Stashing

Wrapped-up Logstasher for easy ActiveSupport::Notifications logging

LogStasher is awesome. It does one thing, and does it well. While you can add information to Logstasher very easily, it is harder to add information that changes over time, for example, the number of SQL queries performed during a request.

Installation

In your Gemfile:

gem 'stashing'

Configure your `<environment>.rb` (for example: `production.rb`)

# The options are the same as LogStasher's
config.stashing.enabled = true
config.stashing.suppress_app_log = false

# Set this to true if you want to enable caching instrumentation
config.stashing.enable_cache_instrumentation = true

Enter Stashing

Stashing is a wrapper around LogStasher. It means that any option you set will be forwarded to LogStasher, Stashing takes care of everything!

Stashing is simply here to help you log metrics based on ActiveSupport::Notifications, by tracking them and adding them to the final payload.

For example, if you want to log the number of SQL queries performed during a request, could can do:

# config/initializers/stashing.rb
Stashing.watch('sql.active_record') do |name, start, finish, id, payload, stash|
  duration = (finish - start) * 1000
  stash[:queries] = stash[:queries].to_i.succ
end

Stashing.watch takes the notification's name in argument, and a block, called every time the notification is triggered, with the following arguments:

name: The notification's name
start: Beginning date for the event
finish: End date for the event
id: ID of the event
payload: Event's payload
stash: A thread-safe hash where you can store the data you want to log. This is reset after each request.

If you want to share a stash between several events, you can assign them to an event_group:

# config/initializers/stashing.rb
Stashing.watch('cache_fetch_hit.active_support', event_group: 'cache') do |*args, stash|
  stash[:fetch_hit] = stash[:fetch_hit].to_i.succ
end

Stashing.watch('cache_generate.active_support', event_group: 'cache') do |*args, stash|
  stash[:generate] = stash[:generate].to_i.succ
end

See a complete example.

Whatever you put in your stash, you'll get back in your log, with either the event_group or the event name as the key:

{"@source":"unknown","@tags":["request"],"@fields":{"method":"GET","path":"/login","format":"html","controller":"session","action":"credential_requestor","status":200,"duration":1265.1,"view":1087.07,"db":89.96,"sql.active_record":{"queries":35,"slowest_query":14.312999999999999},"ip":"127.0.0.1","route":"session#credential_requestor","parameters":"service=http://example.com/login\n","user_id":null,"cas_id":null,"session_id":"e309097c16d4c4bd2ca1474b316e6406","request_id":"6dffb5ea-8075-4e38-b2ba-bb5f5264421a","cache":{"fetch_hit":3}},"@timestamp":"2013-11-21T14:35:08.210091+00:00"}

Stashing

Wrapped-up Logstasher for easy ActiveSupport::Notifications logging

Installation

Configure your <environment>.rb (for example: production.rb)

Enter Stashing

Copyright

Configure your `<environment>.rb` (for example: `production.rb`)