feat(container): narrow build target scope to tracker image needs (closes #1853)

[josecelano]

Summary

Removes --benches --examples --all-targets from all 6 cargo commands in the Containerfile (cargo chef cook × 2, warmup cargo nextest archive × 2, final cargo nextest archive × 2).

Baseline analysis (#1841) confirmed that 27/30 top compile units are unrelated to the runtime image, with benchmarks and examples alone accounting for ~250–300 s of avoidable link cost per profile.

Also fixes a pre-existing .dockerignore bug introduced by #1851: that audit excluded all of contrib/dev-tools/ except su-exec/, but PR #1863 (issue #1852) later added a recipe-stage COPY for contrib/dev-tools/analysis/workspace-coupling/Cargo.toml. That path is a workspace member, so cargo chef prepare requires its manifest. This bug caused local cold builds to fail silently (GHA layer-cache hits masked it in CI). Fix: add !/contrib/dev-tools/analysis/workspace-coupling/Cargo.toml to .dockerignore.

Changes

• Containerfile: remove --benches --examples --all-targets from:
  • cargo chef cook (debug and release)
  • warmup cargo nextest archive (debug and release)
  • final cargo nextest archive (debug and release)
• .dockerignore: add !/contrib/dev-tools/analysis/workspace-coupling/Cargo.toml exception
• docs/issues/open/1853-.../ISSUE.md: T1–T3 DONE, M1/M2 DONE with evidence, AC1/AC2 DONE

Verification

• linter all ✅
• cargo test (all tests) ✅
• Pre-push checks (nightly fmt, check, doc, stable tests) ✅
• Cold no-cache release build: 5m23s ✅
• docker run --rm torrust-tracker:1853-test ls /usr/bin/torrust-tracker /usr/bin/http_health_check → both present ✅
• Release image size: 173 MB ✅

Pending (CI)

• AC3: container workflow timing improvement (CI will show before/after)
• AC4: Docker E2E compatibility (CI testing.yaml)

Related

• Part of EPIC #1840 — Improve PR Workflow Performance
• Depends on baseline #1841
• Fixes .dockerignore regression from #1851 exposed by #1852

[Copilot]

Pull request overview

This PR speeds up container image builds by narrowing the Rust build target scope in the Containerfile to only what’s needed for the tracker runtime image (while still retaining tests), and fixes a .dockerignore regression that could break local cold builds due to a missing workspace member manifest.

Changes:

• Remove --benches --examples --all-targets from cargo chef cook and cargo nextest archive commands in the Containerfile (debug + release, warmup + final archive).
• Add a .dockerignore exception so contrib/dev-tools/analysis/workspace-coupling/Cargo.toml is included in the Docker build context (required by the recipe stage manifest-only COPY).
• Update the issue spec doc for #1853 with completed tasks, verification evidence, and acceptance criteria status.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
Containerfile	Narrows cargo build/archive target flags to reduce unnecessary compilation/linking during image build.
.dockerignore	Ensures a required workspace manifest is included so cargo chef prepare can succeed in local cold builds.
docs/issues/open/1853-1840-workflow-performance-containerfile-target-scope/ISSUE.md	Marks tasks/ACs as done and records verification evidence for the change.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 77.78%. Comparing base (455257c) to head (c33f1b8).

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #1867   +/-   ##
========================================
  Coverage    77.78%   77.78%           
========================================
  Files          382      382           
  Lines        28637    28637           
  Branches     28637    28637           
========================================
+ Hits         22274    22275    +1     
  Misses        6054     6054           
+ Partials       309      308    -1     

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[josecelano]

ACK c33f1b8