Autolaunch a command and restart it on quit on CentOS

I’ve a django-admin command running as a server thanks to gevent. I want this server to run on boot and autorestart on quit.  StackOverflow give me a hint: use Supervisor.

On a Centos 5 distro:

# find supervisor for your distro...
yum search supervisor
# ...and install it
yum install supervisor.noarch
nano /etc/supervisord.conf

At the end of the file, add a new program:

command=/usr/bin/env python26 /usr/local/etc/django-apps/foo/ tcpapi 4114
priority=999                ; the relative start priority (default 999)
autostart=true              ; start at supervisord start (default: true)
autorestart=true            ; retstart at unexpected quit (default: true)
; startsecs=-1                ; number of secs prog must stay running (def. 10)
; startretries=3              ; max # of serial start failures (default 3)
exitcodes=0,2               ; 'expected' exit codes for process (default 0,2)
stopsignal=QUIT             ; signal used to kill process (default TERM)
; stopwaitsecs=10             ; max num secs to wait before SIGKILL (default 10)
; user=root                   ; setuid to this UNIX account to run the program
log_stdout=true             ; if true, log program stdout (default true)
log_stderr=true             ; if true, log program stderr (def false)
logfile=/var/log/myfunnydjangocommand.log    ; child log path, use NONE for none; default AUTO
logfile_maxbytes=1MB        ; max # logfile bytes b4 rotation (default 50MB)
logfile_backups=10          ; # of logfile backups (default 10)

Then, start supervisord.

service supervisord start

Take a look to supervisord log file:

less +G /var/log/supervisor/supervisord.log

You’ll see something like this:

2013-06-07 11:54:16,559 CRIT Supervisor running as root (no user in config file)
2013-06-07 11:54:16,576 INFO /var/tmp/supervisor.sock:Medusa (V1.1.1.1) started at Fri Jun  7 11:54:16 2013
        Hostname: <unix domain socket>
2013-06-07 11:54:16,645 CRIT Running without any HTTP authentication checking
2013-06-07 11:54:16,654 INFO daemonizing the process
2013-06-07 11:54:16,657 INFO supervisord started with pid 19316
2013-06-07 11:54:16,666 INFO spawned: 'myfunnydjangocommand' with pid 19318
2013-06-07 11:54:17,670 INFO success: myfunnydjangocommand entered RUNNING state, process has stayed up for > than 1 seconds (startsecs)

Read documentation about the configuration options but keep in mind your Supervisor version. I don’t use supervisorctl because of this bug, if you get an error simply go with service supervisord… but if you have a newer version this should be already fixed.

Note: myfunnydjangocommand.log doesn’t contain anything useful in my experience but maybe it’s related how I write the output since I’ve written it to use interactively, outputting lines directly to the user. I’ll update this post if I find how to solve this issue.

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