velero/pkg/util/logging/error_location_hook.go

150 lines
3.8 KiB
Go

/*
Copyright 2017, 2019 the Velero contributors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package logging
import (
"fmt"
"strconv"
"strings"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
)
const (
errorFileField = "error.file"
errorFunctionField = "error.function"
)
// ErrorLocationHook is a logrus hook that attaches error location information
// to log entries if an error is being logged and it has stack-trace information
// (i.e. if it originates from or is wrapped by github.com/pkg/errors, or if it
// implements the errorLocationer interface, like errors returned from plugins
// typically do).
type ErrorLocationHook struct{}
func (h *ErrorLocationHook) Levels() []logrus.Level {
return logrus.AllLevels
}
func (h *ErrorLocationHook) Fire(entry *logrus.Entry) error {
errObj, ok := entry.Data[logrus.ErrorKey]
if !ok {
return nil
}
if _, ok := entry.Data[errorFileField]; ok {
// If there is already an error file field, preserve it instead of overwriting it. This field will already exist if
// the log message occurred in the server half of a plugin.
return nil
}
if _, ok := entry.Data[errorFunctionField]; ok {
// If there is already an error function field, preserve it instead of overwriting it. This field will already exist if
// the log message occurred in the server half of a plugin.
return nil
}
err, ok := errObj.(error)
if !ok {
// if the value isn't an error type, skip trying to get location info,
// and just let it be logged as whatever it was
return nil
}
if errorLocationer, ok := err.(errorLocationer); ok {
entry.Data[errorFileField] = fmt.Sprintf("%s:%d", errorLocationer.File(), errorLocationer.Line())
entry.Data[errorFunctionField] = errorLocationer.Function()
return nil
}
if stackErr := getInnermostTrace(err); stackErr != nil {
location := GetFrameLocationInfo(stackErr.StackTrace()[0])
entry.Data[errorFileField] = fmt.Sprintf("%s:%d", location.File, location.Line)
entry.Data[errorFunctionField] = location.Function
}
return nil
}
// LocationInfo specifies the location of a line
// of code.
type LocationInfo struct {
File string
Function string
Line int
}
// GetFrameLocationInfo returns the location of a frame.
func GetFrameLocationInfo(frame errors.Frame) LocationInfo {
// see https://godoc.org/github.com/pkg/errors#Frame.Format for
// details on formatting verbs
functionNameAndFileAndLine := fmt.Sprintf("%+v", frame)
newLineIndex := strings.Index(functionNameAndFileAndLine, "\n")
functionName := functionNameAndFileAndLine[0:newLineIndex]
tabIndex := strings.LastIndex(functionNameAndFileAndLine, "\t")
fileAndLine := strings.Split(functionNameAndFileAndLine[tabIndex+1:], ":")
line, err := strconv.Atoi(fileAndLine[1])
if err != nil {
line = -1
}
return LocationInfo{
File: fileAndLine[0],
Function: functionName,
Line: line,
}
}
type errorLocationer interface {
File() string
Line() int32
Function() string
}
type stackTracer interface {
error
StackTrace() errors.StackTrace
}
type causer interface {
Cause() error
}
// getInnermostTrace returns the innermost error that
// has a stack trace attached
func getInnermostTrace(err error) stackTracer {
var tracer stackTracer
for {
t, isTracer := err.(stackTracer)
if isTracer {
tracer = t
}
c, isCauser := err.(causer)
if isCauser {
err = c.Cause()
} else {
return tracer
}
}
}