Add Eureka Service Discovery (#3369)

Signed-off-by: kangwoo <kangwoo@gmail.com>

config/config_test.go

@@ -34,6 +34,7 @@ import (
 	"github.com/prometheus/prometheus/discovery/dns"
 	"github.com/prometheus/prometheus/discovery/dockerswarm"
 	"github.com/prometheus/prometheus/discovery/ec2"
+	"github.com/prometheus/prometheus/discovery/eureka"
 	"github.com/prometheus/prometheus/discovery/file"
 	"github.com/prometheus/prometheus/discovery/hetzner"
 	"github.com/prometheus/prometheus/discovery/kubernetes"
@@ -677,6 +678,22 @@ var expectedConf = &Config{
 				},
 			},
 		},
+		{
+			JobName: "service-eureka",
+
+			HonorTimestamps: true,
+			ScrapeInterval:  model.Duration(15 * time.Second),
+			ScrapeTimeout:   DefaultGlobalConfig.ScrapeTimeout,
+
+			MetricsPath: DefaultScrapeConfig.MetricsPath,
+			Scheme:      DefaultScrapeConfig.Scheme,
+
+			ServiceDiscoveryConfigs: discovery.Configs{&eureka.SDConfig{
+				Server:          "http://eureka.example.com:8761/eureka",
+				RefreshInterval: model.Duration(30 * time.Second),
+			},
+			},
+		},
 	},
 	AlertingConfig: AlertingConfig{
 		AlertmanagerConfigs: []*AlertmanagerConfig{
@@ -996,6 +1013,14 @@ var expectedErrors = []struct {
 		filename: "hetzner_role.bad.yml",
 		errMsg:   "unknown role",
 	},
+	{
+		filename: "eureka_no_server.bad.yml",
+		errMsg:   "empty or null eureka server",
+	},
+	{
+		filename: "eureka_invalid_server.bad.yml",
+		errMsg:   "invalid eureka server URL",
+	},
 }
 
 func TestBadConfigs(t *testing.T) {

config/testdata/conf.good.yml

@@ -288,6 +288,10 @@ scrape_configs:
         username: abcdef
         password: abcdef
 
+- job_name: service-eureka
+  eureka_sd_configs:
+    - server: 'http://eureka.example.com:8761/eureka'
+
 alerting:
   alertmanagers:
   - scheme: https

config/testdata/eureka_invalid_server.bad.yml

@@ -0,0 +1,5 @@
+scrape_configs:
+
+- job_name: eureka
+  eureka_sd_configs:
+  - server: eureka.com

config/testdata/eureka_no_server.bad.yml

@@ -0,0 +1,5 @@
+scrape_configs:
+
+- job_name: eureka
+  eureka_sd_configs:
+  - server:

discovery/eureka/client.go

@@ -0,0 +1,110 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package eureka
+
+import (
+	"context"
+	"encoding/xml"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+
+	"github.com/pkg/errors"
+)
+
+type Applications struct {
+	VersionsDelta int           `xml:"versions__delta"`
+	AppsHashcode  string        `xml:"apps__hashcode"`
+	Applications  []Application `xml:"application"`
+}
+
+type Application struct {
+	Name      string     `xml:"name"`
+	Instances []Instance `xml:"instance"`
+}
+
+type Port struct {
+	Port    int  `xml:",chardata"`
+	Enabled bool `xml:"enabled,attr"`
+}
+
+type Instance struct {
+	HostName                      string          `xml:"hostName"`
+	HomePageURL                   string          `xml:"homePageUrl"`
+	StatusPageURL                 string          `xml:"statusPageUrl"`
+	HealthCheckURL                string          `xml:"healthCheckUrl"`
+	App                           string          `xml:"app"`
+	IPAddr                        string          `xml:"ipAddr"`
+	VipAddress                    string          `xml:"vipAddress"`
+	SecureVipAddress              string          `xml:"secureVipAddress"`
+	Status                        string          `xml:"status"`
+	Port                          *Port           `xml:"port"`
+	SecurePort                    *Port           `xml:"securePort"`
+	DataCenterInfo                *DataCenterInfo `xml:"dataCenterInfo"`
+	Metadata                      *MetaData       `xml:"metadata"`
+	IsCoordinatingDiscoveryServer bool            `xml:"isCoordinatingDiscoveryServer"`
+	LastUpdatedTimestamp          int             `xml:"lastUpdatedTimestamp"`
+	LastDirtyTimestamp            int             `xml:"lastDirtyTimestamp"`
+	ActionType                    string          `xml:"actionType"`
+	CountryID                     int             `xml:"countryId"`
+	InstanceID                    string          `xml:"instanceId"`
+}
+
+type MetaData struct {
+	Items []Tag `xml:",any"`
+}
+
+type Tag struct {
+	XMLName xml.Name
+	Content string `xml:",innerxml"`
+}
+
+type DataCenterInfo struct {
+	Name     string    `xml:"name"`
+	Class    string    `xml:"class,attr"`
+	Metadata *MetaData `xml:"metadata"`
+}
+
+const appListPath string = "/apps"
+
+func fetchApps(ctx context.Context, server string, client *http.Client) (*Applications, error) {
+	url := fmt.Sprintf("%s%s", server, appListPath)
+
+	request, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, err
+	}
+	request = request.WithContext(ctx)
+
+	resp, err := client.Do(request)
+	if err != nil {
+		return nil, err
+	}
+	defer func() {
+		io.Copy(ioutil.Discard, resp.Body)
+		resp.Body.Close()
+	}()
+
+	if resp.StatusCode/100 != 2 {
+		return nil, errors.Errorf("non 2xx status '%d' response during eureka service discovery", resp.StatusCode)
+	}
+
+	var apps Applications
+	err = xml.NewDecoder(resp.Body).Decode(&apps)
+	if err != nil {
+		return nil, errors.Wrapf(err, "%q", url)
+	}
+	return &apps, nil
+}

discovery/eureka/client_test.go

@@ -0,0 +1,213 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package eureka
+
+import (
+	"context"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/prometheus/prometheus/util/testutil"
+)
+
+func TestFetchApps(t *testing.T) {
+	appsXML := `<applications>
+  <versions__delta>1</versions__delta>
+  <apps__hashcode>UP_4_</apps__hashcode>
+  <application>
+    <name>CONFIG-SERVICE</name>
+    <instance>
+      <instanceId>config-service001.test.com:config-service:8080</instanceId>
+      <hostName>config-service001.test.com</hostName>
+      <app>CONFIG-SERVICE</app>
+      <ipAddr>192.133.83.31</ipAddr>
+      <status>UP</status>
+      <overriddenstatus>UNKNOWN</overriddenstatus>
+      <port enabled="true">8080</port>
+      <securePort enabled="false">8080</securePort>
+      <countryId>1</countryId>
+      <dataCenterInfo class="com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo">
+        <name>MyOwn</name>
+      </dataCenterInfo>
+      <leaseInfo>
+        <renewalIntervalInSecs>30</renewalIntervalInSecs>
+        <durationInSecs>90</durationInSecs>
+        <registrationTimestamp>1596003469304</registrationTimestamp>
+        <lastRenewalTimestamp>1596110179310</lastRenewalTimestamp>
+        <evictionTimestamp>0</evictionTimestamp>
+        <serviceUpTimestamp>1547190033103</serviceUpTimestamp>
+      </leaseInfo>
+      <metadata>
+        <instanceId>config-service001.test.com:config-service:8080</instanceId>
+      </metadata>
+      <homePageUrl>http://config-service001.test.com:8080/</homePageUrl>
+      <statusPageUrl>http://config-service001.test.com:8080/info</statusPageUrl>
+      <healthCheckUrl>http://config-service001.test.com 8080/health</healthCheckUrl>
+      <vipAddress>config-service</vipAddress>
+      <isCoordinatingDiscoveryServer>false</isCoordinatingDiscoveryServer>
+      <lastUpdatedTimestamp>1596003469304</lastUpdatedTimestamp>
+      <lastDirtyTimestamp>1596003469304</lastDirtyTimestamp>
+      <actionType>ADDED</actionType>
+    </instance>
+    <instance>
+      <instanceId>config-service002.test.com:config-service:8080</instanceId>
+      <hostName>config-service002.test.com</hostName>
+      <app>CONFIG-SERVICE</app>
+      <ipAddr>192.133.83.31</ipAddr>
+      <status>UP</status>
+      <overriddenstatus>UNKNOWN</overriddenstatus>
+      <port enabled="true">8080</port>
+      <securePort enabled="false">8080</securePort>
+      <countryId>1</countryId>
+      <dataCenterInfo class="com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo">
+        <name>MyOwn</name>
+      </dataCenterInfo>
+      <leaseInfo>
+        <renewalIntervalInSecs>30</renewalIntervalInSecs>
+        <durationInSecs>90</durationInSecs>
+        <registrationTimestamp>1596003469304</registrationTimestamp>
+        <lastRenewalTimestamp>1596110179310</lastRenewalTimestamp>
+        <evictionTimestamp>0</evictionTimestamp>
+        <serviceUpTimestamp>1547190033103</serviceUpTimestamp>
+      </leaseInfo>
+      <metadata>
+        <instanceId>config-service002.test.com:config-service:8080</instanceId>
+      </metadata>
+      <homePageUrl>http://config-service002.test.com:8080/</homePageUrl>
+      <statusPageUrl>http://config-service002.test.com:8080/info</statusPageUrl>
+      <healthCheckUrl>http://config-service002.test.com:8080/health</healthCheckUrl>
+      <vipAddress>config-service</vipAddress>
+      <isCoordinatingDiscoveryServer>false</isCoordinatingDiscoveryServer>
+      <lastUpdatedTimestamp>1596003469304</lastUpdatedTimestamp>
+      <lastDirtyTimestamp>1596003469304</lastDirtyTimestamp>
+      <actionType>ADDED</actionType>
+    </instance>
+  </application>
+  <application>
+    <name>META-SERVICE</name>
+    <instance>
+      <instanceId>meta-service002.test.com:meta-service:8080</instanceId>
+      <hostName>meta-service002.test.com</hostName>
+      <app>META-SERVICE</app>
+      <ipAddr>192.133.87.237</ipAddr>
+      <status>UP</status>
+      <overriddenstatus>UNKNOWN</overriddenstatus>
+      <port enabled="true">8080</port>
+      <securePort enabled="false">443</securePort>
+      <countryId>1</countryId>
+      <dataCenterInfo class="com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo">
+        <name>MyOwn</name>
+      </dataCenterInfo>
+      <leaseInfo>
+        <renewalIntervalInSecs>30</renewalIntervalInSecs>
+        <durationInSecs>90</durationInSecs>
+        <registrationTimestamp>1535444352472</registrationTimestamp>
+        <lastRenewalTimestamp>1596110168846</lastRenewalTimestamp>
+        <evictionTimestamp>0</evictionTimestamp>
+        <serviceUpTimestamp>1535444352472</serviceUpTimestamp>
+      </leaseInfo>
+      <metadata>
+        <project>meta-service</project>
+        <management.port>8090</management.port>
+      </metadata>
+      <homePageUrl>http://meta-service002.test.com:8080/</homePageUrl>
+      <statusPageUrl>http://meta-service002.test.com:8080/info</statusPageUrl>
+      <healthCheckUrl>http://meta-service002.test.com:8080/health</healthCheckUrl>
+      <vipAddress>meta-service</vipAddress>
+      <secureVipAddress>meta-service</secureVipAddress>
+      <isCoordinatingDiscoveryServer>false</isCoordinatingDiscoveryServer>
+      <lastUpdatedTimestamp>1535444352472</lastUpdatedTimestamp>
+      <lastDirtyTimestamp>1535444352398</lastDirtyTimestamp>
+      <actionType>ADDED</actionType>
+    </instance>
+    <instance>
+      <instanceId>meta-service001.test.com:meta-service:8080</instanceId>
+      <hostName>meta-service001.test.com</hostName>
+      <app>META-SERVICE</app>
+      <ipAddr>192.133.87.236</ipAddr>
+      <status>UP</status>
+      <overriddenstatus>UNKNOWN</overriddenstatus>
+      <port enabled="true">8080</port>
+      <securePort enabled="false">443</securePort>
+      <countryId>1</countryId>
+      <dataCenterInfo class="com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo">
+        <name>MyOwn</name>
+      </dataCenterInfo>
+      <leaseInfo>
+        <renewalIntervalInSecs>30</renewalIntervalInSecs>
+        <durationInSecs>90</durationInSecs>
+        <registrationTimestamp>1535444352472</registrationTimestamp>
+        <lastRenewalTimestamp>1596110168846</lastRenewalTimestamp>
+        <evictionTimestamp>0</evictionTimestamp>
+        <serviceUpTimestamp>1535444352472</serviceUpTimestamp>
+      </leaseInfo>
+      <metadata>
+        <project>meta-service</project>
+        <management.port>8090</management.port>
+      </metadata>
+      <homePageUrl>http://meta-service001.test.com:8080/</homePageUrl>
+      <statusPageUrl>http://meta-service001.test.com:8080/info</statusPageUrl>
+      <healthCheckUrl>http://meta-service001.test.com:8080/health</healthCheckUrl>
+      <vipAddress>meta-service</vipAddress>
+      <secureVipAddress>meta-service</secureVipAddress>
+      <isCoordinatingDiscoveryServer>false</isCoordinatingDiscoveryServer>
+      <lastUpdatedTimestamp>1535444352472</lastUpdatedTimestamp>
+      <lastDirtyTimestamp>1535444352398</lastDirtyTimestamp>
+      <actionType>ADDED</actionType>
+    </instance>
+  </application>
+</applications>`
+
+	// Simulate apps with a valid XML response.
+	respHandler := func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		w.Header().Set("Content-Type", "application/xml")
+		io.WriteString(w, appsXML)
+	}
+	// Create a test server with mock HTTP handler.
+	ts := httptest.NewServer(http.HandlerFunc(respHandler))
+	defer ts.Close()
+
+	apps, err := fetchApps(context.TODO(), ts.URL, &http.Client{})
+	testutil.Ok(t, err)
+
+	testutil.Equals(t, len(apps.Applications), 2)
+	testutil.Equals(t, apps.Applications[0].Name, "CONFIG-SERVICE")
+	testutil.Equals(t, apps.Applications[1].Name, "META-SERVICE")
+
+	testutil.Equals(t, len(apps.Applications[1].Instances), 2)
+	testutil.Equals(t, apps.Applications[1].Instances[0].InstanceID, "meta-service002.test.com:meta-service:8080")
+	testutil.Equals(t, apps.Applications[1].Instances[0].Metadata.Items[0].XMLName.Local, "project")
+	testutil.Equals(t, apps.Applications[1].Instances[0].Metadata.Items[0].Content, "meta-service")
+	testutil.Equals(t, apps.Applications[1].Instances[0].Metadata.Items[1].XMLName.Local, "management.port")
+	testutil.Equals(t, apps.Applications[1].Instances[0].Metadata.Items[1].Content, "8090")
+	testutil.Equals(t, apps.Applications[1].Instances[1].InstanceID, "meta-service001.test.com:meta-service:8080")
+}
+
+func Test500ErrorHttpResponse(t *testing.T) {
+	// Simulate 500 error.
+	respHandler := func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Header().Set("Content-Type", "application/xml")
+		io.WriteString(w, ``)
+	}
+	// Create a test server with mock HTTP handler.
+	ts := httptest.NewServer(http.HandlerFunc(respHandler))
+	defer ts.Close()
+
+	_, err := fetchApps(context.TODO(), ts.URL, &http.Client{})
+	testutil.NotOk(t, err, "5xx HTTP response")
+}

discovery/eureka/eureka.go

@@ -0,0 +1,220 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package eureka
+
+import (
+	"context"
+	"net"
+	"net/http"
+	"net/url"
+	"strconv"
+	"time"
+
+	"github.com/go-kit/kit/log"
+	"github.com/pkg/errors"
+	"github.com/prometheus/common/config"
+	"github.com/prometheus/common/model"
+
+	"github.com/prometheus/prometheus/discovery"
+	"github.com/prometheus/prometheus/discovery/refresh"
+	"github.com/prometheus/prometheus/discovery/targetgroup"
+	"github.com/prometheus/prometheus/util/strutil"
+)
+
+const (
+	// metaLabelPrefix is the meta prefix used for all meta labels.
+	// in this discovery.
+	metaLabelPrefix            = model.MetaLabelPrefix + "eureka_"
+	metaAppInstanceLabelPrefix = metaLabelPrefix + "app_instance_"
+
+	appNameLabel                            = metaLabelPrefix + "app_name"
+	appInstanceHostNameLabel                = metaAppInstanceLabelPrefix + "hostname"
+	appInstanceHomePageURLLabel             = metaAppInstanceLabelPrefix + "homepage_url"
+	appInstanceStatusPageURLLabel           = metaAppInstanceLabelPrefix + "statuspage_url"
+	appInstanceHealthCheckURLLabel          = metaAppInstanceLabelPrefix + "healthcheck_url"
+	appInstanceIPAddrLabel                  = metaAppInstanceLabelPrefix + "ip_addr"
+	appInstanceVipAddressLabel              = metaAppInstanceLabelPrefix + "vip_address"
+	appInstanceSecureVipAddressLabel        = metaAppInstanceLabelPrefix + "secure_vip_address"
+	appInstanceStatusLabel                  = metaAppInstanceLabelPrefix + "status"
+	appInstancePortLabel                    = metaAppInstanceLabelPrefix + "port"
+	appInstancePortEnabledLabel             = metaAppInstanceLabelPrefix + "port_enabled"
+	appInstanceSecurePortLabel              = metaAppInstanceLabelPrefix + "secure_port"
+	appInstanceSecurePortEnabledLabel       = metaAppInstanceLabelPrefix + "secure_port_enabled"
+	appInstanceDataCenterInfoNameLabel      = metaAppInstanceLabelPrefix + "datacenterinfo_name"
+	appInstanceDataCenterInfoMetadataPrefix = metaAppInstanceLabelPrefix + "datacenterinfo_metadata_"
+	appInstanceCountryIDLabel               = metaAppInstanceLabelPrefix + "country_id"
+	appInstanceIDLabel                      = metaAppInstanceLabelPrefix + "id"
+	appInstanceMetadataPrefix               = metaAppInstanceLabelPrefix + "metadata_"
+)
+
+// DefaultSDConfig is the default Eureka SD configuration.
+var DefaultSDConfig = SDConfig{
+	RefreshInterval: model.Duration(30 * time.Second),
+}
+
+func init() {
+	discovery.RegisterConfig(&SDConfig{})
+}
+
+// SDConfig is the configuration for applications running on Eureka.
+type SDConfig struct {
+	Server           string                  `yaml:"server,omitempty"`
+	HTTPClientConfig config.HTTPClientConfig `yaml:",inline"`
+	RefreshInterval  model.Duration          `yaml:"refresh_interval,omitempty"`
+}
+
+// Name returns the name of the Config.
+func (*SDConfig) Name() string { return "eureka" }
+
+// NewDiscoverer returns a Discoverer for the Config.
+func (c *SDConfig) NewDiscoverer(opts discovery.DiscovererOptions) (discovery.Discoverer, error) {
+	return NewDiscovery(c, opts.Logger)
+}
+
+// SetDirectory joins any relative file paths with dir.
+func (c *SDConfig) SetDirectory(dir string) {
+	c.HTTPClientConfig.SetDirectory(dir)
+}
+
+// UnmarshalYAML implements the yaml.Unmarshaler interface.
+func (c *SDConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	*c = DefaultSDConfig
+	type plain SDConfig
+	err := unmarshal((*plain)(c))
+	if err != nil {
+		return err
+	}
+	if len(c.Server) == 0 {
+		return errors.New("eureka_sd: empty or null eureka server")
+	}
+	url, err := url.Parse(c.Server)
+	if err != nil {
+		return err
+	}
+	if len(url.Scheme) == 0 || len(url.Host) == 0 {
+		return errors.New("eureka_sd: invalid eureka server URL")
+	}
+	return c.HTTPClientConfig.Validate()
+}
+
+// Discovery provides service discovery based on a Eureka instance.
+type Discovery struct {
+	*refresh.Discovery
+	client *http.Client
+	server string
+}
+
+// New creates a new Eureka discovery for the given role.
+func NewDiscovery(conf *SDConfig, logger log.Logger) (*Discovery, error) {
+	rt, err := config.NewRoundTripperFromConfig(conf.HTTPClientConfig, "eureka_sd", false, false)
+	if err != nil {
+		return nil, err
+	}
+
+	d := &Discovery{
+		client: &http.Client{Transport: rt},
+		server: conf.Server,
+	}
+	d.Discovery = refresh.NewDiscovery(
+		logger,
+		"eureka",
+		time.Duration(conf.RefreshInterval),
+		d.refresh,
+	)
+	return d, nil
+}
+
+func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
+	apps, err := fetchApps(ctx, d.server, d.client)
+	if err != nil {
+		return nil, err
+	}
+
+	tg := &targetgroup.Group{
+		Source: "eureka",
+	}
+
+	for _, app := range apps.Applications {
+		targets := targetsForApp(&app)
+		tg.Targets = append(tg.Targets, targets...)
+	}
+	return []*targetgroup.Group{tg}, nil
+}
+
+func targetsForApp(app *Application) []model.LabelSet {
+	targets := make([]model.LabelSet, 0, len(app.Instances))
+
+	// Gather info about the app's 'instances'. Each instance is considered a task.
+	for _, t := range app.Instances {
+		var targetAddress string
+		if t.Port != nil {
+			targetAddress = net.JoinHostPort(t.HostName, strconv.Itoa(t.Port.Port))
+		} else {
+			targetAddress = net.JoinHostPort(t.HostName, "80")
+		}
+
+		target := model.LabelSet{
+			model.AddressLabel:  lv(targetAddress),
+			model.InstanceLabel: lv(t.InstanceID),
+
+			appNameLabel:                     lv(app.Name),
+			appInstanceHostNameLabel:         lv(t.HostName),
+			appInstanceHomePageURLLabel:      lv(t.HomePageURL),
+			appInstanceStatusPageURLLabel:    lv(t.StatusPageURL),
+			appInstanceHealthCheckURLLabel:   lv(t.HealthCheckURL),
+			appInstanceIPAddrLabel:           lv(t.IPAddr),
+			appInstanceVipAddressLabel:       lv(t.VipAddress),
+			appInstanceSecureVipAddressLabel: lv(t.SecureVipAddress),
+			appInstanceStatusLabel:           lv(t.Status),
+			appInstanceCountryIDLabel:        lv(strconv.Itoa(t.CountryID)),
+			appInstanceIDLabel:               lv(t.InstanceID),
+		}
+
+		if t.Port != nil {
+			target[appInstancePortLabel] = lv(strconv.Itoa(t.Port.Port))
+			target[appInstancePortEnabledLabel] = lv(strconv.FormatBool(t.Port.Enabled))
+		}
+
+		if t.SecurePort != nil {
+			target[appInstanceSecurePortLabel] = lv(strconv.Itoa(t.SecurePort.Port))
+			target[appInstanceSecurePortEnabledLabel] = lv(strconv.FormatBool(t.SecurePort.Enabled))
+		}
+
+		if t.DataCenterInfo != nil {
+			target[appInstanceDataCenterInfoNameLabel] = lv(t.DataCenterInfo.Name)
+
+			if t.DataCenterInfo.Metadata != nil {
+				for _, m := range t.DataCenterInfo.Metadata.Items {
+					ln := strutil.SanitizeLabelName(m.XMLName.Local)
+					target[model.LabelName(appInstanceDataCenterInfoMetadataPrefix+ln)] = lv(m.Content)
+				}
+			}
+		}
+
+		if t.Metadata != nil {
+			for _, m := range t.Metadata.Items {
+				ln := strutil.SanitizeLabelName(m.XMLName.Local)
+				target[model.LabelName(appInstanceMetadataPrefix+ln)] = lv(m.Content)
+			}
+		}
+
+		targets = append(targets, target)
+
+	}
+	return targets
+}
+
+func lv(s string) model.LabelValue {
+	return model.LabelValue(s)
+}

discovery/eureka/eureka_test.go

@@ -0,0 +1,246 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package eureka
+
+import (
+	"context"
+	"github.com/prometheus/prometheus/util/testutil"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/pkg/errors"
+	"github.com/prometheus/common/model"
+	"github.com/prometheus/prometheus/discovery/targetgroup"
+)
+
+func testUpdateServices(respHandler http.HandlerFunc) ([]*targetgroup.Group, error) {
+	// Create a test server with mock HTTP handler.
+	ts := httptest.NewServer(respHandler)
+	defer ts.Close()
+
+	conf := SDConfig{
+		Server: ts.URL,
+	}
+
+	md, err := NewDiscovery(&conf, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	return md.refresh(context.Background())
+}
+
+func TestEurekaSDHandleError(t *testing.T) {
+	var (
+		errTesting  = errors.Errorf("non 2xx status '%d' response during eureka service discovery", http.StatusInternalServerError)
+		respHandler = func(w http.ResponseWriter, r *http.Request) {
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Header().Set("Content-Type", "application/xml")
+			io.WriteString(w, ``)
+		}
+	)
+	tgs, err := testUpdateServices(respHandler)
+
+	testutil.ErrorEqual(t, err, errTesting)
+	testutil.Equals(t, len(tgs), 0)
+}
+
+func TestEurekaSDEmptyList(t *testing.T) {
+	var (
+		appsXML = `<applications>
+<versions__delta>1</versions__delta>
+<apps__hashcode/>
+</applications>`
+		respHandler = func(w http.ResponseWriter, r *http.Request) {
+			w.WriteHeader(http.StatusOK)
+			w.Header().Set("Content-Type", "application/xml")
+			io.WriteString(w, appsXML)
+		}
+	)
+	tgs, err := testUpdateServices(respHandler)
+	testutil.Ok(t, err)
+	testutil.Equals(t, len(tgs), 1)
+}
+
+func TestEurekaSDSendGroup(t *testing.T) {
+	var (
+		appsXML = `<applications>
+  <versions__delta>1</versions__delta>
+  <apps__hashcode>UP_4_</apps__hashcode>
+  <application>
+    <name>CONFIG-SERVICE</name>
+    <instance>
+      <instanceId>config-service001.test.com:config-service:8080</instanceId>
+      <hostName>config-service001.test.com</hostName>
+      <app>CONFIG-SERVICE</app>
+      <ipAddr>192.133.83.31</ipAddr>
+      <status>UP</status>
+      <overriddenstatus>UNKNOWN</overriddenstatus>
+      <port enabled="true">8080</port>
+      <securePort enabled="false">8080</securePort>
+      <countryId>1</countryId>
+      <dataCenterInfo class="com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo">
+        <name>MyOwn</name>
+      </dataCenterInfo>
+      <leaseInfo>
+        <renewalIntervalInSecs>30</renewalIntervalInSecs>
+        <durationInSecs>90</durationInSecs>
+        <registrationTimestamp>1596003469304</registrationTimestamp>
+        <lastRenewalTimestamp>1596110179310</lastRenewalTimestamp>
+        <evictionTimestamp>0</evictionTimestamp>
+        <serviceUpTimestamp>1547190033103</serviceUpTimestamp>
+      </leaseInfo>
+      <metadata>
+        <instanceId>config-service001.test.com:config-service:8080</instanceId>
+      </metadata>
+      <homePageUrl>http://config-service001.test.com:8080/</homePageUrl>
+      <statusPageUrl>http://config-service001.test.com:8080/info</statusPageUrl>
+      <healthCheckUrl>http://config-service001.test.com 8080/health</healthCheckUrl>
+      <vipAddress>config-service</vipAddress>
+      <isCoordinatingDiscoveryServer>false</isCoordinatingDiscoveryServer>
+      <lastUpdatedTimestamp>1596003469304</lastUpdatedTimestamp>
+      <lastDirtyTimestamp>1596003469304</lastDirtyTimestamp>
+      <actionType>ADDED</actionType>
+    </instance>
+    <instance>
+      <instanceId>config-service002.test.com:config-service:8080</instanceId>
+      <hostName>config-service002.test.com</hostName>
+      <app>CONFIG-SERVICE</app>
+      <ipAddr>192.133.83.31</ipAddr>
+      <status>UP</status>
+      <overriddenstatus>UNKNOWN</overriddenstatus>
+      <port enabled="true">8080</port>
+      <securePort enabled="false">8080</securePort>
+      <countryId>1</countryId>
+      <dataCenterInfo class="com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo">
+        <name>MyOwn</name>
+      </dataCenterInfo>
+      <leaseInfo>
+        <renewalIntervalInSecs>30</renewalIntervalInSecs>
+        <durationInSecs>90</durationInSecs>
+        <registrationTimestamp>1596003469304</registrationTimestamp>
+        <lastRenewalTimestamp>1596110179310</lastRenewalTimestamp>
+        <evictionTimestamp>0</evictionTimestamp>
+        <serviceUpTimestamp>1547190033103</serviceUpTimestamp>
+      </leaseInfo>
+      <metadata>
+        <instanceId>config-service002.test.com:config-service:8080</instanceId>
+      </metadata>
+      <homePageUrl>http://config-service002.test.com:8080/</homePageUrl>
+      <statusPageUrl>http://config-service002.test.com:8080/info</statusPageUrl>
+      <healthCheckUrl>http://config-service002.test.com:8080/health</healthCheckUrl>
+      <vipAddress>config-service</vipAddress>
+      <isCoordinatingDiscoveryServer>false</isCoordinatingDiscoveryServer>
+      <lastUpdatedTimestamp>1596003469304</lastUpdatedTimestamp>
+      <lastDirtyTimestamp>1596003469304</lastDirtyTimestamp>
+      <actionType>ADDED</actionType>
+    </instance>
+  </application>
+  <application>
+    <name>META-SERVICE</name>
+    <instance>
+      <instanceId>meta-service002.test.com:meta-service:8080</instanceId>
+      <hostName>meta-service002.test.com</hostName>
+      <app>META-SERVICE</app>
+      <ipAddr>192.133.87.237</ipAddr>
+      <status>UP</status>
+      <overriddenstatus>UNKNOWN</overriddenstatus>
+      <port enabled="true">8080</port>
+      <securePort enabled="false">443</securePort>
+      <countryId>1</countryId>
+      <dataCenterInfo class="com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo">
+        <name>MyOwn</name>
+      </dataCenterInfo>
+      <leaseInfo>
+        <renewalIntervalInSecs>30</renewalIntervalInSecs>
+        <durationInSecs>90</durationInSecs>
+        <registrationTimestamp>1535444352472</registrationTimestamp>
+        <lastRenewalTimestamp>1596110168846</lastRenewalTimestamp>
+        <evictionTimestamp>0</evictionTimestamp>
+        <serviceUpTimestamp>1535444352472</serviceUpTimestamp>
+      </leaseInfo>
+      <metadata>
+        <project>meta-service</project>
+        <management.port>8090</management.port>
+      </metadata>
+      <homePageUrl>http://meta-service002.test.com:8080/</homePageUrl>
+      <statusPageUrl>http://meta-service002.test.com:8080/info</statusPageUrl>
+      <healthCheckUrl>http://meta-service002.test.com:8080/health</healthCheckUrl>
+      <vipAddress>meta-service</vipAddress>
+      <secureVipAddress>meta-service</secureVipAddress>
+      <isCoordinatingDiscoveryServer>false</isCoordinatingDiscoveryServer>
+      <lastUpdatedTimestamp>1535444352472</lastUpdatedTimestamp>
+      <lastDirtyTimestamp>1535444352398</lastDirtyTimestamp>
+      <actionType>ADDED</actionType>
+    </instance>
+    <instance>
+      <instanceId>meta-service001.test.com:meta-service:8080</instanceId>
+      <hostName>meta-service001.test.com</hostName>
+      <app>META-SERVICE</app>
+      <ipAddr>192.133.87.236</ipAddr>
+      <status>UP</status>
+      <overriddenstatus>UNKNOWN</overriddenstatus>
+      <port enabled="true">8080</port>
+      <securePort enabled="false">443</securePort>
+      <countryId>1</countryId>
+      <dataCenterInfo class="com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo">
+        <name>MyOwn</name>
+      </dataCenterInfo>
+      <leaseInfo>
+        <renewalIntervalInSecs>30</renewalIntervalInSecs>
+        <durationInSecs>90</durationInSecs>
+        <registrationTimestamp>1535444352472</registrationTimestamp>
+        <lastRenewalTimestamp>1596110168846</lastRenewalTimestamp>
+        <evictionTimestamp>0</evictionTimestamp>
+        <serviceUpTimestamp>1535444352472</serviceUpTimestamp>
+      </leaseInfo>
+      <metadata>
+        <project>meta-service</project>
+        <management.port>8090</management.port>
+      </metadata>
+      <homePageUrl>http://meta-service001.test.com:8080/</homePageUrl>
+      <statusPageUrl>http://meta-service001.test.com:8080/info</statusPageUrl>
+      <healthCheckUrl>http://meta-service001.test.com:8080/health</healthCheckUrl>
+      <vipAddress>meta-service</vipAddress>
+      <secureVipAddress>meta-service</secureVipAddress>
+      <isCoordinatingDiscoveryServer>false</isCoordinatingDiscoveryServer>
+      <lastUpdatedTimestamp>1535444352472</lastUpdatedTimestamp>
+      <lastDirtyTimestamp>1535444352398</lastDirtyTimestamp>
+      <actionType>ADDED</actionType>
+    </instance>
+  </application>
+</applications>`
+		respHandler = func(w http.ResponseWriter, r *http.Request) {
+			w.WriteHeader(http.StatusOK)
+			w.Header().Set("Content-Type", "application/xml")
+			io.WriteString(w, appsXML)
+		}
+	)
+
+	tgs, err := testUpdateServices(respHandler)
+	testutil.Ok(t, err)
+	testutil.Equals(t, len(tgs), 1)
+
+	tg := tgs[0]
+	testutil.Equals(t, tg.Source, "eureka")
+	testutil.Equals(t, len(tg.Targets), 4)
+
+	tgt := tg.Targets[0]
+	testutil.Equals(t, tgt[model.AddressLabel], model.LabelValue("config-service001.test.com:8080"))
+
+	tgt = tg.Targets[2]
+	testutil.Equals(t, tgt[model.AddressLabel], model.LabelValue("meta-service002.test.com:8080"))
+}

discovery/install/install.go

@@ -22,6 +22,7 @@ import (
 	_ "github.com/prometheus/prometheus/discovery/dns"          // register dns
 	_ "github.com/prometheus/prometheus/discovery/dockerswarm"  // register dockerswarm
 	_ "github.com/prometheus/prometheus/discovery/ec2"          // register ec2
+	_ "github.com/prometheus/prometheus/discovery/eureka"       // register eureka
 	_ "github.com/prometheus/prometheus/discovery/file"         // register file
 	_ "github.com/prometheus/prometheus/discovery/gce"          // register gce
 	_ "github.com/prometheus/prometheus/discovery/hetzner"      // register hetzner

docs/configuration/configuration.md

@@ -207,6 +207,10 @@ dns_sd_configs:
 ec2_sd_configs:
   [ - <ec2_sd_config> ... ]
 
+# List of Eureka service discovery configurations.
+eureka_sd_configs:
+  [ - <eureka_sd_config> ... ]
+
 # List of file service discovery configurations.
 file_sd_configs:
   [ - <file_sd_config> ... ]
@@ -1381,6 +1385,72 @@ tls_config:
   [ <tls_config> ]
 ```
 
+### `<eureka_sd_config>`
+
+Eureka SD configurations allow retrieving scrape targets using the
+[Eureka](https://github.com/Netflix/eureka) REST API. Prometheus
+will periodically check the REST endpoint and
+create a target for every app instance.
+
+The following meta labels are available on targets during [relabeling](#relabel_config):
+
+* `__meta_eureka_app_name`: the name of the app
+* `__meta_eureka_app_instance_id`: the ID of the app instance
+* `__meta_eureka_app_instance_hostname`: the hostname of the instance
+* `__meta_eureka_app_instance_homepage_url`: the homepage url of the app instance
+* `__meta_eureka_app_instance_statuspage_url`: the status page url of the app instance
+* `__meta_eureka_app_instance_healthcheck_url`: the health check url of the app instance
+* `__meta_eureka_app_instance_ip_addr`: the IP address of the app instance
+* `__meta_eureka_app_instance_vip_address`: the VIP address of the app instance
+* `__meta_eureka_app_instance_secure_vip_address`: the secure VIP address of the app instance
+* `__meta_eureka_app_instance_status`: the status of the app instance
+* `__meta_eureka_app_instance_port`: the port of the app instance
+* `__meta_eureka_app_instance_port_enabled`: the port enabled of the app instance
+* `__meta_eureka_app_instance_secure_port`: the secure port address of the app instance
+* `__meta_eureka_app_instance_secure_port_enabled`: the secure port of the app instance
+* `__meta_eureka_app_instance_country_id`: the country ID of the app instance
+* `__meta_eureka_app_instance_metadata_<metadataname>`: app instance metadata
+* `__meta_eureka_app_instance_datacenterinfo_name`: the datacenter name of the app instance
+* `__meta_eureka_app_instance_datacenterinfo_<metadataname>`: the datacenter metadata
+
+See below for the configuration options for Eureka discovery:
+
+```yaml
+# The URL to connect to the Eureka server.
+server: <string>
+
+# Sets the `Authorization` header on every request with the
+# configured username and password.
+# password and password_file are mutually exclusive.
+basic_auth:
+  [ username: <string> ]
+  [ password: <secret> ]
+  [ password_file: <string> ]
+
+# Sets the `Authorization` header on every request with
+# the configured bearer token. It is mutually exclusive with `bearer_token_file`.
+[ bearer_token: <string> ]
+
+# Sets the `Authorization` header on every request with the bearer token
+# read from the configured file. It is mutually exclusive with `bearer_token`.
+[ bearer_token_file: <filename> ]
+
+# Configures the scrape request's TLS settings.
+tls_config:
+  [ <tls_config> ]
+
+# Optional proxy URL.
+[ proxy_url: <string> ]
+
+# Refresh interval to re-read the app instance list.
+[ refresh_interval: <duration> | default = 30s ]
+```
+
+See [the Prometheus eureka-sd configuration file](/documentation/examples/prometheus-eureka.yml)
+for a practical example on how to set up your Eureka app and your Prometheus
+configuration.
+
+
 ### `<static_config>`
 
 A `static_config` allows specifying a list of targets and a common label set
@@ -1557,6 +1627,10 @@ dns_sd_configs:
 ec2_sd_configs:
   [ - <ec2_sd_config> ... ]
 
+# List of Eureka service discovery configurations.
+eureka_sd_configs:
+  [ - <eureka_sd_config> ... ]
+
 # List of file service discovery configurations.
 file_sd_configs:
   [ - <file_sd_config> ... ]

documentation/examples/prometheus-eureka.yml

@@ -0,0 +1,66 @@
+# A example scrape configuration for running Prometheus with Eureka.
+
+scrape_configs:
+
+  # Make Prometheus scrape itself for metrics.
+  - job_name: 'prometheus'
+    static_configs:
+      - targets: ['localhost:9090']
+
+  # Discover Eureka services to scrape.
+  - job_name: 'eureka'
+
+    # Scrape Eureka itself to discover new services.
+    eureka_sd_configs:
+      - server: http://localhost:8761/eureka
+
+    relabel_configs:
+      # You can use Eureka's application instance metadata.
+      # If you are using SpringBoot, you can add metadata using eureka.instance.metadataMap like this:
+      # application.yaml (spring-boot)
+      # eureka:
+      #  instance:
+      #    metadataMap:
+      #      "prometheus.scrape": "true"
+      #      "prometheus.path": "/actuator/prometheus"
+      #      "prometheus.port": "8080"
+      #
+      #
+      # Example relabel to scrape only application that have
+      # "prometheus.scrape = true" metadata.
+      #  - source_labels: [__meta_eureka_app_instance_metadata_prometheus_scrape]
+      #    action: keep
+      #    regex: true
+      #
+      # application.yaml (spring-boot)
+      # eureka:
+      #  instance:
+      #    metadataMap:
+      #      "prometheus.scrape": "true"
+      #
+      # Example relabel to customize metric path based on application
+      # "prometheus.path = <metric path>" annotation.
+      #  - source_labels: [__meta_eureka_app_instance_metadata_prometheus_path]
+      #    action: replace
+      #    target_label: __metrics_path__
+      #    regex: (.+)
+      #
+      # application.yaml (spring-boot)
+      # eureka:
+      #  instance:
+      #    metadataMap:
+      #      "prometheus.path": "/actuator/prometheus"
+      #
+      # Example relabel to scrape only single, desired port for the application
+      # based on application "prometheus.port = <port>" metadata.
+      #  - source_labels: [__address__, __meta_eureka_app_instance_metadata_prometheus_port]
+      #    action: replace
+      #    regex: ([^:]+)(?::\d+)?;(\d+)
+      #    replacement: $1:$2
+      #    target_label: __address__
+      #
+      # application.yaml (spring-boot)
+      # eureka:
+      #  instance:
+      #    metadataMap:
+      #      "prometheus.port": "8080"