2a2f10f2e9
DockerBuildRunner appended TESTCONTAINERS_HOST_OVERRIDE=localhost after the docker.env entries, so a host could not name another address. A rootless daemon with the slirp4netns port driver publishes ports on 10.0.2.100; vm4006 needs exactly that since its daemon switched. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Co-authored-by: mhoennig <michael@hoennig.de> Reviewed-on: #85
44 lines
2.3 KiB
Markdown
44 lines
2.3 KiB
Markdown
> **WARNING:** This document describes only the change applied in this PR.
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> It may already be outdated once the next PR is merged.
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> Historic PR-documentation is not maintained along with new PRs — treat it as a snapshot, not as current documentation.
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## The Problem
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Since 2026-10-01 every Testcontainers test of hs.hsadmin.ng fails on vm4006 with "Connection to localhost:<port> refused".
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The rootless Docker daemon there runs with the `slirp4netns` port driver now: its unit was rewritten on 2026-09-23 and took effect at a reboot.
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With this driver, `docker-proxy` listens on the child address `10.0.2.100` inside the daemon's network namespace, not on `localhost`.
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A build container with `network: host` lives in that namespace, so Testcontainers must connect to `10.0.2.100`.
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The host set `TESTCONTAINERS_HOST_OVERRIDE: "10.0.2.100"` in `docker.env`, but `DockerBuildRunner` appended its own `TESTCONTAINERS_HOST_OVERRIDE=localhost` after it, and the last `--env` wins.
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## Non-Goals
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- No detection of the port driver; the host knows its daemon, and one line in the machine config says so.
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- No change to the default for hosts that set nothing.
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## The Scenarios
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### Feature: the host decides where Testcontainers reaches its ports
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#### Scenario#85.01: A host override in docker.env wins
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So that a host whose daemon publishes ports elsewhere can say so, and undo it by deleting the line.
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- **Given** a build with `TESTCONTAINERS_HOST_OVERRIDE` in `docker.env`
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- **When** Werkator starts its container
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- **Then** the container gets that value, once
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- **Given** no such entry, **then** the default stays: `localhost` with `network: host`, `host.docker.internal` otherwise
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##### Verified by
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- [DockerBuildRunnerTest](../../src/test/kotlin/de/hoennig/werkator/build/DockerBuildRunnerTest.kt) — the override from `docker.env` passed once; the existing default tests for host and bridge networks
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## The Solution
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`DockerBuildRunner.runArgs` appends its default `TESTCONTAINERS_HOST_OVERRIDE` only when `docker.env` has none.
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Switching back is a configuration change, not a Werkator update: should the daemon go back to the `builtin` port driver, the host deletes its entry and the default applies again.
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## Additional Changes
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- `docs/configuration.md` and the architecture skill describe the default and the override.
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- Version 1.24.1 with its release note.
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