Redirect LOG_FD also when suppressing log messages

[lmagyar]

Proposed Changes

Sadly we must use eval, ${LOG_FD}> /dev/null never redirected, only string constants (like 10> /dev/null are interpreted as file descriptor. This is how bash works.

Related Issues

Summary by CodeRabbit

• Refactor
  • Improved internal supervisor API call execution and logging configuration across startup initialization scripts to enhance reliability and consistency in command processing.

[coderabbitai]

Walkthrough

Three bash scripts in the Tailscale addon are updated to wrap supervisor API calls with eval and incorporate ${LOG_FD} into output redirection, altering how logging and file descriptor streams are handled during startup checks and polling loops without changing control flow logic.

Changes

Cohort / File(s)	Summary
Startup API Calls tailscale/rootfs/etc/s6-overlay/s6-rc.d/forwarding/run, tailscale/rootfs/etc/s6-overlay/s6-rc.d/local-network/run	Wraps bashio::api.supervisor GET calls with eval to adjust output redirection using ${LOG_FD} during network interface initialization checks.
Supervisor Readiness Polling tailscale/rootfs/usr/bin/protect-subnet-routes	Wraps two bashio::api.supervisor GET calls with eval incorporating ${LOG_FD} redirection in the supervisor-readiness polling loop.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• Reinitialize bashio log outputs to the redirected stdout #567 — Updates supervisor API calls to use eval with ${LOG_FD} redirection, matching bashio logging reinitialization patterns.
• Temporary workaround for base image and bashio logging bug #568 — Exports ${LOG_FD} in scripts to enable the eval-based redirections used across startup and polling logic.

Suggested labels

no-stale

Suggested reviewers

• frenck

Poem

🐰 A rabbit hops through logs so bright,
Redirecting streams with eval's might,
Where LOG_FD flows like morning dew,
The scripts now log what they pursue! 📝✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the main change: redirecting LOG_FD when suppressing log messages, which is the core objective across all three modified files.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[lmagyar]

@coderabbitai review

[coderabbitai]

✅ Actions performed

Review triggered.

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[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (1)

tailscale/rootfs/usr/bin/protect-subnet-routes (1)

29-30: Consider a shared silent Supervisor probe helper.

This exact eval + dynamic LOG_FD redirection now appears twice in this file and in both s6 run scripts. A small wrapper would give you one place to validate LOG_FD and one place to adjust the redirection syntax later.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@tailscale/rootfs/usr/bin/protect-subnet-routes` around lines 29 - 30, Extract
the duplicated silent Supervisor probe logic (the eval "bashio::api.supervisor
GET ... &> /dev/null ${LOG_FD}> /dev/null" pattern) into a single helper
function (e.g., supervisor_silent_probe or probe_supervisor) that
validates/normalizes LOG_FD and performs the dynamic redirection, then replace
both occurrences (the while loop condition in protect-subnet-routes and the two
s6 run scripts) with calls to that helper; ensure the helper accepts the full
API path string and returns the original command exit status so existing
while/if logic (using the helper name) works unchanged.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@tailscale/rootfs/etc/s6-overlay/s6-rc.d/forwarding/run`:
- Line 79: LOG_FD is interpolated directly into eval which breaks when it
contains non-digits; add the same guard used in healthcheck/protect-subnets to
validate LOG_FD is numeric before embedding it. Specifically, in forwarding/run
(the eval invoking "bashio::api.supervisor GET /network/interface/default/info
..."), and likewise in protect-subnet-routes and local-network/run, check that
LOG_FD matches a digits-only regex (e.g. ^[0-9]+$) and only append the
redirection token into the eval when that check passes (otherwise fall back to a
safe default or omit the redirection). Reference the existing validation pattern
in healthcheck/protect-subnets and apply it to these eval usages so non-numeric
inherited values do not produce shell syntax errors.

---

Nitpick comments:
In `@tailscale/rootfs/usr/bin/protect-subnet-routes`:
- Around line 29-30: Extract the duplicated silent Supervisor probe logic (the
eval "bashio::api.supervisor GET ... &> /dev/null ${LOG_FD}> /dev/null" pattern)
into a single helper function (e.g., supervisor_silent_probe or
probe_supervisor) that validates/normalizes LOG_FD and performs the dynamic
redirection, then replace both occurrences (the while loop condition in
protect-subnet-routes and the two s6 run scripts) with calls to that helper;
ensure the helper accepts the full API path string and returns the original
command exit status so existing while/if logic (using the helper name) works
unchanged.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: e8b0276c-2761-423a-b7b4-98a7d3c307ae

📥 Commits

Reviewing files that changed from the base of the PR and between 02fbebc and f2323ce.

📒 Files selected for processing (3)

• tailscale/rootfs/etc/s6-overlay/s6-rc.d/forwarding/run
• tailscale/rootfs/etc/s6-overlay/s6-rc.d/local-network/run
• tailscale/rootfs/usr/bin/protect-subnet-routes