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Monthly Review — Month 2: Standard Library, Tooling & Testing

Journal index · Roadmap › Month 2 · Release notes

🎬 Headline

I can read and write real Go programs with the standard library (I/O, encoding, time, HTTP, context, logging), prove them with the testing package (table tests, benchmarks, fuzzing), and ship them behind reproducible tooling and CI — capped by a stdlib-only URL-shortener tagged v0.2.0.

🛠️ Skills Acquired

Skill Confidence (1-5) Evidence (link)
io.Reader/Writer, bufio, fmt verbs, strings/strconv 4 examples/month-02/io-basics, bufio-scan, fmt-verbs
encoding/json (tags, custom marshalers, streaming) 4 examples/month-02/json-tags
time, net/http client + context cancellation, log/slog 4 time-timers, http-context, slog-structured
Testing: table-driven t.Run, httptest, coverage, benchmarks, fuzzing 4 Week 3 exercises, bench-demo, fuzz-roundtrip
Tooling: go vet, golangci-lint, Makefile, build tags, pprof, CI 3 day 050–054, build-tags, pprof
Concurrency-safe stdlib HTTP service 3 urlshortener, urlstore

📦 Projects Completed

  • URL shortener (stdlib-only) — examples/month-02/urlshortener · base62 codes, sync.RWMutex store with de-dup, net/url validation, explicit method checks with Allow, 302 redirects · key learning: maps need a lock under concurrent HTTP, proven with go test -race.

💡 Lessons Learned

  • The standard library is a complete toolbox for I/O, encoding, time, HTTP, and logging — most "I need a library" reflexes were premature.
  • Tests are documentation that runs: table-driven t.Run subtests, httptest for handlers, testing.B for cost, and testing.F for invariants.
  • Tooling turns "works on my machine" into "works in CI": go vet (auto-run by go test), linters as external binaries, a Makefile gate, and GitHub Actions enforcing it.
  • Build constraints + GOOS/GOARCH make cross-platform builds a two-env-var change because the variant is chosen at compile time.

📉 Areas for Improvement

  • Deeper profiling (pprof memory views, runtime/trace) — only scratched the surface.
  • CI maturity: artifacts, required status checks, reusable workflows.
  • Error-handling polish under load (wrapping with %w, sentinel vs typed errors in a service).

🔁 Concepts to Keep Reviewing (carry into spaced repetition)

  • flat vs cum in pprof; when to reach for runtime/trace.
  • The reference time layout 2006-01-02 15:04:05.
  • Build-constraint exhaustiveness (OS × arch × custom tags).
  • The gofmt -l CI gate gotcha (test -z "$(gofmt -l .)").
  • Loop-var capture in parallel subtests; nil-interface trap.

🧑‍💼 Interview Readiness

Area Ready? Notes
Language fundamentals ✅ slices/append aliasing, value vs pointer receivers, error wrapping, zero values — solid from Month 1, reinforced.
Concurrency 🟨 sync.RWMutex + race-tested maps done; channels/worker-pools/context propagation is Month 3 focus.
Web/DB 🟨 stdlib net/http server + httptest strong; no real database/persistence yet.

🎒 Portfolio Updates

  • Updated example index (examples/month-02/README.md) and Week 4 exercise README.
  • New résumé bullet: "Built a concurrency-safe URL shortener in pure Go (net/http, sync.RWMutex, base62), with table-driven + race-enabled tests and a fmt/vet/lint/test CI gate."
  • Pinned/featured: Month 2 examples + urlshortener capstone.
  • Tagged release v0.2.0 + Month 2 review notes.

📊 Metrics

Total hours Days completed Exercises Projects Books/articles Avg confidence
42 28/28 11 1 8 3.7/5

⏭️ Next Month Preview

Month 3 goes deep on concurrency and real services: goroutines, channels and select axioms, worker pools and pipelines, context propagation, graceful shutdown, and evolving the shortener toward persistence and middleware. Prep: re-skim the channel/context notes and set up the Month 3 journal folder.

Suggested commit: docs(journal): month 2 review then git tag -a v0.2.0 -m "Month 2 complete"