Daemon function added to script

README.asciidoc

@@ -10,12 +10,12 @@ nagios-api - presents a REST-like JSON interface to Nagios
 
 SYNOPSIS
 --------
-*nagios-api* ['OPTIONS']
+*nagios-api* ['OPTIONS'] <Action>
 
 
 DEPENDENCIES
 ------------
-Dependencies include: diesel, greenlet and python-openssl bindings
+Dependencies include: python-daemon, diesel, greenlet and python-openssl bindings
 
 
 DESCRIPTION
@@ -32,7 +32,7 @@ USAGE
 Usage is pretty easy:
 
   nagios-api -p 8080 -c /var/lib/nagios3/rw/nagios.cmd \
-             -s /var/cache/nagios3/status.dat -l /var/log/nagios3/nagios.log
+             -s /var/cache/nagios3/status.dat -l /var/log/nagios3/nagios.log console
 
 You must at least provide the status file options. If you don't provide
 the other options, then we will disable that functionality and error to
@@ -74,6 +74,16 @@ so you should be able to get all you need:
 The original raw JSON mode is still supported by passing the --raw
 option.
 
+ACTIONS
+-------
+*console*::
+    Run Nagios-API as console application
+
+*start*::
+    Start Nagios API as daemon
+
+*stop*::
+    Stop Nagios API daemon
 
 OPTIONS
 -------
@@ -112,6 +122,21 @@ http://www.w3.org/TR/cors/[CORS specification].
     If present, we will only print warning/critical messages. Useful if
     you are running this in the background.
 
+*-u, --user*::
+    If present, daemon will run as given user.
+
+*-w, --writelog*::
+    If present, application will write logs into given 'FILE'. Otherwise,
+    console is used.
+
+TROUBLESHOOTING
+---------------
+
+In daemon mode PID file /var/run/nagios/nagios-api.pid should be writable
+by daemon user set in -u option.
+
+If case of daemon starting problems consult /var/log/nagios-api-daemon.log
+file. If should contain start/stop errors.
 
 API
 ---

nagios-api

@@ -20,12 +20,19 @@ import types
 import atexit
 from optparse import OptionParser
 from diesel import Application, Loop, Service, sleep
-from diesel.logmod import log, levels
+from diesel.logmod import diesel_format
+import twiggy
 from diesel.util.lock import synchronized
 from diesel.protocols import http
 from json import dumps
 from nagios import Nagios
 from werkzeug.exceptions import BadRequest
+import daemon
+import lockfile
+from pwd import getpwnam
+import errno
+import signal
+from lockfile.pidlockfile import PIDLockFile
 
 CMDFILE = None
 CMD_ENABLED = False
@@ -35,9 +42,24 @@ NAGIOS = None
 NLOG = []
 NLOGLINES = 0
 ALLOW_ORIGIN = None
-PIDFILE = "/var/run/nagios-api.pid"
+PIDFILE = "/var/run/nagios/nagios-api.pid"
+DAEMON_LOG="/var/log/nagios-api-daemon.log"
 
+## init console logging
+diesel_output = twiggy.outputs.StreamOutput(diesel_format)
 
+def set_log_level(level=twiggy.levels.INFO):
+    twiggy.emitters.clear()
+
+    twiggy.addEmitters(
+        ('*', level, None, diesel_output)
+    )
+
+log = twiggy.log.name("diesel")
+
+set_log_level()
+
+## main code goes below
 def _send_json(req, success, content):
     '''Internal JSON sender.
 
@@ -755,73 +777,135 @@ def read_log(logfile):
             NLOG = NLOG[-1000:]  # Keep the most recent 1k lines.
     f.close()  # Useless?
 
+def touch(fname, times=None):
+    with file(fname, 'a'):
+        os.utime(fname, times)
 
-def main(argv):
-    '''A simple REST API for Nagios3.
-
+def parse_args(argv):
+    '''Parse arguments and set global variables. Returns tuple (options, args)
     '''
     global CMDFILE, CMD_ENABLED, LOG_ENABLED, ALLOW_ORIGIN
-    app = Application()
 
-    parser = OptionParser(description='Give Nagios a REST API.')
+    usage = "usage: %prog [options] <start/stop/console>"
+    parser = OptionParser(description='Give Nagios a REST API.', usage = usage)
     parser.add_option('-o', '--allow-origin', dest='alloworigin', metavar='ORIGIN',
-            help='Access-Control-Allow-Origin header contents')
+                      help='Access-Control-Allow-Origin header contents')
     parser.add_option('-s', '--status-file', dest='statusfile', metavar='FILE',
-            default='/var/cache/nagios3/status.dat', help='The file that contains '
-            'the Nagios status.')
+                      default='/var/cache/nagios3/status.dat', help='The file that contains '
+                                                                    'the Nagios status.')
     parser.add_option('-c', '--command-file', dest='commandfile', metavar='FILE',
-            default='/var/lib/nagios3/rw/nagios.cmd', help='The file to write '
-            'Nagios commands to.')
+                      default='/var/lib/nagios3/rw/nagios.cmd', help='The file to write '
+                                                                     'Nagios commands to.')
     parser.add_option('-l', '--log-file', dest='logfile', metavar='FILE',
-            default='/var/log/nagios3/nagios.log', help='The file Nagios writes '
-            'log events to.')
+                      default='/var/log/nagios3/nagios.log', help='The file Nagios writes '
+                                                                  'log events to.')
     parser.add_option('-b', '--bind', dest='bind_addr', metavar='ADDR',
-            default='', help='The address to listen for requests on.')
+                      default='', help='The address to listen for requests on.')
     parser.add_option('-p', '--port', dest='port', metavar='PORT', type='int',
-            default=6315, help='The port to listen for requests on.')
+                      default=6315, help='The port to listen for requests on.')
     parser.add_option('-q', '--quiet', dest='quiet', action='store_true',
-            help='Quiet mode')
+                      help='Quiet mode')
+    parser.add_option('-u', '--user', dest='user', metavar='USER',
+                      help='User to run daemon as')
+    parser.add_option('-w', '--write-log', dest='writelog', metavar='FILE',
+                      help='The file deamon will write logs to')
     (options, args) = parser.parse_args(args=argv[1:])
 
+    if len(args) != 1:
+        parser.error('Action should be set for this script')
+    if args[0] not in ('console', 'stop', 'start'):
+        parser.error("Unknown action '%s'. Action should be 'console', 'start' or 'stop'" % action)
+
     if not os.path.isfile(options.statusfile):
         parser.error('Status file not found: %s' % options.statusfile)
     if options.port < 0 or options.port > 65535:
         parser.error('Port must be in the range 1..65535.')
 
     if options.quiet:
-        log.min_level = levels.WARNING
+        log.min_level = twiggy.levels.WARNING
 
     if os.path.exists(options.commandfile):
         CMD_ENABLED = True
         CMDFILE = options.commandfile
     if options.alloworigin:
         ALLOW_ORIGIN = options.alloworigin
 
+    if os.path.isfile(options.logfile):
+        LOG_ENABLED = True
+
+    if  options.user is not None:
+        try:
+            pw = getpwnam(options.user)
+            options.uid = pw.pw_uid
+            gid = pw.pw_gid
+
+            if options.writelog is not None:
+                ## create log file and set ownership
+                touch(options.writelog)
+                os.chown(options.writelog, options.uid, gid)
+
+        except KeyError:
+            parser.error("Unknown local user '%s'" % options.user)
+    else:
+        options.uid = None
+
+    return (options, args)
+
+def main(options):
+    '''A simple REST API for Nagios3.
+
+    '''
+
+    if options.writelog is not None:
+        global diesel_output
+        diesel_output = twiggy.outputs.FileOutput(options.writelog, diesel_format)
+        set_log_level()
+
     log.info('Listening on port %d, starting to rock and roll!' % options.port)
+    app = Application()
     app.add_service(Service(http.HttpServer(http_handler), options.port,
             options.bind_addr))
     app.add_loop(Loop(read_status, options.statusfile), keep_alive=True)
     if os.path.isfile(options.logfile):
-        LOG_ENABLED = True
         app.add_loop(Loop(read_log, options.logfile), keep_alive=True)
     app.run()
     return 1
 
-
-def _exitfunc():
-    print "Exiting. Cleaning up PID."
-    os.unlink(PIDFILE)
-
+def stop_by_pidfile(pidfile):
+    str = pidfile.readline(100)
+    if str == "":
+        return None
+    try:
+        n = int(str)
+    except ValueError:
+        return None
+    print "Stopping process %d" % n
+    try:
+        os.kill(n, signal.SIGTERM)
+    except OSError, (code, message):
+        if code != errno.ESRCH:
+            raise
 
 if __name__ == '__main__':
-    pid = str(os.getpid())
-
-    if os.path.isfile(PIDFILE):
-        print "%s already exists, exiting" % PIDFILE
-        sys.exit()
-    else:
-        file(PIDFILE, 'w').write(pid)
-
-    atexit.register(_exitfunc)
-
-    sys.exit(main(sys.argv))
+    (options, args) = parse_args(sys.argv)
+
+    action = args[0]
+    if action == 'console':
+        sys.exit(main(options))
+    elif action == 'stop':
+        if not os.path.exists(PIDFILE):
+            ## pid not found - nothing to do
+            sys.exit(-1)
+        stop_by_pidfile(file(PIDFILE))
+    elif action == 'start':
+        context = daemon.DaemonContext(pidfile = PIDLockFile(PIDFILE))
+        if options.uid is not None:
+            context.uid = options.uid
+
+        if options.writelog is not None:
+            daemon_log = file(DAEMON_LOG, 'a')
+            context.stdout = daemon_log
+            context.stderr = daemon_log
+
+        with context:
+            main(options)

setup.py

@@ -12,6 +12,7 @@
       requires=[
         'diesel(>=3.0)',
         'greenlet(==0.3.4)',
-        'requests'
+        'requests',
+        'pythondaemon(>=1.5.5)'
       ]
      )