Supervisord, Gunicorn (exit status 127; not expected) - django

Question

I am hoping to use supervisor to monitor and run a gunicorn server.
When I run:
/usr/bin/gunicorn app.wsgi:application -c config.conf
it works.
But the exact same command in my supervisor conf file does not work. Any explaination?
supervisor.conf
[supervisord]
[group:app]
programs=gunicorn_app
[program:gunicorn_app]
environment=PYTHONPATH=usr/bin
command=/usr/bin/gunicorn app.wsgi:application -c gunicorn.conf.py
directory=~/path/to/app
autostart=true
autorestart=true
environment=LANG="en_US.UTF-8",LC_ALL="en_US.UTF-8",LC_LANG="en_US.UTF-8"
I'm receiving an error like this:
2016-05-31 22:53:34,786 INFO spawned: 'gunicorn_app' with pid 18763
2016-05-31 22:53:34,789 INFO exited: gunicorn_app (exit status 127; not expected)
2016-05-31 22:53:35,791 INFO spawned: 'gunicorn_app' with pid 18764
2016-05-31 22:53:35,795 INFO exited: gunicorn_app (exit status 127; not expected)
2016-05-31 22:53:37,798 INFO spawned: 'gunicorn_app' with pid 18765
2016-05-31 22:53:37,802 INFO exited: gunicorn_app (exit status 127; not expected)
2016-05-31 22:53:40,807 INFO spawned: 'gunicorn_app' with pid 18766
2016-05-31 22:53:40,810 INFO exited: gunicorn_app (exit status 127; not expected)
I understand that exit code 127 means "command not found" but I can execute the exact same command on the command line.

Answer 1

Try to use absolute path.
/home/path/to/app
not ~/path/to/app

Answer 2

As you rightly said, this code means "command not found" which could be as a result of either:
Supervisor not being able to locate the configuration file
Wrong configuration
Whatever the case, i will recommend you in:
case 1:
make sure you provide the absolute path(full path) path to you gunicorn.conf.py file(.e.g. /home/user/path/to/gunicorn.conf.py)
case 2:
revisit your supervisor configuration file and try to determine where the error may arise. The best way to do so is to locate the log file and open it to verify the cause. In other to facilitate this, I recommend to add to your supervisord.conf file the following:
[program:gunicorn]
# where the configuation file is located on the /home/<user>/path/to/configuration_file
command=/usr/local/bin/gunicorn app.wsgi:application -c /home/<user>/path/to/gunicorn.conf.py
directory=~/path/to/app
autostart=true
autorestart=true
#add this setting to log error
stderr_logfile=/var/log/gunicorn.err.log
stdout_logfile=/var/log/gunicorn.out.log
environment=LANG="en_US.UTF-8",LC_ALL="en_US.UTF-8",LC_LANG="en_US.UTF-8"
NB: The assumption i am making here is that you want to deploy or run a django application using gunicorn. Any error encountered when you lunch your server can be verifying in the gunicorn.err.log file.