envoyproxy/envoy

Indication of connection loss on downstream TCP and HTTP requests

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#21,637 opened on Jun 9, 2022

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area/connectionenhancementhelp wantedno stalebot

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Description

Title: Indication of connection loss on downstream TCP and HTTP requests

Description: Hi Ladies and Gents,

This ticket is the continuation of 21294 that ended with proposal on requesting solution for the described issue as feature.

The request is to:

Indicate TCP connection level issues of downstream client when:

  • connection was established earlier
  • there were http requests received and answered
  • then there is no active http request ongoing
  • something happens on client side with the connection
    • loss of connectivity with client
    • RST is sent from client

With error log information:

  • TCP connection ID
  • and Connection closure reason

In:

  • listener access log

TCP connection listener access log was configured and tried out. Used configuration: base_envoy_config_with_listener_accesslogs.txt.tar.gz Example output that appeared: [2022-06-07T13:43:30.306Z] TCP Connection 100.109.96.1:38321 196 - 0 1780 -

Expected that might %CONNECTION_TERMINATION_DETAILS% operator holds additional information on the connection loss, but showed only "-"

Annotated TCP dump describing visualizing the use case: downstream_client_loss_annotated.pcapng.tar.gz

Contributor guide

Research direction
Examine Envoy's TCP connection handling code (e.g., ConnectionImpl, TcpListener) and access log formatting (FormatterImpl). Determine where connection termination details are available and how to add %CONNECTION TERMINATION DETAILS% to listener access logs. Look at existing access log operators for patterns.
Tech stack
c
Domain
backendnetworking
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
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.
Clear
Prerequisites
C++Envoy internalsTCP networking
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40