foreman only shows line with “started with pid #” and nothing else

问题

When I run foreman I get the following:

 > foreman start
 16:47:56 web.1     | started with pid 27122

Only if I stop it (via ctrl-c) it shows me what is missing:

^CSIGINT received
16:49:26 system    | sending SIGTERM to all processes
16:49:26 web.1     | => Booting Thin
16:49:26 web.1     | => Rails 3.0.0 application starting in development on http://0.0.0.0:5000
16:49:26 web.1     | => Call with -d to detach
16:49:26 web.1     | => Ctrl-C to shutdown server
16:49:26 web.1     | >> Thin web server (v1.3.1 codename Triple Espresso)
16:49:26 web.1     | >> Maximum connections set to 1024
16:49:26 web.1     | >> Listening on 0.0.0.0:5000, CTRL+C to stop
16:49:26 web.1     | >> Stopping ...
16:49:26 web.1     | Exiting
16:49:26 web.1     | >> Stopping ...

How do I fix it?

回答1:

I’ve been able to resolve this issue by 2 different ways:

1. From https://github.com/ddollar/foreman/wiki/Missing-Output:

   If you are not seeing any output from your program, there is a likely chance that it is buffering stdout. Ruby buffers stdout by default. To disable this behavior, add this code as early as possible in your program:

   # ruby
   $stdout.sync = true
   

2. By installing foreman via the heroku toolbelt package

But I still don’t know what’s happening nor why this 2 ways above resolved the issue…

回答2:

My solution was to put $stdout.sync = true at the top of config/environments/development.rb.

Then everything that loads the development environment (incluing thin) will not buffer stdout.

回答3:

"Foreman will display to the terminal output anything written to stdout by the processes it launches." - ddollar See foreman-issues#57

BTW, you can use tailf into Procfile to see logs

web: bundle exec rails server thin -p $PORT
log: tail -f log/development.log

Tip: tailf doesn't exist in OSX, using tail -f -n 40 log/development.log works.

回答4:

If you are using Foreman to run a Python project, rather than a Ryby project, and you're having the same issue, here are some solutions for you. If you are using a Procfile to invoke the python CLI directly, then you can use the '-u' option to avoid stdout buffering:

python -u script.py

If you are using a Procfile to manage a WSGI server, such as invoking gunicorn, flask, bottle, eve, etc., then you can add a ".env" file to the root of your python project, containing the following:

PYTHONUNBUFFERED=True

回答5:

I have the same problem (ruby 1.9.3-p0, rails 3.2rc2, OSX 10.7).

Resolved the issue by using foreman-0.27.0 by adding this line into my Gemfile.

gem 'foreman', '0.27.0'

回答6:

I also had the same problem but with a different solution. (ruby 1.9.2p290, rails 3.1.0, ubuntu 10.04.3)

I changed the line in my Procfile from:

web: bundle exec thin start -p $PORT

to:

web: bundle exec rails server thin -p $PORT

and it no longer gave me an issue.

来源：https://stackoverflow.com/questions/8717198/foreman-only-shows-line-with-started-with-pid-and-nothing-else