Exception Instruction

Exception Type

Defined in github.com/cloudwego/kitex/pkg/kerrors

internal exception

ErrInternalException, framework internal error, it cloud be:

1. ErrNotSupported, "operation not supported", have some operation not supported yet
2. ErrNoResolver, "no resolver available", no resolver is available
3. ErrNoDestService, "no dest service", target service is not specified
4. ErrNoDestAddress, "no dest address", target address is not specified
5. ErrNoConnection, "no connection available", not connection is available
6. ErrNoIvkRequest, "invoker request not set", request is not set in invoker mode

service discovery error

ErrServiceDiscovery, service discovery error, see error message for detail.

get connection error

ErrGetConnection, get connection error, see error message for detail.

loadbalance error

ErrLoadbalance, loadbalance error, see error message for detail.

no more instances to retry

ErrNoMoreInstance, no more instance to retry, see last call error message for detail.

rpc timeout

ErrRPCTimeout, RPC timeout, see error message for detail.

request forbidden

ErrACL, RPC is rejected by ACL, see error message for detail.

forbidden by circuitbreaker

ErrCircuitBreak, request is circuitbreaked, it could be two type of circuitbreak:

1. ErrServiceCircuitBreak, "service circuitbreak", service level circuitbreak encountered, request is rejected.
2. ErrInstanceCircuitBreak, "instance circuitbreak", instance level circuitbreak encountered, request is rejected.

remote or network error

ErrRemoteOrNetwork, remote server error, or network error, see error message for detail.

[remote] indicates the error is returned by server

request over limit

ErrOverlimit, overload protection error, it cloud be:

1. ErrConnOverLimit, "too many connections", connection overload, connection number is over limit
2. ErrQPSOverLimit, "request too frequent", concurrent request overload, concurrent request number is over limit

panic

ErrPanic, panic detected.

[happened in biz handler] indicated panic happened in server handler, usually call stack will attached to error message.

biz error

ErrBiz, server handler error.

retry error

ErrRetry, retry error, see error message for detail.

THRIFT Error Code

These error is thrift Application Exception, usually these error will be wrapped to remote or network error.

Exception Check

Check whether a Kitex error

Use IsKitexError in kerrors package

import "github.com/cloudwego/kitex/pkg/kerrors"
...
isKitexErr := kerrors.IsKitexError(kerrors.ErrInternalException) // return true

Check Specified Error type

Use errors.Is, detailed error cloud use to check detailed error:

import "errors"
import "github.com/cloudwego/kitex/client"
import "github.com/cloudwego/kitex/pkg/kerrors"
...
_, err := echo.NewClient("echo", client.WithResolver(nil)) // return kerrors.ErrNoResolver
...
isKitexErr := errors.Is(err, kerrors.ErrNoResolver) // return true

detailed error is also a basic error:

import "errors"
import "github.com/cloudwego/kitex/client"
import "github.com/cloudwego/kitex/pkg/kerrors"
...
_, err := echo.NewClient("echo", client.WithResolver(nil)) // return kerrors.ErrNoResolver
...
isKitexErr := errors.Is(err, kerrors.ErrInternalException) // return true

Specially, you can use IsTimeoutError in kerrors to check whether it is a timeout error

Get Detailed Error Message

All detailed errors is defined by DetailedError in kerrors, so you can use errors.As to get specified DetailedError, like:

import "errors"
import "github.com/cloudwego/kitex/client"
import "github.com/cloudwego/kitex/pkg/kerrors"
...
_, err := echo.NewClient("echo", client.WithResolver(nil)) // return kerrors.ErrNoResolver
...
var de *kerrors.DetailedError
ok := errors.As(err, &ke) // return true
if de.ErrorType() == kerrors.ErrInternalException {} // return true

DetailedError provide following functions to get detail message.

1. ErrorType() error, used to get basic error type
2. Stack() string, used to get stack (for now only works for ErrPanic)