Redis Client for Crystal

A Redis client for the Crystal programming language.

Features

• Performance (> 680,000 commands per second using pipeline on a MacBook Air with a single client thread)
• Pipelining
• Transactions
• LUA Scripting
• All string commands
• All hash commands
• All list commands
• All set commands
• All hyperloglog commands
• All commands for bit operations
• All sorted set commands
• Publish/subscribe

Installation

Add it to your shard.yml:

dependencies:
  redis:
    github: stefanwille/crystal-redis
    version: ~> 1.10.1

and then install the library into your project:

$ crystal deps

Installation on MacOS X

On MacOS X you may get this warning:

Package libssl was not found in the pkg-config search path.
Perhaps you should add the directory containing `libssl.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libssl' found
Package libcrypto was not found in the pkg-config search path.
Perhaps you should add the directory containing `libcrypto.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libcrypto' found

The problem is that Crystal can't find openssl, because it is not installed by default on MacOS X.

The fix:

1. Install openssl via Homebrew:

$ brew install openssl

2. Set the environment variable PKG_CONFIG_PATH:

$ export PKG_CONFIG_PATH=/usr/local/opt/openssl/lib/pkgconfig

Required Crystal Version

This library needs Crystal version >= 0.24.2

I haven't tested older Crystal versions.

Usage

Require the package:

  require "redis"

then

  redis = Redis.new

Then you can call Redis commands on the redis object:

  redis.set("foo", "bar")
  redis.get("foo")

Examples

To get started, see the examples:

• There is a separate git repository crystal-redis-examples with examples.
• start with this basic example
• look at the other examples
• the spec contains even more usage examples

Documentation

• API documentation - start reading it at the class Redis.
• Redis commands documentation - the original Redis documentation is necessary, as the API documentation above is just a quick reference
• Redis documentation page - general information about Redis and its concepts

Performance

I have benchmarked Crystal-Redis against several other client libraries in various programming languages in this blog article.

Here are some results:

• Crystal: With this library I get > 680,000 commands per second using pipeline on a MacBook Air with a single client thread.

• C: The equivalent program written in C with Hiredis gets me 340,000 commands per second.

• Ruby: Ruby 2.2.1 with the redis-rb and Hiredis driver handles 150,000 commands per second.

Read more results for Go, Java, Node.js.

Status

I have exercised every API method in the spec and built some example programs. There is no production use yet.

I took great care to make this library very usable with respect to API, reliability and documentation.

Development

This project requires a locally running redis server running on port 6379 and with a unix socket located at /tmp/redis.sock. Then you can the specs via

$ crystal spec

See more information.

Questions, Bugs & Support

If you have questions or need help, please open a ticket in the GitHub issue tracker. This way others can benefit from the discussion.