Many flavors of networking IO

This repository is a reference implementation for the article titled "Many flavors of Networking IO". It has the following implementations of TCP servers:

1. Single-Threaded Blocking IO

TCPServer implements "Single thread blocking IO" pattern. The implementation of TCPServer:

• runs a continuous loop in a single goroutine (/main goroutine).
• a new instance of IncomingTCPConnection is created for every new connection.
• The incoming TCP connection is handled in the same main goroutine.
• This pattern involves blocking IO to read from the incoming connection.

2. Multi-Threaded Blocking IO

TCPServer implements "Multi thread blocking IO" pattern. The implementation of TCPServer:

• runs a continuous loop in a single goroutine (/main goroutine).
• a new instance of IncomingTCPConnection is created for every new connection.
• The incoming TCP connection is handled in new goroutine.
• This pattern involves goroutine per connection and blocking IO to read from the incoming connection.

3. Non-blocking with Busy Wait

TCPServer implements "Non-Blocking with Busy-Wait" pattern. The implementation of TCPServer:

• runs a continuous loop in a single goroutine (/main goroutine).
• it marks the server file descriptor non-blocking, this means any IO operations on this file descriptor will not block. However, the file descriptor can be polled.
• an incoming connection is represented by its own file descriptor: connectionFd.
• connectionFd is also marked non-blocking.
• a new client is created (for the incoming connectionFd) which handles the connection by performing busy-wait or polling.
• all the IO operations are non-blocking.

4. Single-Threaded Event loop (using KQueue)

TCPServer implements "Single thread Non-Blocking with event loop" pattern. It starts an event loop which:

• runs in its own goroutine.
• polls the KQueue for events on the subscribed file descriptors.
• if the polled event's file descriptor is same as the server's file descriptor: a new client is accepted,
• else: an existing client for the file descriptor is run.
• all the IO operations are non-blocking, (the only place where blocking happens is in polling Kqueue).

The article is available here.