feat: logx support logs rotation based on size limitation. (zeromicro…

…#1652)

implementation of zeromicro#1652

Totally compatible with the old logx.LogConf. No effect if users do not change their options.

core/logx/config.go

@@ -1,5 +1,12 @@
 package logx
 
+type LogRotationRuleType int
+
+const (
+	LogRotationRuleTypeDaily LogRotationRuleType = iota
+	LogRotationRuleTypeSizeLimit
+)
+
 // A LogConf is a logging config.
 type LogConf struct {
 	ServiceName         string `json:",optional"`
@@ -11,4 +18,14 @@ type LogConf struct {
 	Compress            bool   `json:",optional"`
 	KeepDays            int    `json:",optional"`
 	StackCooldownMillis int    `json:",default=100"`
+	// MaxBackups represents how many backup log files will be kept. 0 means all files will be kept forever.
+	// Only take effect when RotationRuleType is `LogRotationRuleTypeSizeLimit`
+	// NOTE: the level of option `KeepDays` will be higher. Even thougth `MaxBackups` sets 0, log files will
+	// still be removed if the `KeepDays` limitation is reached.
+	MaxBackups int `json:",default=0"`
+	// MaxSize represents how much space the writing log file takes up. 0 means no limit. The unit is `MB`.
+	// Only take effect when RotationRuleType is `LogRotationRuleTypeSizeLimit`
+	MaxSize int `json:",default=0"`
+	// RotationRuleType represents the type of log rotation rule. Default is DailyRotateRule.
+	RotationRuleType LogRotationRuleType `json:",default=LogRotationRuleTypeDaily,options=[LogRotationRuleTypeDaily,LogRotationRuleTypeSizeLimit]"`
 }

core/logx/logs.go

@@ -41,6 +41,9 @@ type (
 		gzipEnabled           bool
 		logStackCooldownMills int
 		keepDays              int
+		maxBackups            int
+		maxSize               int
+		rotationRule          LogRotationRuleType
 	}
 
 	// LogField is a key-value pair that will be added to the log entry.
@@ -294,13 +297,43 @@ func WithGzip() LogOption {
 	}
 }
 
+// WithMaxBackups customizes how many log files backups will be kept.
+func WithMaxBackups(count int) LogOption {
+	return func(opts *logOptions) {
+		opts.maxBackups = count
+	}
+}
+
+// WithMaxSize customizes how much space the writing log file can take up.
+func WithMaxSize(size int) LogOption {
+	return func(opts *logOptions) {
+		opts.maxSize = size
+	}
+}
+
+// WithLogRotationRuleType customizes which log rotation rule to use.
+func WithLogRotationRuleType(r LogRotationRuleType) LogOption {
+	return func(opts *logOptions) {
+		opts.rotationRule = r
+	}
+}
+
 func createOutput(path string) (io.WriteCloser, error) {
 	if len(path) == 0 {
 		return nil, ErrLogPathNotSet
 	}
 
-	return NewLogger(path, DefaultRotateRule(path, backupFileDelimiter, options.keepDays,
-		options.gzipEnabled), options.gzipEnabled)
+	switch options.rotationRule {
+	case LogRotationRuleTypeDaily:
+		return NewLogger(path, DefaultRotateRule(path, backupFileDelimiter, options.keepDays,
+			options.gzipEnabled), options.gzipEnabled)
+	case LogRotationRuleTypeSizeLimit:
+		return NewLogger(path, NewSizeLimitRotateRule(path, backupFileDelimiter, options.keepDays,
+			options.maxSize, options.maxBackups, options.gzipEnabled), options.gzipEnabled)
+	default:
+		return NewLogger(path, DefaultRotateRule(path, backupFileDelimiter, options.keepDays,
+			options.gzipEnabled), options.gzipEnabled)
+	}
 }
 
 func errorAnySync(v interface{}) {

core/logx/readme-cn.md

@@ -8,15 +8,18 @@
 
 ```go
 type LogConf struct {
-	ServiceName         string `json:",optional"`
-	Mode                string `json:",default=console,options=[console,file,volume]"`
-	Encoding            string `json:",default=json,options=[json,plain]"`
-	TimeFormat          string `json:",optional"`
-	Path                string `json:",default=logs"`
-	Level               string `json:",default=info,options=[info,error,severe]"`
-	Compress            bool   `json:",optional"`
-	KeepDays            int    `json:",optional"`
-	StackCooldownMillis int    `json:",default=100"`
+	ServiceName         string              `json:",optional"`
+	Mode                string              `json:",default=console,options=[console,file,volume]"`
+	Encoding            string              `json:",default=json,options=[json,plain]"`
+	TimeFormat          string              `json:",optional"`
+	Path                string              `json:",default=logs"`
+	Level               string              `json:",default=info,options=[info,error,severe]"`
+	Compress            bool                `json:",optional"`
+	KeepDays            int                 `json:",optional"`
+	StackCooldownMillis int                 `json:",default=100"`
+	MaxBackups          int                 `json:",default=0"`
+	MaxSize             int                 `json:",default=0"`
+	RotationRuleType    LogRotationRuleType `json:",default=LogRotationRuleTypeDaily,options=[LogRotationRuleTypeDaily,LogRotationRuleTypeSizeLimit]"`
 }
 ```
 
@@ -37,6 +40,12 @@ type LogConf struct {
 - `Compress`: 是否压缩日志文件，只在 `file` 模式下工作
 - `KeepDays`：日志文件被保留多少天，在给定的天数之后，过期的文件将被自动删除。对 `console` 模式没有影响
 - `StackCooldownMillis`：多少毫秒后再次写入堆栈跟踪。用来避免堆栈跟踪日志过多
+- `MaxBackups`: 多少个日志文件备份将被保存。0代表所有备份都被保存。当`RotationRuleType`被设置为`LogRotationRuleTypeSizeLimit`时才会起作用。注意：`KeepDays`选项的优先级会比`MaxBackups`高，即使`MaxBackups`被设置为0，当达到`KeepDays`上限时备份文件同样会被删除。
+- `MaxSize`: 当前被写入的日志文件最大可占用多少空间。0代表没有上限。单位为`MB`。当`RotationRuleType`被设置为`LogRotationRuleTypeSizeLimit`时才会起作用。
+- `RotationRuleType`: 日志轮转策略类型。默认为`LogRotationRuleTypeDaily`（按天轮转）。
+  - `LogRotationRuleTypeDaily`: 按天轮转。
+  - `LogRotationRuleTypeSizeLimit`: 按日志大小轮转。
+
 
 ## 打印日志方法
 

core/logx/readme.md

@@ -8,15 +8,18 @@ English | [简体中文](readme-cn.md)
 
 ```go
 type LogConf struct {
-	ServiceName         string `json:",optional"`
-	Mode                string `json:",default=console,options=[console,file,volume]"`
-	Encoding            string `json:",default=json,options=[json,plain]"`
-	TimeFormat          string `json:",optional"`
-	Path                string `json:",default=logs"`
-	Level               string `json:",default=info,options=[info,error,severe]"`
-	Compress            bool   `json:",optional"`
-	KeepDays            int    `json:",optional"`
-	StackCooldownMillis int    `json:",default=100"`
+	ServiceName         string              `json:",optional"`
+	Mode                string              `json:",default=console,options=[console,file,volume]"`
+	Encoding            string              `json:",default=json,options=[json,plain]"`
+	TimeFormat          string              `json:",optional"`
+	Path                string              `json:",default=logs"`
+	Level               string              `json:",default=info,options=[info,error,severe]"`
+	Compress            bool                `json:",optional"`
+	KeepDays            int                 `json:",optional"`
+	StackCooldownMillis int                 `json:",default=100"`
+	MaxBackups          int                 `json:",default=0"`
+	MaxSize             int                 `json:",default=0"`
+	RotationRuleType    LogRotationRuleType `json:",default=LogRotationRuleTypeDaily,options=[LogRotationRuleTypeDaily,LogRotationRuleTypeSizeLimit]"`
 }
 ```
 
@@ -37,6 +40,11 @@ type LogConf struct {
 - `Compress`: whether or not to compress log files, only works with `file` mode.
 - `KeepDays`: how many days that the log files are kept, after the given days, the outdated files will be deleted automatically. It has no effect on `console` mode.
 - `StackCooldownMillis`: how many milliseconds to rewrite stacktrace again. It’s used to avoid stacktrace flooding.
+- `MaxBackups`: represents how many backup log files will be kept. 0 means all files will be kept forever. Only take effect when RotationRuleType is `LogRotationRuleTypeSizeLimit`. NOTE: the level of option `KeepDays` will be higher. Even thougth `MaxBackups` sets 0, log files will still be removed if the `KeepDays` limitation is reached.
+- `MaxSize`: represents how much space the writing log file takes up. 0 means no limit. The unit is `MB`. Only take effect when RotationRuleType is `LogRotationRuleTypeSizeLimit`.
+- `RotationRuleType`: represents the type of log rotation rule. Default is LogRotationRuleTypeDaily.
+  - `LogRotationRuleTypeDaily`: rotate the logs by day.
+  - `LogRotationRuleTypeSizeLimit`: rotate the logs by size of logs.
 
 ## Logging methods