Building Asynchronous Microservices with Armeria
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Armeria is a microservices framework that focuses on asynchrony and reactive programming. It implements reactive streams and allows mixing different service types like HTTP, gRPC, and Thrift in a single server. Armeria uses Netty and is high-performance. It provides features like HTTP/2 support, distributed tracing, interceptors, and decorators. The documentation service allows browsing and invoking RPC services. Armeria aims to have an easy to use asynchronous API and be on par with popular web frameworks. It can be used to build asynchronous microservices and the documentation encourages contributing to the project.
Building Asynchronous Microservices with Armeria
- 1. 이희승 (@trustin) ／ 開発1センター ／ LINE Building Asynchronous Microservices with Armeria Armeriaで始める非同期Microservice開発
- 2. Why build another microservice framework?
- 3. Asynchrony ● Most web frameworks are blocking and synchronous. – 1000 concurrent requests require 1000 threads. – In modern systems, a service sends requests to another backend. – Threads are busy doing nothing but just waiting for the backend. – Request queue is not consumed fast enough. – Result: ● Fragile system that falls apart even on a tiny backend failure ● Inefficient system that takes more memory and CPU than what it actually does
- 4. Reactive Streams ● Should we really buffer everything until a response is sent? – Retrieving 100,000 rows from a table ● Why should a client send many requests to reduce the server memory pressure? – Retrieving 1,000 rows 100 times ● What if we want to stream infinitely? – Stock quotes ● Our protocol is not a problem here. – Our ‘blocking’ programming model is blocking ‘us’.
- 5. Better RPC support ● RPC has been hardly a 1st-class citizen in web frameworks. – Distinction from RPC-level and HTTP-level failure – Access logs with RPC-level details – Debugging console ● What if … – We build a microservice framework with RPC at its core?
- 6. More reasons back in 2015 ● Leverage Java 8 syntax – Lambda expressions – Default interface methods – Static interface methods ● Provide ‘working’ HTTP/2 implementation – ‘H2C’ support (HTTP/2 over ‘C’leartext) – OpenSSL-based faster TLS connection
- 7. Better UX for devs ● This is the last yet most important part. ● Nobody wants a framework that’s hard to use. ● Can we design … – a user-friendly asynchronous programming API – … with modest learning curve?
- 8. Our answer – Armeria ● HTTP/2 – Both ciphertext and cleartext, a.k.a. h2 and h2c ● Reactive – Implements Reactive Streams API ● Ability to mix different types of services in a single server – gRPC, Thrift, REST services – Legacy webapps via embedded Tomcat or Jetty ● High-performance – Netty with /dev/epoll transport and BoringSSL SSLEngine ● Easy to learn and fun to use (hopefully)
- 9. Armeria by examples HTTP / REST
- 10. Hello, world!
- 11. Hello, world – Parameterized
- 12. Hello, world – Annotated
- 14. Streaming a million integers
- 16. There are more! ● Query parameters ● Request and response converters ● Exception handlers ● Content type negotiation ● Regular-expression path mapping ● Aims to be on-par or better than <your favorite web framework>
- 17. Armeria by examples Thrift and gRPC
- 18. gRPC & Thrift basics a. Write an IDL file – .proto or .thrift b. A compiler compiles it into .java files. c. Implement interfaces generated at ‘b’.
- 19. gRPC
- 20. Thrift
- 21. Decorating services Separation of concerns
- 22. Intercepting an HTTP request
- 23. Intercepting a RPC request ● Complete access to the RPC call information ● Override the parameters and methods
- 24. Decorator as core extension mechanism ● Request throttling ● Metric collection ● Distributed tracing (Zipkin) ● HTTP content encoding ● HTTP authn/z ● CORS ● Circuit breakers ● Automatic retries ● …
- 25. Distributed tracing with Brave·Zipkin
- 26. Playing better with RPC Armeria documentation service
- 27. Armeria documentation service ● Enabled by adding DocService to ServerBuilder ● Browse and invoke RPC services in an Armeria server ● Supports both gRPC and Thrift ● We have a plan to add: – Support for plain HTTP, like Swagger – Metric monitoring console – Runtime configuration editor, e.g. logger level
- 30. ● Share the URL to reproduce a call.
- 31. All the pieces fit together The ultimate all-in-one micro(?) service
- 34. Armeria client API ● Similar experience to the server-side API – e.g. Common type, Decorators, RPC-friendliness ● Client-specific stuff – Circuit breakers – Automatic retries – Client-side load balancing – Retrofit integration
- 36. Got interested?
- 37. Let’s build Armeria together! ● Use it. ● Ask questions. ● Request new features. ● Tell us what rocks and sucks. ● Consider joining the effort.
- 38. Meet us at GitHub and Slack ● https://github.com/line/armeria ● https://line-slacknow.herokuapp.com/line-armeria/