sitescripts: Script to keep services alive

sitescripts/management/bin/start_services.py

 # coding: utf-8
 
 # This file is part of the Adblock Plus web scripts,
 # Copyright (C) 2006-2012 Eyeo GmbH
 #
 # Adblock Plus is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 3 as
 # published by the Free Software Foundation.
 #
 # Adblock Plus is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
 
 import os, subprocess
 from sitescripts.utils import get_config
 
 def _get_services():
- config = get_config()
- section_name = "keep_alive_services"
- section_keys = config.options(section_name)
- default_keys = config.defaults().keys()
- keys = set(section_keys) - set(default_keys)

[Wladimir Palant, 2012/11/30 10:46:07]

Strange indentation here, one space instead of two?

[Felix Dahlke, 2012/11/30 13:32:28]

Done.

+  config = get_config()
+  section_name = "keep_alive_services"
+  section_keys = config.options(section_name)
+  default_keys = config.defaults().keys()
+  keys = set(section_keys) - set(default_keys)
 
- services = {}
- for key in keys:
-   services[key] = config.get(section_name, key)
- return services
+  services = {}
+  for key in keys:
+    services[key] = config.get(section_name, key)
+  return services
 
 def _process_running(pid):
-  return os.path.isdir(os.path.join("/proc", str(pid)))

[Wladimir Palant, 2012/11/30 10:46:07]

I might have preferred os.kill(..., 0) but this will do as well.

[Felix Dahlke, 2012/11/30 13:32:28]

Didn't know that trick, using it now.

+  try:
+    os.kill(pid, 0)
+    return True
+  except OSError:
+    return False
 
 if __name__ == "__main__":
   services = _get_services()
   for service in services.keys():
     pid_path = os.path.join("/var/run", services[service])
     if os.path.exists(pid_path):
-      with open(pid_path) as file: pid_string = file.read()

[Wladimir Palant, 2012/11/30 10:46:07]

Does this really have to be all on one line?

[Felix Dahlke, 2012/11/30 13:32:28]

Done.

+      with open(pid_path) as file:
+        pid_string = file.read()
 
       try:
         pid = int(pid_string.rstrip())
         if _process_running(pid):
           continue
       except exceptions.ValueError:
         print "'%s' is not a PID." % pid_string
 
     init_path = os.path.join("/etc/init.d", service)
     if not os.path.exists(init_path):
       print "%s does not exist, service is not running and cannot be started." % init_path
       continue
 
     print "%s is not running, starting ..." % service
     subprocess.call([init_path, "start"])