envoyproxy/envoy

[http] Further improvements to Envoy crash logging.

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#11,432 opened on Jun 3, 2020

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area/envoy_loghelp wanted

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Description

Ref: #7300

We have some logging of the active request on crashes under callstacks that have a ScopeTrackerScopeState but those scoped objects are only associated with events under some HCM, UpstreamRequest and timer callstacks. Also, dumped information is fairly limited.

Possible improvements to ScopeTrackerScopeState to increase dump coverage:

  • Have the FileEventImpl or network::ConnectionImpl hold a pointer to the ScopeTrackedObject associated with the current H1 request or active H2 connection. Add a ScopeTrackerScopeState to ConnectionImpl::onFileEvent/FileEventImpl that calls the dump method on the active request's ScopeTrackedObject
  • Implement a ScopeTrackedObject for H2 connections that dumps basic info about active streams and recent stream/connection level events.

Possible improvements to request dumps:

  • LOG endpoints of the downstream and upstream connection
  • If in the middle of H1 header parsing, dump info about contents of read buffer (up to a limit, probably only the first buffer slice)

Contributor guide

Research direction
Investigate the existing ScopeTrackerScopeState and dump mechanism in Envoy. Determine how to integrate it with FileEventImpl and ConnectionImpl for H1/H2 connections. Extend H2 connection to implement ScopeTrackedObject to dump active streams and events.
Tech stack
cpp
Domain
backendobservability
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Over 1 week
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Needs investigation
Prerequisites
C++EnvoyHTTP/2
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30