聊聊klog的info方法

序

本文主要研究一下klog的info方法

Info

k8s.io/klog/v2@v2.4.0/klog.go

// Info logs to the INFO log.
// Arguments are handled in the manner of fmt.Print; a newline is appended if missing.
func Info(args ...interface{}) {
    logging.print(infoLog, logging.logr, logging.filter, args...)
}

Info使用logging.print打印info级别的日志，参数的处理跟fmt.Print类似，若没有换行则会追加换行

InfoDepth

k8s.io/klog/v2@v2.4.0/klog.go

// InfoDepth acts as Info but uses depth to determine which call frame to log.
// InfoDepth(0, "msg") is the same as Info("msg").
func InfoDepth(depth int, args ...interface{}) {
    logging.printDepth(infoLog, logging.logr, logging.filter, depth, args...)
}

InfoDepth可以指定要打印的call frame，Info使用的depth为0

Infoln

k8s.io/klog/v2@v2.4.0/klog.go

// Infoln logs to the INFO log.
// Arguments are handled in the manner of fmt.Println; a newline is always appended.
func Infoln(args ...interface{}) {
    logging.println(infoLog, logging.logr, logging.filter, args...)
}

Infoln的参数处理与fmt.Println类似，总是会新添加换行

Infof

k8s.io/klog/v2@v2.4.0/klog.go

// Infof logs to the INFO log.
// Arguments are handled in the manner of fmt.Printf; a newline is appended if missing.
func Infof(format string, args ...interface{}) {
    logging.printf(infoLog, logging.logr, logging.filter, format, args...)
}

Infof的参数处理与fmt.Printf类似，若没有换行则会追加换行

InfoS

k8s.io/klog/v2@v2.4.0/klog.go

// InfoS structured logs to the INFO log.
// The msg argument used to add constant description to the log line.
// The key/value pairs would be join by "=" ; a newline is always appended.
//
// Basic examples:
// >> klog.InfoS("Pod status updated", "pod", "kubedns", "status", "ready")
// output:
// >> I1025 00:15:15.525108       1 controller_utils.go:116] "Pod status updated" pod="kubedns" status="ready"
func InfoS(msg string, keysAndValues ...interface{}) {
    logging.infoS(logging.logr, logging.filter, msg, keysAndValues...)
}

InfoS用于打印结构化的日志，kv之间用=连接，总是会新添加换行

实例

import (
    "flag"

    "k8s.io/klog/v2"
)

func main() {
    klog.InitFlags(flag.CommandLine)
    defer klog.Flush()
    klog.Info("hello by Info")
    klog.InfoDepth(0, "hello by InfoDepth 0")
    klog.InfoDepth(1, "hello by InfoDepth 1")
    klog.Infoln("hello by Infoln")
    klog.Infof("hello by %s", "Infof")
    klog.InfoS("Pod status updated", "pod", "kubedns", "status", "ready")
}

输出

I1226 22:29:10.258496    6455 klog_demo.go:16] hello by Info
I1226 22:29:10.258619    6455 klog_demo.go:17] hello by InfoDepth 0
I1226 22:29:10.258642    6455 proc.go:204] hello by InfoDepth 1
I1226 22:29:10.258645    6455 klog_demo.go:19] hello by Infoln
I1226 22:29:10.258651    6455 klog_demo.go:20] hello by Infof
I1226 22:29:10.258658    6455 klog_demo.go:21] "Pod status updated" pod="kubedns" status="ready"

小结

klog提供了Info、InfoDepth、Infoln、Infof、InfoS方法；Info使用logging.print打印info级别的日志，参数的处理跟fmt.Print类似，若没有换行则会追加换行；InfoDepth可以指定要打印的call frame，Info使用的depth为0；Infoln的参数处理与fmt.Println类似，总是会新添加换行；Infof的参数处理与fmt.Printf类似，若没有换行则会追加换行；InfoS用于打印结构化的日志，kv之间用=连接，总是会新添加换行

doc

• klog