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Golang / GoLang Production Patterns and Web Standards Interview Questions

How do you profile a Go service in production using pprof?

Go ships a built-in profiler accessible via HTTP when you import net/http/pprof. Adding this to a running service provides CPU profiles, heap snapshots, goroutine dumps, and block profiles without restarting the service.

// Add to main or a dedicated debug server
import _ "net/http/pprof"  // side-effect import registers /debug/pprof/ handlers

// Expose on a separate internal port (never public-facing)
go func() {
    log.Println(http.ListenAndServe("localhost:6060", nil))
}()

// Available endpoints:
// /debug/pprof/             — index page
// /debug/pprof/goroutine    — goroutine dump
// /debug/pprof/heap         — heap snapshot
// /debug/pprof/profile?seconds=30 — 30s CPU profile
// /debug/pprof/trace?seconds=5    — execution trace
// /debug/pprof/block        — goroutine blocking
// /debug/pprof/mutex        — mutex contention

// CLI usage:
// go tool pprof http://localhost:6060/debug/pprof/profile?seconds=30
// > top10          — top CPU-consuming functions
// > web            — opens flame graph in browser
// > list funcName  — annotated source code

// Heap profile:
// go tool pprof http://localhost:6060/debug/pprof/heap
// > top10 -cum     — cumulative allocations
// > alloc_space    — total bytes allocated (not just live)
// > inuse_space    — currently live bytes

// Goroutine leak check:
// curl http://localhost:6060/debug/pprof/goroutine?debug=2
// Shows full stack traces of all goroutines

// Programmatic profiling in tests:
// go test -bench=. -cpuprofile=cpu.out -memprofile=mem.out
// go tool pprof cpu.out

What does the blank import '_ "net/http/pprof"' accomplish?
Why should the pprof debug server be exposed on a separate internal port rather than the public API port?

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