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本文次要钻研一下klog的klogger
logr
go-logr/logr@v0.2.0/logr.go
// Logger represents the ability to log messages, both errors and not.type Logger interface { // Enabled tests whether this Logger is enabled. For example, commandline // flags might be used to set the logging verbosity and disable some info // logs. Enabled() bool // Info logs a non-error message with the given key/value pairs as context. // // The msg argument should be used to add some constant description to // the log line. The key/value pairs can then be used to add additional // variable information. The key/value pairs should alternate string // keys and arbitrary values. Info(msg string, keysAndValues ...interface{}) // Error logs an error, with the given message and key/value pairs as context. // It functions similarly to calling Info with the "error" named value, but may // have unique behavior, and should be preferred for logging errors (see the // package documentations for more information). // // The msg field should be used to add context to any underlying error, // while the err field should be used to attach the actual error that // triggered this log line, if present. Error(err error, msg string, keysAndValues ...interface{}) // V returns an Logger value for a specific verbosity level, relative to // this Logger. In other words, V values are additive. V higher verbosity // level means a log message is less important. It's illegal to pass a log // level less than zero. V(level int) Logger // WithValues adds some key-value pairs of context to a logger. // See Info for documentation on how key/value pairs work. WithValues(keysAndValues ...interface{}) Logger // WithName adds a new element to the logger's name. // Successive calls with WithName continue to append // suffixes to the logger's name. It's strongly reccomended // that name segments contain only letters, digits, and hyphens // (see the package documentation for more information). WithName(name string) Logger}logr相似java的slf4j，其Logger接口定义了Enabled、Info、Error、V、WithValues、WithName办法
klogr
k8s.io/klog/v2@v2.4.0/klogr/klogr.go
type klogger struct { level int prefix string values []interface{}}// New returns a logr.Logger which is implemented by klog.func New() logr.Logger { return klogger{ level: 0, prefix: "", values: nil, }}func (l klogger) Enabled() bool { return bool(klog.V(klog.Level(l.level)).Enabled())}func (l klogger) Info(msg string, kvList ...interface{}) { if l.Enabled() { msgStr := flatten("msg", msg) trimmed := trimDuplicates(l.values, kvList) fixedStr := flatten(trimmed[0]...) userStr := flatten(trimmed[1]...) klog.InfoDepth(framesToCaller(), l.prefix, " ", msgStr, " ", fixedStr, " ", userStr) }}func (l klogger) Error(err error, msg string, kvList ...interface{}) { msgStr := flatten("msg", msg) var loggableErr interface{} if err != nil { loggableErr = err.Error() } errStr := flatten("error", loggableErr) trimmed := trimDuplicates(l.values, kvList) fixedStr := flatten(trimmed[0]...) userStr := flatten(trimmed[1]...) klog.ErrorDepth(framesToCaller(), l.prefix, " ", msgStr, " ", errStr, " ", fixedStr, " ", userStr)}func (l klogger) V(level int) logr.Logger { new := l.clone() new.level = level return new}func (l klogger) WithValues(kvList ...interface{}) logr.Logger { new := l.clone() new.values = append(new.values, kvList...) return new}func (l klogger) WithName(name string) logr.Logger { new := l.clone() if len(l.prefix) > 0 { new.prefix = l.prefix + "/" } new.prefix += name return new}klogger定义了level、prefix、values属性，New办法创立的klogger其level为0；它实现了logr.Logger接口，其Info先判断Enabled，之后调用klog.InfoDepth；其Error办法调用的是klog.ErrorDepth；其V办法先进行clone在对level进行赋值，返回新的logr.Logger；WithValues办法先进行clone，而后设置values，返回新的logr.Logger；WithName办法也是先进行clone，在设置prefix，返回新的logr.Logger
clone
k8s.io/klog/v2@v2.4.0/klogr/klogr.go
func (l klogger) clone() klogger { return klogger{ level: l.level, prefix: l.prefix, values: copySlice(l.values), }}clone办法应用原有的klogger的level、prefix、values创立一个新的klogger
klog.V
k8s.io/klog/v2@v2.4.0/klogr/klogr.go
func V(level Level) Verbose { // This function tries hard to be cheap unless there's work to do. // The fast path is two atomic loads and compares. // Here is a cheap but safe test to see if V logging is enabled globally. if logging.verbosity.get() >= level { return newVerbose(level, true) } // It's off globally but vmodule may still be set. // Here is another cheap but safe test to see if vmodule is enabled. if atomic.LoadInt32(&logging.filterLength) > 0 { // Now we need a proper lock to use the logging structure. The pcs field // is shared so we must lock before accessing it. This is fairly expensive, // but if V logging is enabled we're slow anyway. logging.mu.Lock() defer logging.mu.Unlock() if runtime.Callers(2, logging.pcs[:]) == 0 { return newVerbose(level, false) } v, ok := logging.vmap[logging.pcs[0]] if !ok { v = logging.setV(logging.pcs[0]) } return newVerbose(level, v >= level) } return newVerbose(level, false)}func newVerbose(level Level, b bool) Verbose { if logging.logr == nil { return Verbose{b, nil, logging.filter} } return Verbose{b, logging.logr.V(int(level)), logging.filter}}// Enabled will return true if this log level is enabled, guarded by the value// of v.// See the documentation of V for usage.func (v Verbose) Enabled() bool { return v.enabled}通过logging.verbosity与传入的level进行判断，若大于等于则其enabled为true；klogr.New()默认的level为0
实例
func logrDemo() { log := klogr.New().WithName("MyName").WithValues("user", "you") log.Info("hello", "val1", 1, "val2", map[string]int{"k": 1}) log.V(3).Info("nice to meet you") log.Error(nil, "uh oh", "trouble", true, "reasons", []float64{0.1, 0.11, 3.14}) log.Error(errors.New("an error occurred"), "goodbye", "code", -1)}输入
I1230 23:12:33.388829 2890 klog_demo.go:42] MyName "msg"="hello" "user"="you" "val1"=1 "val2"={"k":1}E1230 23:12:33.389032 2890 klog_demo.go:44] MyName "msg"="uh oh" "error"=null "user"="you" "reasons"=[0.1,0.11,3.14] "trouble"=trueE1230 23:12:33.389055 2890 klog_demo.go:45] MyName "msg"="goodbye" "error"="an error occurred" "user"="you" "code"=-1小结
klogger定义了level、prefix、values属性，New办法创立的klogger其level为0；它实现了logr.Logger接口，其Info先判断Enabled，之后调用klog.InfoDepth；其Error办法调用的是klog.ErrorDepth；其V办法先进行clone在对level进行赋值，返回新的logr.Logger；WithValues办法先进行clone，而后设置values，返回新的logr.Logger；WithName办法也是先进行clone，在设置prefix，返回新的logr.Logger
doc
- klog
- logr