Build concurrent Go microservices

Write idiomatic Go with goroutines, channels, context cancellation, and generics

Concurrent systems requiring fine-grained goroutine lifecycle, bounded resource pools, and time-bounded execution with proper cancellation.

• · Go module structure
• · interface definitions
• · goroutine pool size
• · context timeout
• · job queue

• · concurrent Go code (goroutines + channels)
• · passing go test -race results
• · golangci-lint clean report
• · pprof benchmark results

• · Go 1.21+ compiler
• · go vet (linter)
• · golangci-lint (style/bugs)
• · pprof (profiler)
• · testing (table-driven tests, benchmarks)
• · race detector (-race flag)

• · Go 1.21+ installed
• · Module structure (go.mod, internal/ packages)
• · Interfaces designed (before implementation)
• · Context propagation requirements understood

• · Goroutine leak: no context cancellation or channel close, hangs forever
• · Race condition: concurrent access to shared state without sync primitives
• · Error ignored: _ assignment masks actual failures
• · Panic: used for control flow instead of error returns
• · go vet fails: unresolved imports or type mismatches

• · Core pattern shows proper context cancellation (select on ctx.Done)
• · Error wrapping with %w enables chain tracing
• · Table-driven tests with subtests shown (standard Go practice)
• · Race detector run required before committing (catches concurrent bugs)