Script file to retrieve MQ messages from the queue manager - ibm-mq

Question

I want to write a script file that will append the arrived MQ messages in the Queue Manager in a log file.Please help

Answer 1

If you want all messages arriving on a channel, you can use the LogIP exit from the BlockIP2 page of mrmq.dk. An API exit such as SupportPac MA0W can log all messages put. An API exit can catche messages from local applications as well as those arriving over channels.
If you want to script this, you can use a program such as Q (from SupportPac MA01) to remove the messages from the queue as they arrive and append them to a file.
For example,
#!/usr/bin/ksh
q -IMYQMGR/MY.QUEUE >> logfile.txt
Typically, the script is triggered and configured to append new messages to the file. The problem with this is that it destructively removes the messages. If there is an application of record needing to use those messages it isn't a great solution. You could browse the queue but there's no guarantee of getting the messages before the app of record gets them - and the browse would periodically restart at the head of the queue so you might log the same message twice.
Another scripting option is the Perl MQSeries module. This module exposes all the options of the WMQ API as well as object-oriented methods. If you need something quick and dirty, the Q program is delivered as an executable. If you want something powerful that exposes all the APIs to your script (and don't mind compiling it) the Perl MQSeries module is a great way to go. Here's a code snippet, taken from the module's samples, showing how to GET messages:
while (1) {
$sync_flag = 0;
undef $outcome;
my $request_msg = MQSeries::Message::->new();
my $status = $request_queue->
Get('Message' => $request_msg,
'GetMsgOpts' =>
{
'WaitInterval' => 5000, # 5 seconds
'Options' => (MQSeries::MQGMO_WAIT |
MQSeries::MQGMO_SYNCPOINT_IF_PERSISTENT |
MQSeries::MQGMO_CONVERT |
MQSeries::MQGMO_FAIL_IF_QUIESCING),
},
);
unless ($status) { # Error
my $rc = $request_queue->Reason();
die "Error on 'Get' from queue $qmgr_name/$request_qname:\n" .
"\tReason: $rc (" . MQReasonToText($rc). ")\n";
}
next if ($status < 0); # No message available
One thing people have done in the past is to convert the queue to an alias over a topic. The app that uses the messages is redirected to GET from a new queue and an administrative subscription connects the topic to the new queue. At this point the real app gets all the messages and a new subscription can be made for logging messages going through the topic.