Add basic inotify python script for managing fim slideshow when files are changed

inotify-pictures.py

@@ -0,0 +1,71 @@
+#!/usr/bin/env python3
+
+####################
+# Inspiration / Further Reading
+####################
+# https://github.com/chrisjbillington/inotify_simple
+# https://stackoverflow.com/questions/16148735/how-to-implement-a-watchdog-timer-in-python
+
+####################
+# Dependencies
+####################
+# apt install python3 python3-pip python3-dbus
+# pip3 install inotify_simple
+
+from inotify_simple import INotify, flags
+import os
+from threading import Timer
+
+####################
+# Simple watchdog timer class
+####################
+class Watchdog:
+    def __init__(self, timeout, userHandler=None):  # timeout in seconds
+        self.timeout = timeout
+        self.handler = userHandler if userHandler is not None else self.defaultHandler
+        self.timer = Timer(self.timeout, self.handler)
+        # Do NOT start timer by default ; we want this triggered by reset events that come through
+        #     via the inotify filesystem watcher
+        #self.timer.start()
+
+    def reset(self):
+        self.timer.cancel()
+        self.timer = Timer(self.timeout, self.handler)
+        self.timer.start()
+
+    def stop(self):
+        self.timer.cancel()
+
+    def defaultHandler(self):
+        raise self
+
+####################
+# Setup inotify on folder(s)
+####################
+inotify = INotify()
+watch_flags = flags.CREATE | flags.DELETE
+wd = inotify.add_watch('/tank/pictures', watch_flags)
+
+####################
+# Restart fim slideshow once inotify storm is over (3s timeout)
+####################
+def inotify_handler():
+    print('restarting fim slideshow')
+    import dbus
+    sysbus = dbus.SystemBus()
+    systemd1 = sysbus.get_object('org.freedesktop.systemd1', '/org/freedesktop/systemd1')
+    manager = dbus.Interface(systemd1, 'org.freedesktop.systemd1.Manager')
+    job = manager.RestartUnit('fim.service', 'fail')
+
+####################
+# Watch for inotify events in an infinate loop
+# This will BLOCK waiting for events within inotify.read(None)
+#     This makes it pretty safe for an infinate loop scenario
+####################
+watchdog = Watchdog(3.0, inotify_handler)
+while True:
+    for event in inotify.read(None):
+        print(event)
+        watchdog.reset()
+        for flag in flags.from_mask(event.mask):
+            print('    ' + str(flag))