resolver.go

package nacos_demo

import (
	"context"
	"fmt"

	"github.com/cloudwego/hertz/pkg/app/client/discovery"

	"github.com/nacos-group/nacos-sdk-go/clients/naming_client"
	"github.com/nacos-group/nacos-sdk-go/vo"
)

type nacosResolver struct {
	cli  naming_client.INamingClient
	opts options
}

// NewNacosResolver create a service resolver using nacos.
func NewNacosResolver(cli naming_client.INamingClient, opts ...Option) discovery.Resolver {
	op := options{
		cluster: "DEFAULT",
		group:   "DEFAULT_GROUP",
	}
	for _, option := range opts {
		option(&op)
	}
	return &nacosResolver{cli: cli, opts: op}
}

// Target return a description for the given target that is suitable for being a key for cache.
func (n *nacosResolver) Target(ctx context.Context, target *discovery.TargetInfo) (description string) {
	return target.Host
}

// Resolve a service info by desc.
func (n *nacosResolver) Resolve(ctx context.Context, desc string) (discovery.Result, error) {
	res, err := n.cli.SelectInstances(vo.SelectInstancesParam{
		ServiceName: desc,
		HealthyOnly: true,
		GroupName:   n.opts.group,
		Clusters:    []string{n.opts.cluster},
	})
	if err != nil {
		return discovery.Result{}, err
	}
	if len(res) == 0 {
		return discovery.Result{}, fmt.Errorf("no instance remains for %v", desc)
	}
	instances := make([]discovery.Instance, 0, len(res))
	for _, in := range res {
		if !in.Enable {
			continue
		}
		instances = append(instances, discovery.NewInstance(
			"tcp",
			fmt.Sprintf("%s:%d", in.Ip, in.Port),
			int(in.Weight),
			in.Metadata),
		)
	}
	if len(instances) == 0 {
		return discovery.Result{}, fmt.Errorf("no instance remains for %v", desc)
	}
	return discovery.Result{
		CacheKey:  desc,
		Instances: instances,
	}, nil
}

// Name returns the name of the resolver.
func (n *nacosResolver) Name() string {
	return "nacos" + ":" + n.opts.cluster + ":" + n.opts.group
}

var _ discovery.Resolver = (*nacosResolver)(nil)