YAML syntax for build triggers

We parse all triggers in a configuration YAML and start builds with all matching triggers. This means the order of the triggers doesn't matter.

For example, if you have two Workflows with push triggers with the same branch condition, both will be triggered when a commit is pushed to that branch. In the configuration below, both triggers will launch a build if a commit is pushed to the release branch:

workflows:
  pipeline-tests:
    triggers:
      push:
      - branch: "release"
    [...]
  pipeline-build:
    triggers:
      push: 
      - branch: "*"

If you define multiple trigger conditions, all of them must match to trigger a build. In the example below, a build will be triggered if:

workflows:
  pipeline-builds:
    triggers:
      push:
      - branch: release
        changed_files:
          - path/to/library-a/**

We support wildcards (*) for simple text matching within all types of triggers. Wildcards are a good choice when you don't need the advanced pattern matching capabilities of regular expressions. For example, a trigger based on commit messages starting with fix can be achieved using a wildcard.

Wildcards are useful to match specific, fixed values appearing in the input. We recommend using regexes are needed when multiple alternative values, negation, capturing specific groups of characters or specific character types (for example, numbers only) are needed.

To use regular expressions for a trigger condition, you need to add regex: to its value:

workflows: 
  deploy:
    triggers:
      tag:
      - name:
          regex: '^\d\.\d\.\d$'
      pull_request:
      - comment: "[workflow: deploy]"
        commit_message:
          regex: '.*\[workflow: deploy\].*'