Convert gRPC APIs to use GAPIC

[stephenplusplus]

• Bigtable
  • Generated files are in repo
  • Handwritten API is using generated API
  • Passing through gaxOptions is available on all requests
  • Automatic projectId insertion works
• Datastore
  • Generated files are in repo
  • Handwritten API is using generated API (will be complete when https://github.com/googleapis/nodejs-datastore is live)
  • Passing through gaxOptions is available on all requests (will be complete when https://github.com/googleapis/nodejs-datastore is live)
  • Automatic projectId insertion works
• Language
  • Generated files are in repo
  • Handwritten API is using generated API
  • Passing through gaxOptions is available on all requests
  • Automatic projectId insertion works
• Logging
  • Generated files are in repo
  • Handwritten API is using generated API
  • Passing through gaxOptions is available on all requests
  • Automatic projectId insertion works
• Pub/Sub
  • Generated files are in repo
  • Handwritten API is using generated API
  • Passing through gaxOptions is available on all requests
  • Automatic projectId insertion works
• Spanner
  • Generated files are in repo
  • Handwritten API is using generated API
  • Passing through gaxOptions is available on all requests
  • Automatic projectId insertion works
• Speech
  • Generated files are in repo
  • Handwritten API is using generated API
  • Passing through gaxOptions is available on all requests
  • Automatic projectId insertion works (Not applicable)
• Vision
  • Generated files are in repo
  • Handwritten API is using generated API
  • Passing through gaxOptions is available on all requests
  • Automatic projectId insertion works (Not applicable)

Cursoring Options

options.autoPaginate

Since the generated API accepts this option, I don't believe we'll need common/paginator. We will simply decorate whatever our callback to gax executes with.

options.maxApiCalls

All API calls come with a cost, and autoPaginate: true leaves that out of the user's control. We added this option to give that control back. Is this supported in the generated layer?

options.maxResults

We support this currently, though I don't know if this is supported in the generated layer. It will simply cut off making further requests after this amount has been reached. So a user can effectively say "autopaginate up until 58 results".

Common Methods

Since each resource will still have some or all of a shared set of methods:

• delete
• getMetadata
• setMetadata

and we can still wrap them with helpers like:

• create
• exists
• get

I believe it will require only a small bit of re-factoring to support, but GrpcService & GrpcServiceObject will likely continue to have a use. Alternatively, it might be possible to use the generic Service and ServiceObject if we can find an acceptable amount of convention/configuration.

common/paginator & common/streamify

Will we need these?

common/util.promisify

Will we need this?

Others

Is there anything else I could be missing?

I came up with this list by trying to migrate the Logging handwritten API to use the generated one. I quickly ran into these bumps, and figured we should resolve these and others up front. Ideally, our repo will remain clean of any artifacts of past implementations, so this will involve a thorough review of the utilities we have in common. @callmehiphop feel free to try a similar migration (pick an API) and see if you uncover any other issues.

// cc @callmehiphop @jmuk @bjwatson

[stephenplusplus]

/bump after the big week last week :) Some things are @callmehiphop questions, others are @jmuk questions. Please let me know if you need any clarity.

[callmehiphop]

AFAIK we will not need any of the common stuff you mentioned if a library uses GAX, but code changes will be required to return whatever the GAPIC layer returns to the user from the handwritten.