[Question] GraalVM native support

[jefffang123]

In README I can see GraalVM native image support should be there for both server and client.

And in the latest release 0.3.0 the version for grpc-java is updated to 1.69.0 in BOM.

But grpc-java 1.69.0 seems to introduce a runtime reflection which requires reflection metadata registration, currently when I run the native code built against grpc-java 1.69.+ I can see the errors:

Caused by: java.lang.AssertionError: java.lang.NoSuchMethodException: java.time.Instant.now()
        at io.grpc.internal.InstantTimeProvider.<init>(InstantTimeProvider.java:39)
        at io.grpc.internal.TimeProviderResolverFactory.resolveTimeProvider(TimeProviderResolverFactory.java:27)
        at io.grpc.internal.TimeProvider.<clinit>(TimeProvider.java:27)
        at io.grpc.internal.TransportTracer.<clinit>(TransportTracer.java:30)
        at io.grpc.netty.NettyServerBuilder.<init>(NettyServerBuilder.java:91)
        at io.grpc.netty.NettyServerBuilder.forAddress(NettyServerBuilder.java:147)
        at io.grpc.netty.NettyServerBuilder.forPort(NettyServerBuilder.java:127)
        at io.grpc.netty.NettyServerProvider.builderForPort(NettyServerProvider.java:40)
        at io.grpc.netty.NettyServerProvider.builderForPort(NettyServerProvider.java:25)
        at io.grpc.ServerBuilder.forPort(ServerBuilder.java:44)

Question:

Will spring-grpc repo solve this problem, or do we leave it to upstream libraries, probably not just grpc-java because other dependencies such as protobuf might have these problems in future

Or do we assume this will be solved by community? e.g https://github.com/oracle/graalvm-reachability-metadata

[dsyer]

I think up to now we have been relying on https://github.com/oracle/graalvm-reachability-metadata/tree/master/metadata/io.grpc/grpc-netty. I don't see a reason to change that, but someone will have to send some changes to them. Short term we could add some hints in this project, I suppose. FWIW this works for me in the grpc-server sample (reflect-config.json):

[
	{
	  "condition": {
		"typeReachable": "io.grpc.internal.InstantTimeProvider"
	  },
	  "name": "java.time.Instant",
	  "allDeclaredMethods": true
	}
]