SwiftNIO (Non-blocking IO in Swift)

SwiftNIO is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients.

It's like Netty but in Swift.

Compile, Test and Run

For both Linux and macOS

./swiftw build
./swiftw test
./swiftw run NIOEchoServer

and from some other terminal

echo Hello SwiftNIO | nc localhost 9999

Alternative way using docker-compose

First cd docker and then:

• docker-compose test

  Will create a base image with Swift 4.0 (if missing), compile SwiftNIO and run tests

• docker-compose up echo

  Will create a base image, compile SwiftNIO, and run a sample NIOEchoServer on localhost:9999. Test it by echo Hello SwiftNIO | nc localhost 9999.

• docker-compose up http

  Will create a base image, compile SwiftNIO, and run a sample NIOHTTP1Server on localhost:8888. Test it by curl http://localhost:8888

• docker-compose run swift-nio /scripts/gen-cert.sh

  Will generate self-signed certificate for a TLS Server example.

• docker-compose up tls

  Will create a base image, compile SwiftNIO, and run a sample NIOTLSServer on localhost:4433. It is an echo server that you can test using openssl s_client -crlf -connect localhost:4433.

Prerequisites for Linux (using Docker)

Creating a Docker Image for Linux

# create the docker image for linux (one time or when Dockerfile changes)
$ docker build . -f docker/Dockerfile --build-arg version=4.0 -t=nio

Using the Linux Docker Image

# use the docker image, bind mount the current dir with code
$ docker run -it -v `pwd`:/code -w /code swift-nio bash

# do your thing
$ ./swiftw build
$ ./swiftw test

Testing on Linux

to know which tests to run on linux, swift requires a special mapping file called LinuxMain.swift and explicit mapping of each test case into a static list of tests. this is a real pita, but we are here to help!

# generate linux tests
$ ruby generate_linux_tests.rb

Prerequisites on macOS

Installation of the Dependencies

brew install libressl

TLS

Currently the source tree for SwiftNIO contains bindings for a TLS handler that links against OpenSSL/LibreSSL (more specifically, anything that provides a library called libssl).

This binding can cause numerous issues during the build process on different systems, depending on the environment you're in. These will usually manifest as build errors, either during the compilation stage (due to missing development headers) or during the linker stage (due to an inability to find a library to link).

If you encounter any of these errors, here are your options.

Darwin

On Darwin systems, there is no easily-available copy of libssl.dylib with accompanying development headers. For this reason, we recommend installing libressl from Homebrew (brew install libressl).

Linux

On Linux distributions it is almost always possible to get development headers for the system copy of libssl (e.g. via apt-get install libssl-dev). If you encounter problems during the compile phase, try running this command.

In some unusual situations you may encounter problems during the link phase. This is usually the result of having an extremely locked down system that does not grant you sufficient permissions to the libssl.so on the system.