Documentation
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Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func HTTPError ¶
func HTTPError(w http.ResponseWriter, err error)
HTTPError writes structured error information to w using JSON encoding. The status code is computed with HTTPStatus.
If err is nil it writes:
{"code": "ok", "message": "", "details": null}
func New ¶
func New(code ErrCode, msg string, details ErrDetails) error
New creates a new Error without wrapping another underlying error. If code == OK it returns nil.
func Wrap ¶
Wrap wraps the err, adding additional error information. If err is nil it returns nil.
If err is already an *Error its code, message, and details are copied over to the new error.
The fields are used to update the corresponding field of the error: Passing in an ErrCode updates the Code field. Passing in a string adds context to the error message. Passing in a type that implements ErrDetails updates the Details field, and passing in untyped nil sets Details to nil.
Passing in another type causes Wrap to panic.
Types ¶
type ErrCode ¶
type ErrCode int
ErrCode is an RPC error code.
const ( // OK indicates the operation was successful. OK ErrCode = 0 // Canceled indicates the operation was canceled (typically by the caller). // // Encore will generate this error code when cancellation is requested. Canceled ErrCode = 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. // // Encore will generate this error code in the above two mentioned cases. Unknown ErrCode = 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). // // Encore will generate this error code if the request data cannot be parsed. InvalidArgument ErrCode = 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. // // Encore will generate this error code when the deadline is exceeded. DeadlineExceeded ErrCode = 4 // NotFound means some requested entity (e.g., file or directory) was // not found. // // Encore will not generate this error code. NotFound ErrCode = 5 // AlreadyExists means an attempt to create an entity failed because one // already exists. // // Encore will not generate this error code. AlreadyExists ErrCode = 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). // // Encore will not generate this error code. PermissionDenied ErrCode = 7 // ResourceExhausted indicates some resource has been exhausted, perhaps // a per-user quota, or perhaps the entire file system is out of space. // // Encore will generate this error code in out-of-memory and server overload // situations, or when a message is larger than the configured maximum size. ResourceExhausted ErrCode = 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 // 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. // // Encore will not generate this error code. FailedPrecondition ErrCode = 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 ErrCode = 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. // // Encore will not generate this error code. OutOfRange ErrCode = 11 // Unimplemented indicates operation is not implemented or not // supported/enabled in this service. // // Encore will generate this error code when an endpoint does not exist. Unimplemented ErrCode = 12 // Internal errors. Means some invariants expected by underlying // system has been broken. If you see one of these errors, // something is very broken. // // Encore will generate this error code in several internal error conditions. Internal ErrCode = 13 // 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. // // Encore will generate this error code in aubrupt shutdown of a server process // or network connection. Unavailable ErrCode = 14 // DataLoss indicates unrecoverable data loss or corruption. // // Encore will not generate this error code. DataLoss ErrCode = 15 // Unauthenticated indicates the request does not have valid // authentication credentials for the operation. // // Encore will generate this error code when the authentication metadata // is invalid or missing, and expects auth handlers to return errors with // this code when the auth token is not valid. Unauthenticated ErrCode = 16 )
func Code ¶
Code reports the error code from an error. If err is nil it reports OK. Otherwise if err is not an *Error it reports Unknown.
func (ErrCode) HTTPStatus ¶
HTTPStatus reports a suitable HTTP status code for an error, based on its code. If err is nil it reports 200. If it's not an *Error it reports 500.
func (ErrCode) MarshalJSON ¶
type ErrDetails ¶
type ErrDetails interface {
ErrDetails() // marker method; it need not do anything
}
ErrDetails is a marker interface for telling Encore the type is used for reporting error details.
We require a marker method (as opposed to using interface{}) to facilitate static analysis and to ensure the type can be properly serialized across the network.
func Details ¶
func Details(err error) ErrDetails
Details reports the error details included in the error. If err is nil or the error lacks details it reports nil.
type Error ¶
type Error struct {
Code ErrCode `json:"code"`
Message string `json:"message"`
Details ErrDetails `json:"details"`
}
An Error is an error that provides structured information about the error. It includes an error code, a message, and optionally additional structured details about the error.
Internally it captures an underlying error for printing and for use with errors.Is/As and call stack information.
To provide accurate stack information, users are expected to convert non-Error errors into *Error as close to the root cause as possible. This is made simple with Wrap.
func (*Error) ErrorMessage ¶
ErrorMessage reports the error message, joining this error's message with the messages from any underlying errors.