Add watchdog code

mastodonlisten.py

@@ -3,6 +3,8 @@ from mastodon import Mastodon
 from bs4 import BeautifulSoup
 import argparse
 import datetime
+from threading import Timer
+import os
 
 from kafkaproducer import kafka_producer
 
@@ -10,15 +12,22 @@ from kafkaproducer import kafka_producer
 base_url = ''
 enable_kafka = False
 quiet = False
+watchdog = False
 
-# if enable_kafka:
-topic_name, producer = kafka_producer()
+if enable_kafka:
+    topic_name, producer = kafka_producer()
+else:
+    topic_name, producer = '' , ''
 
-#### Listener for Mastodon events
 
+# Listener for Mastodon events
 class Listener(mastodon.StreamListener):
 
     def on_update(self, status):
+        if watchdog:
+            # reset watchdog timer
+            watchdog.reset()
+
         m_text = BeautifulSoup(status.content, 'html.parser').text
         num_tags = len(status.tags)
         num_chars = len(m_text)
@@ -52,14 +61,43 @@ class Listener(mastodon.StreamListener):
         if not quiet:
             print(f'{m_user} {m_lang}', m_text[:30])
 
+
         if enable_kafka:
             producer.produce(topic = topic_name, value = value_dict)
             producer.flush()
 
+
+class Watchdog:
+    def __init__(self, timeout, userHandler=None): # timeout in seconds
+        self.timeout = timeout
+        if userHandler != None:
+            self.timer = Timer(self.timeout, userHandler)
+        else:
+            self.timer = Timer(self.timeout, self.handler)
+
+    def reset(self):
+        self.timer.cancel()
+        self.timer = Timer(self.timeout, watchExpired)
+        self.timer.start()
+
+    def stop(self):
+        self.timer.cancel()
+
+    def handler(self):
+        raise self;
+
+
+def watchExpired():
+    print('Watchdog expired')
+    # ugly, but expected method for a child process to terminate a fork
+    os._exit(1)
+
+
 def main():
     global base_url
     global enable_kafka
     global quiet
+    global watchdog
 
     parser = argparse.ArgumentParser(
         formatter_class=argparse.ArgumentDefaultsHelpFormatter)
@@ -78,6 +116,12 @@ def main():
         required=False,
         default=False)
 
+    parser.add_argument(
+        '--watchdog',
+        help='enable watchdog timer of n seconds',
+        type=int,
+        required=False)
+
     parser.add_argument(
         '--quiet',
         help='Do not echo a summary of the toot',
@@ -97,6 +141,10 @@ def main():
     enable_kafka=args.enableKafka
     mastodon = Mastodon(api_base_url = base_url)
 
+    if args.watchdog:
+        watchdog = Watchdog(args.watchdog, watchExpired)
+        watchdog.timer.start()
+
     if args.public:
         mastodon.stream_public(Listener())
     else: