SOURCE_BUCKETS has a limit and can't support a long list of buckets

[harriswong]

We would like to be able to set SOURCE_BUCKETS=developer-bucket-* so that each developer's bucket is in the whitelist.

This was okay in 3.0.0 but it stopped allowing * in 4.0.0. We tried adding all our dev buckets as a comma separated value string but we went out of string limit.

It would be good to support regex again. Here is a PR for the proof of concept:
#138

We tested this with a custom built the image and it works with SOURCE_BUCKETS=developer\-bucket\-.*.

[beomseoklee]

We have updated our solution, and I believe your issue has been fixed. If you still see the issue with the latest version (v4.2), please feel free to reopen the issue.

However, as your pull request says, it only accepts the regular expression after launching the solution.

You can refer to the recent changes here

[harriswong]

cc @crpahl