feat(provider): Add Eureka Provider

provider/eureka.go

@@ -0,0 +1,145 @@
+package provider
+
+import (
+	"github.com/ArthurHlt/go-eureka-client/eureka"
+	log "github.com/Sirupsen/logrus"
+	"github.com/cenk/backoff"
+	"github.com/containous/traefik/job"
+	"github.com/containous/traefik/safe"
+	"github.com/containous/traefik/types"
+	"io/ioutil"
+	"strconv"
+	"strings"
+	"text/template"
+	"time"
+)
+
+// Eureka holds configuration of the Eureka provider.
+type Eureka struct {
+	BaseProvider `mapstructure:",squash"`
+	Endpoint     string
+	Delay        string
+}
+
+// Provide allows the provider to provide configurations to traefik
+// using the given configuration channel.
+func (provider *Eureka) Provide(configurationChan chan<- types.ConfigMessage, pool *safe.Pool, _ []types.Constraint) error {
+
+	operation := func() error {
+		configuration, err := provider.buildConfiguration()
+		if err != nil {
+			log.Errorf("Failed to build configuration for Eureka, error: %s", err)
+			return err
+		}
+
+		configurationChan <- types.ConfigMessage{
+			ProviderName:  "eureka",
+			Configuration: configuration,
+		}
+
+		var delay time.Duration
+		if len(provider.Delay) > 0 {
+			var err error
+			delay, err = time.ParseDuration(provider.Delay)
+			if err != nil {
+				log.Errorf("Failed to parse delay for Eureka, error: %s", err)
+				return err
+			}
+		} else {
+			delay = time.Second * 30
+		}
+
+		ticker := time.NewTicker(delay)
+		go func() {
+			for t := range ticker.C {
+
+				log.Debug("Refreshing Eureka " + t.String())
+
+				configuration, err := provider.buildConfiguration()
+				if err != nil {
+					log.Errorf("Failed to refresh Eureka configuration, error: %s", err)
+					return
+				}
+
+				configurationChan <- types.ConfigMessage{
+					ProviderName:  "eureka",
+					Configuration: configuration,
+				}
+			}
+		}()
+		return nil
+	}
+
+	notify := func(err error, time time.Duration) {
+		log.Errorf("Eureka connection error %+v, retrying in %s", err, time)
+	}
+	err := backoff.RetryNotify(operation, job.NewBackOff(backoff.NewExponentialBackOff()), notify)
+	if err != nil {
+		log.Errorf("Cannot connect to Eureka server %+v", err)
+		return err
+	}
+	return nil
+}
+
+// Build the configuration from Eureka server
+func (provider *Eureka) buildConfiguration() (*types.Configuration, error) {
+	var EurekaFuncMap = template.FuncMap{
+		"replace":       replace,
+		"tolower":       strings.ToLower,
+		"getPort":       provider.getPort,
+		"getProtocol":   provider.getProtocol,
+		"getWeight":     provider.getWeight,
+		"getInstanceID": provider.getInstanceID,
+	}
+
+	eureka.GetLogger().SetOutput(ioutil.Discard)
+
+	client := eureka.NewClient([]string{
+		provider.Endpoint,
+	})
+
+	applications, err := client.GetApplications()
+	if err != nil {
+		return nil, err
+	}
+
+	templateObjects := struct {
+		Applications []eureka.Application
+	}{
+		applications.Applications,
+	}
+
+	configuration, err := provider.getConfiguration("templates/eureka.tmpl", EurekaFuncMap, templateObjects)
+	if err != nil {
+		log.Error(err)
+	}
+	return configuration, nil
+}
+
+func (provider *Eureka) getPort(instance eureka.InstanceInfo) string {
+	if instance.SecurePort.Enabled {
+		return strconv.Itoa(instance.SecurePort.Port)
+	}
+	return strconv.Itoa(instance.Port.Port)
+}
+
+func (provider *Eureka) getProtocol(instance eureka.InstanceInfo) string {
+	if instance.SecurePort.Enabled {
+		return "https"
+	}
+	return "http"
+}
+
+func (provider *Eureka) getWeight(instance eureka.InstanceInfo) string {
+	if val, ok := instance.Metadata.Map["traefik.weight"]; ok {
+		return val
+	}
+	return "0"
+}
+
+func (provider *Eureka) getInstanceID(instance eureka.InstanceInfo) string {
+	if val, ok := instance.Metadata.Map["traefik.backend.id"]; ok {
+		return val
+	}
+	return strings.Replace(instance.IpAddr, ".", "-", -1) + "-" + provider.getPort(instance)
+}