IssueTracker

Issue summary:

- According to [1], the Go 1.12 runtime does not provide access to proprietary App Engine APIs.

- The mentioned API is only supported by the already deprecated Go 1.9 Runtime version.

- Some functionalities, like ServingURL [2], in the image package, have no equivalent or similar functionalities in the suggested migration libraries [3].

- Some use cases where ServingURL is used: To serve thumbnail images via their dynamic URLs. SignedURLs are not useful for this because they only would serve the original content, not the thumbnails.

- The Discovery service supports calling the App Engine API [4] and might be a workaround, but since it's highly recommended to migrate from the GAE to Google Cloud Client Libraries in [1, 5], it makes us think that the API will be deprecated soon. However, this last part is not mentioned in the Feature deprecation schedule [6] or in the API's docs [7].

Questions:

- Are there plans to migrate the App Engine API's missing functionalities (like image.ServingURLs) to the Google Cloud client library [8]?

- If not, what is the recommended workaround?


References:

[1] - https://cloud.google.com/appengine/docs/standard/go112/go-differences

[2] - https://godoc.org/google.golang.org/appengine/image#ServingURL

[3] - https://godoc.org/cloud.google.com/go

[4] - https://developers.google.com/discovery/v1/reference/apis/list?apix_params=%7B%22name%22%3A%22appengine%22%7D

[5] - https://cloud.google.com/appengine/docs/standard/go111/go-differences#changes_to_the_app_engine_go_111_runtime

[6] - https://cloud.google.com/appengine/docs/deprecations/

[7] - https://cloud.google.com/appengine/docs/standard/go/reference

[8] - https://godoc.org/cloud.google.com/go