Hi everyone,
Could someone help explain what I am doing wrong in
this code block?
This code block is an excerpt from a larger file that receives
transmitted files via IBM WebSphere MQSeries an drops it to the local
file system.
Transmission of the file works as designed but it has a flaw.
If the file cannot be created for whatever reason, the transmitted
message is lost.
What I am trying to do is ensure that a file transmit is considered
successful only after the created file's checksum matches.
If not, the code should treat it as an error and roll back the message
to MQSeries without a commit.
The basis for this should be around the pymqi.QueueManager class which
is named mq in the block listed below.
On execution, I get the traceback of:
Traceback (most recent call last):
File "M:\MQ\MQ\Scripts\receiver.py", line 269, in ?
receiver.run()
File "M:\MQ\MQ\Scripts\receiver.py", line 109, in run
self.connect()
File "M:\MQ\MQ\Scripts\receiver.py", line 118, in connect
self.qm.begin()
File "c:\python24\lib\site-packages\pymqi.py", line 738, in begin
raise MQMIError(rv[0], rv[1])
pymqi.MQMIError: MQI Error. Comp: 1, Reason 2121: WARNING:
MQRC_NO_EXTERNAL_PARTICIPANTS
Do you have any idea why this might be occurring?
class Receiver(object):
def __init__(self,qm_name,queue_name):
self.qm_name = qm_name
self.queue_name = queue_name
# Will be set later
self.qm = None
self.message = None
def run(self):
self.connect()
self.get()
def connect(self):
"""
Connect to queue manager
"""
try:
self.qm = mq.QueueManager(options.qmanager.upper() )
self.qm.begin()
except mq.PYIFError, err:
mqevlog.event("error",err)
sys.exit(1)
def get(self):
"""
Get a message from queue.
"""
queue = mq.Queue(self.qm, self.queue_name)
pmo = mq.pmo(Options = CMQC.MQPMO_SYNCPOINT)
md = mq.md()
while True:
try:
var = queue.get(self.message, md, pmo )
except mq.MQMIError,e:
if e.reason != CMQC.MQRC_NO_MSG_AVAILABLE:
mqevlog.event("error",e)
sys.exit(1)
break
else:
buff = StringIO(var)
tree = ElementTree(file=buff)
# Extract required elements and assign to local
variables
key = "this should be a well-kept secret"
file_name = tree.find("dest").text
creation_time = tree.find("creation_time").text
contents = tree.find("contents").text
check = tree.find("checksum").text
#Decode temp file
original = file_encoder.decode(contents)
# Drop file to disk
if os.path.exists(file_name) is False:
open(file_name,"wb").write(original)
else:
mqevlog.event(sys.argv[0],"error","Output file
path/name already
exists")
sys.exit(1)
# Get checksum of newly created file
sum=csums.getsum(file_name)
# Compare checksum of created file with value
transmitted
if
csums.checksum_compare(sys.argv[0],sum,check,file_name) == True:
queue.commit()
sys.exit(0)
else:
queue.backout()
mqevlog.event("error","CheckSums of
received/transmitted files do not match")
sys.exit(1)
Any help/insight you can provide on this would be greatly appreciated.
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