nebulex

# Nebulex 🌌
> ### In-Process and Distributed Caching Framework for Elixir.
> Easily craft and deploy different distributed caching topologies in Elixir.
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Nebulex is an in-process and distributed caching framework with a set of
useful and powerful features such as:
  * Inspired by [Ecto][ecto]; simple and fluent API, flexible and
    pluggable architecture (based on adapters).
  * Built-in adapters: local (generational cache), replicated, partitioned and
    multi-level.
  * [Caching Decorators/Annotations](http://hexdocs.pm/nebulex/Nebulex.Caching.Decorators.html)
    to implement different [cache usage patterns][EHCache].
  * Support for different distributed caching topologies, such as:
    Replicated, Partitioned, Near, etc.
  * Different eviction mechanisms, such as time-based eviction through the
    expiry time property (`expire_at`) on the cached objects,
    [multi-queue][multi_queue] or [generational caching][generational_caching]
    (built-in adapter), etc.
  * Object versioning (via `:version` property); useful for
    [Optimistic offline locks][offline_locks] implementation.
  * [Pre/Post execution hooks](http://hexdocs.pm/nebulex/hooks.html). Ability
    to hook any function call for a cache and add custom logic before and/or
    after function execution.
  * Transactions and key-locking (`Nebulex.Adapter.Transaction`).
[ecto]: https://github.com/elixir-ecto/ecto
[multi_queue]: https://en.wikipedia.org/wiki/Cache_replacement_policies#Multi_queue_(MQ)
[generational_caching]: http://fairwaytech.com/2012/09/write-through-and-generational-caching
[offline_locks]: https://martinfowler.com/eaaCatalog/optimisticOfflineLock.html
[EHCache]: https://github.com/ehcache/ehcache3/blob/master/docs/src/docs/asciidoc/user/caching-patterns.adoc
See the [getting started](http://hexdocs.pm/nebulex/getting-started.html) guide
and the [online documentation](http://hexdocs.pm/nebulex/Nebulex.html).
## Usage
You need to add `nebulex` as a dependency to your `mix.exs` file. However,
in the case you want to use an external (non built-in) cache adapter, you
also have to add the proper dependency to your `mix.exs` file.
The supported caches and their adapters are:
Cache        | Nebulex Adapter              | Dependency
:----------- | :----------------------------| :---------
Generational | Nebulex.Adapters.Local       | Built-In
Partitioned  | Nebulex.Adapters.Partitioned | Built-In
Replicated   | Nebulex.Adapters.Replicated  | Built-In
Multi-level  | Nebulex.Adapters.Multilevel  | Built-In
Redis        | NebulexRedisAdapter          | [nebulex_redis_adapter][nebulex_redis_adapter]
Memcached    | NebulexMemcachedAdapter      | [nebulex_memcached_adapter][nebulex_memcached_adapter]
FoundationDB | NebulexFdbAdapter            | [nebulex_fdb_adapter][nebulex_fdb_adapter]
[nebulex_redis_adapter]: https://github.com/cabol/nebulex_redis_adapter
[nebulex_memcached_adapter]: https://github.com/vasuadari/nebulex_memcached_adapter
[nebulex_fdb_adapter]: https://github.com/fire/nebulex_fdb_adapter
For example, if you want to use a built-in cache, you just need to add
`nebulex` to your `mix.exs` file:
```elixir
def deps do
  [
    {:nebulex, "~> 1.2.0"}
  ]
end
```
Then run `mix deps.get` in your shell to fetch the dependencies. If you want to
use another cache adapter, just choose the proper dependency from the table
above.
Finally, in the cache definition, you will need to specify the `adapter`
respective to the chosen dependency. For the local built-in cache it is:
```elixir
defmodule MyApp.Cache do
  use Nebulex.Cache,
    otp_app: :my_app,
    adapter: Nebulex.Adapters.Local
  ...
```
> Check out the [getting started](http://hexdocs.pm/nebulex/getting-started.html)
  guide to learn more about it.
## Important links
 * [Documentation](http://hexdocs.pm/nebulex/Nebulex.html)
 * [Getting Started](http://hexdocs.pm/nebulex/getting-started.html)
 * [Caching Decorators](http://hexdocs.pm/nebulex/caching-decorators.html)
 * [Examples](https://github.com/cabol/nebulex_examples)
## Testing
Testing by default spawns nodes internally for distributed tests.
To run tests that do not require clustering, exclude  the `clustered` tag:
```
$ mix test --exclude clustered
```
If you have issues running the clustered tests try running:
```
$ epmd -daemon
```
before running the tests.
## Benchmarks
Some basic benchmarks were added using [benchee](https://github.com/PragTob/benchee);
to learn more, check out the [benchmarks](./benchmarks) directory.
To run the benchmarks:
```
$ mix run benchmarks/benchmark.exs
```
If you are interested to run more sophisticated load tests, perhaps you should
checkout the [Nebulex Load Tests](https://github.com/cabol/nebulex_examples/tree/master/nebulex_bench)
example, it allows you to run your own performance/load tests against Nebulex,
and it also comes with load tests results.
## Contributing
Contributions to Nebulex are very welcome and appreciated!
Use the [issue tracker](https://github.com/cabol/nebulex/issues) for bug reports
or feature requests. Open a [pull request](https://github.com/cabol/nebulex/pulls)
when you are ready to contribute.
When submitting a pull request you should not update the [CHANGELOG.md](CHANGELOG.md),
and also make sure you test your changes thoroughly, include unit tests
alongside new or changed code.
Before to submit a PR it is highly recommended to run:
 * `mix test` to run tests
 * `mix coveralls.html && open cover/excoveralls.html` to run tests and check
   out code coverage (expected 100%).
 * `mix format && mix credo --strict` to format your code properly and find code
   style issues
 * `mix dialyzer` to run dialyzer for type checking; might take a while on the
   first invocation
## Copyright and License
Copyright (c) 2017, Carlos Bolaños.
Nebulex source code is licensed under the [MIT License](LICENSE).