Improved snf-pithos-tools packages

[pithos] / snf-pithos-tools / pithos / tools / dispatcher.py

diff --git a/snf-pithos-tools/pithos/tools/dispatcher.py b/snf-pithos-tools/pithos/tools/dispatcher.py
index e66b629..8625390 100755 (executable)
--- a/snf-pithos-tools/pithos/tools/dispatcher.py
+++ b/snf-pithos-tools/pithos/tools/dispatcher.py
@@ -38,9 +38,15 @@ import logging
 
 from optparse import OptionParser
 
-from carrot.connection import BrokerConnection
-from carrot.messaging import Consumer
-from carrot.messaging import Publisher
+try:
+    from carrot.connection import BrokerConnection
+    from carrot.messaging import Consumer
+    from carrot.messaging import Publisher
+except ImportError:
+    sys.stderr.write("Dispatcher requires 'carrot' python library to " \
+                     "be installed\n")
+    sys.exit(1)
+
 
 
 BROKER_HOST = 'localhost'
@@ -56,7 +62,7 @@ CONSUMER_KEY = '#'
 DEBUG = False
 
 
-if __name__ == '__main__':
+def main():
     parser = OptionParser()
     parser.add_option('-v', '--verbose', action='store_true', default=False,
                       dest='verbose', help='Enable verbose logging')
@@ -81,14 +87,14 @@ if __name__ == '__main__':
     parser.add_option('--test', action='store_true', default=False,
                       dest='test', help='Produce a dummy message for testing')
     opts, args = parser.parse_args()
-    
+
     if opts.verbose:
         DEBUG = True
     logging.basicConfig(format='%(asctime)s [%(levelname)s] %(name)s %(message)s',
                         datefmt='%Y-%m-%d %H:%M:%S',
                         level=logging.DEBUG if DEBUG else logging.INFO)
     logger = logging.getLogger('dispatcher')
-    
+
     conn = BrokerConnection(hostname=opts.host, port=opts.port,
                             userid=opts.user, password=opts.password,
                             virtual_host=opts.vhost)
@@ -103,7 +109,7 @@ if __name__ == '__main__':
     consumer = Consumer(connection=conn, queue=opts.queue,
                         exchange=opts.exchange, routing_key=opts.key,
                         exchange_type="topic")
-    
+
     callback = None
     if opts.callback:
         cb = opts.callback.rsplit('.', 1)
@@ -111,16 +117,19 @@ if __name__ == '__main__':
             __import__(cb[0])
             cb_module = sys.modules[cb[0]]
             callback = getattr(cb_module, cb[1])
-    
+
     def process_message(message_data, message):
         logger.debug('%s', message_data)
         if callback:
             callback(message_data)
         message.ack()
-    
+
     consumer.register_callback(process_message)
     try:
         consumer.wait()
     except KeyboardInterrupt:
         pass
 
+if __name__ == '__main__':
+    main()
+