README
¶
errors
import "github.com/juju/errors"
The juju/errors provides an easy way to annotate errors without losing the original error context.
The exported New and Errorf functions are designed to replace the
errors.New and fmt.Errorf functions respectively. The same underlying
error is there, but the package also records the location at which the error
was created.
A primary use case for this library is to add extra context any time an error is returned from a function.
if err := SomeFunc(); err != nil {
return err
}
This instead becomes:
if err := SomeFunc(); err != nil {
return errors.Trace(err)
}
which just records the file and line number of the Trace call, or
if err := SomeFunc(); err != nil {
return errors.Annotate(err, "more context")
}
which also adds an annotation to the error.
When you want to check to see if an error is of a particular type, a helper
function is normally exported by the package that returned the error, like the
os package does. The underlying cause of the error is available using the
Cause function.
os.IsNotExist(errors.Cause(err))
The result of the Error() call on an annotated error is the annotations joined
with colons, then the result of the Error() method for the underlying error
that was the cause.
err := errors.Errorf("original")
err = errors.Annotatef(err, "context")
err = errors.Annotatef(err, "more context")
err.Error() -> "more context: context: original"
Obviously recording the file, line and functions is not very useful if you cannot get them back out again.
errors.ErrorStack(err)
will return something like:
first error
github.com/juju/errors/annotation_test.go:193:
github.com/juju/errors/annotation_test.go:194: annotation
github.com/juju/errors/annotation_test.go:195:
github.com/juju/errors/annotation_test.go:196: more context
github.com/juju/errors/annotation_test.go:197:
The first error was generated by an external system, so there was no location associated. The second, fourth, and last lines were generated with Trace calls, and the other two through Annotate.
Sometimes when responding to an error you want to return a more specific error for the situation.
if err := FindField(field); err != nil {
return errors.Wrap(err, errors.NotFoundf(field))
}
This returns an error where the complete error stack is still available, and
errors.Cause() will return the NotFound error.
func AlreadyExistsf
func AlreadyExistsf(format string, args ...interface{}) error
AlreadyExistsf returns an error which satisfies IsAlreadyExists().
func Annotate
func Annotate(other error, message string) error
Annotate is used to add extra context to an existing error. The location of the Annotate call is recorded with the annotations. The file, line and function are also recorded.
For example:
if err := SomeFunc(); err != nil {
return errors.Annotate(err, "failed to frombulate")
}
func Annotatef
func Annotatef(other error, format string, args ...interface{}) error
Annotatef is used to add extra context to an existing error. The location of the Annotate call is recorded with the annotations. The file, line and function are also recorded.
For example:
if err := SomeFunc(); err != nil {
return errors.Annotatef(err, "failed to frombulate the %s", arg)
}
func BadRequestf
func BadRequestf(format string, args ...interface{}) error
BadRequestf returns an error which satisfies IsBadRequest().
func Cause
func Cause(err error) error
Cause returns the cause of the given error. This will be either the original error, or the result of a Wrap or Mask call.
Cause is the usual way to diagnose errors that may have been wrapped by the other errors functions.
func DeferredAnnotatef
func DeferredAnnotatef(err *error, format string, args ...interface{})
DeferredAnnotatef annotates the given error (when it is not nil) with the given format string and arguments (like fmt.Sprintf). If *err is nil, DeferredAnnotatef does nothing. This method is used in a defer statement in order to annotate any resulting error with the same message.
For example:
defer DeferredAnnotatef(&err, "failed to frombulate the %s", arg)
func Details
func Details(err error) string
Details returns information about the stack of errors wrapped by err, in the format:
[{filename:99: error one} {otherfile:55: cause of error one}]
This is a terse alternative to ErrorStack as it returns a single line.
func ErrorStack
func ErrorStack(err error) string
ErrorStack returns a string representation of the annotated error. If the error passed as the parameter is not an annotated error, the result is simply the result of the Error() method on that error.
If the error is an annotated error, a multi-line string is returned where each line represents one entry in the annotation stack. The full filename from the call stack is used in the output.
first error
github.com/juju/errors/annotation_test.go:193:
github.com/juju/errors/annotation_test.go:194: annotation
github.com/juju/errors/annotation_test.go:195:
github.com/juju/errors/annotation_test.go:196: more context
github.com/juju/errors/annotation_test.go:197:
func Errorf
func Errorf(format string, args ...interface{}) error
Errorf creates a new annotated error and records the location that the error is created. This should be a drop in replacement for fmt.Errorf.
For example:
return errors.Errorf("validation failed: %s", message)
func Forbiddenf
func Forbiddenf(format string, args ...interface{}) error
Forbiddenf returns an error which satistifes IsForbidden()
func IsAlreadyExists
func IsAlreadyExists(err error) bool
IsAlreadyExists reports whether the error was created with AlreadyExistsf() or NewAlreadyExists().
func IsBadRequest
func IsBadRequest(err error) bool
IsBadRequest reports whether err was created with BadRequestf() or NewBadRequest().
func IsForbidden
func IsForbidden(err error) bool
IsForbidden reports whether err was created with Forbiddenf() or NewForbidden().
func IsMethodNotAllowed
func IsMethodNotAllowed(err error) bool
IsMethodNotAllowed reports whether err was created with MethodNotAllowedf() or NewMethodNotAllowed().
func IsNotAssigned
func IsNotAssigned(err error) bool
IsNotAssigned reports whether err was created with NotAssignedf() or NewNotAssigned().
func IsNotFound
func IsNotFound(err error) bool
IsNotFound reports whether err was created with NotFoundf() or NewNotFound().
func IsNotImplemented
func IsNotImplemented(err error) bool
IsNotImplemented reports whether err was created with NotImplementedf() or NewNotImplemented().
func IsNotProvisioned
func IsNotProvisioned(err error) bool
IsNotProvisioned reports whether err was created with NotProvisionedf() or NewNotProvisioned().
func IsNotSupported
func IsNotSupported(err error) bool
IsNotSupported reports whether the error was created with NotSupportedf() or NewNotSupported().
func IsNotValid
func IsNotValid(err error) bool
IsNotValid reports whether the error was created with NotValidf() or NewNotValid().
func IsUnauthorized
func IsUnauthorized(err error) bool
IsUnauthorized reports whether err was created with Unauthorizedf() or NewUnauthorized().
func IsUserNotFound
func IsUserNotFound(err error) bool
IsUserNotFound reports whether err was created with UserNotFoundf() or NewUserNotFound().
func Mask
func Mask(other error) error
Mask hides the underlying error type, and records the location of the masking.
func Maskf
func Maskf(other error, format string, args ...interface{}) error
Mask masks the given error with the given format string and arguments (like fmt.Sprintf), returning a new error that maintains the error stack, but hides the underlying error type. The error string still contains the full annotations. If you want to hide the annotations, call Wrap.
func MethodNotAllowedf
func MethodNotAllowedf(format string, args ...interface{}) error
MethodNotAllowedf returns an error which satisfies IsMethodNotAllowed().
func New
func New(message string) error
New is a drop in replacement for the standard library errors module that records the location that the error is created.
For example:
return errors.New("validation failed")
func NewAlreadyExists
func NewAlreadyExists(err error, msg string) error
NewAlreadyExists returns an error which wraps err and satisfies IsAlreadyExists().
func NewBadRequest
func NewBadRequest(err error, msg string) error
NewBadRequest returns an error which wraps err that satisfies IsBadRequest().
func NewForbidden
func NewForbidden(err error, msg string) error
NewForbidden returns an error which wraps err that satisfies IsForbidden().
func NewMethodNotAllowed
func NewMethodNotAllowed(err error, msg string) error
NewMethodNotAllowed returns an error which wraps err that satisfies IsMethodNotAllowed().
func NewNotAssigned
func NewNotAssigned(err error, msg string) error
NewNotAssigned returns an error which wraps err that satisfies IsNotAssigned().
func NewNotFound
func NewNotFound(err error, msg string) error
NewNotFound returns an error which wraps err that satisfies IsNotFound().
func NewNotImplemented
func NewNotImplemented(err error, msg string) error
NewNotImplemented returns an error which wraps err and satisfies IsNotImplemented().
func NewNotProvisioned
func NewNotProvisioned(err error, msg string) error
NewNotProvisioned returns an error which wraps err that satisfies IsNotProvisioned().
func NewNotSupported
func NewNotSupported(err error, msg string) error
NewNotSupported returns an error which wraps err and satisfies IsNotSupported().
func NewNotValid
func NewNotValid(err error, msg string) error
NewNotValid returns an error which wraps err and satisfies IsNotValid().
func NewUnauthorized
func NewUnauthorized(err error, msg string) error
NewUnauthorized returns an error which wraps err and satisfies IsUnauthorized().
func NewUserNotFound
func NewUserNotFound(err error, msg string) error
NewUserNotFound returns an error which wraps err and satisfies IsUserNotFound().
func NotAssignedf
func NotAssignedf(format string, args ...interface{}) error
NotAssignedf returns an error which satisfies IsNotAssigned().
func NotFoundf
func NotFoundf(format string, args ...interface{}) error
NotFoundf returns an error which satisfies IsNotFound().
func NotImplementedf
func NotImplementedf(format string, args ...interface{}) error
NotImplementedf returns an error which satisfies IsNotImplemented().
func NotProvisionedf
func NotProvisionedf(format string, args ...interface{}) error
NotProvisionedf returns an error which satisfies IsNotProvisioned().
func NotSupportedf
func NotSupportedf(format string, args ...interface{}) error
NotSupportedf returns an error which satisfies IsNotSupported().
func NotValidf
func NotValidf(format string, args ...interface{}) error
NotValidf returns an error which satisfies IsNotValid().
func Trace
func Trace(other error) error
Trace adds the location of the Trace call to the stack. The Cause of the resulting error is the same as the error parameter. If the other error is nil, the result will be nil.
For example:
if err := SomeFunc(); err != nil {
return errors.Trace(err)
}
func Unauthorizedf
func Unauthorizedf(format string, args ...interface{}) error
Unauthorizedf returns an error which satisfies IsUnauthorized().
func UserNotFoundf
func UserNotFoundf(format string, args ...interface{}) error
UserNotFoundf returns an error which satisfies IsUserNotFound().
func Wrap
func Wrap(other, newDescriptive error) error
Wrap changes the Cause of the error. The location of the Wrap call is also stored in the error stack.
For example:
if err := SomeFunc(); err != nil {
newErr := &packageError{"more context", private_value}
return errors.Wrap(err, newErr)
}
func Wrapf
func Wrapf(other, newDescriptive error, format string, args ...interface{}) error
Wrapf changes the Cause of the error, and adds an annotation. The location of the Wrap call is also stored in the error stack.
For example:
if err := SomeFunc(); err != nil {
return errors.Wrapf(err, simpleErrorType, "invalid value %q", value)
}
type Err
type Err struct {
// contains filtered or unexported fields
}
Err holds a description of an error along with information about where the error was created.
It may be embedded in custom error types to add extra information that this errors package can understand.
func NewErr
func NewErr(format string, args ...interface{}) Err
NewErr is used to return an Err for the purpose of embedding in other structures. The location is not specified, and needs to be set with a call to SetLocation.
For example:
type FooError struct {
errors.Err
code int
}
func NewFooError(code int) error {
err := &FooError{errors.NewErr("foo"), code}
err.SetLocation(1)
return err
}
func NewErrWithCause
func NewErrWithCause(other error, format string, args ...interface{}) Err
NewErrWithCause is used to return an Err with cause by other error for the purpose of embedding in other structures. The location is not specified, and needs to be set with a call to SetLocation.
For example:
type FooError struct {
errors.Err
code int
}
func (e *FooError) Annotate(format string, args ...interface{}) error {
err := &FooError{errors.NewErrWithCause(e.Err, format, args...), e.code}
err.SetLocation(1)
return err
})
func (*Err) Cause
func (e *Err) Cause() error
The Cause of an error is the most recent error in the error stack that meets one of these criteria: the original error that was raised; the new error that was passed into the Wrap function; the most recently masked error; or nil if the error itself is considered the Cause. Normally this method is not invoked directly, but instead through the Cause stand alone function.
func (*Err) Error
func (e *Err) Error() string
Error implements error.Error.
func (*Err) Format
func (e *Err) Format(s fmt.State, verb rune)
Format implements fmt.Formatter When printing errors with %+v it also prints the stack trace. %#v unsurprisingly will print the real underlying type.
func (*Err) Location
func (e *Err) Location() (filename string, line int)
Location is the file and line of where the error was most recently created or annotated.
func (*Err) Message
func (e *Err) Message() string
Message returns the message stored with the most recent location. This is the empty string if the most recent call was Trace, or the message stored with Annotate or Mask.
func (*Err) SetLocation
func (e *Err) SetLocation(callDepth int)
SetLocation records the source location of the error at callDepth stack frames above the call.
func (*Err) StackTrace
func (e *Err) StackTrace() []string
StackTrace returns one string for each location recorded in the stack of errors. The first value is the originating error, with a line for each other annotation or tracing of the error.
func (*Err) Underlying
func (e *Err) Underlying() error
Underlying returns the previous error in the error stack, if any. A client
should not ever really call this method. It is used to build the error
stack and should not be introspected by client calls. Or more
specifically, clients should not depend on anything but the Cause of an
error.
Generated by godoc2md
Documentation
¶
Overview ¶
Package errors provides an easy way to annotate errors without losing the original error context.
The exported `New` and `Errorf` functions are designed to replace the `errors.New` and `fmt.Errorf` functions respectively. The same underlying error is there, but the package also records the location at which the error was created.
A primary use case for this library is to add extra context any time an error is returned from a function.
if err := SomeFunc(); err != nil {
return err
}
This instead becomes:
if err := SomeFunc(); err != nil {
return errors.Trace(err)
}
which just records the file and line number of the Trace call, or
if err := SomeFunc(); err != nil {
return errors.Annotate(err, "more context")
}
which also adds an annotation to the error.
When you want to check to see if an error is of a particular type, a helper function is normally exported by the package that returned the error, like the `os` package does. The underlying cause of the error is available using the `Cause` function.
os.IsNotExist(errors.Cause(err))
The result of the `Error()` call on an annotated error is the annotations joined with colons, then the result of the `Error()` method for the underlying error that was the cause.
err := errors.Errorf("original")
err = errors.Annotatef(err, "context")
err = errors.Annotatef(err, "more context")
err.Error() -> "more context: context: original"
Obviously recording the file, line and functions is not very useful if you cannot get them back out again.
errors.ErrorStack(err)
will return something like:
first error github.com/juju/errors/annotation_test.go:193: github.com/juju/errors/annotation_test.go:194: annotation github.com/juju/errors/annotation_test.go:195: github.com/juju/errors/annotation_test.go:196: more context github.com/juju/errors/annotation_test.go:197:
The first error was generated by an external system, so there was no location associated. The second, fourth, and last lines were generated with Trace calls, and the other two through Annotate.
Sometimes when responding to an error you want to return a more specific error for the situation.
if err := FindField(field); err != nil {
return errors.Wrap(err, errors.NotFoundf(field))
}
This returns an error where the complete error stack is still available, and `errors.Cause()` will return the `NotFound` error.
Index ¶
- Constants
- func AlreadyExistsf(format string, args ...interface{}) error
- func Annotate(other error, message string) error
- func Annotatef(other error, format string, args ...interface{}) error
- func As(err error, target interface{}) bool
- func AsType[T error](err error) (T, bool)
- func BadRequestf(format string, args ...interface{}) error
- func Cause(err error) error
- func DeferredAnnotatef(err *error, format string, args ...interface{})
- func Details(err error) string
- func ErrorStack(err error) string
- func Errorf(format string, args ...interface{}) error
- func Forbiddenf(format string, args ...interface{}) error
- func HasType[T error](err error) bool
- func Hide(err error) error
- func Is(err, target error) bool
- func IsAlreadyExists(err error) booldeprecated
- func IsBadRequest(err error) booldeprecated
- func IsForbidden(err error) booldeprecated
- func IsMethodNotAllowed(err error) booldeprecated
- func IsNotAssigned(err error) booldeprecated
- func IsNotFound(err error) booldeprecated
- func IsNotImplemented(err error) booldeprecated
- func IsNotProvisioned(err error) booldeprecated
- func IsNotSupported(err error) booldeprecated
- func IsNotValid(err error) booldeprecated
- func IsNotYetAvailable(err error) booldeprecated
- func IsQuotaLimitExceeded(err error) booldeprecated
- func IsTimeout(err error) booldeprecated
- func IsUnauthorized(err error) booldeprecated
- func IsUserNotFound(err error) booldeprecated
- func Mask(other error) error
- func Maskf(other error, format string, args ...interface{}) error
- func MethodNotAllowedf(format string, args ...interface{}) error
- func New(message string) error
- func NewAlreadyExists(err error, msg string) error
- func NewBadRequest(err error, msg string) error
- func NewForbidden(err error, msg string) error
- func NewMethodNotAllowed(err error, msg string) error
- func NewNotAssigned(err error, msg string) error
- func NewNotFound(err error, msg string) error
- func NewNotImplemented(err error, msg string) error
- func NewNotProvisioned(err error, msg string) error
- func NewNotSupported(err error, msg string) error
- func NewNotValid(err error, msg string) error
- func NewNotYetAvailable(err error, msg string) error
- func NewQuotaLimitExceeded(err error, msg string) error
- func NewTimeout(err error, msg string) error
- func NewUnauthorized(err error, msg string) error
- func NewUserNotFound(err error, msg string) error
- func NotAssignedf(format string, args ...interface{}) error
- func NotFoundf(format string, args ...interface{}) error
- func NotImplementedf(format string, args ...interface{}) error
- func NotProvisionedf(format string, args ...interface{}) error
- func NotSupportedf(format string, args ...interface{}) error
- func NotValidf(format string, args ...interface{}) error
- func NotYetAvailablef(format string, args ...interface{}) error
- func QuotaLimitExceededf(format string, args ...interface{}) error
- func SetLocation(err error, callDepth int) error
- func Timeoutf(format string, args ...interface{}) error
- func Trace(other error) error
- func Unauthorizedf(format string, args ...interface{}) error
- func Unwrap(err error) error
- func UserNotFoundf(format string, args ...interface{}) error
- func WithType(err error, errType ConstError) error
- func Wrap(other, newDescriptive error) error
- func Wrapf(other, newDescriptive error, format string, args ...interface{}) error
- type ConstError
- type Err
- func (e *Err) Cause() error
- func (e *Err) Error() string
- func (e *Err) Format(s fmt.State, verb rune)
- func (e *Err) Location() (function string, line int)
- func (e *Err) Message() string
- func (e *Err) SetLocation(callDepth int)
- func (e *Err) StackTrace() []string
- func (e *Err) Underlying() error
- func (e *Err) Unwrap() error
- type Locationer
Examples ¶
Constants ¶
const ( // Timeout represents an error on timeout. Timeout = ConstError("timeout") // NotFound represents an error when something has not been found. NotFound = ConstError("not found") // UserNotFound represents an error when a non-existent user is looked up. UserNotFound = ConstError("user not found") Unauthorized = ConstError("unauthorized") // NotImplemented represents an error when something is not // implemented. NotImplemented = ConstError("not implemented") // AlreadyExists represents and error when something already exists. AlreadyExists = ConstError("already exists") // NotSupported represents an error when something is not supported. NotSupported = ConstError("not supported") // NotValid represents an error when something is not valid. NotValid = ConstError("not valid") // NotProvisioned represents an error when something is not yet provisioned. NotProvisioned = ConstError("not provisioned") // NotAssigned represents an error when something is not yet assigned to // something else. NotAssigned = ConstError("not assigned") // BadRequest represents an error when a request has bad parameters. BadRequest = ConstError("bad request") // MethodNotAllowed represents an error when an HTTP request // is made with an inappropriate method. MethodNotAllowed = ConstError("method not allowed") // Forbidden represents an error when a request cannot be completed because of // missing privileges. Forbidden = ConstError("forbidden") // QuotaLimitExceeded is emitted when an action failed due to a quota limit check. QuotaLimitExceeded = ConstError("quota limit exceeded") // NotYetAvailable is the error returned when a resource is not yet available // but it might be in the future. NotYetAvailable = ConstError("not yet available") )
Different types of errors
Variables ¶
This section is empty.
Functions ¶
func AlreadyExistsf ¶
AlreadyExistsf returns an error which satisfies Is(err, AlreadyExists) and the Locationer interface.
func Annotate ¶
Annotate is used to add extra context to an existing error. The location of the Annotate call is recorded with the annotations. The file, line and function are also recorded.
For example:
if err := SomeFunc(); err != nil {
return errors.Annotate(err, "failed to frombulate")
}
func Annotatef ¶
Annotatef is used to add extra context to an existing error. The location of the Annotate call is recorded with the annotations. The file, line and function are also recorded.
For example:
if err := SomeFunc(); err != nil {
return errors.Annotatef(err, "failed to frombulate the %s", arg)
}
func AsType ¶
AsType finds the first error in err's chain that is assignable to type T, and if a match is found, returns that error value and true. Otherwise, it returns T's zero value and false.
AsType is equivalent to errors.As, but uses a type parameter and returns the target, to avoid having to define a variable before the call. For example, callers can replace this:
var pathError *fs.PathError
if errors.As(err, &pathError) {
fmt.Println("Failed at path:", pathError.Path)
}
With:
if pathError, ok := errors.AsType[*fs.PathError](err); ok {
fmt.Println("Failed at path:", pathError.Path)
}
Example ¶
package main
import (
"fmt"
"github.com/juju/errors"
)
type MyError struct {
Message string
}
func (m *MyError) Error() string {
return m.Message
}
func main() {
myErr := &MyError{Message: "these are not the droids you're looking for"}
err := fmt.Errorf("wrapped: %w", myErr)
myErr, is := errors.AsType[*MyError](err)
fmt.Println(is)
fmt.Println(myErr.Message)
}
Output: true these are not the droids you're looking for
func BadRequestf ¶
BadRequestf returns an error which satisfies Is(err, BadRequest) and the Locationer interface.
func Cause ¶
Cause returns the cause of the given error. This will be either the original error, or the result of a Wrap or Mask call.
Cause is the usual way to diagnose errors that may have been wrapped by the other errors functions.
func DeferredAnnotatef ¶
DeferredAnnotatef annotates the given error (when it is not nil) with the given format string and arguments (like fmt.Sprintf). If *err is nil, DeferredAnnotatef does nothing. This method is used in a defer statement in order to annotate any resulting error with the same message.
For example:
defer DeferredAnnotatef(&err, "failed to frombulate the %s", arg)
func Details ¶
Details returns information about the stack of errors wrapped by err, in the format:
[{filename:99: error one} {otherfile:55: cause of error one}]
This is a terse alternative to ErrorStack as it returns a single line.
func ErrorStack ¶
ErrorStack returns a string representation of the annotated error. If the error passed as the parameter is not an annotated error, the result is simply the result of the Error() method on that error.
If the error is an annotated error, a multi-line string is returned where each line represents one entry in the annotation stack. The full filename from the call stack is used in the output.
first error github.com/juju/errors/annotation_test.go:193: github.com/juju/errors/annotation_test.go:194: annotation github.com/juju/errors/annotation_test.go:195: github.com/juju/errors/annotation_test.go:196: more context github.com/juju/errors/annotation_test.go:197:
func Errorf ¶
Errorf creates a new annotated error and records the location that the error is created. This should be a drop in replacement for fmt.Errorf.
For example:
return errors.Errorf("validation failed: %s", message)
func Forbiddenf ¶
Forbiddenf returns an error which satistifes Is(err, Forbidden) and the Locationer interface.
func HasType ¶
HasType is a function wrapper around AsType dropping the where return value from AsType() making a function that can be used like this:
return HasType[*MyError](err)
Or
if HasType[*MyError](err) {}
Example ¶
package main
import (
"fmt"
"github.com/juju/errors"
)
type MyError struct {
Message string
}
func (m *MyError) Error() string {
return m.Message
}
func main() {
myErr := &MyError{Message: "these are not the droids you're looking for"}
err := fmt.Errorf("wrapped: %w", myErr)
is := errors.HasType[*MyError](err)
fmt.Println(is)
}
Output: true
func Hide ¶
Hide takes an error and silences it's error string from appearing in fmt like
Example ¶
package main
import (
stderrors "errors"
"fmt"
"github.com/juju/errors"
)
func main() {
myConstError := errors.ConstError("I don't want to be fmt printed")
err := fmt.Errorf("don't show this error%w", errors.Hide(myConstError))
fmt.Println(err)
fmt.Println(stderrors.Is(err, myConstError))
}
Output: don't show this error true
func IsAlreadyExists
deprecated
func IsBadRequest
deprecated
func IsForbidden
deprecated
func IsMethodNotAllowed
deprecated
func IsNotAssigned
deprecated
func IsNotFound
deprecated
func IsNotImplemented
deprecated
func IsNotProvisioned
deprecated
func IsNotSupported
deprecated
func IsNotValid
deprecated
func IsNotYetAvailable
deprecated
func IsQuotaLimitExceeded
deprecated
func IsUnauthorized
deprecated
func IsUserNotFound
deprecated
func Maskf ¶
Maskf masks the given error with the given format string and arguments (like fmt.Sprintf), returning a new error that maintains the error stack, but hides the underlying error type. The error string still contains the full annotations. If you want to hide the annotations, call Wrap.
func MethodNotAllowedf ¶
MethodNotAllowedf returns an error which satisfies Is(err, MethodNotAllowed) and the Locationer interface.
func New ¶
New is a drop in replacement for the standard library errors module that records the location that the error is created.
For example:
return errors.New("validation failed")
func NewAlreadyExists ¶
NewAlreadyExists returns an error which wraps err and satisfies Is(err, AlreadyExists) and the Locationer interface.
func NewBadRequest ¶
NewBadRequest returns an error which wraps err and satisfies Is(err, BadRequest) and the Locationer interface.
func NewForbidden ¶
NewForbidden returns an error which wraps err and satisfies Is(err, Forbidden) and the Locationer interface.
func NewMethodNotAllowed ¶
NewMethodNotAllowed returns an error which wraps err and satisfies Is(err, MethodNotAllowed) and the Locationer interface.
func NewNotAssigned ¶
NewNotAssigned returns an error which wraps err and satisfies Is(err, NotAssigned) and the Locationer interface.
func NewNotFound ¶
NewNotFound returns an error which wraps err and satisfies Is(err, NotFound) and the Locationer interface.
func NewNotImplemented ¶
NewNotImplemented returns an error which wraps err and satisfies Is(err, NotImplemented) and the Locationer interface.
func NewNotProvisioned ¶
NewNotProvisioned returns an error which wraps err and satisfies Is(err, NotProvisioned) and the Locationer interface.
func NewNotSupported ¶
NewNotSupported returns an error which satisfies Is(err, NotSupported) and the Locationer interface.
func NewNotValid ¶
NewNotValid returns an error which wraps err and satisfies Is(err, NotValid) and the Locationer interface.
func NewNotYetAvailable ¶
NewNotYetAvailable returns an error which wraps err and satisfies Is(err, NotYetAvailable) and the Locationer interface.
func NewQuotaLimitExceeded ¶
NewQuotaLimitExceeded returns an error which wraps err and satisfies Is(err, QuotaLimitExceeded) and the Locationer interface.
func NewTimeout ¶
NewTimeout returns an error which wraps err and satisfies Is(err, Timeout) and the Locationer interface.
func NewUnauthorized ¶
NewUnauthorized returns an error which wraps err and satisfies Is(err, Unathorized) and the Locationer interface.
func NewUserNotFound ¶
NewUserNotFound returns an error which wraps err and satisfies Is(err, UserNotFound) and the Locationer interface.
func NotAssignedf ¶
NotAssignedf returns an error which satisfies Is(err, NotAssigned) and the Locationer interface.
func NotFoundf ¶
NotFoundf returns an error which satisfies Is(err, NotFound) and the Locationer interface.
func NotImplementedf ¶
NotImplementedf returns an error which satisfies Is(err, NotImplemented) and the Locationer interface.
func NotProvisionedf ¶
NotProvisionedf returns an error which satisfies Is(err, NotProvisioned) and the Locationer interface.
func NotSupportedf ¶
NotSupportedf returns an error which satisfies Is(err, NotSupported) and the Locationer interface.
func NotValidf ¶
NotValidf returns an error which satisfies Is(err, NotValid) and the Locationer interface.
func NotYetAvailablef ¶
NotYetAvailablef returns an error which satisfies Is(err, NotYetAvailable) and the Locationer interface.
func QuotaLimitExceededf ¶
QuotaLimitExceededf returns an error which satisfies Is(err, QuotaLimitExceeded) and the Locationer interface.
func SetLocation ¶
SetLocation takes a given error and records where in the stack SetLocation was called from and returns the wrapped error with the location information set. The returned error implements the Locationer interface. If err is nil then a nil error is returned.
func Timeoutf ¶
Timeoutf returns an error which satisfies Is(err, Timeout) and the Locationer interface.
func Trace ¶
Trace adds the location of the Trace call to the stack. The Cause of the resulting error is the same as the error parameter. If the other error is nil, the result will be nil.
For example:
if err := SomeFunc(); err != nil {
return errors.Trace(err)
}
Example ¶
package main
import (
"fmt"
"github.com/juju/errors"
)
func main() {
var err1 error = fmt.Errorf("something wicked this way comes")
var err2 error = nil
// Tracing a non nil error will return an error
fmt.Println(errors.Trace(err1))
// Tracing nil will return nil
fmt.Println(errors.Trace(err2))
}
Output: something wicked this way comes <nil>
func Unauthorizedf ¶
Unauthorizedf returns an error that satisfies Is(err, Unauthorized) and the Locationer interface.
func Unwrap ¶
Unwrap is a proxy for the Unwrap function in Go's standard `errors` library (pkg.go.dev/errors).
func UserNotFoundf ¶
UserNotFoundf returns an error which satisfies Is(err, UserNotFound) and the Locationer interface.
func WithType ¶
func WithType(err error, errType ConstError) error
WithType is responsible for annotating an already existing error so that it also satisfies that of a ConstError. The resultant error returned should satisfy Is(err, errType). If err is nil then a nil error will also be returned.
Now with Go's Is, As and Unwrap support it no longer makes sense to Wrap() 2 errors as both of those errors could be chains of errors in their own right. WithType aims to solve some of the usefulness of Wrap with the ability to make a pre-existing error also satisfy a ConstError type.
func Wrap ¶
Wrap changes the Cause of the error. The location of the Wrap call is also stored in the error stack.
For example:
if err := SomeFunc(); err != nil {
newErr := &packageError{"more context", private_value}
return errors.Wrap(err, newErr)
}
Types ¶
type Err ¶
type Err struct {
// contains filtered or unexported fields
}
Err holds a description of an error along with information about where the error was created.
It may be embedded in custom error types to add extra information that this errors package can understand.
func NewErr ¶
NewErr is used to return an Err for the purpose of embedding in other structures. The location is not specified, and needs to be set with a call to SetLocation.
For example:
type FooError struct {
errors.Err
code int
}
func NewFooError(code int) error {
err := &FooError{errors.NewErr("foo"), code}
err.SetLocation(1)
return err
}
func NewErrWithCause ¶
NewErrWithCause is used to return an Err with cause by other error for the purpose of embedding in other structures. The location is not specified, and needs to be set with a call to SetLocation.
For example:
type FooError struct {
errors.Err
code int
}
func (e *FooError) Annotate(format string, args ...interface{}) error {
err := &FooError{errors.NewErrWithCause(e.Err, format, args...), e.code}
err.SetLocation(1)
return err
})
func (*Err) Cause ¶
Cause returns the most recent error in the error stack that meets one of these criteria: the original error that was raised; the new error that was passed into the Wrap function; the most recently masked error; or nil if the error itself is considered the Cause. Normally this method is not invoked directly, but instead through the Cause stand alone function.
func (*Err) Format ¶
Format implements fmt.Formatter When printing errors with %+v it also prints the stack trace. %#v unsurprisingly will print the real underlying type.
func (*Err) Location ¶
Location returns the package path-qualified function name and line of where the error was most recently created or annotated.
func (*Err) Message ¶
Message returns the message stored with the most recent location. This is the empty string if the most recent call was Trace, or the message stored with Annotate or Mask.
func (*Err) SetLocation ¶
SetLocation records the package path-qualified function name of the error at callDepth stack frames above the call.
func (*Err) StackTrace ¶
StackTrace returns one string for each location recorded in the stack of errors. The first value is the originating error, with a line for each other annotation or tracing of the error.
func (*Err) Underlying ¶
Underlying returns the previous error in the error stack, if any. A client should not ever really call this method. It is used to build the error stack and should not be introspected by client calls. Or more specifically, clients should not depend on anything but the `Cause` of an error.
type Locationer ¶
type Locationer interface {
// Location returns the path-qualified function name where the error was
// created and the line number
Location() (function string, line int)
}
Locationer is an interface that represents a certain class of errors that contain the location information from where they were raised.
Source Files