Redis::Throttle

Redis based rate limit and concurrency throttling.

Installation

Add this line to your application's Gemfile:

gem "redis-throttle"

And then execute:

$ bundle install

Or install it yourself as:

$ gem install redis-throttle

Usage

Concurrency Limit

# Allow 1 concurrent calls. If call takes more than 10 seconds, consider it
# gone (as if process died, or by any other reason did not called `#release`):
concurrency = Redis::Throttle.concurrency(:bucket_name,
  :limit => 1,
  :ttl   => 10
)

concurrency.acquire(:token => "abc") # => "abc"
concurrency.acquire(:token => "xyz") # => nil

concurrency.release(:token => "abc")

concurrency.acquire(:token => "xyz") # => "xyz"

Rate Limit

# Allow 1 calls per 10 seconds:
rate_limit = Redis::Throttle.rate_limit(:bucket_name,
  :limit  => 1,
  :period => 10
)

rate_limit.acquire # => "6a6c6546-268d-4216-bcf3-3139b8e11609"
rate_limit.acquire # => nil

sleep 10

rate_limit.acquire # => "e2926a90-2cf4-4bff-9401-65f3a70d32bd"

Multi-strategy

throttle = Redis::Throttle
  .concurrency(:db, :limit => 3, :ttl => 900)
  .rate_limit(:api_minutely, :limit => 1, :period => 60)
  .rate_limit(:api_hourly, :limit => 10, :period => 3600)

throttle.call(:token => "abc") do
  # do something if all strategies are resolved
end

You can also compose multiple throttlers together:

db_limiter  = Redis::Throttle.concurrency(:db, :limit => 3, :ttl => 900)
api_limiter = Redis::Throttle
  .rate_limit(:api_minutely, :limit => 1, :period => 60)
  .rate_limit(:api_hourly, :limit => 10, :period => 3600)

(db_limiter + api_limiter).call do
  # ...
end

With ConnectionPool

If you're using connection_pool, you can pass its #with method as connection builder:

pool     = ConnectionPool.new { Redis.new }
throttle = Redis::Throttle.new(:redis => pool.method(:with))

With Sidekiq

Sidekiq: uses ConnectionPool, so you can use the same approach:

throttle = Redis::Throttle.new(:redis => Sidekiq.redis_pool.method(:with))

Or, you can use its .redis method directly:

throttle = Redis::Throttle.new(:redis => Sidekiq.method(:redis))

Compatibility

This library aims to support and is tested against:

• Ruby
  • MRI 2.6.x
  • MRI 2.7.x
  • MRI 3.0.x
  • MRI 3.1.x
• Redis
  • 4.x
  • 5.x
  • 6.x
• redis-rb
  • 4.2.x
  • 4.3.x
  • 4.4.x
• redis-namespace
  • 1.8.x

If something doesn't work on one of these versions, it's a bug.

This library may inadvertently work (or seem to work) on other Ruby versions, however support will only be provided for the versions listed above.

If you would like this library to support another Ruby version or implementation, you may volunteer to be a maintainer. Being a maintainer entails making sure all tests run and pass on that implementation. When something breaks on your implementation, you will be responsible for providing patches in a timely fashion. If critical issues for a particular implementation exist at the time of a major release, support for that Ruby version may be dropped.

Same rules apply to Redis, redis-rb, and redis-namespace support.

Development

After checking out the repo, run bundle install to install dependencies. Then, run bundle exec rake spec to run the tests with ruby-rb client.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to [rubygems.org][].

Contributing

• Fork redis-throttle
• Make your changes
• Ensure all tests pass (bundle exec rake)
• Send a merge request
• If we like them we'll merge them
• If we've accepted a patch, feel free to ask for commit access!

Appreciations

Huge thanks to @freemanoid, @petethepig, and @dervus for criticism and suggestions.

Alternatives

• redis-gcra

Copyright

Copyright (c) 2020-2022 Alexey Zapparov
See LICENSE.txt for further details.