README
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internal errors
The package interrors is an addition to the
juju/errors; interrors provides helpers
to handle internal errors which should not be reported to the user.
When building, say, a backend service, we often want to distinguish public
errors (e.g. caused by the invalid input received from a client) and internal
errors, like the failure to execute SQL query or something else. In the former
case, the client should be provided with the descriptive error message like
handling bookmarks: saving bookmark "foo bar": URL can't be empty. In the
latter case though, the client should only get internal error, and we want to
log the exact (and descriptive) internal error for us to examine.
Consider:
errOrig := errors.New("specific error")
err := errOrig
err = errors.Annotatef(err, "some context")
err = errors.Annotatef(err, "some more context")
fmt.Println(err) // Prints "some more context: some context: specific error"
Now, if it was actually an internal error which we don't want to show to a client, here's what we can do:
internalServerError := errors.New("internal server error")
err = interrors.WrapInternalError(err, internalServerError)
So from now on, err can be further wrapped using errors.Annotatef() or
friends, but it will behave like the cause was internalServerError, not
errOrig.
err = errors.Annotatef(err, "some public context")
fmt.Println(err) // Prints "some public context: internal server error"
errors.Cause(err) // Returns internalServerError
errors.ErrorStack(err) // Returns stack up to internalServerError, not further
And, of course, there are helpers to get the details of an internal error back.
fmt.Println(interrors.InternalErr(err)) // Prints "some more context: some context: specific error"
fmt.Println(interrors.InternalCause(err)) // Prints "specific error"
fmt.Println(interrors.ErrorStack(err)) // Prints full error stack, from "some public context" to "specific error"
The error stack printed by interrors.ErrorStack(err) would look like:
/path/to/file.go:46: specific error
/path/to/file.go:49: some context
/path/to/file.go:50: some more context
internal server error
/path/to/file.go:55: some public context
Documentation
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Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func ErrorStack ¶
ErrorStack is similar to errors.ErrorStack, but it also includes the stack of the internal error, if given err is an internal error wrapper.
func InternalCause ¶
InternalCause is like InternalErr, but it returns the original cause of the error.
func InternalErr ¶
InternalErr takes an error, and if it's an internal error wrapper, returns the underlying internal error (which might still be wrapped with errors.Trace() or some such). Otherwise, just returns the given err back.
err is an "internal error wrapper" if it's a value returned from WrapInternalError, which can be further wrapped into errors.Trace() or friends.
func IsInternalError ¶
IsInternalError reports whether the given err is an internal error wrapper.
func WrapInternalError ¶
WrapInternalError wraps two errors: internal intError and external pubError. All standard operations on the resulting error will behave as if pubError was the original cause, thus hiding the internal error, which is only retrievable with the accessor functions below.
func WrapInternalErrorf ¶
WrapInternalErrorf takes an internal error, creates a new (public) error with the formatted message, and calls WrapInternalError with those two errors.
Types ¶
This section is empty.
Source Files