Talk about apolloConfiguration for dubo-go

sequence

This article mainly studies apolloConfiguration of Dubo-Go

apolloConfiguration

Dubbo – go – v1.4.2 / config_center/Apollo/impl. Go

const (
	apolloProtocolPrefix = "http://"
	apolloConfigFormat   = "%s.%s"
)

type apolloConfiguration struct {
	url *common.URL

	listeners sync.Map
	appConf   *agollo.AppConfig
	parser    parser.ConfigurationParser
}
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• ApolloConfiguration defines URL, Listeners, appConf, and Parser attributes

newApolloConfiguration

Dubbo – go – v1.4.2 / config_center/Apollo/impl. Go

func newApolloConfiguration(url *common.URL) (*apolloConfiguration, error) {
	c := &apolloConfiguration{
		url: url,
	}
	configAddr := c.getAddressWithProtocolPrefix(url)
	configCluster := url.GetParam(constant.CONFIG_CLUSTER_KEY, "")

	appId := url.GetParam(constant.CONFIG_APP_ID_KEY, "")
	namespaces := getProperties(url.GetParam(constant.CONFIG_NAMESPACE_KEY, cc.DEFAULT_GROUP))
	c.appConf = &agollo.AppConfig{
		AppId:         appId,
		Cluster:       configCluster,
		NamespaceName: namespaces,
		Ip:            configAddr,
	}

	agollo.InitCustomConfig(func() (*agollo.AppConfig, error) {
		return c.appConf, nil
	})

	return c, agollo.Start()
}
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• The newApolloConfiguration method creates AppConfig, then agollo.InitCustomConfig, and finally agollo.Start()

GetProperties

Dubbo – go – v1.4.2 / config_center/Apollo/impl. Go

func (c *apolloConfiguration) GetProperties(key string, opts ... cc.Option) (string, error) { /** * when group is not null, we are getting startup configs(config file) from Config Center, for example: * key=dubbo.propertie */ config := agollo.GetConfig(key) if config == nil { return "", errors.New(fmt.Sprintf("nothing in namespace:%s ", key)) } return config.GetContent(agollo.Properties), nil }Copy the code

• GetProperties executes agollo.GetConfig(key) to GetConfig, and config.getcontent (agollo.Properties) to GetProperties

AddListener

Dubbo – go – v1.4.2 / config_center/Apollo/impl. Go

func (c *apolloConfiguration) AddListener(key string, listener cc.ConfigurationListener, opts ... cc.Option) { k := &cc.Options{} for _, opt := range opts { opt(k) } key = k.Group + key l, _ := c.listeners.LoadOrStore(key, NewApolloListener()) l.(*apolloListener).AddListener(listener) }Copy the code

• LoadOrStore(key, NewApolloListener()) and L. (*apolloListener).addListener (listener)

RemoveListener

Dubbo – go – v1.4.2 / config_center/Apollo/impl. Go

func (c *apolloConfiguration) RemoveListener(key string, listener cc.ConfigurationListener, opts ... cc.Option) { k := &cc.Options{} for _, opt := range opts { opt(k) } key = k.Group + key l, ok := c.listeners.Load(key) if ok { l.(*apolloListener).RemoveListener(listener) } }Copy the code

• (*apolloListener).removelistener (listener)

NewApolloListener

Dubbo – go – v1.4.2 / config_center/Apollo/listener. Go

type apolloListener struct {
	listeners map[config_center.ConfigurationListener]struct{}
}

// NewApolloListener ...
func NewApolloListener() *apolloListener {
	return &apolloListener{
		listeners: make(map[config_center.ConfigurationListener]struct{}, 0),
	}
}
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• NewApolloListener create apolloListener

OnChange

Dubbo – go – v1.4.2 / config_center/Apollo/listener. Go

// OnChange ...
func (a *apolloListener) OnChange(changeEvent *agollo.ChangeEvent) {
	for key, change := range changeEvent.Changes {
		for listener := range a.listeners {
			listener.Process(&config_center.ConfigChangeEvent{
				ConfigType: getChangeType(change.ChangeType),
				Key:        key,
				Value:      change.NewValue,
			})
		}
	}
}
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• The OnChange method receives a ChangeEvent and then iterates over the Listeners, executing the listener.process callback

summary

ApolloConfiguration defines URL, Listeners, appConf, and Parser attributes. The newApolloConfiguration method creates AppConfig, then agollo.InitCustomConfig, and finally agollo.Start()

doc

• apollo/impl.go