Guide for gRPC

[wtlucy]

The Open Liberty grpc-1.0 and grpcClient-1.0 features are currently in beta; we're hoping to GA in 20.0.0.11. The epic is at: OpenLiberty/open-liberty#8637

I have a few internal samples of basic applications at https://github.ibm.com/wtlucy/liberty_grpc_samples/ that could be useful for this guide. I intend to create a more up-to-date sample in a public repo as well; I will provide a link that in this issue.

Since Liberty's gRPC integration is not covered by any existing spec, I want to be sure that we cover how Liberty-deployable apps are created. That will include:

• overview of how to create and use .proto protocol buffer interfaces
• basic guidance for how gRPC applications need to be compiled (protobuf-maven-plugin or protobuf-gradle-plugin)
• simple example of a grpc-1.0 service implementation and a corresponding grpcClient-1.0 consumer
• war packaging including the generated source
• Details for configuring a gRPC service via the new @io.openliberty.grpc.GrpcService

Potential topics for an advanced guide:

• Security
  • securing grpc-1.0 services via SSL, and authorization via @RolesAllowed
  • configuring grpcClient-1.0 for SSL
• Monitoring integration with mpMetrics

[hutchig]

Is this still live? @rutavshah ?
I am the new technical owner of gRPC on Liberty and would be happy to help progress.
As well as https://github.ibm.com/wtlucy/liberty_grpc_samples/ there is also https://github.com/OpenLiberty/sample-grpc
but appears to use docker - which I imagine could be podman or something similar these days?

[yeekangc]

Let us proceed to publish this guide.

[yeekangc]

@gkwan-ibm, please confirm "end-to-end testing".