python/examples/tx_recv.py

#!/usr/bin/env python
#
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.
#

from __future__ import print_function
import optparse
from proton import Url
from proton.reactor import Container
from proton.handlers import MessagingHandler, TransactionHandler


class TxRecv(MessagingHandler, TransactionHandler):
    def __init__(self, url, messages, batch_size):
        super(TxRecv, self).__init__(prefetch=0, auto_accept=False)
        self.url = Url(url)
        self.expected = messages
        self.batch_size = batch_size
        self.current_batch = 0
        self.committed = 0

    def on_start(self, event):
        self.container = event.container
        self.conn = self.container.connect(self.url)
        self.receiver = self.container.create_receiver(self.conn, self.url.path)
        self.container.declare_transaction(self.conn, handler=self)
        self.transaction = None

    def on_message(self, event):
        print(event.message.body)
        self.transaction.accept(event.delivery)
        self.current_batch += 1
        if self.current_batch == self.batch_size:
            self.transaction.commit()
            self.transaction = None

    def on_transaction_declared(self, event):
        self.receiver.flow(self.batch_size)
        self.transaction = event.transaction

    def on_transaction_committed(self, event):
        self.committed += self.current_batch
        self.current_batch = 0
        if self.expected == 0 or self.committed < self.expected:
            self.container.declare_transaction(self.conn, handler=self)
        else:
            event.connection.close()

    def on_disconnected(self, event):
        self.current_batch = 0


parser = optparse.OptionParser(usage="usage: %prog [options]")
parser.add_option("-a", "--address", default="localhost:5672/examples",
                  help="address from which messages are received (default %default)")
parser.add_option("-m", "--messages", type="int", default=100,
                  help="number of messages to receive; 0 receives indefinitely (default %default)")
parser.add_option("-b", "--batch-size", type="int", default=10,
                  help="number of messages in each transaction (default %default)")
opts, args = parser.parse_args()

try:
    Container(TxRecv(opts.address, opts.messages, opts.batch_size)).run()
except KeyboardInterrupt:
    pass