Go Practice

Master goroutines, channels, interfaces, and simplicity-driven design.

Language Essentials

Concept	Details
Memory Model	GC, stack-allocated by default, escape analysis, pointers but no arithmetic
Type System	Static, structural typing, interfaces (implicit), generics (1.18+)
Error Handling	`error` interface, multiple returns, `errors.Is`/`As`, no exceptions
Concurrency	Goroutines, channels, `select`, `sync` package, `context` cancellation
Build	`go build`, modules (`go.mod`), `go test`, `go vet`
Standard	Go 1.22+

Key Idioms

Accept interfaces, return structs
if err != nil — explicit error checking
Table-driven tests with testing package
context.Context threaded through call chains
Channel direction in function signatures (chan<-, <-chan)
Embedding for composition over inheritance
defer for cleanup, runs LIFO

Reference Documentation

A Tour of Go — free, interactive
Effective Go — free, essential reading
Go standard library — API docs
Go Blog — official articles
The Go Programming Language (Donovan & Kernighan) — comprehensive

Practising these

practice/bin/ol list  build go          # which of these have references yet
practice/bin/ol start build go 01       # clone it stubbed into .scratchpad/
practice/bin/ol check build go 01       # run it; exit code is the verdict
practice/bin/ol diff  build go 01       # your attempt against the reference

Exercises are ordered by concept, not by difficulty, so pick by the stars rather than by the number. An exercise listed below with no reference yet is a row in this table and nothing more; see the practice path for how the harness works.

Exercises

#	Exercise	Concepts	Difficulty
01	Concurrent web crawler	Goroutines, channels, `sync.WaitGroup`, rate limiting; course version: `ag.06`	⭐⭐⭐
02	In-memory key-value store	`sync.RWMutex`, interfaces, HTTP handler; course version: `gw.06`	⭐⭐
03	Worker pool	Bounded concurrency, `context` cancellation; course version: `dur.04`	⭐⭐⭐
04	Generic sorted set	Generics, type constraints, `cmp.Ordered`; course version: `dur.07`	⭐⭐⭐
05	Log-structured storage	`io.Reader`/`Writer`, binary encoding, file I/O; course version: `dur.01`	⭐⭐⭐⭐
06	Pub/sub message broker	Channels, fan-out, `select`, graceful shutdown; course version: `dur.03`	⭐⭐⭐
07	Rate limiter (token bucket)	`time.Ticker`, atomic operations, middleware; course version: `gw.03`	⭐⭐
08	Raft consensus (simplified)	State machines, RPC, leader election; course version: `dur.10`	⭐⭐⭐⭐⭐
09	Dependency injection container	Reflection, interfaces, `sync.Once`	⭐⭐⭐
10	gRPC service + client	Protocol buffers, streaming, interceptors; course version: `dur.04`	⭐⭐⭐⭐