refactor(contrib/registry/etcd): use service ID as Registry.ctxMap key instead of service pointer

[1911860538]

The code modification is based on two points:

• It is not recommended to use pointer as key in Go map.
• Changing the service ID to be the key in ctxMap offers better performance. Detailed performance tests will be provided below.

test_kratos_registry.go

package test_kratos_registry

import (
	"context"
	"testing"
	"time"
)

type ServiceInstance struct {
	ID        string            `json:"id"`
	Name      string            `json:"name"`
	Version   string            `json:"version"`
	Metadata  map[string]string `json:"metadata"`
	Endpoints []string          `json:"endpoints"`
}

type options struct {
	ctx       context.Context
	namespace string
	ttl       time.Duration
	maxRetry  int
}

type Registry struct {
	opts   *options
	ctxMap map[*ServiceInstance]context.CancelFunc
}

func (r *Registry) Register(ctx context.Context, service *ServiceInstance) {
	_, cancel := context.WithCancel(r.opts.ctx)
	r.ctxMap[service] = cancel
}

func (r *Registry) Deregister(ctx context.Context, service *ServiceInstance) {
	if cancel, ok := r.ctxMap[service]; ok {
		cancel()
		delete(r.ctxMap, service)
	}
}

type serviceCancel struct {
	svc    *ServiceInstance
	cancel context.CancelFunc
}

type RegistryNew struct {
	opts   *options
	ctxMap map[string]*serviceCancel
}

func (r *RegistryNew) Register(ctx context.Context, service *ServiceInstance) {
	_, cancel := context.WithCancel(r.opts.ctx)
	r.ctxMap[service.ID] = &serviceCancel{
		svc:    service,
		cancel: cancel,
	}
}

func (r *RegistryNew) Deregister(ctx context.Context, service *ServiceInstance) {
	if svcCancel, ok := r.ctxMap[service.ID]; ok {
		svcCancel.cancel()
		delete(r.ctxMap, service.ID)
	}
}

func newServiceInstances() []*ServiceInstance {
	return []*ServiceInstance{
		{
			ID:        "1",
			Name:      "service1",
			Version:   "v1",
			Metadata:  map[string]string{"key1": "value1"},
			Endpoints: []string{"http://addr1:port1"},
		},
		{
			ID:        "2",
			Name:      "service2",
			Version:   "v2",
			Metadata:  map[string]string{"key2": "value2"},
			Endpoints: []string{"http://addr2:port2"},
		},
		{
			ID:        "3",
			Name:      "service3",
			Version:   "v3",
			Metadata:  map[string]string{"key3": "value3"},
			Endpoints: []string{"http://addr3:port3"},
		},
		{
			ID:        "4",
			Name:      "service4",
			Version:   "v4",
			Metadata:  map[string]string{"key4": "value4"},
			Endpoints: []string{"http://addr4:port4"},
		},
	}
}

func BenchmarkRegisterRegister(b *testing.B) {
	r := &Registry{
		opts: &options{
			ctx: context.Background(),
		},
		ctxMap: make(map[*ServiceInstance]context.CancelFunc),
	}
	b.ResetTimer()
	b.ReportAllocs()

	for i := 0; i < b.N; i++ {
		for _, svc := range newServiceInstances() {
			r.Register(context.Background(), svc)
			//break
		}
	}
}

func BenchmarkRegisterNewRegister(b *testing.B) {
	r := &RegistryNew{
		opts: &options{
			ctx: context.Background(),
		},
		ctxMap: make(map[string]*serviceCancel),
	}
	b.ResetTimer()
	b.ReportAllocs()

	for i := 0; i < b.N; i++ {
		for _, svc := range newServiceInstances() {
			r.Register(context.Background(), svc)
			//break
		}
	}
}

func BenchmarkRegisterDeregister(b *testing.B) {
	r := &Registry{
		opts: &options{
			ctx: context.Background(),
		},
		ctxMap: make(map[*ServiceInstance]context.CancelFunc),
	}
	b.ResetTimer()
	b.ReportAllocs()

	for i := 0; i < b.N; i++ {
		for _, svc := range newServiceInstances() {
			r.Deregister(context.Background(), svc)
			//break
		}
	}
}

func BenchmarkRegisterNewDeregister(b *testing.B) {
	r := &RegistryNew{
		opts: &options{
			ctx: context.Background(),
		},
		ctxMap: make(map[string]*serviceCancel),
	}
	b.ResetTimer()
	b.ReportAllocs()

	for i := 0; i < b.N; i++ {
		for _, svc := range newServiceInstances() {
			r.Deregister(context.Background(), svc)
			//break
		}
	}
}

benchmark output:

goos: darwin
goarch: arm64
pkg: test_code/test_kratos_registry
cpu: Apple M3 Pro
BenchmarkRegisterRegister
BenchmarkRegisterRegister-11         	 1000000	      1814 ns/op	    2454 B/op	      24 allocs/op
BenchmarkRegisterNewRegister
BenchmarkRegisterNewRegister-11      	 1783624	       764.8 ns/op	    2176 B/op	      28 allocs/op
BenchmarkRegisterDeregister
BenchmarkRegisterDeregister-11       	16407162	        71.50 ns/op	       0 B/op	       0 allocs/op
BenchmarkRegisterNewDeregister
BenchmarkRegisterNewDeregister-11    	17581944	        69.60 ns/op	       0 B/op	       0 allocs/op
PASS

Process finished with the exit code 0