grpc-go/balancer/weightedroundrobin/weightedroundrobin.go

77 lines
2.4 KiB
Go

/*
*
* Copyright 2019 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
// Package weightedroundrobin provides an implementation of the weighted round
// robin LB policy, as defined in [gRFC A58].
//
// # Experimental
//
// Notice: This package is EXPERIMENTAL and may be changed or removed in a
// later release.
//
// [gRFC A58]: https://github.com/grpc/proposal/blob/master/A58-client-side-weighted-round-robin-lb-policy.md
package weightedroundrobin
import (
"fmt"
"google.golang.org/grpc/resolver"
)
// attributeKey is the type used as the key to store AddrInfo in the
// BalancerAttributes field of resolver.Address.
type attributeKey struct{}
// AddrInfo will be stored in the BalancerAttributes field of Address in order
// to use weighted roundrobin balancer.
type AddrInfo struct {
Weight uint32
}
// Equal allows the values to be compared by Attributes.Equal.
func (a AddrInfo) Equal(o any) bool {
oa, ok := o.(AddrInfo)
return ok && oa.Weight == a.Weight
}
// SetAddrInfo returns a copy of addr in which the BalancerAttributes field is
// updated with addrInfo.
func SetAddrInfo(addr resolver.Address, addrInfo AddrInfo) resolver.Address {
addr.BalancerAttributes = addr.BalancerAttributes.WithValue(attributeKey{}, addrInfo)
return addr
}
// SetAddrInfoInEndpoint returns a copy of endpoint in which the Attributes
// field is updated with addrInfo.
func SetAddrInfoInEndpoint(endpoint resolver.Endpoint, addrInfo AddrInfo) resolver.Endpoint {
endpoint.Attributes = endpoint.Attributes.WithValue(attributeKey{}, addrInfo)
return endpoint
}
// GetAddrInfo returns the AddrInfo stored in the BalancerAttributes field of
// addr.
func GetAddrInfo(addr resolver.Address) AddrInfo {
v := addr.BalancerAttributes.Value(attributeKey{})
ai, _ := v.(AddrInfo)
return ai
}
func (a AddrInfo) String() string {
return fmt.Sprintf("Weight: %d", a.Weight)
}