- Add support for the file logger with log rotation and compression

Signed-off-by: Valery Piashchynski <[email protected]>

3 files changed, 98 insertions, 8 deletions

diff --git a/plugins/logger/config.go b/plugins/logger/config.go
index d2236cac..6ef56661 100644
--- a/plugins/logger/config.go
+++ b/plugins/logger/config.go
@@ -1,10 +1,12 @@
 package logger
 
 import (
+	"os"
 	"strings"
 
 	"go.uber.org/zap"
 	"go.uber.org/zap/zapcore"
+	"gopkg.in/natefinch/lumberjack.v2"
 )
 
 // ChannelConfig configures loggers per channel.
@@ -13,9 +15,57 @@ type ChannelConfig struct {
 	Channels map[string]Config `mapstructure:"channels"`
 }
 
+// FileLoggerConfig structure represents configuration for the file logger
+type FileLoggerConfig struct {
+	// Filename is the file to write logs to.  Backup log files will be retained
+	// in the same directory.  It uses <processname>-lumberjack.log in
+	// os.TempDir() if empty.
+	LogOutput string `mapstructure:"log_output"`
+
+	// MaxSize is the maximum size in megabytes of the log file before it gets
+	// rotated. It defaults to 100 megabytes.
+	MaxSize int `mapstructure:"max_size"`
+
+	// MaxAge is the maximum number of days to retain old log files based on the
+	// timestamp encoded in their filename.  Note that a day is defined as 24
+	// hours and may not exactly correspond to calendar days due to daylight
+	// savings, leap seconds, etc. The default is not to remove old log files
+	// based on age.
+	MaxAge int `mapstructure:"max_age"`
+
+	// MaxBackups is the maximum number of old log files to retain.  The default
+	// is to retain all old log files (though MaxAge may still cause them to get
+	// deleted.)
+	MaxBackups int `mapstructure:"max_backups"`
+
+	// Compress determines if the rotated log files should be compressed
+	// using gzip. The default is not to perform compression.
+	Compress bool `mapstructure:"compress"`
+}
+
+func (fl *FileLoggerConfig) InitDefaults() *FileLoggerConfig {
+	if fl.LogOutput == "" {
+		fl.LogOutput = os.TempDir()
+	}
+
+	if fl.MaxSize == 0 {
+		fl.MaxSize = 100
+	}
+
+	if fl.MaxAge == 0 {
+		fl.MaxAge = 24
+	}
+
+	if fl.MaxBackups == 0 {
+		fl.MaxBackups = 10
+	}
+
+	return fl
+}
+
 type Config struct {
 	// Mode configures logger based on some default template (development, production, off).
-	Mode string `mapstructure:"mode"`
+	Mode Mode `mapstructure:"mode"`
 
 	// Level is the minimum enabled logging level. Note that this is a dynamic
 	// level, so calling ChannelConfig.Level.SetLevel will atomically change the log
@@ -38,17 +88,20 @@ type Config struct {
 	// sends error-level logs to a different location from info- and debug-level
 	// logs, see the package-level AdvancedConfiguration example.
 	ErrorOutput []string `mapstructure:"errorOutput"`
+
+	// File logger options
+	FileLogger *FileLoggerConfig `mapstructure:"file_logger_options"`
 }
 
 // BuildLogger converts config into Zap configuration.
 func (cfg *Config) BuildLogger() (*zap.Logger, error) {
 	var zCfg zap.Config
-	switch strings.ToLower(cfg.Mode) {
-	case "off", "none":
+	switch Mode(strings.ToLower(string(cfg.Mode))) {
+	case off, none:
 		return zap.NewNop(), nil
-	case "production":
+	case production:
 		zCfg = zap.NewProductionConfig()
-	case "development":
+	case development:
 		zCfg = zap.Config{
 			Level:       zap.NewAtomicLevelAt(zap.DebugLevel),
 			Development: true,
@@ -72,7 +125,7 @@ func (cfg *Config) BuildLogger() (*zap.Logger, error) {
 			OutputPaths:      []string{"stderr"},
 			ErrorOutputPaths: []string{"stderr"},
 		}
-	case "raw":
+	case raw:
 		zCfg = zap.Config{
 			Level:    zap.NewAtomicLevelAt(zap.InfoLevel),
 			Encoding: "console",
@@ -120,13 +173,38 @@ func (cfg *Config) BuildLogger() (*zap.Logger, error) {
 		zCfg.ErrorOutputPaths = cfg.ErrorOutput
 	}
 
+	// if we also have a file logger specified in the config
+	// init it
+	// otherwise - return standard config
+	if cfg.FileLogger != nil {
+		// init absent options
+		cfg.FileLogger.InitDefaults()
+
+		w := zapcore.AddSync(
+			&lumberjack.Logger{
+				Filename:   cfg.FileLogger.LogOutput,
+				MaxSize:    cfg.FileLogger.MaxSize,
+				MaxAge:     cfg.FileLogger.MaxAge,
+				MaxBackups: cfg.FileLogger.MaxBackups,
+				Compress:   cfg.FileLogger.Compress,
+			},
+		)
+
+		core := zapcore.NewCore(
+			zapcore.NewJSONEncoder(zCfg.EncoderConfig),
+			w,
+			zCfg.Level,
+		)
+		return zap.New(core), nil
+	}
+
 	return zCfg.Build()
 }
 
 // InitDefault Initialize default logger
 func (cfg *Config) InitDefault() {
 	if cfg.Mode == "" {
-		cfg.Mode = "development"
+		cfg.Mode = development
 	}
 	if cfg.Level == "" {
 		cfg.Level = "debug"
diff --git a/plugins/logger/enums.go b/plugins/logger/enums.go
new file mode 100644
index 00000000..803eace0
--- /dev/null
+++ b/plugins/logger/enums.go
@@ -0,0 +1,12 @@
+package logger
+
+// Mode represents available logger modes
+type Mode string
+
+const (
+	none        Mode = "none"
+	off         Mode = "off"
+	production  Mode = "production"
+	development Mode = "development"
+	raw         Mode = "raw"
+)
diff --git a/plugins/logger/zap_adapter.go b/plugins/logger/zap_adapter.go
index 6d865519..fab59844 100644
--- a/plugins/logger/zap_adapter.go
+++ b/plugins/logger/zap_adapter.go
@@ -10,7 +10,7 @@ type ZapAdapter struct {
 	zl *zap.Logger
 }
 
-// Create NewZapAdapter which uses general log interface
+// NewZapAdapter ... which uses general log interface
 func NewZapAdapter(zapLogger *zap.Logger) *ZapAdapter {
 	return &ZapAdapter{
 		zl: zapLogger.WithOptions(zap.AddCallerSkip(1)),