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Zero-footprint Ruby In-Memory Thread-Safe Cache: when a naive implementation is enough

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In Memory Cache for Ruby

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It's a simple Ruby gem for in-memory cache. Read this blog post to understand what Zache is for.

First, install it:

gem install zache

Then, use it like this:

require 'zache'
zache = Zache.new
# Expires in 5 minutes
v = zache.get(:count, lifetime: 5 * 60) { expensive() }

If you omit the lifetime parameter, the key will never expire.

By default Zache is thread-safe. It locks the entire cache on each get call. You turn that off by using sync argument:

zache = Zache.new(sync: false)
v = zache.get(:count) { expensive() }

You may use "dirty" mode, which will return you an expired value, while calculation is waiting. Say, you have something in the cache, but it's expired. Then, you call get with a long running block. The thread waits, while another one calls get again. That second thread won't wait, but will receive what's left in the cache. This is a very convenient mode for situations when you don't really care about data accuracy, but performance is an issue.

The entire API is documented here (there are many other convenient methods).

How to contribute

Read these guidelines. Make sure you build is green before you contribute your pull request. You will need to have Ruby 2.3+ and Bundler installed. Then:

bundle update
bundle exec rake

If it's clean and you don't see any error messages, submit your pull request.