Rack::JsonLogs
Rack::JsonLogs is a gem that helps log sanely in production.
Ever request will log a JSON object to the real stdout, containing the
following (note: whitespace added here for clarity, in production it would only
be a single line, for easier processig through tools like grep
):
{
"request": "GET /hello",
"from": "server-1",
"stdout": "This contains the STDOUT\nLines are separated by \\n",
"stderr": "This contains the STDERR\nLines are separated by \\n",
"exception": {
"message": "Throwing an exception on purpose.",
"backtrace": [
"config.ru:9:in `block (2 levels) in <main>'",
".../rack-json-logs/lib/rack-json-logs.rb:23:in `call'",
".../rack-json-logs/lib/rack-json-logs.rb:23:in `call'",
"etc... you get the idea"
]
}
}
Rack::JsonLogs comes with a command-line tool to which you can pipe the log files, which will be pretty-printed for legibility and in color:
$ tail -F my.log | json-log-pp
Request: GET /hello
From: server-1
stdout:
hello world
stderr:
bye world
Exception: exception on purpose
config.ru:12:in `block (2 levels) in <main>'
/Users/kenneth/Dropbox/dev/azure/rack-json-logs/lib/rack-json-logs.rb:24:in `call'
/Users/kenneth/Dropbox/dev/azure/rack-json-logs/lib/rack-json-logs.rb:24:in `call'
/Users/kenneth/.rvm/gems/ruby-1.9.3-p327/gems/thin-1.5.0/lib/thin/connection.rb:81:in `block in pre_process'
/Users/kenneth/.rvm/gems/ruby-1.9.3-p327/gems/thin-1.5.0/lib/thin/connection.rb:79:in `catch'
/Users/kenneth/.rvm/gems/ruby-1.9.3-p327/gems/thin-1.5.0/lib/thin/connection.rb:79:in `pre_process'
/Users/kenneth/.rvm/gems/ruby-1.9.3-p327/gems/thin-1.5.0/lib/thin/connection.rb:54:in `process'
/Users/kenneth/.rvm/gems/ruby-1.9.3-p327/gems/thin-1.5.0/lib/thin/connection.rb:39:in `receive_data'
/Users/kenneth/.rvm/gems/ruby-1.9.3-p327/gems/eventmachine-1.0.0/lib/eventmachine.rb:187:in `run_machine'
/Users/kenneth/.rvm/gems/ruby-1.9.3-p327/gems/eventmachine-1.0.0/lib/eventmachine.rb:187:in `run'
/Users/kenneth/.rvm/gems/ruby-1.9.3-p327/gems/thin-1.5.0/lib/thin/backends/base.rb:63:in `start'
/Users/kenneth/.rvm/gems/ruby-1.9.3-p327/gems/thin-1.5.0/lib/thin/server.rb:159:in `start'
/Users/kenneth/.rvm/gems/ruby-1.9.3-p327/gems/thin-1.5.0/lib/thin/controllers/controller.rb:86:in `start'
/Users/kenneth/.rvm/gems/ruby-1.9.3-p327/gems/thin-1.5.0/lib/thin/runner.rb:187:in `run_command'
/Users/kenneth/.rvm/gems/ruby-1.9.3-p327/gems/thin-1.5.0/lib/thin/runner.rb:152:in `run!'
/Users/kenneth/.rvm/gems/ruby-1.9.3-p327/gems/thin-1.5.0/bin/thin:6:in `<top (required)>'
/Users/kenneth/.rvm/gems/ruby-1.9.3-p327/bin/thin:19:in `load'
/Users/kenneth/.rvm/gems/ruby-1.9.3-p327/bin/thin:19:in `<main>'
/Users/kenneth/.rvm/gems/ruby-1.9.3-p327/bin/ruby_noexec_wrapper:14:in `eval'
/Users/kenneth/.rvm/gems/ruby-1.9.3-p327/bin/ruby_noexec_wrapper:14:in `<main>'
Request: GET /hello
From: server-2
stdout:
hello world
stderr:
bye world
Installation
Add this line to your application's Gemfile:
gem 'rack-json-logs'
And then execute:
$ bundle
Or install it yourself as:
$ gem install rack-json-logs
Usage
Using Rack::JsonLogs is easy, all you need to do is add it to your middleware stack:
use Rack::JsonLogger
Contributing
- Fork it
- Create your feature branch (
git checkout -b my-new-feature
) - Commit your changes (
git commit -am 'Add some feature'
) - Push to the branch (
git push origin my-new-feature
) - Create new Pull Request