Optionally no pid file is written (pid_file=False) when notifier.loop

with daemonize=True is called.

python2/examples/daemon.py

@@ -36,8 +36,13 @@ def on_loop(notifier, counter):
 # Notifier instance spawns a new process when daemonize is set to True. This
 # child process' PID is written to /tmp/pyinotify.pid (it also automatically
 # deletes it when it exits normally). If no custom pid_file is provided it
-# would write it more traditionally under /var/run/. /tmp/stdout.txt is used
-# as stdout stream thus traces of events will be written in it. callback is 
-# the above function and will be called after each event loop.
-notifier.loop(daemonize=True, callback=on_loop_func,
-              pid_file='/tmp/pyinotify.pid', stdout='/tmp/stdout.txt')
+# would write it more traditionally under /var/run/. Note that in both cases
+# the caller must ensure the pid file doesn't exist when this method is called
+# othewise it will raise an exception. /tmp/stdout.txt is used as stdout 
+# stream thus traces of events will be written in it. callback is the above 
+# function and will be called after each event loop.
+try:
+    notifier.loop(daemonize=True, callback=on_loop_func,
+                  pid_file='/tmp/pyinotify.pid', stdout='/tmp/stdout.txt')
+except pyinotify.NotifierError, err:
+    print >> sys.stderr, err

python2/pyinotify.py

@@ -1202,15 +1202,17 @@ def process_events(self):
     def __daemonize(self, pid_file=None, stdin=os.devnull, stdout=os.devnull,
                     stderr=os.devnull):
         """
-        pid_file: file to which the pid will be written.
+        pid_file: file where the pid will be written. If pid_file=None the pid
+                  is written to /var/run/<sys.argv[0]|pyinotify>.pid, if 
+                  pid_file=False no pid_file is written.
         stdin, stdout, stderr: files associated to common streams.
         """
         if pid_file is None:
             dirname = '/var/run/'
             basename = os.path.basename(sys.argv[0]) or 'pyinotify'
             pid_file = os.path.join(dirname, basename + '.pid')
 
-        if os.path.lexists(pid_file):
+        if pid_file != False and os.path.lexists(pid_file):
             err = 'Cannot daemonize: pid file %s already exists.' % pid_file
             raise NotifierError(err)
 
@@ -1244,12 +1246,13 @@ def fork_daemon():
         fork_daemon()
 
         # Write pid
-        flags = os.O_WRONLY|os.O_CREAT|os.O_NOFOLLOW|os.O_EXCL
-        fd_pid = os.open(pid_file, flags, 0600)
-        os.write(fd_pid, str(os.getpid()) + '\n')
-        os.close(fd_pid)
-
-        atexit.register(lambda : os.unlink(pid_file))
+        if pid_file != False:
+            flags = os.O_WRONLY|os.O_CREAT|os.O_NOFOLLOW|os.O_EXCL
+            fd_pid = os.open(pid_file, flags, 0600)
+            os.write(fd_pid, str(os.getpid()) + '\n')
+            os.close(fd_pid)
+            # Register unlink function
+            atexit.register(lambda : os.unlink(pid_file))
 
 
     def _sleep(self, ref_time):
@@ -1279,7 +1282,12 @@ def loop(self, callback=None, daemonize=False, **args):
         @type daemonize: boolean
         @param args: Optional and relevant only if daemonize is True. Remaining
                      keyworded arguments are directly passed to daemonize see
-                     __daemonize() method.
+                     __daemonize() method. If pid_file=None or is set to a
+                     pathname the caller must ensure the file does not exist
+                     before this method is called otherwise an exception 
+                     pyinotify.NotifierError will be raised. If pid_file=False
+                     it is still daemonized but the pid is not written in any
+                     file.
         @type args: various
         """
         if daemonize:

python3/pyinotify.py

@@ -1163,15 +1163,17 @@ def process_events(self):
     def __daemonize(self, pid_file=None, stdin=os.devnull, stdout=os.devnull,
                     stderr=os.devnull):
         """
-        pid_file: file to which the pid will be written.
+        pid_file: file where the pid will be written. If pid_file=None the pid
+                  is written to /var/run/<sys.argv[0]|pyinotify>.pid, if 
+                  pid_file=False no pid_file is written.
         stdin, stdout, stderr: files associated to common streams.
         """
         if pid_file is None:
             dirname = '/var/run/'
             basename = os.path.basename(sys.argv[0]) or 'pyinotify'
             pid_file = os.path.join(dirname, basename + '.pid')
 
-        if os.path.lexists(pid_file):
+        if pid_file != False and os.path.lexists(pid_file):
             err = 'Cannot daemonize: pid file %s already exists.' % pid_file
             raise NotifierError(err)
 
@@ -1205,13 +1207,14 @@ def fork_daemon():
         fork_daemon()
 
         # Write pid
-        flags = os.O_WRONLY|os.O_CREAT|os.O_NOFOLLOW|os.O_EXCL
-        fd_pid = os.open(pid_file, flags, 0o0600)
-        os.write(fd_pid,  bytes(str(os.getpid()) + '\n',
-                                locale.getpreferredencoding()))
-        os.close(fd_pid)
-
-        atexit.register(lambda : os.unlink(pid_file))
+        if pid_file != False:
+            flags = os.O_WRONLY|os.O_CREAT|os.O_NOFOLLOW|os.O_EXCL
+            fd_pid = os.open(pid_file, flags, 0o0600)
+            os.write(fd_pid,  bytes(str(os.getpid()) + '\n',
+                                    locale.getpreferredencoding()))
+            os.close(fd_pid)
+            # Register unlink function
+            atexit.register(lambda : os.unlink(pid_file))
 
 
     def _sleep(self, ref_time):
@@ -1241,7 +1244,12 @@ def loop(self, callback=None, daemonize=False, **args):
         @type daemonize: boolean
         @param args: Optional and relevant only if daemonize is True. Remaining
                      keyworded arguments are directly passed to daemonize see
-                     __daemonize() method.
+                     __daemonize() method. If pid_file=None or is set to a
+                     pathname the caller must ensure the file does not exist
+                     before this method is called otherwise an exception 
+                     pyinotify.NotifierError will be raised. If pid_file=False
+                     it is still daemonized but the pid is not written in any
+                     file.
         @type args: various
         """
         if daemonize: