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loadbalance.go
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loadbalance.go
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/*
* Copyright (c) 2017, The Easegress Authors
* All rights reserved.
*
* 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 grpcproxy
import (
"sync"
"github.com/megaease/easegress/v2/pkg/logger"
"github.com/megaease/easegress/v2/pkg/protocols"
"github.com/megaease/easegress/v2/pkg/protocols/grpcprot"
)
const (
// LoadBalancePolicyForward is the load balance policy of forward.
LoadBalancePolicyForward = "forward"
)
type forwardLoadBalancer struct {
servers sync.Pool
forwardKey string
}
func newForwardLoadBalancer(spec *LoadBalanceSpec) *forwardLoadBalancer {
return &forwardLoadBalancer{
servers: sync.Pool{
New: func() interface{} {
return &Server{}
},
},
forwardKey: spec.ForwardKey,
}
}
// ChooseServer implements the LoadBalancer interface
func (f *forwardLoadBalancer) ChooseServer(req protocols.Request) *Server {
grpcreq, ok := req.(*grpcprot.Request)
if !ok {
panic("not a gRPC request")
}
target := grpcreq.RawHeader().GetFirst(f.forwardKey)
if target == "" {
logger.Debugf("request %v from %v context no target address %s", grpcreq.FullMethod(), grpcreq.RealIP(), target)
return nil
}
if s, ok := f.servers.Get().(*Server); ok {
s.URL = target
return s
}
return nil
}
// ReturnServer returns the server to the load balancer.
func (f *forwardLoadBalancer) ReturnServer(s *Server, req protocols.Request, resp protocols.Response) {
f.servers.Put(s)
}
// Close closes the load balancer.
func (f *forwardLoadBalancer) Close() {
}