feat: fail fast when DOCKER_HOST points to an external daemon (workflow-scope DinD) by Copilot · Pull Request #1909 · github/gh-aw-firewall

Copilot · 2026-04-11T15:14:57Z

Workflow-scope DinD (DOCKER_HOST=tcp://localhost:2375) silently breaks AWF because Docker Compose routes container creation through the DinD daemon's network namespace, where AWF's fixed subnet (172.30.0.0/24) and iptables DNAT rules are unreachable from the runner.

Changes

Fail-fast check (src/cli.ts): checkDockerHost() inspects DOCKER_HOST at startup. Any value other than the two canonical local sockets (unix:///var/run/docker.sock, unix:///run/docker.sock) exits immediately with a clear error:

❌ DOCKER_HOST is set to an external daemon (tcp://localhost:2375). AWF requires the
local Docker daemon (default socket). Workflow-scope DinD is incompatible with AWF's
network isolation model. See the "Workflow-Scope DinD Incompatibility" section in
docs/usage.md for details and workarounds.

Documentation (docs/usage.md): New Workflow-Scope DinD Incompatibility subsection under Limitations — explains root cause, the error message, and the --enable-dind workaround for agents that genuinely need Docker access.
Tests (src/cli.test.ts): 7 unit tests for checkDockerHost() covering absent/undefined env var, both valid local socket paths, TCP, TLS TCP, and non-standard unix socket.

Add checkDockerHost() to src/cli.ts that inspects DOCKER_HOST on startup. If it points at a non-default socket (e.g. tcp://localhost:2375 for a DinD sidecar), AWF exits immediately with a clear error explaining why it is incompatible and pointing at the new docs section. Also add a "Workflow-Scope DinD Incompatibility" section to docs/usage.md documenting the root cause, the error message users will see, and the --enable-dind workaround for agents that genuinely need Docker access. Agent-Logs-Url: https://github.com/github/gh-aw-firewall/sessions/d99ee10d-b3d6-4811-a197-9eb8bb15da2a

Copilot

Pull request overview

Adds an early-startup guard to prevent AWF from running when DOCKER_HOST is configured to use workflow-scope DinD (or any non-default Docker socket), since that breaks AWF’s network/iptables isolation assumptions.

Changes:

Add checkDockerHost() and invoke it in the main CLI action to fail fast on unsupported DOCKER_HOST values.
Add unit tests covering allowed/blocked DOCKER_HOST cases.
Document the workflow-scope DinD incompatibility and the --enable-dind workaround.

Show a summary per file

File	Description
src/cli.ts	Introduces `checkDockerHost()` and a startup fail-fast check before running the main workflow.
src/cli.test.ts	Adds targeted unit tests for the new `checkDockerHost()` validation behavior.
docs/usage.md	Documents why workflow-scope DinD breaks AWF and provides guidance/workarounds.

Copilot's findings

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Files reviewed: 3/3 changed files
Comments generated: 2

Copilot · 2026-04-11T15:41:52Z

+  return {
+    valid: false,
+    error:
+      `DOCKER_HOST is set to an external daemon (${dockerHost}). ` +
+      'AWF requires the local Docker daemon (default socket). ' +
+      'Workflow-scope DinD is incompatible with AWF\'s network isolation model. ' +
+      'See the "Workflow-Scope DinD Incompatibility" section in docs/usage.md for details and workarounds.',
+  };


checkDockerHost() rejects non-default unix:// sockets (e.g. unix:///tmp/custom-docker.sock) but the returned error always says "external daemon", which is inaccurate/misleading for local unix sockets. Either (a) change the wording to something like "unsupported DOCKER_HOST value" and explicitly list the only supported socket values, or (b) loosen the check to allow any unix:// socket and only block remote schemes (tcp://, ssh://, etc.).

Copilot · 2026-04-11T15:41:53Z

+      }
+    });
+
+    it('should return invalid for a TLS TCP daemon', () => {


This test name implies TLS based only on port 2376, but TLS is controlled by DOCKER_TLS_VERIFY/cert env vars, not the port number. Consider renaming to avoid encoding an assumption (e.g., "should return invalid for a TCP daemon on a non-default port").

Suggested change

it('should return invalid for a TLS TCP daemon', () => {

it('should return invalid for a TCP daemon on a non-default port', () => {

github-actions · 2026-04-11T16:41:25Z

Documentation Preview

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Built from commit da58570

github-actions · 2026-04-11T16:41:36Z

⚠️ Coverage Regression Detected

This PR decreases test coverage. Please add tests to maintain coverage levels.

Overall Coverage

Metric	Base	PR	Delta
Lines	85.33%	85.35%	📈 +0.02%
Statements	85.18%	85.20%	📈 +0.02%
Functions	87.45%	87.50%	📈 +0.05%
Branches	77.69%	77.67%	📉 -0.02%

📁 Per-file Coverage Changes (2 files)

File	Lines (Before → After)	Statements (Before → After)
`src/cli.ts`	61.0% → 61.1% (+0.10%)	61.4% → 61.5% (+0.09%)
`src/docker-manager.ts`	85.9% → 86.2% (+0.32%)	85.5% → 85.8% (+0.31%)

Coverage comparison generated by scripts/ci/compare-coverage.ts

github-actions · 2026-04-11T16:55:34Z

Smoke Test Results — run 24287094163

✅ GitHub MCP: "fix: remove duplicate paragraph..." / "fix: loosen checkDockerHost..."
✅ Playwright: github.com title contains "GitHub"
✅ File write: /tmp/gh-aw/agent/smoke-test-claude-24287094163.txt created and verified
✅ Bash: file content confirmed

Overall: PASS

💥 [THE END] — Illustrated by Smoke Claude

github-actions · 2026-04-11T16:55:44Z

🤖 Smoke Test Results

Test	Status
GitHub MCP (`#1913 fix: remove duplicate paragraph...`)	✅
GitHub.com connectivity (HTTP 200)	✅
File write/read (`smoke-test-copilot-24287094158.txt`)	✅

Overall: PASS · PR by @app/copilot-swe-agent · Assignees: @lpcox @Copilot

📰 BREAKING: Report filed by Smoke Copilot

github-actions · 2026-04-11T16:56:20Z

Smoke Test Results
PR Titles: feat: fail fast when DOCKER_HOST points to an external daemon (workflow-scope DinD); fix: loosen checkDockerHost to accept any unix:// socket; fix misleading test name

GitHub MCP last 2 merged PRs ✅
safeinputs-gh PR query ❌
Playwright github.com title contains GitHub ✅
Tavily search returned results ❌
File write in /tmp/gh-aw/agent ✅
Bash cat verification ✅
Discussion query + mystical comment ❌
npm ci && npm run build ✅
Overall: FAIL

🔮 The oracle has spoken through Smoke Codex

github-actions · 2026-04-11T16:56:29Z

Chroot Version Comparison Results

Runtime	Host Version	Chroot Version	Match?
Python	Python 3.12.13	Python 3.12.3	❌ NO
Node.js	v24.14.1	v20.20.2	❌ NO
Go	go1.22.12	go1.22.12	✅ YES

Overall: ❌ Not all tests passed — Python and Node.js versions differ between host and chroot environment.

Tested by Smoke Chroot

github-actions · 2026-04-11T16:56:50Z

Smoke Test: GitHub Actions Services Connectivity ✅

All checks passed:

Check	Result
Redis PING (`host.docker.internal:6379`)	✅ `PONG`
PostgreSQL ready (`host.docker.internal:5432`)	✅ `accepting connections`
PostgreSQL `SELECT 1` (db: `smoketest`, user: `postgres`)	✅ returned `1`

Note: redis-cli was not pre-installed; Redis was tested via nc (raw RESP protocol).

🔌 Service connectivity validated by Smoke Services

github-actions · 2026-04-11T16:57:50Z

🏗️ Build Test Suite Results

Ecosystem	Project	Build/Install	Tests	Status
Bun	elysia	✅	1/1 passed	✅ PASS
Bun	hono	✅	1/1 passed	✅ PASS
C++	fmt	✅	N/A	✅ PASS
C++	json	✅	N/A	✅ PASS
Deno	oak	N/A	1/1 passed	✅ PASS
Deno	std	N/A	1/1 passed	✅ PASS
.NET	hello-world	✅	N/A	✅ PASS
.NET	json-parse	✅	N/A	✅ PASS
Go	color	✅	1/1 passed	✅ PASS
Go	env	✅	1/1 passed	✅ PASS
Go	uuid	✅	1/1 passed	✅ PASS
Java	gson	✅	1/1 passed	✅ PASS
Java	caffeine	✅	1/1 passed	✅ PASS
Node.js	clsx	✅	all passed	✅ PASS
Node.js	execa	✅	all passed	✅ PASS
Node.js	p-limit	✅	all passed	✅ PASS
Rust	fd	✅	1/1 passed	✅ PASS
Rust	zoxide	✅	1/1 passed	✅ PASS

Overall: 8/8 ecosystems passed — ✅ PASS

Notes

Java: Maven required -Dmaven.repo.local=/tmp/gh-aw/agent/m2repo workaround because the default ~/.m2/repository directory was not writable in this runner environment. Both projects compiled and tested successfully once the alternate repo path was used.

Generated by Build Test Suite for issue #1909 · ● 644.3K · ◷

Initial plan

36c3292

Copilot AI assigned Copilot and lpcox Apr 11, 2026

Copilot started work on behalf of lpcox April 11, 2026 15:15 View session

Copilot AI linked an issue Apr 11, 2026 that may be closed by this pull request

[awf] docker-manager: workflow-scope DinD (DOCKER_HOST) breaks AWF container networking #1898

Closed

Copilot AI changed the title ~~[WIP] Fix Docker-in-Docker workflow scope for AWF~~ feat: fail fast when DOCKER_HOST points to an external daemon (workflow-scope DinD) Apr 11, 2026

Copilot AI requested a review from lpcox April 11, 2026 15:21

Copilot finished work on behalf of lpcox April 11, 2026 15:21

lpcox marked this pull request as ready for review April 11, 2026 15:38

lpcox requested a review from Mossaka as a code owner April 11, 2026 15:38

Copilot AI review requested due to automatic review settings April 11, 2026 15:38

Copilot started reviewing on behalf of lpcox April 11, 2026 15:39 View session

Copilot AI reviewed Apr 11, 2026

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Copilot AI mentioned this pull request Apr 11, 2026

fix: loosen checkDockerHost to accept any unix:// socket; fix misleading test name #1912

Merged

Merge branch 'main' into copilot/fix-dind-container-networking

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[aw] No-Op Runs #1668

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Merge branch 'main' into copilot/fix-dind-container-networking

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lpcox merged commit 8c9668c into main Apr 11, 2026
30 of 32 checks passed

lpcox deleted the copilot/fix-dind-container-networking branch April 11, 2026 16:52

	it('should return invalid for a TLS TCP daemon', () => {
	it('should return invalid for a TCP daemon on a non-default port', () => {

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Copilot AI commented Apr 11, 2026 •

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