matagus · March 11, 2011 10:35 · Jun 8, 2009
diff --git a/daemonextension.py b/daemonextension.py
@@ -0,0 +1,183 @@
+"""
+Copyright (c) 2009, Sean Creeley
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+
+  * Redistributions of source code must retain the above copyright notice, this
+      list of conditions and the following disclaimer.
+  * Redistributions in binary form must reproduce the above copyright notice, 
+      this list of conditions and the following disclaimer in the documentation 
+      and/or other materials provided with the distribution.
+  * Neither the name of the Optaros, Inc. nor the names of its contributors may 
+      be used to endorse or promote products derived from this software without 
+      specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
+INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
+NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, 
+OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
+WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
+POSSIBILITY OF SUCH DAMAGE.
+
+=============
+DaemonCommand
+=============
+
+Django Management Command for starting a daemon.
+
+Use
+===
+
+Simple use of daemon command::
+
+    from daemonextension import DaemonCommand
+    from django.conf import settings
+    import os
+    
+    class Command(DaemonCommand):
+        
+        stdout = os.path.join(settings.DIRNAME, "log/cubbyscott.out")
+        stderr = os.path.join(settings.DIRNAME, "log/cubbyscott.err")
+        pidfile = os.path.join(settings.DIRNAME, "pid/cb_link.pid")
+        
+        def handle_daemon(self, *args, **options):
+            from flopsy import Connection, Consumer
+            consumer = Consumer(connection=Connection())
+            consumer.declare(queue='links', 
+                             exchange='cubbyscott', 
+                             routing_key='importer', auto_delete=False)
+            
+            def message_callback(message):
+                print 'Recieved: ' + message.body
+                consumer.channel.basic_ack(message.delivery_tag)
+            
+            consumer.register(message_callback)
+            
+            consumer.wait()
+
+call::
+
+    python python manage.py linkconsumer
+    
+"""
+
+from django.core.management.base import BaseCommand
+from optparse import make_option
+
+import daemon
+from daemon import pidlockfile
+
+class DaemonCommand(BaseCommand):
+
+    option_list = BaseCommand.option_list + (
+        make_option('--chroot_directory', action='store', dest='chroot_directory',
+            help='Full path to a directory to set as the effective root directory of \
+            the process.'),
+        make_option('--working_directory', action='store', dest='working_directory',
+            default="/",
+            help='Full path of the working directory to which the process should \
+            change on daemon start.'),
+        make_option('--umask', action='store', dest='umask', default=0, type="int",
+            help='File access creation mask ("umask") to set for the process on \
+            daemon start.'),
+        make_option('--pidfile', action='store', dest='pidfile',
+            help='Context manager for a PID lock file. When the daemon context opens \
+            and closes, it enters and exits the `pidfile` context manager.'),
+        make_option('--detach_process', action='store', dest='detach_process', 
+            help='If ``True``, detach the process context when opening the daemon \
+            context; if ``False``, do not detach.'),
+        make_option('--uid', action='store', dest='uid', 
+            help='The user ID ("UID") value to switch the process to on daemon start.'),
+        make_option('--gid', action='store', dest='gid', 
+            help='The group ID ("GID") value to switch the process to on daemon start.'),
+        make_option('--prevent_core', action='store', dest='prevent_core', default=True,
+            help='If true, prevents the generation of core files, in order to avoid \
+            leaking sensitive information from daemons run as `root`.'),
+        make_option('--stdin', action='store', dest='stdin', 
+            help='Standard In'),
+        make_option('--stdout', action='store', dest='stdout',
+            help='Standard Out'),
+        make_option('--stderr', action='store', dest='stderr',
+            help='Standard Error'),
+    )
+    help = 'Create a daemon'
+
+    chroot_directory = None
+    working_directory = '/'
+    umask = 0
+    detach_process = True
+    prevent_core = True
+    stdin = None
+    stdout = None
+    stderr = None
+    pidfile = None
+    uid = None
+    gid = None    
+
+
+    def get_option_value(self, options, name, expected=None):
+        value = options.get(name)
+        if value == expected:
+            value = getattr(self, name)
+        print name, ' ', value
+        return value
+
+    def handle(self, *args, **options):
+        """
+        Takes the options and starts a daemon context from them. 
+        
+        Example::
+        
+            python manage.py linkconsumer --pidfile=/var/run/cb_link.pid 
+                --stdout=/var/log/cb/links.out --stderr=/var/log/cb/links.err
+        
+        """
+        context = daemon.DaemonContext()
+
+        context.chroot_directory = self.get_option_value(options, 'chroot_directory')
+        context.working_directory = self.get_option_value(options, 'working_directory', '/')
+        context.umask = self.get_option_value(options, 'umask', 0)
+        context.detach_process = self.get_option_value(options, 'detach_process')
+        context.prevent_core = self.get_option_value(options, 'prevent_core', True)
+
+        #Get file objects
+        stdin =  self.get_option_value(options, 'stdin')
+        if stdin is not None:
+            context.stdin = open(stdin, "r")
+
+        stdout = self.get_option_value(options, 'stdout')
+        if stdout is not None:
+            context.stdout = open(stdout, "a+")
+
+        stderr = self.get_option_value(options, 'stderr')
+        if stderr is not None:
+            context.stderr = open(stderr, "a+")  
+
+        #Make pid lock file
+        pidfile = self.get_option_value(options, 'pidfile')
+        if pidfile is not None:
+            context.pidfile=pidlockfile.PIDLockFile(pidfile)
+
+        uid = self.get_option_value(options, 'uid')
+        if uid is not None:
+            context.uid = uid
+
+        gid = self.get_option_value(options, 'gid')
+        if gid is not None:
+            context.gid = uid
+
+        context.open()        
+
+        self.handle_daemon(*args, **options)
+
+    def handle_daemon(self, *args, **options):
+        """
+        Perform the command's actions in the given daemon context
+        """
+        raise NotImplementedError()