Go 语言如何配置 log
一、日志三大类
创建项目并初始化用vscode 打开
~/Code/go via 🐹 v1.20.3 via 🅒 base
➜ mcd demo
Code/go/demo via 🐹 v1.20.3 via 🅒 base
➜ go mod init
go: cannot determine module path for source directory /Users/qiaopengjun/Code/go/demo (outside GOPATH, module path must be specified)
Example usage:
'go mod init example.com/m' to initialize a v0 or v1 module
'go mod init example.com/m/v2' to initialize a v2 module
Run 'go help mod init' for more information.
Code/go/demo via 🐹 v1.20.3 via 🅒 base
➜ go mod init demo # 初始化当前文件夹, 创建go.mod文件
go: creating new go.mod: module demo
Code/go/demo via 🐹 v1.20.3 via 🅒 base
➜ c
Code/go/demo via 🐹 v1.20.3 via 🅒 base
➜
main.go 文件
package main
import "log"
func init() {
}
func main() {
log.Println("1234")
// log.Fatalln("1234")
// log.Panicln("1234")
}
运行 log.Println
Code/go/demo via 🐹 v1.20.3 via 🅒 base
➜ go run .
2023/06/04 22:16:25 1234
Code/go/demo via 🐹 v1.20.3 via 🅒 base
➜
main.go 文件
package main
import "log"
func init() {
}
func main() {
// log.Println("1234")
log.Fatalln("1234")
// log.Panicln("1234")
}
运行 log.Fatalln
Code/go/demo via 🐹 v1.20.3 via 🅒 base
➜ go run .
2023/06/04 22:17:45 1234
exit status 1
Code/go/demo via 🐹 v1.20.3 via 🅒 base
➜
相当于
package main
import (
"log"
"os"
)
func init() {
}
func main() {
// log.Println("1234")
log.Fatalln("1234")
os.Exit(1)
// log.Panicln("1234")
}
main.go 文件
package main
import (
"log"
)
func init() {
}
func main() {
// log.Println("1234")
// log.Fatalln("1234")
// os.Exit(1)
log.Panicln("1234")
}
运行 log.Panicln
Code/go/demo via 🐹 v1.20.3 via 🅒 base
➜ go run .
2023/06/04 22:20:42 1234
panic: 1234
goroutine 1 [running]:
log.Panicln({0x14000092f58?, 0x0?, 0x1400004e768?})
/usr/local/go/src/log/log.go:398 +0x64
main.main()
/Users/qiaopengjun/Code/go/demo/main.go:17 +0x44
exit status 2
Code/go/demo via 🐹 v1.20.3 via 🅒 base
➜
日志三大类
package main
import (
"log"
)
func init() {
}
func main() {
log.Println("1234")
log.Fatalln("1234")
log.Panicln("1234")
log.Panic("1234")
log.Panicf("1234, %d", 5678)
}
二、配置日志
设置前缀
package main
import (
"log"
)
func init() {
log.SetPrefix("LOG: ") // 设置前缀
}
func main() {
log.Println("1234")
// log.Fatalln("1234")
// log.Panicln("1234")
// log.Panic("1234")
// log.Panicf("1234, %d", 5678)
}
运行
Code/go/demo via 🐹 v1.20.3 via 🅒 base
➜ go run .
LOG: 2023/06/04 22:26:08 1234
Code/go/demo via 🐹 v1.20.3 via 🅒 base
➜
设置输出
package main
import (
"log"
"os"
)
func init() {
log.SetPrefix("LOG: ") // 设置前缀
f, err := os.OpenFile("./log.log", os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0644)
if err != nil {
log.Fatalf("open log file failed with error: %v", err)
}
log.SetOutput(f) // 设置输出
}
func main() {
log.Println("1234")
// log.Fatalln("1234")
// log.Panicln("1234")
// log.Panic("1234")
// log.Panicf("1234, %d", 5678)
}
运行
Code/go/demo via 🐹 v1.20.3 via 🅒 base
➜ go run .
Code/go/demo via 🐹 v1.20.3 via 🅒 base
➜
log.log
LOG: 2023/06/04 22:32:00 1234
设置 flag
main.go 文件
package main
import (
"log"
"os"
)
func init() {
log.SetPrefix("LOG: ") // 设置前缀
f, err := os.OpenFile("./log.log", os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0644)
if err != nil {
log.Fatalf("open log file failed with error: %v", err)
}
log.SetOutput(f) // 设置输出
log.SetFlags(log.Ldate | log.Ltime | log.Lmicroseconds | log.Llongfile)
// const (
// Ldate = 1 << iota // 1 << 0 = 000000001 = 1
// Ltime // 1 << 1 = 000000010 = 2
// Lmicroseconds // 1 << 2 = 000000100 = 4
// Llongfile // 1 << 3 = 000001000 = 8
// Lshortfile // 1 << 4 = 000010000 = 16
// ...
// )
}
func main() {
log.Println("1234")
// log.Fatalln("1234")
// log.Panicln("1234")
// log.Panic("1234")
// log.Panicf("1234, %d", 5678)
}
源码
const (
Ldate = 1 << iota // the date in the local time zone: 2009/01/23
Ltime // the time in the local time zone: 01:23:23
Lmicroseconds // microsecond resolution: 01:23:23.123123. assumes Ltime.
Llongfile // full file name and line number: /a/b/c/d.go:23
Lshortfile // final file name element and line number: d.go:23. overrides Llongfile
LUTC // if Ldate or Ltime is set, use UTC rather than the local time zone
Lmsgprefix // move the "prefix" from the beginning of the line to before the message
LstdFlags = Ldate | Ltime // initial values for the standard logger 默认flag
)
运行
Code/go/demo via 🐹 v1.20.3 via 🅒 base
➜ go run .
Code/go/demo via 🐹 v1.20.3 via 🅒 base
➜
log.log
LOG: 2023/06/04 22:32:00 1234
LOG: 2023/06/04 22:43:12.984321 /Users/qiaopengjun/Code/go/demo/main.go:30: 1234
