counter

Global, Atomic Counter in Redis

The 2 most mature and commonly used Redis drivers in Go are:

• gomodule/redigo
• mediocregopher/radix

A full list of Redis drivers for Go is available here.

In this recipe, we will implement a global, atomic counter using Redis using the Radix driver. Why not just implement a counter locally in the Go program instead. Sure, we can do that if it's just 1 client running a single thread. But in a concurrent context where we have multiple goroutines or in a distributed system, we need to have a system to support an atomic increment operation across the network. Redis provides support for a counter via the INCR command.

Setup

1. Start redis.

   $ docker-compose up

2. In the another shell, you can connect to Redis via the CLI tool:

   $ docker-compose exec redis redis-cli

3. Run Go program.

   $ go run ./main.go

4. Shut down and remove the container when you are done.

   $ docker-compose down

5. Alternatively, you can run everything with just 2 commands.

   $ make run
   $ make teardown    # Run this to remove the container

Reference and Credits

• Tutorial: Design and implementation of a simple Twitter clone using PHP and the Redis key-value store
• GoDoc: mediocreogopher/radix