
pr: none

resources:
  repositories:
    - repository: Grand
      type: git
      name: Automotive/Grand
      ref: master
      endpoint: Grand
    - repository: CICD
      type: git
      name: pipelines
      ref: master
  pipelines:
    - pipeline: Grand
      source: 'Grand'
      project: Automotive
      trigger: true

variables:
  - template: variables.yml

stages:
    - stage: DEV
      displayName: 'Development'
      variables:
        - name: environment
          value: ${{ variables.env_dev}}
      pool:
        name: ${{ variables.agent_dev }}
      jobs:
        - deployment: DEV
          displayName: 'Deploying to DEV'
      # Rest of the code   
  - stage: PRD
    displayName: 'Production Stage'
    variables:
      - name: environment
        value: ${{ variables.prd }}
    pool:
      name: ${{ variables.agent_prd }}
    jobs:
      - deployment: PRDDeploy
        displayName: 'Deploying to PRD'
    # Rest of the code

Above pipeline deploys changes to DEV stage, and than to PRD stage.

Now I'm trying to modify the pipeline to work in such a way that, for example:

• when a change comes from the dev or deploy branch, then only the DEV stage will be run
• when a change comes from feature or hotfix branches, it will go directly to PRD
• when it comes from master as it has been until now, then it will go to both DEV and PRD.

So far it works only with the last condition, my first attempt leads to errors, because I am not sure how to pass those branch names from the first to main pipelines and modify that second one.

When you use the pipeline.resources.repository.trigger there are additional pipeline variables available:

resources.pipeline.<Alias>.projectName
resources.pipeline.<Alias>.projectID
resources.pipeline.<Alias>.pipelineName
resources.pipeline.<Alias>.pipelineID
resources.pipeline.<Alias>.runName
resources.pipeline.<Alias>.runID
resources.pipeline.<Alias>.runURI
resources.pipeline.<Alias>.sourceBranch
resources.pipeline.<Alias>.sourceCommit
resources.pipeline.<Alias>.sourceProvider
resources.pipeline.<Alias>.requestedFor
resources.pipeline.<Alias>.requestedForID

Based on your triggers, it looks like you're using either a "tag" or commits to "master" to trigger the pipeline. You should be able to use $(resources.pipeline.Grand.sourceBranch) to get the originating branch. According to this answer, when a build is triggered by a tag, the sourceBranch will start with /refs/tags/<tag-name>.

Based on this, you should be able to do something like the following:

#first pipeline
trigger:
  tags:
    include:
    - '*'
  branches:
    include:
    - master

...

```yaml
# main_pipeline.yml
trigger: none

resources:
  pipelines:
  - pipeline: Grand # this is the alias
    source: 'Grand'
    project: Automotive
    trigger: true

stages:
- stage: dev
  condition: |
    or(
      startsWith(variables['resources.pipeline.Grand.sourceBranch', 'refs/tags/dev'),
      eq(variables['resource.pipeline.Grand.sourceBranch', 'refs/heads/master')
      )
  ...

- stage: prod
  condition: |
     or(
      startsWith(variables['resources.pipeline.Grand.sourceBranch', 'refs/tags/feature'),
      eq(variables['resource.pipeline.Grand.sourceBranch', 'refs/heads/master')
     )
  ...