This will trigger a container tagged with the user identity which will then be passed to our existing CD system downstream because of reasons. But I have to know who pushed to the branch to do this. How is this information exposed in CircleCI?
The documentation has a section for built-in environment variables:
The relevant snippet:
CIRCLE_USERNAME String The GitHub or Bitbucket username of the user who triggered the build.
You can see all the automatic env vars in a build by opening the run step “Spin up Environment” once it has run.