CompletableFuture - SupplyAsync for gRPC client Call

[Bhuvi Viji]

Hi,

I have Service A which has to call Service B and C asynchronously. So i used Java 8 CompletableFuture supplyAsync method.

Problem: 

Service A gets JWT token from the caller , using Server interceptor it validates the token and if the token is valid it is set in the gRPC Context to propagate token to further client calls.

When i put the CompletableFuture , it creates a new thread for Service B and C calls so the gRPC context where the token set is lost. Service B and C calls are failing with missing token.

Background: Earlier Service A calls only B. So the ServerInterceptor which sets the token was available in clientInterceptor for calling B.

As a new enhancement added Service C call.

[zda...@google.com]

You might use 

CompletableFuture.supplyAsync(Supplier<U> supplier, Executor executor)

and pass the second argument as context.fixedContextExecutor() or Context.currentContextExecutor().

[Bhuvi Viji]

Thank you. I have used Context.attach and detach . will try out this option as well.