Option to use existing version if present, otherwise upload deployment-package

From the readme:

You can also use the action to deploy an existing version. To do this simply omit the deployment-package input parameter. The action will then assume that the version you pass in throught version_label already exists in Beanstalk and attempt to deploy that.

I am interested in a solution to the situation where the desired behavior is to:

1. use the already deployed version if it exists
2. otherwise, create the version from deployment-package

Basically, ignore deployment-package if the version already exists on s3.

This would address the following error that occurs if you deploy to multiple environments as demonstrated in https://github.com/einaregilsson/beanstalk-deploy/issues/5#issuecomment-571128797:

Deployment failed: Error: Version XXXX already exists in S3!

In our case, XXXX is the source commit hash, so we don’t have to worry about version being ambiguous.

[dhimmel]

Could possibly add some kind of optional use_existing_version_if_available: true or something like that

I think the option makes sense for backwards compatibility and out of precaution… I could imagine situations where users don’t intend to create a duplicate version number and perhaps the failure would be good in that case.

OTOH there are presumably few users currently, so backwards incompatibility probably is not a huge deal. And given the usefulness of this action, I presume it will have many more users in the future. So not a bad time to make changes.

Anyways no strong opinion here. Whatever form it’s implemented, I think it’d be useful!

[einaregilsson]

@juan-ntsprint Thanks, I’ll add that to the docs 🙂