REST in Peace. Long live gRPC! @JavaLandConf

This session focuses on modern and efficient Inter Process Communication (IPC) for microservices. We start with a REST API, built using JAX-RS and Quarkus to briefly discuss the pros and cons of this approach. Then, we will extend the API with an efficient Protobuf payload representation in order to finally transform the API into a fully fledged high-performance gRPC interface definition. But that's not all! To put some extra icing on the cake, this talk will demonstrate how to consume the gRPC service from a JavaScript web client and also how to completely generate a matching REST API from an enhanced gRPC interface definition to ensure full interoperability in a microservice architecture.

Transcript

1. qaware.de REST in Peace. Long live gRPC! JavaLand 2022 Mario-Leander Reimer mario-leander.reimer@qaware.de @LeanderReimer
2. 2 Mario-Leander Reimer Principal Software Architect @LeanderReimer #cloudnativenerd #qaware
3. Agenda QAware | 3 QAware | 3 REST Beer Service REST Beer Service GET /api/beers POST /api/beers GET /api/beers/{asin} PUT /api/beers/{asin} DELETE /api/beers/{asin} application/json application/x-protobuf gRPC Beer Service gRPC Beer Service gRPC Beer Web UI gRPC Beer Client gRPC Beer Gateway application/json gRPC Beer Nginx gRPC gRPC gRPC gRPC gRPC Web UI
4. https://github.com/lreimer/from-rest-to-grpc
5. “One cannot not communicate.” - Paul Watzlawick
6. A Quick History Lesson on Inter Process Communication (IPC) QAware | 6 DCOM 18.09.1996 Win95 RPC 14.01.1976 RFC 707 REST 2000 by Roy T. Fielding Java RMI Feb 1997 JDK 1.1 HTTP/1.0 Mai 1996 RFC 1945 HTTP/1.1 Juni 1999 RFC 2616 HTTP/2.0 Mai 2015 RFC 7540 SOAP 1.2 2003 RPC Oct 1983 Birrel und Nielson CORBA 1.0 Oct 1991 CORBA 2.0 August 1996 CORBA 2.3 Juni 1999 XML-RPC 1998 gRPC 1.0 Aug 2016 RESTful Applications 2014 (?) CORBA 3.0 July 2002
7. HTTP/1.1 200 OK Content-Length: 139 Content-Type: application/json; charset=utf-8 Date: Wed, 10 Nov 2021 10:21:54 GMT { "alcohol": 5.6, "asin": "B01AU6LWNC", "brand": "Augustiner Brauerei München", "country": "Germany", "name": "Edelstoff Exportbier", "type": "Lager" } GET /api/beers/B01AU6LWNC HTTP/1.1 Accept: application/json Accept-Encoding: gzip, deflate Connection: keep-alive Host: localhost:8080 User-Agent: HTTPie/2.5.0 REST APIs GET /api/beers POST /api/beers GET /api/beers/{asin} PUT /api/beers/{asin} DELETE /api/beers/{asin}
8. Richardson REST Maturity Model QAware | 8 https://martinfowler.com/articles/richardsonMaturityModel.html POST /bookingService HTTP/1.1 [various other headers] <makeBookingRequest date="2010-01-04" persons="2"/> POST /bookings HTTP/1.1 [various other headers] <getBookingRequest id="ID-1234567890" user"lreimer"/> GET /bookings/1234567890?user=lreimer HTTP/1.1 Accept: application/json [various other headers] GET /bookings/1234567890?user=lreimer HTTP/1.1 Accept: application/json Link: /users/lreimer [various other headers]
9. QAware | 9 1. The network is reliable 2. Latency is zero 3. Bandwidth is infinite 4. The network is secure 5. Topology doesn’t change 6. There is one administrator 7. Transport cost is zero 8. The network is homogeneous The 8 Fallacies of Distributed Computing
10. Protocol Buffers are a language-neutral, platform-neutral extensible mechanism for serializing structured data. QAware | 10 ▪ https://developers.google.com/protocol-buffers ▪ Like XML or JSON - just smaller, faster and easier! ▪ Google Protobuf uses an efficient binary format to serialize data structures. ▪ An Interface Definition Language (IDL) is used to define data structures and message payloads ▪ Protocol Buffers supports code generation for Java, Python, Objective-C, C++, Kotlin, Dart, Go, Ruby und C#. ▪ Protobuf supports evolution as well as extension of schemas. Backwards and forwards compatibility are supported: – you must not change the tag numbers of any existing fields. – you may delete fields. – you may add new fields but you must use fresh tag numbers (i.e. tag numbers that were never used in this protocol buffer, not even by deleted fields).
11. syntax = "proto3"; option java_package = "hands.on.grpc"; option java_outer_classname = "BeerProtos"; package beer; message Beer { string asin = 1; string name = 2; string brand = 3; string country = 4; float alcohol = 5; enum BeerType{ IndianPaleAle = 0; SessionIpa = 1; Lager = 2; } BeerType type = 6; } // Protobuf marshalling protoBeer = BeerProtos.Beer.newBuilder() .setAsin("B079V9ZDNY") .setName("Drunken Sailor") .build(); byte[] bytes = protoBeer.toByteArray(); // Protobuf unmarshalling protoBeer = BeerProtos.Beer.parseFrom(bytes); $ ./gradlew generateProto $ protoc -I=$SRC_DIR --java_out=$DST_DIR $SRC_DIR/beer.proto
12. gRPC. A modern, high performance, open source and universal RPC framework. ▪ Uses HTTP/2 as modern Web-friendly transport protocol (Multiplexing, TLS, compression, …) ▪ Supports several types of communication: classic request-response as well as streaming from Client-side, Server-side, Uni- and Bi-Directional ▪ Uses Protocol Buffers as efficient binary payload format ▪ Support various load balancing options: proxy, client-side and look-aside balancing ▪ Flexible support for tracing, health checks and authentication ▪ Client and server code can be generated from the IDL easily for several languages – https://github.com/grpc/grpc-go – https://buf.build ▪ gRPC Gateway and gRPC Web projects from the ecosystem enable good interoperability – https://grpc-ecosystem.github.io/grpc-gateway/ – https://grpc.io/docs/platforms/web/quickstart/ ▪ gRPC is a CNCF incubating project QAware | 12
13. syntax = "proto3"; option java_package = "hands.on.grpc"; option java_outer_classname = "BeerProtos"; import "google/protobuf/empty.proto"; package beer; service BeerService { rpc AllBeers (google.protobuf.Empty) returns (GetBeersResponse) {} rpc GetBeer (GetBeerRequest) returns (GetBeerResponse) {} rpc CreateBeer (CreateBeerRequest) returns (google.protobuf.Empty) {} rpc UpdateBeer (UpdateBeerRequest) returns (google.protobuf.Empty) {} rpc DeleteBeer (DeleteBeerRequest) returns (google.protobuf.Empty) {} } // more Protobuf message definitions ...
14. Come and enjoy a Cloud Fitness Espresso, take part in our awesome price draw, and don't miss our epic Cloud Native Battle “gRPC vs REST”! Meet us at Booth #208
15. qaware.de QAware GmbH Aschauer Straße 32 81549 München Tel. +49 89 232315-0 info@qaware.de twitter.com/qaware linkedin.com/company/qaware-gmbh xing.com/companies/qawaregmbh slideshare.net/qaware github.com/qaware