redis/error.go

145 lines
2.8 KiB
Go

package redis
import (
"context"
"io"
"net"
"strings"
"github.com/go-redis/redis/v8/internal/pool"
"github.com/go-redis/redis/v8/internal/proto"
)
// ErrClosed performs any operation on the closed client will return this error.
var ErrClosed = pool.ErrClosed
type Error interface {
error
// RedisError is a no-op function but
// serves to distinguish types that are Redis
// errors from ordinary errors: a type is a
// Redis error if it has a RedisError method.
RedisError()
}
var _ Error = proto.RedisError("")
func shouldRetry(err error, retryTimeout bool) bool {
switch err {
case io.EOF, io.ErrUnexpectedEOF:
return true
case nil, context.Canceled, context.DeadlineExceeded:
return false
}
if v, ok := err.(timeoutError); ok {
if v.Timeout() {
return retryTimeout
}
return true
}
s := err.Error()
if s == "ERR max number of clients reached" {
return true
}
if strings.HasPrefix(s, "LOADING ") {
return true
}
if strings.HasPrefix(s, "READONLY ") {
return true
}
if strings.HasPrefix(s, "CLUSTERDOWN ") {
return true
}
if strings.HasPrefix(s, "TRYAGAIN ") {
return true
}
return false
}
func isRedisError(err error) bool {
_, ok := err.(proto.RedisError)
return ok
}
func isBadConn(err error, allowTimeout bool, addr string) bool {
switch err {
case nil:
return false
case context.Canceled, context.DeadlineExceeded:
return true
}
if isRedisError(err) {
switch {
case isReadOnlyError(err):
// Close connections in read only state in case domain addr is used
// and domain resolves to a different Redis Server. See #790.
return true
case isMovedSameConnAddr(err, addr):
// Close connections when we are asked to move to the same addr
// of the connection. Force a DNS resolution when all connections
// of the pool are recycled
return true
default:
return false
}
}
if allowTimeout {
if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
return false
}
}
return true
}
func isMovedError(err error) (moved bool, ask bool, addr string) {
if !isRedisError(err) {
return
}
s := err.Error()
switch {
case strings.HasPrefix(s, "MOVED "):
moved = true
case strings.HasPrefix(s, "ASK "):
ask = true
default:
return
}
ind := strings.LastIndex(s, " ")
if ind == -1 {
return false, false, ""
}
addr = s[ind+1:]
return
}
func isLoadingError(err error) bool {
return strings.HasPrefix(err.Error(), "LOADING ")
}
func isReadOnlyError(err error) bool {
return strings.HasPrefix(err.Error(), "READONLY ")
}
func isMovedSameConnAddr(err error, addr string) bool {
redisError := err.Error()
if !strings.HasPrefix(redisError, "MOVED ") {
return false
}
return strings.HasSuffix(redisError, " "+addr)
}
//------------------------------------------------------------------------------
type timeoutError interface {
Timeout() bool
}