客户端在创建连接的时候会出现如下几类错误：
- Canceled resolveAddress出现出错, 连接取消
- Unavailable 创建连接失败的时候
- Internal IO错误
- DeadlineExceeded, 连接超时
// toRPCErr converts an error into an error from the status package.
func toRPCErr(err error) error {
if err == nil || err == io.EOF {
return err
}
if err == io.ErrUnexpectedEOF {
return status.Error(codes.Internal, err.Error())
}
if _, ok := status.FromError(err); ok {
return err
}
switch e := err.(type) {
case transport.ConnectionError:
return status.Error(codes.Unavailable, e.Desc)
default:
switch err {
case context.DeadlineExceeded:
return status.Error(codes.DeadlineExceeded, err.Error())
case context.Canceled:
return status.Error(codes.Canceled, err.Error())
}
}
return status.Error(codes.Unknown, err.Error())
}import (
"google.golang.org/grpc/codes"
"google.golang.org/grpc/status"
)
// 服务端返回错误码, 第一个参数：错误码，第二个参数：错误的详细信息
status.Error(codes.NotFound, "xxx")
// 客户端解析GRPC标准错误
// 如果ok == false, 那么说明，服务端没有按照GRPC的标准返回cuowu
ev, ok := status.FromError(err)
if ok {
ev.Code()
}
// 客户端更详细的解析GRPC错误可以参考文档：https://godoc.org/google.golang.org/grpc/status下述总结，只局限于自己的总结使用建议
业务错误码： InvalidArgument, NotFound, AlreadyExists, PermissionDenied, ResourceExhausted, Aborted, OutOfRange, DataLoss, Unimplemented
系统错误码： Canceled, DeadlineExceeded, FailedPrecondition, Internal, Unavailable, Unauthenticated
例如：Unimplemented 也可以作为rpc接口未实现的错误返回，此时属于系统错误码
Unknown 任何未知错误都可以使用，不局限于业务或系统
FailedPrecondition 业务请求时不能match相关条件可以使用，此时属于业务错误码，但慎用，建议详细归类至其他的错误码
建议加入retry中间件的错误码： Canceled, DeadlineExceeded, Internal, Unavailable
// OK is returned on success.
// 不能用于错误是返回的code码，否则服务端会报错
OK Code = 0
// Canceled indicates the operation was canceled (typically by the caller).
// 请求被中途取消，一般情况下比较难出现，不能用于业务的错误码
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.
// 网络处理中也可能出现，业务错误码可以使用，一般不建议
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).
// 业务错误码，非法的参数
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.
// 客户端或服务端处理超时，与配置参数相关，不能用于业务错误码
DeadlineExceeded Code = 4
// NotFound means some requested entity (e.g., file or directory) was
// not found.
// 服务端未找到请求的资源，业务错误码
NotFound Code = 5
// AlreadyExists means an attempt to create an entity failed because one
// already exists.
// 创建的请求资源已经存在，业务错误码
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).
// 客户端没有权限，业务错误码
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.
// 服务端提供的资源配额已用光，一般用于限速等错误，业务错误码
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.
// 客户端的请求操作被拒绝，可细分为Unavailable, Aborted, FailedPrecondition，不建议作为业务错误码
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.
// 服务端处理并发请求时，突然中止，比如预见非常规错误，数据库事务中止， 业务错误码
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.
// 数组越界等，业务错误码
OutOfRange Code = 11
// Unimplemented indicates operation is not implemented or not
// supported/enabled in this service.
// 客户端的请求，服务端尚未实现，业务错误码
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.
// 内部错误，比如IO等，不建议作为业务错误码
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.
// 网络不可达等，不建议作为业务错误码
Unavailable Code = 14
// DataLoss indicates unrecoverable data loss or corruption.
// 数据缺失，业务错误码
DataLoss Code = 15
// Unauthenticated indicates the request does not have valid
// authentication credentials for the operation.
// 未被授权，业务错误码
Unauthenticated Code = 16