# SlackLogDevice

LogDevice implementation that post logs on a Slack channel.

## Setup

Just add this into your `Gemfile`:

```ruby
gem 'slack_log_device'
```

Then, just run a `bundle install`.

## Usage

```ruby
require 'slack_log_device'

logger = Logger.new(SlackLogDevice.new(webhook_url: 'https://hooks.slack.com/services/...', username: 'MyApp'))
logger.level = Logger::INFO
logger.warn('BAM!')
```

Then, the logged message will be writen to webhook's configured channel.

Note that the messages written are buffered in order to avoid consecutive
request.

## Options

- `auto_flush`: To flush messages directly when a message is written (disabled
by default).
- `channel`: The channel to post message on (webhook configured channel by
default). It can be a channel (if starting with `#`) or a specific user (if
starting with a `@`).
- `flush_delay`: The delay in seconds to send buffered messages (1 by default).
- `max_buffer_size`: The max messages count to flush them (10 messages by
default).
- `timeout`: The timeout in seconds to send message to slack (5 by default).
- `username`: The username to post message as (nil by default).
- `webhook_url`: The URL of the webhook (mandatory).

## Formatter

`slack_log_device` provides a log formatter to have a pretty output for slack.
It can be configured like this:

```ruby
logger.formatter = SlackLogDevice.formatter
```

`SlackLogDevice.formatter` method also accepts block to transform logged
message, example:

```ruby
logger.formatter = SlackLogDevice.formatter { |message| message.reverse }
```

You can also add custom metadata to message sent to slack, here is how to do
it:

```ruby
logger.formatter = SlackLogDevice.formatter(extra_metadata: {
  'User' => -> (options) { ENV['USER'] },
  'Machine' => `uname -a`,
})
```

If you use [Ruby on Rails](http://rubyonrails.org/), you will get some
metadata like current HTTP method, URL, remote address and User-Agent (see
Rails configuration section).

If you need more, use `:extra_metadata` option. Note that blocks specified
with `:extra_metadata` option are invoked with options that may contains
`:request` option (if present).

## Rails configuration

For a rails application, it is recommanded to use following configuration into
`config/environments/production.rb` file:

```ruby
SlackLogDevice.enable_rails_logging!
config.logger = ActiveSupport::Logger.new(SlackLogDevice.new(webhook_url: 'https://hooks.slack.com/services/...', username: 'MyRailsApp'))
config.logger.formatter = SlackLogDevice.formatter
config.log_level = :warn
```

`SlackLogDevice.enable_rails_logging!` instruction put current request into
thread in order to make it available by slack formatter.

## Executing test suite

This project is fully tested with [Rspec 3](http://github.com/rspec/rspec).
Just run `bundle exec rake` (after a `bundle install`).