# Quantum
[Cron](https://en.wikipedia.org/wiki/Cron)-like job scheduler for [Elixir](http://elixir-lang.org/).
[](https://hex.pm/packages/quantum)
[](https://hexdocs.pm/quantum)
[](https://travis-ci.org/quantum-elixir/quantum-core)
[](https://coveralls.io/r/quantum-elixir/quantum-core?branch=master)
[](http://inch-ci.org/github/quantum-elixir/quantum-core)
[](https://hex.pm/packages/quantum)
> **This README follows master, which may not be the currently published version**. Here are the
[docs for the latest published version of Quantum](https://hexdocs.pm/quantum/readme.html).
> :warning: **If you're using a version below `v2.2.6`, please update immediately.** :warning:
> See [Issue #321](https://github.com/quantum-elixir/quantum-core/issues/321) for more details.
## Setup
To use Quantum in your project, edit the `mix.exs` file and add Quantum to
**1. the list of dependencies:**
```elixir
defp deps do
[{:quantum, "~> 2.3"},
{:timex, "~> 3.0"}]
end
```
**2. and create a scheduler for your app:**
```elixir
defmodule YourApp.Scheduler do
use Quantum.Scheduler,
otp_app: :your_app
end
```
**3. and your application's supervision tree:**
```elixir
defmodule YourApp.Application do
use Application
def start(_type, _args) do
import Supervisor.Spec, warn: false
children = [
# This is the new line
worker(YourApp.Scheduler, [])
]
opts = [strategy: :one_for_one, name: YourApp.Supervisor]
Supervisor.start_link(children, opts)
end
end
```
## Troubleshooting
To see more transparently what `quantum` is doing, configure the `logger` to display `:debug` messages.
```elixir
config :logger,
level: :debug
```
If you want do use the logger in debug-level without the messages from quantum:
```elixir
config :your_app, YourApp.Scheduler,
debug_logging: false
```
If you encounter any problems with `quantum`, please search if there is already an
[open issue](https://github.com/quantum-elixir/quantum-core/issues) addressing the problem.
Otherwise feel free to [open an issue](https://github.com/quantum-elixir/quantum-core/issues/new). Please include debug logs.
## Migrate to V2
See the [Migration Guide](https://hexdocs.pm/quantum/migrate-v2.html).
## Usage
Configure your cronjobs in your `config/config.exs` like this:
```elixir
config :your_app, YourApp.Scheduler,
jobs: [
# Every minute
{"* * * * *", {Heartbeat, :send, []}},
# Every 15 minutes
{"*/15 * * * *", fn -> System.cmd("rm", ["/tmp/tmp_"]) end},
# Runs on 18, 20, 22, 0, 2, 4, 6:
{"0 18-6/2 * * *", fn -> :mnesia.backup('/var/backup/mnesia') end},
# Runs every midnight:
{"@daily", {Backup, :backup, []}}
]
```
More details on the usage can be found in the [Documentation](https://hexdocs.pm/quantum/configuration.html)
## Contribution
This project uses the [Collective Code Construction Contract (C4)](http://rfc.zeromq.org/spec:42/C4/) for all code changes.
> "Everyone, without distinction or discrimination, SHALL have an equal right to become a Contributor under the
terms of this contract."
### tl;dr
1. Check for [open issues](https://github.com/quantum-elixir/quantum-core/issues) or [open a new issue](https://github.com/quantum-elixir/quantum-core/issues/new) to start a discussion around [a problem](https://www.youtube.com/watch?v=_QF9sFJGJuc).
2. Issues SHALL be named as "Problem: _description of the problem_".
3. Fork the [quantum-elixir repository on GitHub](https://github.com/quantum-elixir/quantum-core) to start making your changes
4. If possible, write a test which shows that the problem was solved.
5. Send a pull request.
6. Pull requests SHALL be named as "Solution: _description of your solution_"
7. Your pull request is merged and you are added to the [list of contributors](https://github.com/quantum-elixir/quantum-core/graphs/contributors)
## License
[Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0)
