Filtering headers by prefix

Here is an example of using the |filter modifier with arrow functions to filter dictionary keys.

• automation
• output

• 
  start:
    set:
      message_headers:
        x-gitlab-project: abc123
        x-blah: def456
        x-example: ghi789
    return:
      gitlab_headers@json: {{message_headers|filter((v,k) => k is prefixed ('x-gitlab'))|json_encode}}
  
  

• 
  __return:
    gitlab_headers:
      x-gitlab-project: abc123