pull-request-action/README.md

# Automated Branch Pull Requests

This action will open a pull request to master branch (or otherwise specified)
whenever a branch with some prefix is pushed to. The idea is that you can
set up some workflow that pushes content to branches of the repostory,
and you would then want this push reviewed for merge to master.

Here is an example of what to put in your `.github/main.workflow` file to
trigger the action.

```
workflow "Create Pull Request" {
  on = "push"
  resolves = "Create New Pull Request"
}

action "Create New Pull Request" {
  uses = "vsoch/pull-request-action@master"
  secrets = [
    "GITHUB_TOKEN"
  ]
  env = {
    BRANCH_PREFIX = "update/"
    PULL_REQUEST_BRANCH = "master"
  }
}
```

Environment variables include:

  - **BRANCH_PREFIX**: the prefix to filter to. If the branch doesn't start with the prefix, it will be ignored
  - **PULL_REQUEST_BRANCH**: the branch to issue the pull request to. Defaults to master.
  - **PULL_REQUEST_BODY**: the body for the pull request (optional)
  - **PULL_REQUEST_TITLE**: the title for the pull request  (optional)

## Example use Case: Update Registry

As an example, I created this action to be intended for an 
[organizational static registry](https://www.github.com/singularityhub/registry-org) for container builds. 
Specifically, you have modular repositories building container recipes, and then opening pull requests to the 
registry to update it. 

 - the container collection content should be generated from a separate GitHub repository, including the folder structure (manifests, tags, collection README) that are expected.
 - the container collection metadata is pushed to a new branch on the registry repository, with namespace matching the GitHub repository, meaning that each GitHub repository always has a unique branch for its content.
 - pushing this branch that starts with the prefix (update/<namespace>) triggers the GitHub actions to open the pull request.

If the branch is already open for PR, it updates it.