devyhia / berlin-ruby-talk

Agenda:

Show Rails App

• rails new RailsApp --database=postgresql
• rake db:create
• Handle root in ApplicationController.
• Log access
• Log errors
• logger.info
• ActiveRecord
• rails g model User name:string
• rake db:migrate
• Count or insert ​_(and check the log)_​

Show Sinatra App

• Create App

  require 'sinatra/base'
  class Talk < Sinatra::Application
      set :environment, "development"
  
      get "/" do
        "Hello World!"
      end
  
      run!
  end
  

• Test Access log
• Test logger.info
• Test ActiveRecord
• Install Sinatra ActiveRecord gem install sinatra-activerecord.
• Hook database to the Sinatra App:

set :database, {
    database: "RailsExample_development",
    adapter: "postgresql",
    host: "localhost",
    encoding: "unicode",
    pool: 5,
    username: "postgres"
}

Try to log

• It's all working in $stdout!! But where is the log file?

Doesn't work? Search on Google.

• Follow official Sinatra documentation. http://recipes.sinatrarb.com/p/middleware/rack_commonlogger
• Follow official Access Log + Error. https://spin.atomicobject.com/2013/11/12/production-logging-sinatra/
• After deep thought ... maybe redirect $stdout & $stderr ...? Brilliant idea!
  • Except that it breaks Passenger in production!
• Okay! I log on my own. Write in my own file. logger.info is working!! wohoooo!!
  • You would need to override the default RACK logger everywhere. Models? Controllers? Sidekiq Workers? You name it ... Not very maintainable.
• Okay, I override env["rack.logger"] ... But should I do that in a configure block? Or on every request? Maybe on every single request.
  • Oh it's all working now.
• But wait! Where is my ActiveRecord stuff?
  • Plug it in :) ActiveRecord::Base.logger = Logger.new("log/#{settings.environment}.log")
• Did I forget something?
  • Cassandra? Yes, you need to plug that.
  • Oh Sidekiq? RabbitMQ? You need to plug these, as well.

::Logger.class_eval { alias :write :'<<' }
access_logger = ::Logger.new("#{settings.root}/log/#{settings.environment}.log")
error_logger = ::File.new("#{settings.root}/log/#{settings.environment}.log","a+")
error_logger.sync = true

configure do
  use ::Rack::CommonLogger, access_logger
  ActiveRecord::Base.logger = access_logger
end

before {
  env["rack.errors"] = error_logger
  env["rack.logger"] = access_logger
}

Organize the log

• Well, now you have a bulk of crappy meaningless text in your log file. Congratulations!
  • You might consider writing logs to different files? Could be a good idea. Now you have all of these log files.
    • log/development.access.log
    • log/development.error.log
    • log/development.sql.log
    • log/development.debug.log
    • log/development.cassandra.log
    • log/development.etc.log

SemanticLogger?

• But wait ... Why you need all of this? You can use the SemanticLogger ... And, have:
  • SemanticLogger["SQL"]
    • That works!
  • SemanticLogger["Access"]
    • That works!
  • SemanticLogger["Error"]
    • Ops!! This takes a file (or, technically, any object that exposes << or write functions).
      • Create your own class, and pass it env["rack.error"] ... hehe!!

What the fuck!!

• Wtf! Wait a sec ... Why is this so fucking complicated? That's why, at Minodes, we created the sinatra-logger gem.
  • Just one line and you're up and running: logger filename: "log/#{settings.environment}.log", level: :info
• Logging in your next awesome Sinatra API should be a painless experience! :)
• Thank you!