yegor256/zache

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It's a simple Ruby gem for in-memory cache.
Read [this blog post](https://www.yegor256.com/2019/02/05/zache.html)
to understand what Zache is for.

First, install it:

```bash
$ gem install zache
```

Then, use it like this

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

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

```ruby
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](https://www.rubydoc.info/github/yegor256/zache/master/Zache)
(there are many other convenient methods).

That's it.

## How to contribute

Read [these guidelines](https://www.yegor256.com/2014/04/15/github-guidelines.html).
Make sure you build is green before you contribute
your pull request. You will need to have [Ruby](https://www.ruby-lang.org/en/) 2.3+ and
[Bundler](https://bundler.io/) installed. Then:

```
$ bundle update
$ bundle exec rake
```

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