errors

package module
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Published: Dec 5, 2019 License: MIT Imports: 3 Imported by: 4

README

errors

Build Status GitHub tag (latest SemVer) GoDoc Go Report Card codecov

Nestable errors for golang dev.

Take a look at: https://play.golang.org/p/bsGjRAWJDOA

Import

import "gtihub.com/hedzr/errors"

ExtErr

error with message
var (
  errBug1 = errors.New("bug 1")
  errBug2 = errors.New("bug 2")
  errBug3 = errors.New("bug 3")
)

func main() {
  err := errors.New("something").Attach(errBug1, errBug2)
  err2 := errors.New(errBug3)

  log.Println(err, err2)
}

CodedErr

error with a code
var(
  errNotFound = errors.NewCodedError(errors.NotFound)
  errNotFoundMsg = errors.NewCodedError(errors.NotFound).Msg("not found")
)
Predefined error codes

The builtin error codes are copied from Google gRPC codes but negatived.

The numbers -1..-999 are reserved.

register your error codes:

The user-defined error codes (must be < -1000, or > 0) could be registered into errors.Code with its codename.

For example (run it at play-ground: https://play.golang.org/p/ifUvABaPEoJ):

package main

import (
	"fmt"
	"github.com/hedzr/errors"
	"io"
)

const (
	BUG1001 errors.Code = 1001
	BUG1002 errors.Code = 1002
)

var (
	errBug1001 = errors.NewCodedError(BUG1001).Msg("something is wrong").Attach(io.EOF)
)

func init() {
	BUG1001.Register("BUG1001")
	BUG1002.Register("BUG1002")
}

func main() {
	fmt.Println(BUG1001.String())
	fmt.Println(errBug1001)
}

Result:

BUG1001
001001|BUG1001|something is wrong, EOF

replacement of go errors

As a replacement, the functions are copied from go errors, such as:

  • Is(err, target) bool
  • As(err, target) bool
  • Unwrap(err) error

LICENSE

MIT

Documentation

Overview

Package errors defines the generic error codes, nestable ExtErr object.

Index

Examples

Constants

View Source
const (
	// AppName const
	AppName = "errors"
	// Version const
	Version = "1.1.0"
	// VersionInt const
	VersionInt = 0x010100
)

Variables

This section is empty.

Functions

func As added in v1.1.0

func As(err error, target interface{}) bool

As finds the first error in err's chain that matches target, and if so, sets target to that error value and returns true.

The chain consists of err itself followed by the sequence of errors obtained by repeatedly calling Unwrap.

An error matches target if the error's concrete value is assignable to the value pointed to by target, or if the error has a method As(interface{}) bool such that As(target) returns true. In the latter case, the As method is responsible for setting target.

As will panic if target is not a non-nil pointer to either a type that implements error, or to any interface type. As returns false if err is nil.

Example
package main

import (
	"fmt"
	"github.com/hedzr/errors"
	"os"
)

func main() {
	if _, err := os.Open("non-existing"); err != nil {
		var pathError *os.PathError
		if errors.As(err, &pathError) {
			fmt.Println("Failed at path:", pathError.Path)
		} else {
			fmt.Println(err)
		}
	}

}
Output:

Failed at path: non-existing

func Is added in v1.1.0

func Is(err, target error) bool

Is reports whether any error in err's chain matches target.

The chain consists of err itself followed by the sequence of errors obtained by repeatedly calling Unwrap.

An error is considered to match a target if it is equal to that target or if it implements a method Is(error) bool such that Is(target) returns true.

func Unwrap added in v1.1.0

func Unwrap(err error) error

Unwrap returns the result of calling the Unwrap method on err, if err's type contains an Unwrap method returning error. Otherwise, Unwrap returns nil.

Types

type Code

type Code int32

A Code is an signed 32-bit error code copied from gRPC spec but negatived.

const (
	// OK is returned on success.
	OK Code = 0

	// Canceled indicates the operation was canceled (typically by the caller).
	Canceled Code = -1

	// Unknown error. An example of where this error may be returned is
	// if a Status value received from another address space belongs to
	// an error-space that is not known in this address space. Also
	// errors raised by APIs that do not return enough error information
	// may be converted to this error.
	Unknown Code = -2

	// InvalidArgument indicates client specified an invalid argument.
	// Note that this differs from FailedPrecondition. It indicates arguments
	// that are problematic regardless of the state of the system
	// (e.g., a malformed file name).
	InvalidArgument Code = -3

	// DeadlineExceeded means operation expired before completion.
	// For operations that change the state of the system, this error may be
	// returned even if the operation has completed successfully. For
	// example, a successful response from a server could have been delayed
	// long enough for the deadline to expire.
	DeadlineExceeded Code = -4

	// NotFound means some requested entity (e.g., file or directory) was
	// not found.
	NotFound Code = -5

	// AlreadyExists means an attempt to create an entity failed because one
	// already exists.
	AlreadyExists Code = -6

	// PermissionDenied indicates the caller does not have permission to
	// execute the specified operation. It must not be used for rejections
	// caused by exhausting some resource (use ResourceExhausted
	// instead for those errors). It must not be
	// used if the caller cannot be identified (use Unauthenticated
	// instead for those errors).
	PermissionDenied Code = -7

	// ResourceExhausted indicates some resource has been exhausted, perhaps
	// a per-user quota, or perhaps the entire file system is out of space.
	ResourceExhausted Code = -8

	// FailedPrecondition indicates operation was rejected because the
	// system is not in a state required for the operation's execution.
	// For example, directory to be deleted may be non-empty, an rmdir
	// operation is applied to a non-directory, etc.
	//
	// A litmus test that may help a service implementor in deciding
	// between FailedPrecondition, Aborted, and Unavailable:
	//  (a) Use Unavailable if the client can retry just the failing call.
	//  (b) Use Aborted if the client should retry at a higher-level
	//      (e.g., restarting a read-modify-write sequence).
	//  (c) Use FailedPrecondition if the client should not retry until
	//      the system state has been explicitly fixed. E.g., if an "rmdir"
	//      fails because the directory is non-empty, FailedPrecondition
	//      should be returned since the client should not retry unless
	//      they have first fixed up the directory by deleting files from it.
	//  (d) Use FailedPrecondition if the client performs conditional
	//      REST Get/Update/Delete on a resource and the resource on the
	//      server does not match the condition. E.g., conflicting
	//      read-modify-write on the same resource.
	FailedPrecondition Code = -9

	// Aborted indicates the operation was aborted, typically due to a
	// concurrency issue like sequencer check failures, transaction aborts,
	// etc.
	//
	// See litmus test above for deciding between FailedPrecondition,
	// Aborted, and Unavailable.
	Aborted Code = -10

	// OutOfRange means operation was attempted past the valid range.
	// E.g., seeking or reading past end of file.
	//
	// Unlike InvalidArgument, this error indicates a problem that may
	// be fixed if the system state changes. For example, a 32-bit file
	// system will generate InvalidArgument if asked to read at an
	// offset that is not in the range [0,2^32-1], but it will generate
	// OutOfRange if asked to read from an offset past the current
	// file size.
	//
	// There is a fair bit of overlap between FailedPrecondition and
	// OutOfRange. We recommend using OutOfRange (the more specific
	// error) when it applies so that callers who are iterating through
	// a space can easily look for an OutOfRange error to detect when
	// they are done.
	OutOfRange Code = -11

	// Unimplemented indicates operation is not implemented or not
	// supported/enabled in this service.
	Unimplemented Code = -12

	// Internal errors. Means some invariants expected by underlying
	// system has been broken. If you see one of these errors,
	// something is very broken.
	Internal Code = -13

	// Unavailable indicates the service is currently unavailable.
	// This is a most likely a transient condition and may be corrected
	// by retrying with a backoff. Note that it is not always safe to retry
	// non-idempotent operations.
	//
	// See litmus test above for deciding between FailedPrecondition,
	// Aborted, and Unavailable.
	Unavailable Code = -14

	// DataLoss indicates unrecoverable data loss or corruption.
	DataLoss Code = -15

	// Unauthenticated indicates the request does not have valid
	// authentication credentials for the operation.
	Unauthenticated Code = -16

	// RateLimited indicates some flow control algorithm is running and applied.
	// = HTTP Code 429
	RateLimited = -17

	// MinErrorCode is the lower bound
	MinErrorCode = -1000
)

func (Code) Register

func (c Code) Register(codeName string) (errno Code)

Register register a code and its token string for using later

func (Code) String

func (c Code) String() string

type CodedErr

type CodedErr struct {
	ExtErr
	// contains filtered or unexported fields
}

CodedErr adds a error code

func NewCodedError added in v1.1.0

func NewCodedError(code Code) *CodedErr

NewCodedError error object with nested errors

func (*CodedErr) Attach added in v1.1.0

func (e *CodedErr) Attach(errors ...error) *CodedErr

Attach attaches the nested errors into CodedErr

func (*CodedErr) Code

func (e *CodedErr) Code(code Code) *CodedErr

Code put another code into CodedErr

func (*CodedErr) Error

func (e *CodedErr) Error() string

func (*CodedErr) Msg added in v1.1.0

func (e *CodedErr) Msg(msg string, args ...interface{}) *CodedErr

Msg encodes a formattable msg with args into ExtErr

func (*CodedErr) Nest added in v1.1.0

func (e *CodedErr) Nest(errors ...error) *CodedErr

Nest attaches the nested errors into CodedErr

type ExtErr

type ExtErr struct {
	// contains filtered or unexported fields
}

ExtErr is a nestable error object

func New

func New(msg string, args ...interface{}) *ExtErr

New ExtErr error object with message and allows attach more nested errors

func NewWithError

func NewWithError(errors ...error) *ExtErr

NewWithError ExtErr error object with nested errors

func (*ExtErr) Attach added in v1.1.0

func (e *ExtErr) Attach(errors ...error) *ExtErr

Attach attaches the nested errors into ExtErr

func (*ExtErr) Error

func (e *ExtErr) Error() string

func (*ExtErr) Msg added in v1.1.0

func (e *ExtErr) Msg(msg string, args ...interface{}) *ExtErr

Msg encodes a formattable msg with args into ExtErr

func (*ExtErr) Nest added in v1.1.0

func (e *ExtErr) Nest(errors ...error) *ExtErr

Nest attaches the nested errors into ExtErr

func (*ExtErr) Unwrap added in v1.1.0

func (e *ExtErr) Unwrap() error

Unwrap returns the result of calling the Unwrap method on err, if err's type contains an Unwrap method returning error. Otherwise, Unwrap returns nil.

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