GCS backend for rocksdb-cloud

[bkkenkre]

As of now, rocksdb-cloud only seems to support AWS-S3 as the backend for cloud backup. This request is to support Google Cloud Storage (GCS) as well. This can leverage the CloudStorageProvider refactoring being introduced by Issue #71.

[dhruba]

Thanks for doing this bkkenkre.

@mrambacher : do you need any of your pending pull requests committed that can help the port to GCS env?

[mrambacher]

The StorageProvider work will make it easier to develop a GCS backend. I am currently not blocked on reviews -- I owe you folks smaller PRs.

[dhruba]

Ok got it. we will wait to see smaller patches from you @mrambacher.

[bkkenkre]

Thanks @mrambacher. Is your patch for Issue #71 stable ? I assuming the smaller PRs will eventually lead to the same patch, right ? I want to take that patch and start working on GCS part, while the your PRs are getting reviewed.

[mrambacher]

For the most part, you should only need to write a GCSStorageProvider. The StorageProvider class in this PR will be close to what you need and should get you started.

There will be other changes coming to do things like initialization versus construction, but this should get you a fair ways.

I believe the only piece not covered by the StorageProvider is how to deal with the cloud manifest file (where to write it). One goal is to move as much functionality as possible out of the AwsEnv into components that can be either reused (CloudEnvImpl) or replaced (S3StorageProvider).

[mrambacher]

@bkkenkre Any updates on the GCS backend? Anything I can help with?

[bkkenkre]

Hi @mrambacher, Sorry I am not able to get to finishing this. I had gotten some tests working with GCS with the code that I had mailed you and Dhruba sometime back but didn't get time to product-ionize it. I have un-assigned myself for now in case somebody wants to take over.

[manishrawat1992]

Hi @mrambacher, @bkkenkre. Is GCP code under some branch. Can you please share this work.