## `roo_on_rails` [![Gem Version](https://badge.fury.io/rb/roo_on_rails.svg)](https://badge.fury.io/rb/roo_on_rails) [![Build Status](https://travis-ci.org/deliveroo/roo_on_rails.svg?branch=master)](https://travis-ci.org/deliveroo/roo_on_rails) [![Code Climate](https://codeclimate.com/repos/58809e664ab8420081007382/badges/3489b7689ab2e0cf5d61/gpa.svg)](https://codeclimate.com/repos/58809e664ab8420081007382/feed)

A gem that makes following our [guidelines](http://deliveroo.engineering/guidelines/services/) easy.

## Installation

Add this line at the top of your Rails application's Gemfile:

```ruby
gem 'roo_on_rails'
```

Remove the following gems from your Gemfile, as they're provided and configured
by `roo_on_rails`:

- `dotenv`
- `newrelic_rpm`

Remove the following configuration files:

- `newrelic.yml` or `config/newrelic.yml`

Also remove any other gem-specific configuration from your repository.

And then execute:

    $ bundle

Then re-run your test suite to make sure everything is shipshape.

## Usage

Run the following from your app's top-level directory:

```
bundle exec roo_on_rails
```

This will run a series of checks of your application's setup, as descirbed
below.


## Features

### App validation

Running the `roo_on_rails` script currently checks for:

- compliant Heroku app naming;
- presence of the Heroku preboot flag;
- correct Github master branch protection.

### New Relic configuration

We enforce configuration of New Relic.

1. Your app must be loaded with a `NEW_RELIC_LICENSE_KEY` environment variable,
   otherwise it will abort.
2. No `new_relic.yml` file may be presentin your app. Overrides to New Relic settings
   through [environment
   variables](https://docs.newrelic.com/docs/agents/ruby-agent/installation-configuration/ruby-agent-configuration)
   is permitted.

No further configuration is required for production apps as the gem configures our standard settings.

However if you have Heroku's [review apps](https://devcenter.heroku.com/articles/github-integration-review-apps) enabled then you will need to update `app.json` so that it lists `NEW_RELIC_LICENSE_KEY` in the `env` section, so that this key is copied from the parent app (only keys listed here will be created on the review app; either generated, if that is specified, or otherwise copied).

More documentation is available [directly from heroku](https://devcenter.heroku.com/articles/github-integration-review-apps#inheriting-config-vars) but the block below has been helpful in other apps:

```json
"env": {
  "NEW_RELIC_LICENSE_KEY": {
    "description": "The New Relic licence key",
    "required": true
  },
  "SECRET_KEY_BASE": {
    "description": "A secret basis for the key which verifies the integrity of signed cookies.",
    "generator": "secret"
  },
  "RACK_ENV": {
    "description": "The name of the environment for Rack."
  },
  "RAILS_ENV": {
    "description": "The name of the environment for Rails."
  }
},
```

### Rack middleware

We'll insert the following middlewares into the rails stack:

1. `Rack::Timeout`: sets a timeout for all requests. Use `RACK_SERVICE_TIMEOUT` (default 15) and `RACK_WAIT_TIMEOUT` (default 30) to customise.
2. `Rack::SslEnforcer`: enforces HTTPS.
3. `Rack::Deflater`: compresses responses from the application, can be disabled with `ROO_ON_RAILS_RACK_DEFLATE` (default: 'YES').

### Database configuration

The database statement timeout will be set to a low value by default. Use `DATABASE_STATEMENT_TIMEOUT` (milliseconds, default 200) to customise.

For database creation and migration (specifically the `db:create`, `db:migrate`, `db:migrate:down` and `db:rollback` tasks) a much higher statement timeout is set by default. Use `MIGRATION_STATEMENT_TIMEOUT` (milliseconds, default 10000) to customise.

_Note: This configuration is not supported in Rails 3 and will be skipped. Set statement timeouts directly in the database._

### Sidekiq

When `SIDEKIQ_ENABLED` is set we'll:

 - check for the existence of a worker line in your Procfile
 - add SLA style queues to your worker list
 - check for a HIREFIRE_TOKEN and if it's set enable SLA based autoscaling

The following ENV are available:

 - `SIDEKIQ_ENABLED`
 - `SIDEKIQ_THREADS` (default: 25) - Sets sidekiq concurrency value
 - `SIDEKIQ_DATABASE_REAPING_FREQUENCY` (default: 10) - For sidekiq processes the amount of time in seconds rails will wait before attempting to find and recover connections from dead threads

### Logging

For clearer and machine-parseable log output, there in an extension to be able to add context to your logs which is output as [logfmt](https://brandur.org/logfmt) key/value pairs after the log message.

```ruby
# in application.rb

Rails.logger = RooOnRails::ContextLogging.new(ActiveSupport::Logger.new($stdout))
```

You can then add context using the `with` method:

```ruby
logger.with(a: 1, b: 2) { logger.info 'Stuff' }
logger.with(a: 1) { logger.with(b: 2) { logger.info('Stuff') } }
logger.with(a: 1, b: 2).info('Stuff')
```

See the [class documentation](/deliveroo/roo_on_rails/tree/master/lib/roo_on_rails/context_logging.rb) for further details.

## Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/deliveroo/roo_on_rails.


## License

The gem is available as open source under the terms of the [MIT License](http://opensource.org/licenses/MIT).