add log rotation config

config/config.go

@@ -43,9 +43,33 @@ func SetGlobal(c *Config) {
 }
 
 type LogConfig struct {
-	Output string `yaml:",omitempty" json:"output,omitempty"`
-	Level  string `yaml:",omitempty" json:"level,omitempty"`
-	Format string `yaml:",omitempty" json:"format,omitempty"`
+	Output   string             `yaml:",omitempty" json:"output,omitempty"`
+	Level    string             `yaml:",omitempty" json:"level,omitempty"`
+	Format   string             `yaml:",omitempty" json:"format,omitempty"`
+	Rotation *LogRotationConfig `yaml:",omitempty" json:"rotation,omitempty"`
+}
+
+type LogRotationConfig struct {
+	// MaxSize is the maximum size in megabytes of the log file before it gets
+	// rotated. It defaults to 100 megabytes.
+	MaxSize int `yaml:"maxSize,omitempty" json:"maxSize,omitempty"`
+	// 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 `yaml:"maxAge,omitempty" json:"maxAge,omitempty"`
+	// 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 `yaml:"maxBackups,omitempty" json:"maxBackups,omitempty"`
+	// LocalTime determines if the time used for formatting the timestamps in
+	// backup files is the computer's local time. The default is to use UTC
+	// time.
+	LocalTime bool `yaml:"localTime,omitempty" json:"localTime,omitempty"`
+	// Compress determines if the rotated log files should be compressed
+	// using gzip. The default is not to perform compression.
+	Compress bool `yaml:"compress,omitempty" json:"compress,omitempty"`
 }
 
 type ProfilingConfig struct {