[#369] Add fileLogger config reloading after SIGHUP

Declared fileLogger struct in log_http.go, turn existing funcs to methods. Add ReloadFileLogger method

Signed-off-by: Nikita Zinkevich <n.zinkevich@yadro.com>

api/middleware/log_http.go

@@ -11,43 +11,62 @@ import (
 
 	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/internal/logs"
 	"go.uber.org/zap"
-	"go.uber.org/zap/zapcore"
 	"gopkg.in/natefinch/lumberjack.v2"
 )
 
-type LogHTTPConfig struct {
+type (
-	Enabled    bool
+	LogHTTPConfig struct {
-	MaxBody    int64
+		Enabled    bool
-	MaxLogSize int
+		MaxBody    int64
-	OutputPath string
+		MaxLogSize int
-	UseGzip    bool
+		OutputPath string
-}
+		UseGzip    bool
-
-// getFileLogger returns file logger for http requests or creates new if not exists.
-func (h *LogHTTPConfig) getFileLogger() (*zap.Logger, error) {
-	c := newLoggerConfig()
-	c.OutputPaths = []string{h.OutputPath}
-	if h.OutputPath != StdoutPath && h.OutputPath != StderrPath && h.OutputPath != "" {
-		err := h.registerOutputSink()
-		if err != nil {
-			return nil, err
-		}
-		c.OutputPaths[0] = SinkName + ":" + h.OutputPath
 	}
 
-	return c.Build()
+	fileLogger struct {
+		*zap.Logger
+		logRoller *lumberjack.Logger
+	}
+
+	// Implementation of zap.Sink for using lumberjack
+	lumberjackSink struct {
+		*lumberjack.Logger
+	}
+)
+
+var filelog = fileLogger{}
+
+// newFileLogger returns registers zap sink and returns new fileLogger
+func newFileLogger(conf *LogHTTPConfig) (fileLogger, error) {
+	var flog = fileLogger{}
+	c := flog.newLoggerConfig()
+	c.OutputPaths = []string{conf.OutputPath}
+	if conf.OutputPath != StdoutPath && conf.OutputPath != StderrPath && conf.OutputPath != "" {
+		err := flog.registerOutputSink(conf)
+		if err != nil {
+			return flog, err
+		}
+		c.OutputPaths[0] = SinkName + ":" + conf.OutputPath
+	}
+	log, err := c.Build()
+	if err != nil {
+		return flog, err
+	}
+	flog.Logger = log
+
+	return flog, nil
 }
 
-// registerOutputSink registers sink for logger file output.
+// registerOutputSink creates and registers sink for logger file output.
-func (h *LogHTTPConfig) registerOutputSink() error {
+func (f *fileLogger) registerOutputSink(conf *LogHTTPConfig) error {
-	logRoller := &lumberjack.Logger{
+	f.logRoller = &lumberjack.Logger{
-		Filename: h.OutputPath,
+		Filename: conf.OutputPath,
-		MaxSize:  h.MaxLogSize,
+		MaxSize:  conf.MaxLogSize,
-		Compress: h.UseGzip,
+		Compress: conf.UseGzip,
 	}
 	err := zap.RegisterSink(SinkName, func(_ *url.URL) (zap.Sink, error) {
 		return lumberjackSink{
-			Logger: logRoller,
+			Logger: f.logRoller,
 		}, nil
 	})
 	if err != nil {
@@ -57,18 +76,33 @@ func (h *LogHTTPConfig) registerOutputSink() error {
 	return nil
 }
 
-type lumberjackSink struct {
+func (lumberjackSink) Sync() error {
-	*lumberjack.Logger
+	return nil
 }
 
-func (lumberjackSink) Sync() error {
+func ReloadFileLogger(conf *LogHTTPConfig) error {
+	if filelog.logRoller == nil {
+		return nil
+	}
+	filelog.logRoller.MaxSize = conf.MaxLogSize
+	filelog.logRoller.Compress = conf.UseGzip
+
+	if filelog.logRoller.Filename != conf.OutputPath {
+		filelog.logRoller.Filename = conf.OutputPath
+		if err := filelog.logRoller.Rotate(); err != nil {
+			return err
+		}
+	}
+
 	return nil
 }
 
 // LogHTTP logs http parameters from s3 request.
 func LogHTTP(l *zap.Logger, config *LogHTTPConfig) Func {
-	fileLogger, err := config.getFileLogger()
+	var err error
+	filelog, err = newFileLogger(config)
 	if err != nil {
+		l.Warn(logs.FailedToInitializeHTTPLogger)
 		return func(h http.Handler) http.Handler {
 			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 				h.ServeHTTP(w, r)
@@ -81,7 +115,7 @@ func LogHTTP(l *zap.Logger, config *LogHTTPConfig) Func {
 				h.ServeHTTP(w, r)
 				return
 			}
-			var httplog = fileLogger.With(
+			var httplog = filelog.With(
 				zap.String("from", r.RemoteAddr),
 				zap.String("URI", r.RequestURI),
 				zap.String("method", r.Method),
@@ -102,7 +136,7 @@ func LogHTTP(l *zap.Logger, config *LogHTTPConfig) Func {
 }
 
 // newLoggerConfig creates new zap.Config with disabled base fields.
-func newLoggerConfig() zap.Config {
+func (*fileLogger) newLoggerConfig() zap.Config {
 	c := zap.NewProductionConfig()
 	c.DisableCaller = true
 	c.DisableStacktrace = true

docs/configuration.md

@@ -390,9 +390,9 @@ http_logging:
 |----------------|--------|---------------|---------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
 | `enabled`      | bool   | yes           | false         | Flag to enable the logger.                                                                                                                                                                  |
 | `max_body`     | int    | yes           | 1024          | Max body size for log output in bytes.                                                                                                                                                      |
-| `max_log_size` | int    | no            | 50            | Log file size threshold (in megabytes) to be moved in backup file. After reaching  threshold, initial filename is appended with timestamp. And new empty file with initial name is created. |
+| `max_log_size` | int    | yes           | 50            | Log file size threshold (in megabytes) to be moved in backup file. After reaching  threshold, initial filename is appended with timestamp. And new empty file with initial name is created. |
-| `gzip`         | bool   | no            | false         | Whether to enable Gzip compression for backup log files.                                                                                                                                    |
+| `gzip`         | bool   | yes           | false         | Whether to enable Gzip compression for backup log files.                                                                                                                                    |
-| `destination`  | string | no            | stdout        | Specify path for log output. Accepts log file path, or "stdout" and "stderr" reserved words to print in output streams.                                                                     |
+| `destination`  | string | yes           | stdout        | Specify path for log output. Accepts log file path, or "stdout" and "stderr" reserved words to print in output streams.                                                                     |
 
 
 ### `cache` section

internal/logs/logs.go

@@ -101,8 +101,10 @@ const (
 	FailedToResolveCID                                   = "failed to resolve CID"                                                                             // Debug in ../../api/middleware/metrics.go
 	RequestStart                                         = "request start"                                                                                     // Info in ../../api/middleware/reqinfo.go
 	RequestHTTP                                          = "http request"                                                                                      // Info in ../../api/middleware/log_http.go
+	FailedToInitializeHTTPLogger                         = "failed to initialize http logger"                                                                  // Warn in ../../api/middleware/log_http.go
+	FailedToReloadHTTPFileLogger                         = "failed to reload http file logger"                                                                 // Warn in ../../api/middleware/log_http.go
+	FailedToGetRequestBody                               = "failed to get request body"                                                                        // Warn in ../../api/middleware/log_http.go
 	LogHTTPDisabledInThisBuild                           = "http logging disabled in this build"                                                               // Warn in ../../api/middleware/log_http_stub.go
-	FailedToGetRequestBody                               = "failed to get request body"                                                                        // Warn in ../../api/middleware/log_http_stub.go
 	FailedToUnescapeObjectName                           = "failed to unescape object name"                                                                    // Warn in ../../api/middleware/reqinfo.go
 	InvalidDefaultMaxAge                                 = "invalid defaultMaxAge"                                                                             // Fatal in ../../cmd/s3-gw/app_settings.go
 	CantShutDownService                                  = "can't shut down service"                                                                           // Panic in ../../cmd/s3-gw/service.go