Getting round the problems with amqsevt.

There is a great sample program amqsevt(a) for printing out data from queues in PCF format, for example event queues, and stats and accounting. I use this to output the data in json format and then process it in python scripts or other tools which handle json format.
Ive noticed a couple of tiny problems with it – which are easy to get round.  I spotted these when trying to parse a file with the json data in it.

  • The output is sometimes like {..} {..} which is not strictly valid json.  It should be [{…},{..}] but hard to create this when streaming the data.  I got json.decoder.JSONDecodeError: Extra data:….
  • It sometimes reports hex strings as very large decimal numbers for example
    • “msgId” :      “414D5120514D412020202020202020202908BA5CF4C9AB23” is OK
    •  “correlId” :   0000000000000000000000000000000000000000000000000 and the json parser complains.  I had json.decoder.JSONDecodeError: Expecting ‘,’ delimiter pointing to the middle of the line with the problem.

I fixed these by passing the json through the great utility jq which cleans this up.

For example

/opt/mqm/samp/bin/amqsevt -m QMA -q SYSTEM.ADMIN.TRACE.ACTIVITY.QUEUE -o json|jq -c .  |python
and use the python code
for x in range(…):
     line = sys.stdin.readline()
     if not line: break
     j = json.loads(line)

jq also cleans up the “correlId” :  000000000000000000000000000000000000000000000  to
“correlId” :   0

Build the sample

To build amqsevta.c, I used the make file

cparms = -Wno-write-strings -g 
clibs = -I. -I../inc -I'/usr/include' -I'/opt/mqm/inc'
rpath = -rpath=/opt/mqm/lib64 -Wl,-rpath=/usr/lib64 
lparms = -L /opt/mqm/lib64 -Wl,$(rpath) -lmqic_r -lpthread 
% : %.c
     gcc -m64 $(cparms) $(clibs) $< -o $@ $(lparms)

and the command make -f xxxx amqsevta


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