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Error Handling

Ryan SUAbout 5 min

Error Type

Video tutorial

Simple Admin has three error types

  • ApiError : Api error, used to return error return information with http status code
  • CodeError : The business code type is wrong, the error status code is uniformly 200, and the detailed status code is in the return body
  • Status Error: RPC error

RPC Error

status.Error(codes.Internal, result.Error.Error())

Just return status.Error

Easy way

errorx.NewInternalError(msg)

errorx.NewInvalidArgumentError(msg)

errorx.NewNotFoundError(msg)

errorx.NewAlreadyExistsError(msg)

errorx.NewUnauthenticatedError

Code Error

Use CodeError to return error in API layer.

errorx.CodeError(enum.InvalidArgument, "Please log in")

Easy Way


func NewCodeCanceledError(msg string) error {
 return &CodeError{Code: 1, Msg: msg}
}

func NewCodeInvalidArgumentError(msg string) error {
 return &CodeError{Code: 3, Msg: msg}
}

func NewCodeNotFoundError(msg string) error {
 return &CodeError{Code: 5, Msg: msg}
}

func NewCodeAlreadyExistsError(msg string) error {
 return &CodeError{Code: 6, Msg: msg}
}

func NewCodeAbortedError(msg string) error {
 return &CodeError{Code: 10, Msg: msg}
}

func NewCodeInternalError(msg string) error {
 return &CodeError{Code: 13, Msg: msg}
}

func NewCodeUnavailableError(msg string) error {
 return &CodeError{Code: 14, Msg: msg}
}

func NewDefaultError(msg string) error {
 return NewCodeError(defaultCode, msg)
}

Error code

All error codes are in github.com/suyuan32/simple-admin-common/enum/errorcode. The first 17 error codes are the same as grpc, you can also add your own error code.

package enum

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

 // Canceled indicates the operation was canceled (typically by the caller).
 //
 // The gRPC framework will generate this error code when cancellation
 // is requested.
 Canceled int = 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.
 //
 // The gRPC framework will generate this error code in the above two
 // mentioned cases.
 Unknown int = 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).
 //
 // This error code will not be generated by the gRPC framework.
 InvalidArgument int = 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.
 //
 // The gRPC framework will generate this error code when the deadline is
 // exceeded.
 DeadlineExceeded int = 4

 // NotFound means some requested entity (e.g., file or directory) was
 // not found.
 //
 // This error code will not be generated by the gRPC framework.
 NotFound int = 5

 // AlreadyExists means an attempt to create an entity failed because one
 // already exists.
 //
 // This error code will not be generated by the gRPC framework.
 AlreadyExists int = 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).
 //
 // This error code will not be generated by the gRPC core framework,
 // but expect authentication middleware to use it.
 PermissionDenied int = 7

 // ResourceExhausted indicates some resource has been exhausted, perhaps
 // a per-user quota, or perhaps the entire file system is out of space.
 //
 // This error code will be generated by the gRPC framework in
 // out-of-memory and server overload situations, or when a message is
 // larger than the configured maximum size.
 ResourceExhausted int = 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.
 //
 // This error code will not be generated by the gRPC framework.
 FailedPrecondition int = 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.
 //
 // This error code will not be generated by the gRPC framework.
 Aborted int = 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.
 //
 // This error code will not be generated by the gRPC framework.
 OutOfRange int = 11

 // Unimplemented indicates operation is not implemented or not
 // supported/enabled in this service.
 //
 // This error code will be generated by the gRPC framework. Most
 // commonly, you will see this error code when a method implementation
 // is missing on the server. It can also be generated for unknown
 // compression algorithms or a disagreement as to whether an RPC should
 // be streaming.
 Unimplemented int = 12

 // Internal errors. Means some invariants expected by underlying
 // system has been broken. If you see one of these errors,
 // something is very broken.
 //
 // This error code will be generated by the gRPC framework in several
 // internal error conditions.
 Internal int = 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.
 //
 // This error code will be generated by the gRPC framework during
 // abrupt shutdown of a server process or network connection.
 Unavailable int = 14

 // DataLoss indicates unrecoverable data loss or corruption.
 //
 // This error code will not be generated by the gRPC framework.
 DataLoss int = 15

 // Unauthenticated indicates the request does not have valid
 // authentication credentials for the operation.
 //
 // The gRPC framework will generate this error code when the
 // authentication metadata is invalid or a Credentials callback fails,
 // but also expect authentication middleware to generate it.
 Unauthenticated int = 16
)

Warning

the code which is not 0 will show message in front-end, front-end control it via api ErrorMessageMode.

ApiError

errorx.NewApiError(httpCode, msg)

Easy Way


func NewApiErrorWithoutMsg(code int) error {
 return &ApiError{Code: code, Msg: ""}
}

func NewApiInternalError(msg string) error {
 return &ApiError{Code: http.StatusInternalServerError, Msg: msg}
}

func NewApiBadRequestError(msg string) error {
 return &ApiError{Code: http.StatusBadRequest, Msg: msg}
}

func NewApiUnauthorizedError(msg string) error {
 return &ApiError{Code: http.StatusUnauthorized, Msg: msg}
}

func NewApiForbiddenError(msg string) error {
 return &ApiError{Code: http.StatusForbidden, Msg: msg}
}

func NewApiNotFoundError(msg string) error {
 return &ApiError{Code: http.StatusNotFound, Msg: msg}
}

func NewApiBadGatewayError(msg string) error {
 return &ApiError{Code: http.StatusBadGateway, Msg: msg}
}

If you add the tag --trans_err=true to generate Api files, it will add translation in handler.

goctls api go --api ./api/desc/core.api --dir ./api --trans_err=true
package api

import (
 "net/http"

 "github.com/zeromicro/go-zero/rest/httpx"

 "github.com/suyuan32/simple-admin-core/api/internal/logic/api"
 "github.com/suyuan32/simple-admin-core/api/internal/svc"
 "github.com/suyuan32/simple-admin-core/api/internal/types"
)

// swagger:route post /api api CreateOrUpdateApi
//
// Create or update API information | 创建或更新API
//
// Create or update API information | 创建或更新API
//
// Parameters:
//  + name: body
//    require: true
//    in: body
//    type: CreateOrUpdateApiReq
//
// Responses:
//  200: BaseMsgResp

func CreateOrUpdateApiHandler(svcCtx *svc.ServiceContext) http.HandlerFunc {
 return func(w http.ResponseWriter, r *http.Request) {
  var req types.CreateOrUpdateApiReq
  if err := httpx.Parse(r, &req); err != nil {
   httpx.Error(w, err)
   return
  }

  l := api.NewCreateOrUpdateApiLogic(r, svcCtx)
  resp, err := l.CreateOrUpdateApi(&req)
  if err != nil {
   err = svcCtx.Trans.TransError(r.Header.Get("Accept-Language"), err)
   httpx.Error(w, err)
  } else {
   httpx.OkJson(w, resp)
  }
 }
}

err = svcCtx.Trans.TransError(r.Context(), err)

Warning

CodeError puts the error code in response body, all the status is 200 StatusOK. If you want to response with status code such as 400,please use errorx.ApiError .