fix(daemon): reuse cached service binary on startup

[wizzomafizzo]

Summary

• keep daemon startup/restart executing the cached service binary instead of the source zaparoo.sh
• tolerate cached service ctime drift while preserving strict source metadata checks
• add startup timing logs and daemon tests for cache reuse, ctime drift, and source replacement while running

Checked

• go test ./pkg/service/daemon/ ./pkg/service/
• golangci-lint run pkg/service/daemon pkg/service

Summary by CodeRabbit

• Bug Fixes

  • Improved service-binary cache validation and manifest handling to more reliably reuse cached launch copies and tolerate benign timestamp drift without forcing recopy.

• Chores

  • Added detailed startup timing and debug logs for various initialization phases.

• Tests

  • Added unit tests covering cached-binary/manifest validity and cache-miss launch behavior; simplified a test helper to use port 0.

[coderabbitai]

Worried about impact? Review this PR in Change Stack to explore blast radius before you approve or request changes.

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 0831b99f-b66a-4244-b0bb-91302ba70069

📥 Commits

Reviewing files that changed from the base of the PR and between 2319057 and ce4a318.

📒 Files selected for processing (2)

• pkg/api/client/client_test.go
• pkg/service/daemon/daemon_test.go

🚧 Files skipped from review as they are similar to previous changes (1)

• pkg/service/daemon/daemon_test.go

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📝 Walkthrough

Walkthrough

Refactors manifest-based service-binary cache validation into a reusable helper with launch-specific matching; updates prepareBinary to delegate cache lookups and prune caches on hit; adds tests covering cache reuse behavior; and instruments service startup with timing/debug logs.

Changes

Service Binary Caching Refactor and Startup Instrumentation

Layer / File(s)	Summary
Cache validation helpers and metadata matching pkg/service/daemon/daemon.go	New cachedServiceBinaryFromManifest centralizes manifest and cached-binary validation; new matchesServiceMetadataForLaunch implements launch-specific rules that treat ServiceModTimeNS==0 as a wildcard while requiring size.
prepareBinary refactor and debug logging pkg/service/daemon/daemon.go	prepareBinary delegates manifest cache lookup to cachedServiceBinaryFromManifest (with launchValidation=true); on cache hit prunes other cached binaries. Adds debug logs: restartExecConfig logs selected serviceBin path and Start logs serviceBin with preparation duration.
Cache behavior test cases pkg/service/daemon/daemon_test.go	Adds TestPrepareBinary_UsesValidManifestCache, TestPrepareBinary_UsesCacheWhenOnlyChangeTimeDrifts, and TestStart_CacheMissLaunchesCachedCopy to validate manifest-based cache reuse, tolerance for change-time drift, and startup behavior with cached copies.
Service startup timing and observability pkg/service/service.go	Adds timing instrumentation and structured debug duration logs around environment setup, platform pre-start, DB open, mappings/launcher load, launcher cache init, API readiness timing, and per-cache loads for tag/slug caches; preserves existing error handling.
Client test simplification pkg/api/client/client_test.go	Replaces dynamic ephemeral port probing with unusedPort() returning 0 and removes the net import, simplifying tests that expect no listener.

Sequence Diagram

sequenceDiagram
  participant prepareBinary
  participant cachedServiceBinaryFromManifest
  participant matchesServiceMetadataForLaunch
  prepareBinary->>cachedServiceBinaryFromManifest: call with launchValidation=true
  cachedServiceBinaryFromManifest->>cachedServiceBinaryFromManifest: validate manifest source metadata
  cachedServiceBinaryFromManifest->>cachedServiceBinaryFromManifest: check ServicePath equals cache path
  cachedServiceBinaryFromManifest->>cachedServiceBinaryFromManifest: validate ServicePath is cache-contained
  cachedServiceBinaryFromManifest->>matchesServiceMetadataForLaunch: check cached binary metadata
  matchesServiceMetadataForLaunch-->>cachedServiceBinaryFromManifest: metadata match result
  alt Cache hit
    cachedServiceBinaryFromManifest->>cachedServiceBinaryFromManifest: ensure executable, log cache usage
    cachedServiceBinaryFromManifest-->>prepareBinary: return cached path
  else Cache miss
    cachedServiceBinaryFromManifest->>cachedServiceBinaryFromManifest: log metadata mismatch details
    cachedServiceBinaryFromManifest-->>prepareBinary: return no cache hit
  end

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Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

Possibly related PRs

• ZaparooProject/zaparoo-core#760: Related changes to pkg/service/daemon/daemon.go around service-binary caching/manifest validation and restart config.

Poem

🐰
I hopped through manifests, small and neat,
Found cached binaries snug and sweet,
I pruned the piles and timed the start,
A hopping log of every part—
Cache held fast, the service beats its heart.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'fix(daemon): reuse cached service binary on startup' directly aligns with the primary objective: refactoring daemon startup to execute cached service binaries instead of the source script, with manifest-based caching logic.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/service-binary-cache-startup

---

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@pkg/service/daemon/daemon_test.go`:
- Around line 256-280: The test TestStart_CacheMissLaunchesCachedCopy currently
overwrites the source script at sourcePath but never verifies that the cached
copy is still used; after writing the new contents to sourcePath, either call
svc.Restart() (or svc.Start() again) and assert the running service still logs
the original "started:" entry in eventLog and/or the PID from svc.Pid() remains
from the cached binary, or assert that the eventLog does not contain the string
"replaced" to prove the new source was not executed; update assertions
accordingly to validate cached-copy behavior.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

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

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 09ba3f7c-fcf5-4592-ae0b-8f8d246f9f68

📥 Commits

Reviewing files that changed from the base of the PR and between 46b1d7c and 2319057.

📒 Files selected for processing (3)

• pkg/service/daemon/daemon.go
• pkg/service/daemon/daemon_test.go
• pkg/service/service.go

[sentry]

Codecov Report

❌ Patch coverage is 75.90361% with 20 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
pkg/service/service.go	54.16%	11 Missing ⚠️
pkg/service/daemon/daemon.go	84.74%	5 Missing and 4 partials ⚠️

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