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.

+
+ 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.

+
+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.

+
+      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"])