go-eureka-client

Non-offical implementation of Spring Cloud Eureka client.

Tips: Non-full-features, only some basic and useful features implemented.

Spring Cloud Eureka Configurations

FEATURES	Support
AvailabilityZones	√
ServiceUrl	√
UseDnsForFetchingServiceUrls	√
RegisterWithEureka	√
PreferSameZoneEureka	√
FilterOnlyUpInstances	√
RegistryFetchIntervalSeconds	√
FetchRegistry	√
EurekaServerPort	√
EurekaServerUrlContexts	√

go-eureka-client extended features

FEATURES	Support
AutoUpdateDnsServiceUrls	√
AutoUpdateDnsServiceUrlsIntervals	√
HeartbeatIntervals	√

Samples

Sample 1

Get Eureka server urls from configuration, e.g:

    config := eureka.GetDefaultEurekaClientConfig()
    config.UseDnsForFetchingServiceUrls = false
    config.Region = "region-cn-hd-1"
    config.AvailabilityZones = map[string]string{
        "region-cn-hd-1": "zone-cn-hz-1",
    }
    config.ServiceUrl = map[string]string{
        "zone-cn-hz-1": "http://192.168.20.236:9001/eureka,http://192.168.20.237:9001/eureka",
    }

    // custom logger
    //eureka.SetLogger(func(level int, format string, a ...interface{}) {
    //    if level == eureka.LevelError {
    //        fmt.Println("[custom logger error] " + format, a)
    //    }else {
    //        fmt.Println("[custom logger debug] " + format, a)
    //    }
    //})

    // run eureka client async
    eureka.DefaultClient.Config(config).
        Register("APP_ID_CLIENT_FROM_CONFIG", 9000).
        Run()

    select {}

Full sample code, refer to: samples/client_from_config.go

Sample 2

Get Eureka server urls from dns(TXT Record) lookup, e.g:

    config := eureka.GetDefaultEurekaClientConfig()
    config.UseDnsForFetchingServiceUrls = true
    config.Region = "region-cn-hd-1"
    config.AvailabilityZones = map[string]string{
        "region-cn-hd-1": "zone-cn-hz-1",
    }
    config.EurekaServerDNSName = "dev.ms-registry.xf.io"
    config.EurekaServerUrlContext = "eureka"
    config.EurekaServerPort = "9001"

    // custom logger
    //eureka.SetLogger(func(level int, format string, a ...interface{}) {
    //    if level == eureka.LevelError {
    //        fmt.Println("[custom logger error] " + format, a)
    //    }else {
    //        fmt.Println("[custom logger debug] " + format, a)
    //    }
    //})

    // run eureka client async
    eureka.DefaultClient.Config(config).
        Register("APP_ID_CLIENT_FROM_DNS", 9000).
        Run()

    select {}

Full sample code, refer to: samples/client_from_dns.go

Sample 3

Eureka Server REST api util, e.g:

    config := eureka.GetDefaultEurekaClientConfig()
    config.UseDnsForFetchingServiceUrls = false
    config.Region = "region-cn-hd-1"
    config.AvailabilityZones = map[string]string{
        "region-cn-hd-1": "zone-cn-hz-1",
    }
    config.ServiceUrl = map[string]string{
        "zone-cn-hz-1": "http://192.168.20.236:9001/eureka,http://192.168.20.237:9001/eureka",
    }

    c := eureka.DefaultClient.Config(config)
    api, err := c.Api()
    if err != nil {
        log.Fatalln("Failed to pick EurekaServerApi instance, err=", err.Error())
    }
    instances, err := api.QueryAllInstances()
    if err != nil {
        log.Fatalln("Failed to query all instances, err=", err.Error())
    }

    log.Println("all instances: ", instances)

Full sample code, refer to: samples/eureka_api_rest.go

Eureka server Rest api supported, refer to list below:

Operation	HTTP action	Support
Register new application instance	POST /eureka/v2/apps/appID	√
De-register application instance	DELETE /eureka/v2/apps/appID/instanceID	√
Send application instance heartbeat	PUT /eureka/v2/apps/appID/instanceID	√
Query for all instances	GET /eureka/v2/apps	√
Query for all appID instances	GET /eureka/v2/apps/appID	√
Query for a specific appID/instanceID	GET /eureka/v2/apps/appID/instanceID	√
Query for a specific instanceID	GET /eureka/v2/instances/instanceID	√
Take instance out of service	PUT /eureka/v2/apps/appID/instanceID/status?value=OUT_OF_SERVICE	√
Move instance back into service (remove override)	DELETE /eureka/v2/apps/appID/instanceID/status?value=UP (The value=UP is optional, it is used as a suggestion for the fallback status due to removal of the override)	√
Update metadata	PUT /eureka/v2/apps/appID/instanceID/metadata?key=value	√
Query for all instances under a particular vip address	GET /eureka/v2/vips/vipAddress	×
Query for all instances under a particular secure vip address	GET /eureka/v2/svips/svipAddress	×

Registry screenshots

Client heartbeat