feat(diagnostics): add pprof profiling (#1627)

* feat(tracing): enable tracing

* of course the squash didn't work.

* gah. always nice when there's 40 csets.

* might as well.

* refactor: tracing to diagnostics

* feat: add note about the magic methods from pprof

---------

Co-authored-by: ze0s <ze0s@riseup.net>

cmd/autobrr/main.go

@@ -14,6 +14,7 @@ import (
 	"github.com/autobrr/autobrr/internal/auth"
 	"github.com/autobrr/autobrr/internal/config"
 	"github.com/autobrr/autobrr/internal/database"
+	"github.com/autobrr/autobrr/internal/diagnostics"
 	"github.com/autobrr/autobrr/internal/download_client"
 	"github.com/autobrr/autobrr/internal/events"
 	"github.com/autobrr/autobrr/internal/feed"
@@ -64,6 +65,8 @@ func main() {
 	// init dynamic config
 	cfg.DynamicReload(log)
 
+	diagnostics.SetupProfiling(cfg.Config.ProfilingEnabled, cfg.Config.ProfilingHost, cfg.Config.ProfilingPort)
+
 	// setup server-sent-events
 	serverEvents := sse.New()
 	serverEvents.CreateStreamWithOpts("logs", sse.StreamOpts{MaxEntries: 1000, AutoReplay: true})

internal/config/config.go

@@ -85,6 +85,15 @@ checkForUpdates = true
 # Session secret
 #
 sessionSecret = "{{ .sessionSecret }}"
+
+# Golang pprof profiling and tracing
+#
+#profiling = false
+#
+#profilingHost = "127.0.0.1"
+#
+# Default: 6060
+#profilingPort = 6060
 `
 
 func (c *AppConfig) writeConfig(configPath string, configFile string) error {
@@ -210,6 +219,9 @@ func (c *AppConfig) defaults() {
 		PostgresPass:        "",
 		PostgresSSLMode:     "disable",
 		PostgresExtraParams: "",
+		ProfilingEnabled:    false,
+		ProfilingHost:       "127.0.0.1",
+		ProfilingPort:       6060,
 	}
 
 }
@@ -302,6 +314,21 @@ func (c *AppConfig) loadFromEnv() {
 	if v := os.Getenv(prefix + "POSTGRES_EXTRA_PARAMS"); v != "" {
 		c.Config.PostgresExtraParams = v
 	}
+
+	if v := os.Getenv(prefix + "PROFILING"); v != "" {
+		c.Config.ProfilingEnabled = strings.EqualFold(strings.ToLower(v), "true")
+	}
+
+	if v := os.Getenv(prefix + "PROFILING_HOST"); v != "" {
+		c.Config.ProfilingHost = v
+	}
+
+	if v := os.Getenv(prefix + "PROFILING_PORT"); v != "" {
+		i, _ := strconv.ParseInt(v, 10, 32)
+		if i > 0 {
+			c.Config.ProfilingPort = int(i)
+		}
+	}
 }
 
 func validDatabaseType(v string) bool {

internal/diagnostics/profiling.go

@@ -0,0 +1,30 @@
+// Copyright (c) 2021 - 2024, Ludvig Lundgren and the autobrr contributors.
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+package diagnostics
+
+import (
+	"fmt"
+	"net/http"
+	_ "net/http/pprof"
+
+	"github.com/rs/zerolog/log"
+)
+
+// SetupProfiling pprof profiling
+func SetupProfiling(enabled bool, host string, port int) {
+	if enabled {
+		go func() {
+			// pprof has an init method which adds the following endpoints
+			// http.HandleFunc(prefix+"/debug/pprof/", Index)
+			// http.HandleFunc(prefix+"/debug/pprof/cmdline", Cmdline)
+			// http.HandleFunc(prefix+"/debug/pprof/profile", Profile)
+			// http.HandleFunc(prefix+"/debug/pprof/symbol", Symbol)
+			// http.HandleFunc(prefix+"/debug/pprof/trace", Trace)
+			err := http.ListenAndServe(fmt.Sprintf("%s:%d", host, port), nil)
+			if err != nil {
+				log.Printf("Error starting profiling server: %v", err)
+			}
+		}()
+	}
+}

internal/domain/config.go

@@ -24,6 +24,9 @@ type Config struct {
 	PostgresPass        string `toml:"postgresPass"`
 	PostgresSSLMode     string `toml:"postgresSSLMode"`
 	PostgresExtraParams string `toml:"postgresExtraParams"`
+	ProfilingEnabled    bool   `toml:"profiling"`
+	ProfilingHost       string `toml:"profilingHost"`
+	ProfilingPort       int    `toml:"profilingPort"`
 }
 
 type ConfigUpdate struct {