[tor-bugs] #8662 [Torperf]: Make Torperf log circuit failures

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#8662: Make Torperf log circuit failures
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 Reporter:  karsten      |          Owner:     
     Type:  enhancement  |         Status:  new
 Priority:  normal       |      Milestone:     
Component:  Torperf      |        Version:     
 Keywords:               |         Parent:     
   Points:               |   Actualpoints:     
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 Mike, Rob, and I briefly discussed at the dev meeting that we could make
 Torperf log circuit failures by adding REASON and REMOTE_REASON from CIRC
 events to Torperf's output whenever a request fails.

 I can see how Torperf learns about circuit failures, but I'm yet unsure
 how to include this information in its output.  Torperf outputs exactly
 one line per measurement.  But if a circuit fails before attaching
 Torperf's measurement stream to it, we'll never learn about that circuit
 in the context of this measurement.  And I assume this isn't just about
 circuits failing after they got a stream attached, right?

 Here are a few options:

  * We don't include circuit failure information in Torperf's results, but
 log CIRC events locally to a separate file.  These CIRC event log files
 won't be archived or made publicly available.  This may work if we're only
 looking for changes in CIRC failures within the next few weeks or so.

  * We add a new field to Torperf's output collecting all CIRC failures
 since the last measurement.  This is somewhat similar to the QUANTILE and
 TIMEOUT fields that contain values from the last received BUILDTIMEOUT_SET
 event.

  * We give up the one-output-line-per-measurement format and add further
 information to Torperf's output.  This is a rather big data format change
 though.  If we were to do this, we should also move QUANTILE and TIMEOUT
 to their own lines.

 Thoughts?

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/8662>
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