[GitHub] rabbah commented on issue #2282: Distributed tracing support #2192

[gi...@git.apache.org]

rabbah commented on issue #2282: Distributed tracing support #2192
URL: https://github.com/apache/incubator-openwhisk/pull/2282#issuecomment-308475467
 
 
   I already raised some objections to these changes. I'll summarize them:
   
   1. the added overhead on the activation message in space means messages that were already working will no longer work in a production system for the same payload; this is a concern
   2. will need a test to ensure that whatever the desired invariant are from the sampling is actually being captured
   3. in addition to a test for the sampling itself, we need a test to confirm that when the sample rate is 0 (ie no tracing), the size of the activation message is not affected
   
   I have a general concern about accepting one-offs and deferring the refactoring. Who's committing to doing the refactoring? Further, as I noticed, in some deployments, this will not be enabled at all. So we are incurring additional overhead for some deployments without articulating the gains. I think we have to be extra vigilant on this point as we have more contributors now and more community partners and just today there was a discussion about just this PR and why the OpenTracing (http://opentracing.io/) is not used instead of a direct integration. 
   
   I have only made a cursory pass over the code but if you want to pursue this in its current form, I think I and others will likely want to make a more critical pass over the actual code.
 
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