improve helper utilities

bin/drain-queue

@@ -0,0 +1,48 @@
+#!/usr/bin/env python
+# vim: set sw=4 et:
+import os
+import sys
+import argparse
+import logging
+import socket
+from kombu import Connection, Exchange, Queue
+
+arg_parser = argparse.ArgumentParser(prog=os.path.basename(sys.argv[0]),
+        description='drain-queue - consume messages from AMQP queue',
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter)
+arg_parser.add_argument('-u', '--url', dest='amqp_url', default='amqp://guest:guest@localhost:5672/%2f',
+        help='URL identifying the AMQP server to talk to')
+arg_parser.add_argument('--exchange', dest='amqp_exchange', default='umbra',
+        help='AMQP exchange name')
+arg_parser.add_argument('--queue', dest='amqp_queue', default='urls',
+        help='AMQP queue name')
+arg_parser.add_argument('-n', '--no-ack', dest='no_ack', action="store_const",
+        default=False, const=True, help="leave messages on the queue (default: remove them from the queue)")
+arg_parser.add_argument('-r', '--run-forever', dest='run_forever', action="store_const",
+        default=False, const=True, help="run forever, waiting for new messages to appear on the queue (default: exit when all messages in the queue have been consumed)")
+arg_parser.add_argument('-v', '--verbose', dest='log_level',
+        action="store_const", default=logging.INFO, const=logging.DEBUG)
+args = arg_parser.parse_args(args=sys.argv[1:])
+
+logging.basicConfig(stream=sys.stderr, level=args.log_level,
+        format='%(asctime)s %(process)d %(levelname)s %(threadName)s %(name)s.%(funcName)s(%(filename)s:%(lineno)d) %(message)s')
+
+def print_and_maybe_ack(body, message):
+    print(body)
+    if not args.no_ack:
+        message.ack()
+
+exchange = Exchange(args.amqp_exchange, 'direct', durable=True)
+queue = Queue(args.amqp_queue, exchange=exchange)
+try:
+    with Connection(args.amqp_url) as conn:
+        with conn.Consumer(queue, callbacks=[print_and_maybe_ack]) as consumer:
+            while True:
+                try:
+                    conn.drain_events(timeout=0.5)
+                except socket.timeout:
+                    if not args.run_forever:
+                        logging.debug("exiting, no messages left on the queue")
+                        break
+except KeyboardInterrupt:
+    logging.debug("exiting, stopped by user")