Rails 3.2: 12 Factor App

Question

In the logging section of the web app manifesto "The Twelve Factor App", it suggests that each process send logs to STDOUT.

If I am doing Rails development locally with a process for the web server ("rails server") and a Sidekiq process for the background jobs ("bundle exec sidekiq"), I would like the logs to appear in a single stream, but I would still like to use STDOUT in my models, views, controllers, and Sidekiq workers.

Is there a way or a tool to be able to merge the two STDOUT streams together so that the logs are stored in a stream so that they can be viewed by tailing a single file?

Answer 1

Use foreman. You define your processes in a Procfile

web:    rails server
worker: bundle exec sidekiq

and run them with foreman start.

Further reading:

• http://blog.daviddollar.org/2011/05/06/introducing-foreman.html
• https://devcenter.heroku.com/articles/procfile

Answer 2

It'll depend what OS you're running on I expect.

On a unix-like console you could run both processes in the background on a single console:

> rails server &
> bundle exec sidekiq &

That'll spit out stdout for both to the current console but you'll need to close them explicitly by pid, e.g. kill `pgrep -f rails`

Alternatively you can run each of them and append their output to a file which you can then tail (each of these in separate console windows):

> rails server >> combined_output.txt
> bundle exec sidekiq >> combined_output.txt
> tail -f combined_output.txt