gRPC Widya Rarasati Software Engineer Widya Rarasati - Software Engineer 

What is gRPC? gRPC stands for gRPC Remote Procedure Calls. Open sourced version of Stubby RPC used in Google. https://github.com/grpc/grpc/blob/master/doc/g_stands_for.md 

Why gRPC? ● strict service contracts using Protobuf ● data serialization ● efficient network communication ● Support many common languages: C++, Java, Python, Ruby, Node.js, C#, Go, PHP, Objective-C TL;DR gRPC replace HTTP+JSON. 

https://www.slideshare.net/borisovalex/enabling-googley-microservices-with-http2-and-grpc 

What makes gRPC faster ● More efficient data encoding data is kept in binary (in client memory and on the wire) ● HTTP/2 multiplexed requests over a single connection 

https://www.slideshare.net/borisovalex/enabling-googley-microservices-with-http2-and-grpc 

https://www.slideshare.net/borisovalex/enabling-googley-microservices-with-http2-and-grpc 

https://www.slideshare.net/borisovalex/enabling-googley-microservices-with-http2-and-grpc 

How To Use gRPC 

Protobuf as Service Definition 

Deadline instead of Timeout1 How long the client is willing to wait for an answer. When deadline reached RPC will fail with DEADLINE_EXCEEDED status code response = blockingStub.withDeadlineAfter( deadlineMs, TimeUnit.MILLISECONDS) .sayHello(request); 

gRPC Deadline1 Deadline are automatically propagated, and can be accessed by the receiver Context context = Context.current(); context.getDeadline().isExpired(); context.getDealine().timeRemaining( MILLISECONDS); context.getDeadline().runOnExpiration(() -> { cleaupResources(); logger.info(“Deadline exceded” ); }) 

gRPC Cancellation When the caller is not interested in the result any more… RPC will fail with CANCELLED status code. Server (receiver) access cancellation status by: streamObserver.isCancelled(); streamObserver.setOnCancelHandler(() -> { cleaupResources(); logger.info(“Call canceled by client.” ); }) 

Reference 1)https://cloudplatform.googleblog.com/2016/08/gRPC-a-true-Internet-scale-RPC-framework-is- now-1-and-ready-for-production-deployments.html 2)https://cloud.google.com/blog/big-data/2016/03/announcing-grpc-alpha-for-google-cloud-pub sub 3)https://www.slideshare.net/borisovalex/enabling-googley-microservices-with-http2-and-grpc 4)https://developers.google.com/protocol-buffers/docs/reference/overview 5)https://grpc.io/blog/deadlines 

Existing GGB gRPC Implementation PROS CONS Service Contract Manageable contract version No status code for each rpc in protobuf Connection Efficiency Using single TCP connection Infrequently request traffic Logging Can do it in gRPC interceptor Missing readability of HTTP request traffic 

Other things about gRPC: - Channel https://github.com/grpc/grpc/blob/master/doc/connectivity-semantics-and-ap i.md - Reflection Server https://github.com/grpc/grpc-go/blob/master/Documentation/server-reflectio n-tutorial.md - Client cancel StreamObserver response = blockingStub.sayHello(request); ((ClientCallStreamObserver) response.).cancel() 

Thank You