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[FAB-3012] Copy callstack from lower level error
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This change adds the ability to copy the callstack and error message
from a lower level error into a later error. For example, an error may
occur in a common utility function that a different package may want to
wrap with its own component/reason code, error message, and callstack
while retaining the details from the wrapped error.

Change-Id: Id143640bbaaba7bf125b343dbc614d046acbfd1a
Signed-off-by: Will Lahti <wtlahti@us.ibm.com>
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@wlahti
wlahti committed Apr 19, 2017
1 parent eba4a20 commit c1684d0
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Showing 4 changed files with 298 additions and 116 deletions.
154 changes: 87 additions & 67 deletions core/errors/errors.go
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
/*
Copyright Digital Asset Holdings, LLC 2016 All Rights Reserved.
Copyright IBM Corp. 2017 All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
Expand All @@ -19,8 +20,8 @@ package errors
import (
"bytes"
"fmt"
"regexp"
"runtime"
"strings"

"github.com/hyperledger/fabric/common/flogging"
logging "github.com/op/go-logging"
Expand All @@ -29,135 +30,151 @@ import (
// MaxCallStackLength is the maximum length of the stored call stack
const MaxCallStackLength = 30

var errorLogger = logging.MustGetLogger("error")
var (
errorLogger = logging.MustGetLogger("error")
componentPattern = "[A-Za-z]{3}"
reasonPattern = "[0-9]{3}"
)

// CallStackError is a general interface for
// Fabric errors
// CallStackError is a general interface for Fabric errors
type CallStackError interface {
error
GetStack() string
GetErrorCode() string
GetComponentCode() string
GetReasonCode() string
Message() string
GenerateStack(bool) CallStackError
WrapError(error) CallStackError
}

type callstack []uintptr

// the main idea is to have an error package
// HLError is the 'super class' of all errors
// It has a predefined, general error message
// One has to create his own error in order to
// create something more useful
type hlError struct {
// callError is the 'super class' of all errors
type callError struct {
stack callstack
componentcode string
reasoncode string
message string
args []interface{}
stackGetter func(callstack) string
prevErr error
}

// newHLError creates a general HL error with a predefined message
// and a stacktrace.
func newHLError(debug bool) *hlError {
e := &hlError{}
setupHLError(e, debug)
return e
}

func setupHLError(e *hlError, debug bool) {
e.componentcode = "UTILITY"
e.reasoncode = "UNKNOWNERROR"
e.message = "An unknown error occurred."
if !debug {
func setupCallError(e *callError, generateStack bool) {
if !generateStack {
e.stackGetter = noopGetStack
return
}
e.stackGetter = getStack
stack := make([]uintptr, MaxCallStackLength)
skipCallersAndSetupHL := 2
length := runtime.Callers(skipCallersAndSetupHL, stack[:])
skipCallersAndSetup := 2
length := runtime.Callers(skipCallersAndSetup, stack[:])
e.stack = stack[:length]
}

// Error comes from the error interface
func (h *hlError) Error() string {
return h.Message()
func (e *callError) Error() string {
return e.Message()
}

// GetStack returns the call stack as a string
func (h *hlError) GetStack() string {
return h.stackGetter(h.stack)
func (e *callError) GetStack() string {
return e.stackGetter(e.stack)
}

// GetComponentCode returns the component name
func (h *hlError) GetComponentCode() string {
return h.componentcode
func (e *callError) GetComponentCode() string {
return e.componentcode
}

// GetReasonCode returns the reason code - i.e. why the error occurred
func (h *hlError) GetReasonCode() string {
return h.reasoncode
func (e *callError) GetReasonCode() string {
return e.reasoncode
}

// GetErrorCode returns a formatted error code string
func (h *hlError) GetErrorCode() string {
return fmt.Sprintf("%s_%s", h.componentcode, h.reasoncode)
func (e *callError) GetErrorCode() string {
return fmt.Sprintf("%s:%s", e.componentcode, e.reasoncode)
}

// Message returns the corresponding error message for this error in default
// language.
func (h *hlError) Message() string {
message := h.GetErrorCode() + " - " + fmt.Sprintf(h.message, h.args...)

func (e *callError) Message() string {
message := e.GetErrorCode() + " - " + fmt.Sprintf(e.message, e.args...)
// check that the error has a callstack before proceeding
if h.GetStack() != "" {
// initialize logging level for errors from core.yaml. it can also be set
// for code running on the peer dynamically via CLI using
// "peer logging setlevel error <log-level>"
errorLogLevelString := flogging.GetModuleLevel("error")

if errorLogLevelString == logging.DEBUG.String() {
message = appendCallStack(message, h.GetStack())
if e.GetStack() != "" {
// stacktrace is enabled when `logging.error` in core.yaml is set to
// DEBUG. it can also be toggled for code running on the peer dynamically
// via CLI using `peer logging setlevel error <log-level>`
errorLevel := flogging.GetModuleLevel("error")
if errorLevel == logging.DEBUG.String() {
message = appendCallStack(message, e.GetStack())
}
}

if e.prevErr != nil {
message += "\nCaused by: " + e.prevErr.Error()
}
return message
}

func appendCallStack(message string, callstack string) string {
messageWithCallStack := message + "\n" + callstack

return messageWithCallStack
return message + "\n" + callstack
}

// Error creates a CallStackError using a specific Component Code and
// Reason Code (no callstack is recorded)
// Error creates a CallStackError using a specific component code and reason
// code (no callstack is generated)
func Error(componentcode string, reasoncode string, message string, args ...interface{}) CallStackError {
return newCustomError(componentcode, reasoncode, message, false, args...)
return newError(componentcode, reasoncode, message, args...).GenerateStack(false)
}

// ErrorWithCallstack creates a CallStackError using a specific Component Code and
// Reason Code and fills its callstack
// ErrorWithCallstack creates a CallStackError using a specific component code
// and reason code and generates its callstack
func ErrorWithCallstack(componentcode string, reasoncode string, message string, args ...interface{}) CallStackError {
return newCustomError(componentcode, reasoncode, message, true, args...)
return newError(componentcode, reasoncode, message, args...).GenerateStack(true)
}

func newError(componentcode string, reasoncode string, message string, args ...interface{}) CallStackError {
e := &callError{}
e.setErrorFields(componentcode, reasoncode, message, args...)
return e
}

// GenerateStack generates the callstack for a CallStackError
func (e *callError) GenerateStack(flag bool) CallStackError {
setupCallError(e, flag)
return e
}

// WrapError wraps a previous error into a CallStackError
func (e *callError) WrapError(prevErr error) CallStackError {
e.prevErr = prevErr
return e
}

func newCustomError(componentcode string, reasoncode string, message string, generateStack bool, args ...interface{}) CallStackError {
e := &hlError{}
setupHLError(e, generateStack)
if componentcode != "" {
e.componentcode = strings.ToUpper(componentcode)
func (e *callError) setErrorFields(componentcode string, reasoncode string, message string, args ...interface{}) {
if isValidComponentOrReasonCode(componentcode, componentPattern) {
e.componentcode = componentcode
}
if reasoncode != "" {
e.reasoncode = strings.ToUpper(reasoncode)
if isValidComponentOrReasonCode(reasoncode, reasonPattern) {
e.reasoncode = reasoncode
}
if message != "" {
e.message = message
}
e.args = args
return e
}

func isValidComponentOrReasonCode(componentOrReasonCode string, regExp string) bool {
if componentOrReasonCode == "" {
return false
}
re, _ := regexp.Compile(regExp)
matched := re.FindString(componentOrReasonCode)
if len(matched) != len(componentOrReasonCode) {
return false
}
return true
}

func getStack(stack callstack) string {
Expand All @@ -169,12 +186,15 @@ func getStack(stack callstack) string {
// are not useful for debugging
const firstNonErrorModuleCall int = 2
stack = stack[firstNonErrorModuleCall:]
for _, pc := range stack {
for i, pc := range stack {
f := runtime.FuncForPC(pc)
file, line := f.FileLine(pc)
buf.WriteString(fmt.Sprintf("%s:%d %s\n", file, line, f.Name()))
if i != len(stack)-1 {
buf.WriteString(fmt.Sprintf("%s:%d %s\n", file, line, f.Name()))
} else {
buf.WriteString(fmt.Sprintf("%s:%d %s", file, line, f.Name()))
}
}

return fmt.Sprintf("%s", buf.Bytes())
}

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