Question

I’m trying to build a very simple sinatra app deployed on heroku.

our app is not outputting stuff to a web browser, it’s communicating with another computer via an API. so my usual trick of just printing a little extra debugging info to the browser while I’m using the app doesnt work.

the sample code I’ve seen for related apps show multiple ‘puts’ or ‘p’ statement used ot sort of see what’s going on…

where does the output go that I can see that output as the program executes, or afterwards.

and in general, if you’re flailing around with code hosted at Heroku that’s just not doing what you want, what IS the easiest way to at various places in the code output messages like “foo equals 123” so you can see that output to figure out what’s happening in the code?

p and puts dont output so the logs I can see when I type “heroku logs” for example…

Answer 1

According to http://docs.heroku.com/logging you should be able to have puts and p just go to your log if you add the basic logger (which has apparently been added by default to all apps created after February 2nd, 2011).

For non-Heroku basic log-to-file with Sinatra and Logger:

require 'logger'
Dir.mkdir('logs') unless File.exist?('logs')
$log = Logger.new('logs/output.log','weekly')

configure :production do
  $log.level = Logger::WARN
end
configure :development do
  $log.level = Logger::DEBUG
end

get "/" do
  $log.debug "Hello, World!"
end