IBM MQ Error - Reason 2012: FAILED: MQRC_ENVIRONMENT_ERROR

Question

I am trying to connect with IBM MQ using Python's 'pymqi' library.

I want to use the transaction capability in the IBM MQ but it showing me MQI Error. Comp: 2, Reason 2012: FAILED: MQRC_ENVIRONMENT_ERROR.

The code is working as regular but it error happened after adding qmgr.begin() statement.

Required assistance.

import logging
from datetime import datetime
import pymqi

logging.basicConfig(level=logging.INFO)
queue_manager = 'QM1'
channel = b'DEV.APP.SVRCONN'
host = '127.0.0.1'
port = '1414'
queue_name = 'DEV.QUEUE.1'

conn_info = f'{host}({port})'
conn_info = conn_info.encode('utf-8')
user = 'app'
password = 'xxxxxx'

# Setting up CD() parameters
cd = pymqi.CD()
cd.ChannelName = channel
cd.ConnectionName = conn_info
cd.ChannelType = pymqi.CMQC.MQCHT_CLNTCONN
cd.TransportType = pymqi.CMQC.MQXPT_TCP

# Message to be sent
message = f'Message sent to {queue_name} at: {datetime.now()}'

kwargs = {
    'user': user,
    'password': password,
    'cd': cd
}

try:
    # Connect to the queue manager
    qmgr = pymqi.QueueManager(None)
    qmgr.connect_with_options(queue_manager, **kwargs)

    # Start a transaction
    qmgr.begin()

    try:
        # Open the queue within the transaction
        queue = pymqi.Queue(qmgr, queue_name)

        # Put a message to the queue within the transaction
        queue.put(message)
        logging.info(message)

        # Close the queue within the transaction
        queue.close()

        # Commit the transaction
        qmgr.commit()

    except pymqi.MQMIError as e:
        # Rollback the transaction in case of an error
        logging.error(f"MQI error: {e}")
        qmgr.backout()
        raise

    finally:
        # End the transaction
        qmgr.disconnect()

except pymqi.MQMIError as e:
    logging.error(f"MQI error: {e}")

Answer 1

qmgr.begin() will use MQBEGIN which is not allowed on a client connection.

Local transactions in MQ are automatically started if you do a put or get with the syncpoint option set. This is suitable if want a transaction that only includes updates involving a single MQ queue manager. You can specify the syncpoint option on put as follows:

md = pymqi.MD()
pmo = pymqi.PMO()
pmo.Options = pymqi.CMQC.MQPMO_SYNCPOINT
queue.put(message,md,pmo)

Global transactions coordinated by MQ are only allowed for bindings connection applications, not for clients.

Global transactions including MQ using client connection need to use an XA-compliant external transaction coordinator and configure the MQ extended transactional client. This is documented here: https://www.ibm.com/docs/en/ibm-mq/9.3?topic=server-configuring-extended-transactional-client.

The application will need to use the transaction manager coordination calls rather than MQ calls for operations like commit or backout.