github.com/tickoalcantara12/micro/v3@v3.0.0-20221007104245-9d75b9bcbab9/service/client/lookup.go (about)

     1  // Copyright 2020 Asim Aslam
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     https://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  //
    15  // Original source: github.com/micro/go-micro/v3/client/lookup.go
    16  
    17  package client
    18  
    19  import (
    20  	"context"
    21  	"sort"
    22  
    23  	"github.com/tickoalcantara12/micro/v3/service/errors"
    24  	"github.com/tickoalcantara12/micro/v3/service/router"
    25  )
    26  
    27  // LookupFunc is used to lookup routes for a service
    28  type LookupFunc func(context.Context, Request, CallOptions) ([]string, error)
    29  
    30  // LookupRoute for a request using the router and then choose one using the selector
    31  func LookupRoute(ctx context.Context, req Request, opts CallOptions) ([]string, error) {
    32  	// check to see if an address was provided as a call option
    33  	if len(opts.Address) > 0 {
    34  		return opts.Address, nil
    35  	}
    36  
    37  	// construct the router query
    38  	query := []router.LookupOption{}
    39  
    40  	// if a custom network was requested, pass this to the router. By default the router will use it's
    41  	// own network, which is set during initialisation.
    42  	if len(opts.Network) > 0 {
    43  		query = append(query, router.LookupNetwork(opts.Network))
    44  	}
    45  
    46  	// lookup the routes which can be used to execute the request
    47  	routes, err := opts.Router.Lookup(req.Service(), query...)
    48  	if err == router.ErrRouteNotFound {
    49  		return nil, errors.InternalServerError("go.micro.client", "service %s: %s", req.Service(), err.Error())
    50  	} else if err != nil {
    51  		return nil, errors.InternalServerError("go.micro.client", "error getting next %s node: %s", req.Service(), err.Error())
    52  	}
    53  
    54  	// sort by lowest metric first
    55  	sort.Slice(routes, func(i, j int) bool {
    56  		return routes[i].Metric < routes[j].Metric
    57  	})
    58  
    59  	var addrs []string
    60  
    61  	for _, route := range routes {
    62  		addrs = append(addrs, route.Address)
    63  	}
    64  
    65  	return addrs, nil
    66  }