github.com/cloudwego/hertz@v0.9.3/pkg/app/middlewares/client/sd/discovery.go (about)

     1  /*
     2   * Copyright 2022 CloudWeGo Authors
     3   *
     4   * Licensed under the Apache License, Version 2.0 (the "License");
     5   * you may not use this file except in compliance with the License.
     6   * You may obtain a copy of the License at
     7   *
     8   *     http://www.apache.org/licenses/LICENSE-2.0
     9   *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   */
    16  
    17  package sd
    18  
    19  import (
    20  	"context"
    21  
    22  	"github.com/cloudwego/hertz/pkg/app/client"
    23  	"github.com/cloudwego/hertz/pkg/app/client/discovery"
    24  	"github.com/cloudwego/hertz/pkg/app/client/loadbalance"
    25  	"github.com/cloudwego/hertz/pkg/protocol"
    26  )
    27  
    28  // Discovery will construct a middleware with BalancerFactory.
    29  func Discovery(resolver discovery.Resolver, opts ...ServiceDiscoveryOption) client.Middleware {
    30  	options := &ServiceDiscoveryOptions{
    31  		Balancer: loadbalance.NewWeightedBalancer(),
    32  		LbOpts:   loadbalance.DefaultLbOpts,
    33  		Resolver: resolver,
    34  	}
    35  	options.Apply(opts)
    36  
    37  	lbConfig := loadbalance.Config{
    38  		Resolver: options.Resolver,
    39  		Balancer: options.Balancer,
    40  		LbOpts:   options.LbOpts,
    41  	}
    42  
    43  	f := loadbalance.NewBalancerFactory(lbConfig)
    44  	return func(next client.Endpoint) client.Endpoint {
    45  		return func(ctx context.Context, req *protocol.Request, resp *protocol.Response) (err error) {
    46  			if req.Options() != nil && req.Options().IsSD() {
    47  				ins, err := f.GetInstance(ctx, req)
    48  				if err != nil {
    49  					return err
    50  				}
    51  				req.SetHost(ins.Address().String())
    52  			}
    53  			return next(ctx, req, resp)
    54  		}
    55  	}
    56  }