# sigurd
Small gem to manage executing looping processes and signal handling.
# Installation
Add this line to your application's Gemfile:
```ruby
gem 'sigurd'
```
And then execute:
$ bundle
Or install it yourself as:
$ gem install sigurd
# Versioning
We use a version of semver for this gem. Any change in previous behavior
(something works differently or something old no longer works)
is denoted with a bump in the minor version (0.4 -> 0.5). Patch versions
are for bugfixes or new functionality which does not affect existing code. You
should be locking your Gemfile to the minor version:
```ruby
gem 'sigurd', '0.0.1'
```
# Usage
Sigurd exposes two classes for use with a third class. The ideas is as follows:
* You have any object which responds to the `start` and `stop` methods.
This object is called a "Runner". When the `stop` method is called,
the runner should gracefully shut down.
* You create an `Executor` class - this manages a thread pool for a
list of runners.
* You create a `SignalHandler` which is the topmost object. This will
handle the signals sent by the system and gracefully forward the
requests. You pass the executor into the SignalHandler.
* Finally, you call `start` on the `SignalHandler` to begin the execution.
Sample code:
```ruby
class TestRunner
def start
loop do
break if @signal_to_stop
# do some logic here
end
end
def stop
@signal_to_stop = true
end
end
runners = (1..2).map { TestRunner.new }
executor = Sigurd::Executor.new(runners, sleep_seconds: 5, logger: Logger.new(STDOUT))
Sigurd::SignalHandler.new(executor).run!
```
If you have only a single runner, you can pass it into the `SignalHandler`
directly, without using an `Executor`:
```ruby
Sigurd::SignalHandler.new(runner).run!
```
By default, if any of your runners fails, Sigurd will use an exponential
backoff to wait before restarting it. You can instead use the `sleep_seconds`
setting to always sleep a fixed amount of time before retrying. There
is no limit to retries.
## Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/flipp-oss/sigurd .
### Linting
Sigurd uses Rubocop to lint the code. Please run Rubocop on your code
before submitting a PR.
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