User manual

• What is Armeria?

• Want a quick tour?

• Features

  • HTTP/2
  • Integration with gRPC and Thrift
  • Essential features for building microservices
  • Interactive web-based debug console
  • Completely asynchronous and reactive
  • Compatibility with existing Java EE web applications
  • Even higher performance on Linux

What is Armeria?

Armeria is your go-to microservice framework for any situation. You can build any type of microservice leveraging your favorite technologies, including gRPC, Thrift, Kotlin, Retrofit, Reactive Streams, Spring Boot and Dropwizard.

It is open-sourced by the creator of Netty and his colleagues at LY Corporation.

Want a quick tour?

Check out the recent introductory talk (slides):

Features

HTTP/2

• Supports HTTP/2 on both TLS and cleartext connections
• Supports protocol upgrade via both HTTP/2 connection preface and traditional HTTP/1 upgrade request
• Fully compatible with existing HTTP/1 servers
• Integrated PROXY protocol support for interoperability with load balancers such as HAProxy and AWS ELB.

Integration with gRPC and Thrift

• Your gRPC or Thrift service implementation runs on top of Armeria without any modification.
• Works with the official gRPC or Thrift-over-HTTP client
• Works with the code generated by the official Protobuf or Thrift IDL compiler
• Supports various protocol combinations, such as:
  • gRPC-over-HTTP/1 & 2
  • Thrift-over-HTTP/1 & 2
  • gRPC-Web
• See Running a Thrift service and Running a gRPC service.

Essential features for building microservices

• Metrics
• Circuit breaker
• Client-side health-check and load-balancing
• Service discovery from various sources such as DNS and ZooKeeper
  • See Client-side load balancing and service discovery.
• Distributed call tracing via Zipkin

Interactive web-based debug console

• Browse the list of available RPC operations
• Invoke an RPC operation via a web form
• Share an RPC request with your colleagues so they can reproduce the problem easily
  • Just like sharing a cURL command, but works for RPC
• See Browsing and invoking services with DocService.

Completely asynchronous and reactive

• Built on top of Reactive Streams and Java 8 CompletableFuture
• Asynchronous connection pool ensures your application never blocks even on pool exhaustion.
• Domain name lookups are also fully asynchronous thanks to Netty’s asynchronous domain name resolver.

Compatibility with existing Java EE web applications

• Runs any Java EE web applications such as Spring Boot on the same TCP/IP port
• Your Java EE web application speaks HTTP/2!
• See Embedding a servlet container.

Even higher performance on Linux

• JNI-based socket I/O
• BoringSSL-based TLS connections