Fix daemon dependency

README.txt

@@ -6,7 +6,7 @@ Prerequisites:
 
   # Runtime and build environments
   sudo apt-get install python2.7 python2.7-dev python-setuptools
-  sudo apt-get install python-numpy python-scipy
+  sudo apt-get install python-numpy python-scipy python-daemon
 
   nilmdb (1.8.1+)
 

nilmtools/pipewatch.py

@@ -15,6 +15,7 @@ import threading
 import select
 import signal
 import Queue
+import daemon
 
 def parse_args(argv = None):
     parser = argparse.ArgumentParser(
@@ -29,6 +30,8 @@ def parse_args(argv = None):
     Intended for use with ethstream (generator) and nilm-insert
     (consumer).  Commands are executed through the shell.
     """)
+    parser.add_argument("-d", "--daemon", action="store_true",
+                        help="Run in background")
     parser.add_argument("-l", "--lock", metavar="FILENAME", action="store",
                         default=tempfile.gettempdir() +
                         "/nilm-pipewatch.lock",
@@ -74,16 +77,8 @@ def watcher_thread(queue, procs):
                 return
         time.sleep(0.25)
 
-def main(argv = None):
-    args = parse_args(argv)
-
-    with open(args.lock, "w") as lockfile:
-        if not nilmdb.utils.lock.exclusive_lock(lockfile):
-            printf("pipewatch process already running (according to %s)\n",
-                   args.lock)
-            sys.exit(0)
-
-
+def pipewatch(args):
+    # Run the processes, etc
     with open(os.devnull, "r") as devnull:
         generator = subprocess.Popen(args.generator, shell = True,
                                      bufsize = -1, close_fds = True,
@@ -146,6 +141,24 @@ def main(argv = None):
         if gret == 0 and cret == 0:
             sys.exit(0)
         sys.exit(1)
+
+def main(argv = None):
+    args = parse_args(argv)
+
+    lockfile = open(args.lock, "w")
+    if not nilmdb.utils.lock.exclusive_lock(lockfile):
+        printf("pipewatch process already running (according to %s)\n",
+               args.lock)
+        sys.exit(0)
+    try:
+        # Run as a daemon if requested, otherwise run directly.
+        if args.daemon:
+            with daemon.DaemonContext(files_preserve = [ lockfile ]):
+                pipewatch(args)
+        else:
+            pipewatch(args)
+    finally:
+        # Clean up lockfile
         try:
             os.unlink(args.lock)
         except OSError:

setup.py

@@ -64,6 +64,7 @@ setup(name='nilmtools',
       install_requires = [ 'nilmdb >= 1.8.1',
                            'numpy',
                            'scipy',
+                           'python-daemon >= 1.5',
                            #'matplotlib',
                            ],
       packages = [ 'nilmtools',