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From Bill Freeman <ke1g...@gmail.com>
Subject Re: Questions from a novice
Date Fri, 05 Apr 2013 16:45:02 GMT
Ken,

Yes, with the patch in, I get callbacks to my qmf.console.Console sub-class
instance's callback methods for both V1 and V2 updates.

There are some differences in the plumbing:

    V1 initial updates carry properties only.  V2 initial updates carry
both properties and statistics.  Both are sent to the objectProps()
callback.

    Subsequent updates carry only statistics, for both V1 and V2.  However,
for V1 these updates are sent to the objectStats() callback, while for V2
they are sent to the objectProps() callback.  (I wonder if this was
intended, or whether these were intended to go to objectStats() in V2 as
well).

Hereafter "oid" is an instance of qmf.console.ObjectId acquired by calling
the getObjectId() method of the qmf.console.Object instance that is passed
to the callbacks.

Yes, str(oid) is much prettier for V2.  Having the final component be the
queue name clearly assures stability across broker restarts and unrelated
configurations.  I had trouble with that belief for the hash that is the
final component of the same string for V1.

But the first 4 (dash separated) components of str(oid) don't seem useful
for my purpose of a within broker unique and restart stable identifier.
(Those first four come from oid.getFlags(), oid.getSequence(),
oid.getBrokerBank(), and oid.getAgentBank(), and turn into single digit
numbers for my test case.)  I think that oid.getObject() (returns
oid.objectName, using this directly might be clearer) is more than enough
(on a V2 ObjectId instance, anyway).  Please let me know if you disagree.

oid.isV2 seems to be the correct place to check to know which sort of
record I have.  For now, it I only want to process one kind of record (the
useful V1 and V2 information is redundant) I'm going to use this flag.

However, it would be nice to know how to get the console to only subscribe
to the V2 queues.  It's not clear that I can require the brokers to be
reconfigured as no v1, so it would be nice if there were a console option.
I'll do a bit more reading of the source code, but if anyone can shortcut
that, I'd appreciate it.

Bill

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