
The Passport: A Tool for Better Metrics (2016) - llambda
https://eng.fitbit.com/the-passport-a-tool-for-better-metrics/
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ipsocannibal
We actually adopted this model of metric generation for our Netty based
application. From our experience there are a couple of call outs I would like
to mention.

1\. You need to publish the graph of your application state transitions along
with examples passports of known "good" executions. Without these passports
have limited value for debugging because they themselves don't give a clear
indication of what should have happened. Frankly, I've found passports to be
unreadible without referencing the state transition diagram.

2\. Your application state transitions change overtime. So must your
passports. Depending on how you've implemented your application this can be
either trivial or maddening. In both cases though the passport change needs to
occur along with the application change. Otherwise you passports will no
longer be reflective of what your application currently is doing.

