feature request: support grpc servers on android

[brandondutra]

Running a grpc server on android in java is not supported. Running an HTTP server on android is well supported and has many legitimate use cases. The same should be true for running a grpc server on android.

This need has come up in many issues. And the general suggestion is to use c++. Such as in #3041 #2273 #2227 and others. See also questions from stack overflow.

The docs are also misleading. In https://grpc.io/docs/quickstart/android.html it is not clearly stated that the server is not running in android, and this is not supported.

If the choice to not support android servers in java is continued, then the docs need to be made clear of this fact.

[ericgribkoff]

I sent out some PRs to clarify the documentation. We can use this issue to track demand for on-device servers.

I'll note that we intend to support gRPC C++ servers on Android: this is known to work right now, and I'll be adding interop tests for on-device servers later this quarter. For many use cases requiring an on-device server, this should be sufficient.

Netty, as of 4.1, does officially support (but not test, see http://netty.io/wiki/new-and-noteworthy-in-4.1.html#wiki-h3-3) Android so we could consider the same with gRPC.

@brandondutra if you have any insight in the potential issues brought up with on-device Android servers in #2273, please share. Specifically, we've done a lot of work on network reliability for Android clients but it's unclear how any of this would translate to server implementations.

[louiewh]

Yes, it is very convenient if support grpc servers on android。

[hameno]

Would be nice to support gRPC Servers on Android Things devices.

[daviderickson]

+1

[gpwclark]

+1