ocaml/dune

Flush output buffers on SIGTERM

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#3,882 opened on Oct 21, 2020

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good first issue

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Description

We're currently using dune runtest in OCaml-CI as the standard way of running tests for a package. If some of the tests for a package get stuck in a deadlock, the CI job will kill the process after 60 minutes. Unfortunately, this means that the logs of the stalled test run are lost.

We could switch to using dune runtest --no-buffer in the CI, but this creates less readable (interleaved) test output. One possible alternative would be for Dune to flush its output buffers before responding to SIGTERM (probably keeping the old behaviour for SIGKILL). What do you think?

Contributor guide

Research direction
Investigate how Dune currently handles output buffering and signal handling (SIGTERM). Look at the main loop and signal handlers to understand where to add a flush of stdout/stderr buffers before exiting. Ensure that SIGKILL still does not flush, as requested.
Tech stack
None
Domain
build systemdevopsdeveloper experience
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
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
OCamlsignal handling basics
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50