feat(pprof): add pprof HTTP server (#807)

- `PPROF_ENABLED=no`
- `PPROF_BLOCK_PROFILE_RATE=0`
- `PPROF_MUTEX_PROFILE_RATE=0`
- `PPROF_HTTP_SERVER_ADDRESS=":6060"`

internal/configuration/sources/env/helpers.go

@@ -21,6 +21,14 @@ func envToCSV(envKey string) (values []string) {
 	return lowerAndSplit(csv)
 }
 
+func envToInt(envKey string) (n int, err error) {
+	s := os.Getenv(envKey)
+	if s == "" {
+		return 0, nil
+	}
+	return strconv.Atoi(s)
+}
+
 func envToStringPtr(envKey string) (stringPtr *string) {
 	s := os.Getenv(envKey)
 	if s == "" {

internal/configuration/sources/env/pprof.go

@@ -0,0 +1,29 @@
+package env
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/qdm12/gluetun/internal/pprof"
+)
+
+func readPprof() (settings pprof.Settings, err error) {
+	settings.Enabled, err = envToBoolPtr("PPROF_ENABLED")
+	if err != nil {
+		return settings, fmt.Errorf("environment variable PPROF_ENABLED: %w", err)
+	}
+
+	settings.BlockProfileRate, err = envToInt("PPROF_BLOCK_PROFILE_RATE")
+	if err != nil {
+		return settings, fmt.Errorf("environment variable PPROF_BLOCK_PROFILE_RATE: %w", err)
+	}
+
+	settings.MutexProfileRate, err = envToInt("PPROF_MUTEX_PROFILE_RATE")
+	if err != nil {
+		return settings, fmt.Errorf("environment variable PPROF_MUTEX_PROFILE_RATE: %w", err)
+	}
+
+	settings.HTTPServer.Address = os.Getenv("PPROF_HTTP_SERVER_ADDRESS")
+
+	return settings, nil
+}

internal/configuration/sources/env/reader.go

@@ -82,6 +82,11 @@ func (r *Reader) Read() (settings settings.Settings, err error) {
 		return settings, err
 	}
 
+	settings.Pprof, err = readPprof()
+	if err != nil {
+		return settings, err
+	}
+
 	return settings, nil
 }