54 lines
		
	
	
		
			1.6 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			54 lines
		
	
	
		
			1.6 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
package client
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import (
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	"context"
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	"sort"
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	"github.com/unistack-org/micro/v3/errors"
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	"github.com/unistack-org/micro/v3/router"
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)
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// LookupFunc is used to lookup routes for a service
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type LookupFunc func(context.Context, Request, CallOptions) ([]string, error)
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// LookupRoute for a request using the router and then choose one using the selector
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func LookupRoute(ctx context.Context, req Request, opts CallOptions) ([]string, error) {
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	// check to see if an address was provided as a call option
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	if len(opts.Address) > 0 {
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		return opts.Address, nil
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	}
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	if opts.Router == nil {
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		return nil, router.ErrRouteNotFound
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	}
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	// construct the router query
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	query := []router.QueryOption{router.QueryService(req.Service())}
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	// if a custom network was requested, pass this to the router. By default the router will use it's
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	// own network, which is set during initialisation.
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	if len(opts.Network) > 0 {
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		query = append(query, router.QueryNetwork(opts.Network))
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	}
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	// lookup the routes which can be used to execute the request
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	routes, err := opts.Router.Lookup(query...)
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	if err == router.ErrRouteNotFound {
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		return nil, errors.InternalServerError("go.micro.client", "service %s: %s", req.Service(), err.Error())
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	} else if err != nil {
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		return nil, errors.InternalServerError("go.micro.client", "error getting next %s node: %s", req.Service(), err.Error())
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	}
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	// sort by lowest metric first
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	sort.Slice(routes, func(i, j int) bool {
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		return routes[i].Metric < routes[j].Metric
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	})
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	addrs := make([]string, 0, len(routes))
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	for _, route := range routes {
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		addrs = append(addrs, route.Address)
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	}
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	return addrs, nil
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}
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