# Hammer
A rate-limiter for Elixir, with pluggable storage backends.
[](https://travis-ci.org/ExHammer/hammer)
[](https://coveralls.io/github/ExHammer/hammer?branch=master)
## Installation
Hammer is [available in Hex](https://hex.pm/packages/hammer), the package can be installed
by adding `hammer` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[{:hammer, "~> 5.0"}]
end
```
## Documentation
On hexdocs: [https://hexdocs.pm/hammer/frontpage.html](https://hexdocs.pm/hammer/frontpage.html)
The [Tutorial](https://hexdocs.pm/hammer/tutorial.html) is an especially good place to start.
## Usage
Example:
```elixir
defmodule MyApp.VideoUpload do
def upload(video_data, user_id) do
case Hammer.check_rate("upload_video:#{user_id}", 60_000, 5) do
{:allow, _count} ->
# upload the video, somehow
{:deny, _limit} ->
# deny the request
end
end
end
```
The `Hammer` module provides the following functions:
- `check_rate(id, scale_ms, limit)`
- `inspect_bucket(id, scale_ms, limit)`
- `delete_buckets(id)`
Backends are configured via `Mix.Config`:
```elixir
config :hammer,
backend: {Hammer.Backend.ETS, [expiry_ms: 60_000 * 60 * 4,
cleanup_interval_ms: 60_000 * 10,
pool_size: 2,
pool_max_overflow: 4]}
```
See the [Tutorial](https://hexdocs.pm/hammer/tutorial.html) for more.
See the [Hammer Testbed](https://github.com/ExHammer/hammer-testbed) app for an example of
using Hammer in a Phoenix application.
## Available Backends
- Hammer.Backend.ETS (provided with Hammer)
- [Hammer.Backend.Redis](https://github.com/ExHammer/hammer-backend-redis)
## Getting Help
If you're having trouble, either open an issue on this repo, or reach out to the maintainers ([@shanekilkelly](https://twitter.com/shanekilkelly)) on Twitter.
## Acknowledgements
Hammer was inspired by the [ExRated](https://github.com/grempe/ex_rated) library, by [grempe](https://github.com/grempe).
