Check first for existing branches before creating them

[wrandall22]

This PR is another attempt at fixing issue #10 after the reversion in #12. I found the echo lines to be helpful, but we can delete them if desired.

[wrandall22]

This needs more work still, unfortunately, GetBranch fails with an exception instead of returning an empty object when the branch does not exist, so this needs some error handling.

[wrandall22]

I believe this is working now (tested on a non-existing and existing branch). However, there is a side effect of a log in the console: sh: "branch":: unknown operand that shows up when the branch does exist.

[coelhucas]

Is there anything else missing we could do to merge this one? cc @yinlinchen @wrandall22

I'd be glad to help if needed, these errors for existing branches are bothering us a lot here 😅

[Copilot]

Pull Request Overview

This PR ensures that a new Amplify branch is only created when it does not already exist, addressing issue #10. Key changes include:

• Adding a branch existence check using aws amplify get-branch.
• Conditional branch creation with appropriate echo statements.
• Maintaining debug logging for deployment feedback.

Comments suppressed due to low confidence (1)

entrypoint.sh:59

• Similarly, in the create-branch command, wrapping the variables in quotes can help ensure robust parsing of parameters.

sh -c "aws amplify create-branch --app-id=${AmplifyAppId} --branch-name=$BRANCH_NAME  \

[Copilot]

To avoid potential issues with word splitting or globbing, consider quoting the variables (e.g., "${AmplifyAppId}", "$BRANCH_NAME", "${AWS_REGION}") in the shell command.

[wrandall22]

Is there anything else missing we could do to merge this one?

We have been using it in production for over a year with our fork. Haven't seen any issues with it that I'm aware of. We also made another change here later.