Go Advanced

🐹 Go Advanced (target: Go 1.25+)

1. Language mastery

• Types, structs, embedding (composition), methods, pointer vs value receivers
• Interfaces: implicit satisfaction, small interfaces, “accept interfaces, return structs”, nil-interface gotcha
• Slices (len/cap/backing array aliasing), maps, strings/runes/bytes
• Errors: wrapping (%w), errors.Is/As, sentinel vs typed errors, panic/recover (rarely)
• Generics: type parameters, constraints, when to use them (and when not)
• Iterators (range over functions, iter.Seq), slices/maps packages
• defer semantics, closures, and the loop variable (changed in 1.22)
• Packages, modules, internal packages, project layout (keep it simple)

2. Concurrency → Concurrency

• Goroutines, channels, select, context, sync, errgroup, singleflight
• Scheduler (G-M-P), preemption, GOMAXPROCS (container-aware by default in newer versions; verify for yours)
• Go memory model; race detector

3. Runtime & performance

• Escape analysis (go build -gcflags=-m), stack vs heap
• GC (concurrent mark-sweep, GOGC, GOMEMLIMIT)
• pprof (CPU, heap, goroutine, mutex, block), go tool trace, benchmarks + benchstat
• sync.Pool, preallocation, strings.Builder

4. Stdlib you must know

net/http (incl. the 1.22+ routing patterns), encoding/json, database/sql, context, log/slog, testing, io, bufio, time, os/signal

5. Testing

• Table-driven tests, subtests, t.Parallel, test helpers, golden files
• Fuzzing (go test -fuzz), benchmarks, httptest
• Mocks via interfaces (or gomock/mockery), Testcontainers-go

🧪 Labs (🟢 warm-up → 🟡 core → 🔴 hard → ⚫ boss)

• 🟢 Tour of Go concurrency exercises; Go by Example end to end
• 🟡 Concurrent crawler: worker pool + rate limit + context cancel + goleak
• 🟡 Writing an Interpreter in Go ch. 1–3 → orbit-expr
• 🔴 Build your own Redis in Go (CodeCrafters/codingchallenges)
• 🔴 pprof a leaky, allocation-heavy service; cut allocations by 50%
• ⚫ 1BRC in Go (W4) · MIT 6.5840 labs (Phase 3)

🧠 Cognitive tasks

• Predict → verify: escape analysis of 5 functions (-gcflags=-m)
• Reproduce the typed-nil-interface bug and slice aliasing; explain both from the runtime structs
• Trade-off debate: channels vs mutex for Orbit’s lease table

🛰️ Orbit integration

• orbit-dag → orbit-engine; orbit-worker, llm-gateway, hooks, stream are all Go

Go deeper

⚙️ Go Runtime Internals · 🧩 GoF Patterns (Java & Go) · Concurrency Patterns

Resources

• Learning Go 2e (Bodner) ⭐ · Concurrency in Go (Cox-Buday) ⭐ · 100 Go Mistakes and How to Avoid Them (Harsanyi) ⭐
• Let’s Go / Let’s Go Further (Edwards) → Go Backend Development
• Tour of Go, Go by Example, Effective Go, the Go blog, Ardan Labs Ultimate Go (Bill Kennedy)

Interview questions interview-q

• How does the Go scheduler work? What’s the G-M-P model?
• What’s a goroutine leak? How do you prevent one?
• Why can a nil pointer inside an interface make err != nil true?
• Buffered vs unbuffered channels: semantics and use cases