main_pprof.go

// Copyright 2024-2026 George (earentir) Pantazis (https://earentir.dev)
// SPDX-License-Identifier: GPL-2.0-only

package main

import (
	"context"
	"log/slog"
	"net/http"
	"net/http/pprof"
	"sync"
	"time"
)

var (
	pprofMu     sync.Mutex
	pprofServer *http.Server
)

// startPprof serves net/http/pprof on addr (/debug/pprof/...). addr must be non-empty.
func startPprof(addr string, logger *slog.Logger) {
	pprofMu.Lock()
	defer pprofMu.Unlock()
	if pprofServer != nil {
		return
	}
	mux := http.NewServeMux()
	mux.HandleFunc("/debug/pprof/", pprof.Index)
	mux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
	mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
	mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
	mux.HandleFunc("/debug/pprof/trace", pprof.Trace)
	srv := &http.Server{
		Addr:              addr,
		Handler:           mux,
		ReadHeaderTimeout: 10 * time.Second,
		ReadTimeout:       60 * time.Second,
		WriteTimeout:      60 * time.Second,
		IdleTimeout:       120 * time.Second,
	}
	pprofServer = srv
	go func() {
		if logger != nil {
			logger.Info("pprof HTTP server listening (go tool pprof http://HOST/debug/pprof/)", "addr", addr)
		}
		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			if logger != nil {
				logger.Error("pprof server exited", "error", err)
			}
		}
	}()
}

func stopPprof() {
	pprofMu.Lock()
	srv := pprofServer
	pprofServer = nil
	pprofMu.Unlock()
	if srv == nil {
		return
	}
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	_ = srv.Shutdown(ctx)
}