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logger/caller.go

106 lines
2.4 KiB
Go

package logger
import (
"runtime"
"strings"
"sync"
"github.com/sirupsen/logrus"
)
var (
// qualified package name, cached at first use
logrusPackage string
// Positions in the call stack when tracing to report the calling method
minimumCallerDepth int
// Used for caller information initialisation
callerInitOnce sync.Once
)
const (
maximumCallerDepth int = 25
knownLogrusFrames int = 8
)
func init() {
// start at the bottom of the stack before the package-name cache is primed
minimumCallerDepth = 1
}
// getPackageName reduces a fully qualified function name to the package name
// There really ought to be to be a better way...
func getPackageName(f string) string {
for {
lastPeriod := strings.LastIndex(f, ".")
lastSlash := strings.LastIndex(f, "/")
if lastPeriod > lastSlash {
f = f[:lastPeriod]
} else {
break
}
}
return f
}
// getCaller retrieves the name of the first non-logrus calling function
func getCaller() *runtime.Frame {
// cache this package's fully-qualified name
callerInitOnce.Do(func() {
pcs := make([]uintptr, maximumCallerDepth)
_ = runtime.Callers(0, pcs)
// dynamic get the package name and the minimum caller depth
for i := 0; i < maximumCallerDepth; i++ {
funcName := runtime.FuncForPC(pcs[i]).Name()
if strings.Contains(funcName, "getCaller") {
logrusPackage = getPackageName(funcName)
break
}
}
minimumCallerDepth = knownLogrusFrames
})
// Restrict the lookback frames to avoid runaway lookups
pcs := make([]uintptr, maximumCallerDepth)
depth := runtime.Callers(minimumCallerDepth, pcs)
frames := runtime.CallersFrames(pcs[:depth])
for f, again := frames.Next(); again; f, again = frames.Next() {
pkg := getPackageName(f.Function)
// If the caller isn't part of this package, we're done
if pkg != logrusPackage && pkg != "github.com/sirupsen/logrus" {
return &f //nolint:scopelint
}
}
// if we got here, we failed to find the caller's context
return nil
}
// CallerHook is a hook designed for dealing with logs in test scenarios.
type CallerHook struct{}
// NewCallerHook installs a test hook for a given local logger.
func NewCallerHook(logger *logrus.Logger) *CallerHook {
hook := new(CallerHook)
logger.Hooks.Add(hook)
return hook
}
func (t *CallerHook) Fire(e *logrus.Entry) error {
if e.HasCaller() {
e.Caller = getCaller()
}
return nil
}
func (t *CallerHook) Levels() []logrus.Level {
return logrus.AllLevels
}