[#702] Reload config level on SIGHUP

Signed-off-by: Denis Kirillov <denis@nspcc.ru>

cmd/s3-gw/app.go

@@ -6,7 +6,10 @@ import (
 	"fmt"
 	"net"
 	"net/http"
+	"os"
+	"os/signal"
 	"strconv"
+	"syscall"
 	"time"
 
 	"github.com/gorilla/mux"
@@ -42,6 +45,17 @@ type (
 
 		webDone chan struct{}
 		wrkDone chan struct{}
+
+		settings *appSettings
+	}
+
+	appSettings struct {
+		LogLevel zap.AtomicLevel
+	}
+
+	Logger struct {
+		logger *zap.Logger
+		lvl    zap.AtomicLevel
 	}
 
 	tlsConfig struct {
@@ -54,7 +68,9 @@ type (
 	}
 )
 
-func newApp(ctx context.Context, l *zap.Logger, v *viper.Viper) *App {
+func newApp(ctx context.Context, log *Logger, v *viper.Viper) *App {
+	l := log.logger
+
 	var (
 		key    *keys.PrivateKey
 		err    error
@@ -245,8 +261,8 @@ func (a *App) Wait() {
 	a.log.Info("application finished")
 }
 
-// Server runs HTTP server to handle S3 API requests.
-func (a *App) Server(ctx context.Context) {
+// Serve runs HTTP server to handle S3 API requests.
+func (a *App) Serve(ctx context.Context) {
 	var (
 		err  error
 		lis  net.Listener
@@ -299,7 +315,18 @@ func (a *App) Server(ctx context.Context) {
 		}
 	}()
 
-	<-ctx.Done()
+	sigs := make(chan os.Signal, 1)
+	signal.Notify(sigs, syscall.SIGHUP)
+
+LOOP:
+	for {
+		select {
+		case <-ctx.Done():
+			break LOOP
+		case <-sigs:
+			a.configReload()
+		}
+	}
 
 	ctx, cancel := context.WithTimeout(context.Background(), defaultShutdownTimeout)
 	defer cancel()
@@ -312,6 +339,31 @@ func (a *App) Server(ctx context.Context) {
 	close(a.webDone)
 }
 
+func (a *App) configReload() {
+	a.log.Info("SIGHUP config reload started")
+
+	if !a.cfg.IsSet(cmdConfig) {
+		a.log.Warn("failed to reload config because it's missed")
+		return
+	}
+	if err := readConfig(a.cfg); err != nil {
+		a.log.Warn("failed to reload config", zap.Error(err))
+		return
+	}
+
+	a.updateSettings()
+
+	a.log.Info("SIGHUP config reload completed")
+}
+
+func (a *App) updateSettings() {
+	if lvl, err := getLogLevel(a.cfg); err != nil {
+		a.log.Warn("log level won't be updated", zap.Error(err))
+	} else {
+		a.settings.LogLevel.SetLevel(lvl)
+	}
+}
+
 func getNotificationsOptions(v *viper.Viper, l *zap.Logger) *notifications.Options {
 	cfg := notifications.Options{}
 	cfg.URL = v.GetString(cfgNATSEndpoint)

cmd/s3-gw/app_settings.go

@@ -15,6 +15,7 @@ import (
 	"github.com/spf13/pflag"
 	"github.com/spf13/viper"
 	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
 )
 
 const (
@@ -183,7 +184,7 @@ func newSettings() *viper.Viper {
 
 	flags.StringP(cmdWallet, "w", "", `path to the wallet`)
 	flags.String(cmdAddress, "", `address of wallet account`)
-	config := flags.String(cmdConfig, "", "config path")
+	flags.String(cmdConfig, "", "config path")
 
 	flags.Duration(cfgHealthcheckTimeout, defaultHealthcheckTimeout, "set timeout to check node health during rebalance")
 	flags.Duration(cfgConnectTimeout, defaultConnectTimeout, "set timeout to connect to NeoFS nodes")
@@ -291,12 +292,79 @@ func newSettings() *viper.Viper {
 	}
 
 	if v.IsSet(cmdConfig) {
-		if cfgFile, err := os.Open(*config); err != nil {
-			panic(err)
-		} else if err := v.ReadConfig(cfgFile); err != nil {
+		if err := readConfig(v); err != nil {
 			panic(err)
 		}
 	}
 
 	return v
 }
+
+func readConfig(v *viper.Viper) error {
+	cfgFileName := v.GetString(cmdConfig)
+	cfgFile, err := os.Open(cfgFileName)
+	if err != nil {
+		return err
+	}
+	if err = v.ReadConfig(cfgFile); err != nil {
+		return err
+	}
+
+	return cfgFile.Close()
+}
+
+// newLogger constructs a Logger instance for the current application.
+// Panics on failure.
+//
+// Logger contains a logger is built from zap's production logging configuration with:
+//   - parameterized level (debug by default)
+//   - console encoding
+//   - ISO8601 time encoding
+//
+// and atomic log level to dynamically change it.
+//
+// Logger records a stack trace for all messages at or above fatal level.
+//
+// See also zapcore.Level, zap.NewProductionConfig, zap.AddStacktrace.
+func newLogger(v *viper.Viper) *Logger {
+	lvl, err := getLogLevel(v)
+	if err != nil {
+		panic(err)
+	}
+
+	c := zap.NewProductionConfig()
+	c.Level = zap.NewAtomicLevelAt(lvl)
+	c.Encoding = "console"
+	c.EncoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
+
+	l, err := c.Build(
+		zap.AddStacktrace(zap.NewAtomicLevelAt(zap.FatalLevel)),
+	)
+	if err != nil {
+		panic(fmt.Sprintf("build zap logger instance: %v", err))
+	}
+
+	return &Logger{
+		logger: l,
+		lvl:    c.Level,
+	}
+}
+
+func getLogLevel(v *viper.Viper) (zapcore.Level, error) {
+	var lvl zapcore.Level
+	lvlStr := v.GetString(cfgLoggerLevel)
+	err := lvl.UnmarshalText([]byte(lvlStr))
+	if err != nil {
+		return lvl, fmt.Errorf("incorrect logger level configuration %s (%v), "+
+			"value should be one of %v", lvlStr, err, [...]zapcore.Level{
+			zapcore.DebugLevel,
+			zapcore.InfoLevel,
+			zapcore.WarnLevel,
+			zapcore.ErrorLevel,
+			zapcore.DPanicLevel,
+			zapcore.PanicLevel,
+			zapcore.FatalLevel,
+		})
+	}
+	return lvl, nil
+}

cmd/s3-gw/main.go

@@ -2,68 +2,19 @@ package main
 
 import (
 	"context"
-	"fmt"
 	"os/signal"
 	"syscall"
-
-	"github.com/spf13/viper"
-	"go.uber.org/zap"
-	"go.uber.org/zap/zapcore"
 )
 
-// newLogger constructs a zap.Logger instance for the current application.
-// Panics on failure.
-//
-// Logger is built from zap's production logging configuration with:
-//   - parameterized level (debug by default)
-//   - console encoding
-//   - ISO8601 time encoding
-//
-// Logger records a stack trace for all messages at or above fatal level.
-//
-// See also zapcore.Level, zap.NewProductionConfig, zap.AddStacktrace.
-func newLogger(v *viper.Viper) *zap.Logger {
-	var lvl zapcore.Level
-	lvlStr := v.GetString(cfgLoggerLevel)
-
-	err := lvl.UnmarshalText([]byte(lvlStr))
-	if err != nil {
-		panic(fmt.Sprintf("incorrect logger level configuration %s (%v), "+
-			"value should be one of %v", lvlStr, err, [...]zapcore.Level{
-			zapcore.DebugLevel,
-			zapcore.InfoLevel,
-			zapcore.WarnLevel,
-			zapcore.ErrorLevel,
-			zapcore.DPanicLevel,
-			zapcore.PanicLevel,
-			zapcore.FatalLevel,
-		}))
-	}
-
-	c := zap.NewProductionConfig()
-	c.Level = zap.NewAtomicLevelAt(lvl)
-	c.Encoding = "console"
-	c.EncoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
-
-	l, err := c.Build(
-		zap.AddStacktrace(zap.NewAtomicLevelAt(zap.FatalLevel)),
-	)
-	if err != nil {
-		panic(fmt.Sprintf("build zap logger instance: %v", err))
-	}
-
-	return l
-}
-
 func main() {
-	var (
-		v    = newSettings()
-		l    = newLogger(v)
-		g, _ = signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP)
-		a    = newApp(g, l, v)
-	)
+	g, _ := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
 
-	go a.Server(g)
+	v := newSettings()
+	l := newLogger(v)
+
+	a := newApp(g, l, v)
+
+	go a.Serve(g)
 
 	a.Wait()
 }