lib/promscrape: add Prometheus-compatible service discovery for Consul aka consul_sd_configs

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/330

app/vmagent/README.md

@@ -143,10 +143,11 @@ The following scrape types in [scrape_config](https://prometheus.io/docs/prometh
   * if `zone` arg is missing, then `vmagent` uses the zone for the instance where it runs;
   * if `zone` arg equals to `"*"`, then `vmagent` discovers all the zones for the given project;
   * `zone` may contain arbitrary number of zones, i.e. `zone: [us-east1-a, us-east1-b]`.
+* `consul_sd_configs` - for scraping targets registered in Consul.
+  See [consul_sd_config](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#consul_sd_config) for details.
 
 The following service discovery mechanisms will be added to `vmagent` soon:
 
-* [consul_sd_config](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#consul_sd_config)
 * [dns_sd_config](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#dns_sd_config)
 
 

docs/Single-server-VictoriaMetrics.md

@@ -262,6 +262,7 @@ Currently the following [scrape_config](https://prometheus.io/docs/prometheus/la
 * [kubernetes_sd_config](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#kubernetes_sd_config)
 * [ec2_sd_config](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#ec2_sd_config)
 * [gce_sd_config](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#gce_sd_config)
+* [consul_sd_config](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#consul_sd_config)
 
 In the future other `*_sd_config` types will be supported.
 

docs/vmagent.md

@@ -143,10 +143,11 @@ The following scrape types in [scrape_config](https://prometheus.io/docs/prometh
   * if `zone` arg is missing, then `vmagent` uses the zone for the instance where it runs;
   * if `zone` arg equals to `"*"`, then `vmagent` discovers all the zones for the given project;
   * `zone` may contain arbitrary number of zones, i.e. `zone: [us-east1-a, us-east1-b]`.
+* `consul_sd_configs` - for scraping targets registered in Consul.
+  See [consul_sd_config](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#consul_sd_config) for details.
 
 The following service discovery mechanisms will be added to `vmagent` soon:
 
-* [consul_sd_config](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#consul_sd_config)
 * [dns_sd_config](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#dns_sd_config)
 
 

lib/promscrape/config.go

@@ -14,6 +14,7 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promauth"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/prompbmarshal"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promrelabel"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape/discovery/consul"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape/discovery/ec2"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape/discovery/gce"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape/discovery/kubernetes"
@@ -62,6 +63,7 @@ type ScrapeConfig struct {
 	StaticConfigs        []StaticConfig              `yaml:"static_configs"`
 	FileSDConfigs        []FileSDConfig              `yaml:"file_sd_configs"`
 	KubernetesSDConfigs  []kubernetes.SDConfig       `yaml:"kubernetes_sd_configs"`
+	ConsulSDConfigs      []consul.SDConfig           `yaml:"consul_sd_configs"`
 	EC2SDConfigs         []ec2.SDConfig              `yaml:"ec2_sd_configs"`
 	GCESDConfigs         []gce.SDConfig              `yaml:"gce_sd_configs"`
 	RelabelConfigs       []promrelabel.RelabelConfig `yaml:"relabel_configs"`
@@ -156,6 +158,19 @@ func (cfg *Config) getKubernetesSDScrapeWork() []ScrapeWork {
 	return dst
 }
 
+// getConsulSDScrapeWork returns `consul_sd_configs` ScrapeWork from cfg.
+func (cfg *Config) getConsulSDScrapeWork() []ScrapeWork {
+	var dst []ScrapeWork
+	for i := range cfg.ScrapeConfigs {
+		sc := &cfg.ScrapeConfigs[i]
+		for j := range sc.ConsulSDConfigs {
+			sdc := &sc.ConsulSDConfigs[j]
+			dst = appendConsulScrapeWork(dst, sdc, cfg.baseDir, sc.swc)
+		}
+	}
+	return dst
+}
+
 // getEC2SDScrapeWork returns `ec2_sd_configs` ScrapeWork from cfg.
 func (cfg *Config) getEC2SDScrapeWork() []ScrapeWork {
 	var dst []ScrapeWork
@@ -309,6 +324,15 @@ func appendKubernetesScrapeWork(dst []ScrapeWork, sdc *kubernetes.SDConfig, base
 	return appendScrapeWorkForTargetLabels(dst, swc, targetLabels, "kubernetes_sd_config")
 }
 
+func appendConsulScrapeWork(dst []ScrapeWork, sdc *consul.SDConfig, baseDir string, swc *scrapeWorkConfig) []ScrapeWork {
+	targetLabels, err := consul.GetLabels(sdc, baseDir)
+	if err != nil {
+		logger.Errorf("error when discovering consul nodes for `job_name` %q: %s; skipping it", swc.jobName, err)
+		return dst
+	}
+	return appendScrapeWorkForTargetLabels(dst, swc, targetLabels, "consul_sd_config")
+}
+
 func appendEC2ScrapeWork(dst []ScrapeWork, sdc *ec2.SDConfig, swc *scrapeWorkConfig) []ScrapeWork {
 	targetLabels, err := ec2.GetLabels(sdc)
 	if err != nil {

lib/promscrape/discovery/consul/agent.go

@@ -0,0 +1,28 @@
+package consul
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+// Agent is Consul agent.
+//
+// See https://www.consul.io/api/agent.html#read-configuration
+type Agent struct {
+	Config AgentConfig
+}
+
+// AgentConfig is Consul agent config.
+//
+// See https://www.consul.io/api/agent.html#read-configuration
+type AgentConfig struct {
+	Datacenter string
+}
+
+func parseAgent(data []byte) (*Agent, error) {
+	var a Agent
+	if err := json.Unmarshal(data, &a); err != nil {
+		return nil, fmt.Errorf("cannot unmarshal agent info from %q: %s", data, err)
+	}
+	return &a, nil
+}

lib/promscrape/discovery/consul/agent_test.go

@@ -0,0 +1,81 @@
+package consul
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestParseAgentFailure(t *testing.T) {
+	f := func(s string) {
+		t.Helper()
+		a, err := parseAgent([]byte(s))
+		if err == nil {
+			t.Fatalf("expecting non-nil error")
+		}
+		if a != nil {
+			t.Fatalf("unexpected non-nil Agent: %v", a)
+		}
+	}
+	f(``)
+	f(`[1,23]`)
+}
+
+func TestParseAgentSuccess(t *testing.T) {
+	data := `
+{
+  "Config": {
+    "Datacenter": "dc1",
+    "NodeName": "foobar",
+    "NodeID": "9d754d17-d864-b1d3-e758-f3fe25a9874f",
+    "Server": true,
+    "Revision": "deadbeef",
+    "Version": "1.0.0"
+  },
+  "DebugConfig": {
+  },
+  "Coord": {
+    "Adjustment": 0,
+    "Error": 1.5,
+    "Vec": [0,0,0,0,0,0,0,0]
+  },
+  "Member": {
+    "Name": "foobar",
+    "Addr": "10.1.10.12",
+    "Port": 8301,
+    "Tags": {
+      "bootstrap": "1",
+      "dc": "dc1",
+      "id": "40e4a748-2192-161a-0510-9bf59fe950b5",
+      "port": "8300",
+      "role": "consul",
+      "vsn": "1",
+      "vsn_max": "1",
+      "vsn_min": "1"
+    },
+    "Status": 1,
+    "ProtocolMin": 1,
+    "ProtocolMax": 2,
+    "ProtocolCur": 2,
+    "DelegateMin": 2,
+    "DelegateMax": 4,
+    "DelegateCur": 4
+  },
+  "Meta": {
+    "instance_type": "i2.xlarge",
+    "os_version": "ubuntu_16.04"
+  }
+}
+`
+	a, err := parseAgent([]byte(data))
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+	aExpected := &Agent{
+		Config: AgentConfig{
+			Datacenter: "dc1",
+		},
+	}
+	if !reflect.DeepEqual(a, aExpected) {
+		t.Fatalf("unexpected Agent parsed;\ngot\n%v\nwant\n%v", a, aExpected)
+	}
+}

lib/promscrape/discovery/consul/api.go

@@ -0,0 +1,135 @@
+package consul
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net/url"
+	"os"
+	"strings"
+
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promauth"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape/discoveryutils"
+)
+
+// apiConfig contains config for API server
+type apiConfig struct {
+	client       *discoveryutils.Client
+	tagSeparator string
+	services     []string
+	tags         []string
+	datacenter   string
+	allowStale   bool
+	nodeMeta     map[string]string
+}
+
+var configMap = discoveryutils.NewConfigMap()
+
+func getAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
+	v, err := configMap.Get(sdc, func() (interface{}, error) { return newAPIConfig(sdc, baseDir) })
+	if err != nil {
+		return nil, err
+	}
+	return v.(*apiConfig), nil
+}
+
+func newAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
+	token, err := getToken(sdc.Token)
+	if err != nil {
+		return nil, err
+	}
+	var ba *promauth.BasicAuthConfig
+	if len(sdc.Username) > 0 {
+		ba = &promauth.BasicAuthConfig{
+			Username: sdc.Username,
+			Password: sdc.Password,
+		}
+		token = ""
+	}
+	ac, err := promauth.NewConfig(baseDir, ba, token, "", sdc.TLSConfig)
+	if err != nil {
+		return nil, fmt.Errorf("cannot parse auth config: %s", err)
+	}
+	apiServer := sdc.Server
+	if apiServer == "" {
+		apiServer = "localhost:8500"
+	}
+	if !strings.Contains(apiServer, "://") {
+		scheme := sdc.Scheme
+		if scheme == "" {
+			scheme = "http"
+		}
+		apiServer = scheme + "://" + apiServer
+	}
+	client, err := discoveryutils.NewClient(apiServer, ac)
+	if err != nil {
+		return nil, fmt.Errorf("cannot create HTTP client for %q: %s", apiServer, err)
+	}
+	tagSeparator := ","
+	if sdc.TagSeparator != nil {
+		tagSeparator = *sdc.TagSeparator
+	}
+	dc, err := getDatacenter(client, sdc.Datacenter)
+	if err != nil {
+		return nil, err
+	}
+	cfg := &apiConfig{
+		client: client,
+
+		tagSeparator: tagSeparator,
+		services:     sdc.Services,
+		tags:         sdc.Tags,
+		datacenter:   dc,
+		allowStale:   sdc.AllowStale,
+		nodeMeta:     sdc.NodeMeta,
+	}
+	return cfg, nil
+}
+
+func getToken(token string) (string, error) {
+	if token != "" {
+		return token, nil
+	}
+	if tokenFile := os.Getenv("CONSUL_HTTP_TOKEN_FILE"); tokenFile != "" {
+		data, err := ioutil.ReadFile(tokenFile)
+		if err != nil {
+			return "", fmt.Errorf("cannot read consul token file %q; probably, `token` arg is missing in `consul_sd_config`? error: %s", tokenFile, err)
+		}
+		return string(data), nil
+	}
+	token = os.Getenv("CONSUL_HTTP_TOKEN")
+	// Allow empty token - it shouls work if authorization is disabled in Consul
+	return token, nil
+}
+
+func getDatacenter(client *discoveryutils.Client, dc string) (string, error) {
+	if dc != "" {
+		return dc, nil
+	}
+	// See https://www.consul.io/api/agent.html#read-configuration
+	data, err := client.GetAPIResponse("/v1/agent/self")
+	if err != nil {
+		return "", fmt.Errorf("cannot query consul agent info: %s", err)
+	}
+	a, err := parseAgent(data)
+	if err != nil {
+		return "", err
+	}
+	return a.Config.Datacenter, nil
+}
+
+func getAPIResponse(cfg *apiConfig, path string) ([]byte, error) {
+	separator := "?"
+	if strings.Contains(path, "?") {
+		separator = "&"
+	}
+	path += fmt.Sprintf("%sdc=%s", separator, url.QueryEscape(cfg.datacenter))
+	if cfg.allowStale {
+		path += "&stale"
+	}
+	if len(cfg.nodeMeta) > 0 {
+		for k, v := range cfg.nodeMeta {
+			path += fmt.Sprintf("&node-meta=%s", url.QueryEscape(k+":"+v))
+		}
+	}
+	return cfg.client.GetAPIResponse(path)
+}

lib/promscrape/discovery/consul/consul.go

@@ -0,0 +1,40 @@
+package consul
+
+import (
+	"fmt"
+
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promauth"
+)
+
+// SDConfig represents service discovery config for Consul.
+//
+// See https://prometheus.io/docs/prometheus/latest/configuration/configuration/#consul_sd_config
+type SDConfig struct {
+	Server       string              `yaml:"server"`
+	Token        string              `yaml:"token"`
+	Datacenter   string              `yaml:"datacenter"`
+	Scheme       string              `yaml:"scheme"`
+	Username     string              `yaml:"username"`
+	Password     string              `yaml:"password"`
+	TLSConfig    *promauth.TLSConfig `yaml:"tls_config"`
+	Services     []string            `yaml:"services"`
+	Tags         []string            `yaml:"tags"`
+	NodeMeta     map[string]string   `yaml:"node_meta"`
+	TagSeparator *string             `yaml:"tag_separator"`
+	AllowStale   bool                `yaml:"allow_stale"`
+	// RefreshInterval time.Duration `yaml:"refresh_interval"`
+	// refresh_interval is obtained from `-promscrape.consulSDCheckInterval` command-line option.
+}
+
+// GetLabels returns Consul labels according to sdc.
+func GetLabels(sdc *SDConfig, baseDir string) ([]map[string]string, error) {
+	cfg, err := getAPIConfig(sdc, baseDir)
+	if err != nil {
+		return nil, fmt.Errorf("cannot get API config: %s", err)
+	}
+	ms, err := getServiceNodesLabels(cfg)
+	if err != nil {
+		return nil, fmt.Errorf("error when fetching service nodes data from Consul: %s", err)
+	}
+	return ms, nil
+}

lib/promscrape/discovery/consul/service_node.go

@@ -0,0 +1,245 @@
+package consul
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/url"
+	"strconv"
+	"strings"
+
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape/discoveryutils"
+)
+
+// getServiceNodesLabels returns labels for Consul service nodes obtained from the given cfg
+func getServiceNodesLabels(cfg *apiConfig) ([]map[string]string, error) {
+	sns, err := getAllServiceNodes(cfg)
+	if err != nil {
+		return nil, err
+	}
+	var ms []map[string]string
+	for _, sn := range sns {
+		ms = sn.appendTargetLabels(ms, cfg.tagSeparator)
+	}
+	return ms, nil
+}
+
+func getAllServiceNodes(cfg *apiConfig) ([]ServiceNode, error) {
+	// Obtain a list of services
+	// See https://www.consul.io/api/catalog.html#list-services
+	data, err := getAPIResponse(cfg, "/v1/catalog/services")
+	if err != nil {
+		return nil, fmt.Errorf("cannot obtain services: %s", err)
+	}
+	var m map[string][]string
+	if err := json.Unmarshal(data, &m); err != nil {
+		return nil, fmt.Errorf("cannot parse services response %q: %s", data, err)
+	}
+	serviceNames := make(map[string]bool)
+	for serviceName, tags := range m {
+		if !shouldCollectServiceByName(cfg.services, serviceName) {
+			continue
+		}
+		if !shouldCollectServiceByTags(cfg.tags, tags) {
+			continue
+		}
+		serviceNames[serviceName] = true
+	}
+
+	// Query all the serviceNames in parallel
+	type response struct {
+		sns []ServiceNode
+		err error
+	}
+	responsesCh := make(chan response, len(serviceNames))
+	for serviceName := range serviceNames {
+		go func(serviceName string) {
+			sns, err := getServiceNodes(cfg, serviceName)
+			responsesCh <- response{
+				sns: sns,
+				err: err,
+			}
+		}(serviceName)
+	}
+	var sns []ServiceNode
+	err = nil
+	for i := 0; i < len(serviceNames); i++ {
+		resp := <-responsesCh
+		if resp.err != nil && err == nil {
+			err = resp.err
+		}
+		sns = append(sns, resp.sns...)
+	}
+	if err != nil {
+		return nil, err
+	}
+	return sns, nil
+}
+
+func shouldCollectServiceByName(filterServices []string, service string) bool {
+	if len(filterServices) == 0 {
+		return true
+	}
+	for _, filterService := range filterServices {
+		if filterService == service {
+			return true
+		}
+	}
+	return false
+}
+
+func shouldCollectServiceByTags(filterTags, tags []string) bool {
+	if len(filterTags) == 0 {
+		return true
+	}
+	for _, filterTag := range filterTags {
+		hasTag := false
+		for _, tag := range tags {
+			if tag == filterTag {
+				hasTag = true
+				break
+			}
+		}
+		if !hasTag {
+			return false
+		}
+	}
+	return true
+}
+
+func getServiceNodes(cfg *apiConfig, serviceName string) ([]ServiceNode, error) {
+	// See https://www.consul.io/api/health.html#list-nodes-for-service
+	path := fmt.Sprintf("/v1/health/service/%s", serviceName)
+	var tagsArgs []string
+	for _, tag := range cfg.tags {
+		tagsArgs = append(tagsArgs, fmt.Sprintf("tag=%s", url.QueryEscape(tag)))
+	}
+	if len(tagsArgs) > 0 {
+		path += "?" + strings.Join(tagsArgs, "&")
+	}
+	data, err := getAPIResponse(cfg, path)
+	if err != nil {
+		return nil, fmt.Errorf("cannot obtain instances for serviceName=%q: %s", serviceName, err)
+	}
+	return parseServiceNodes(data)
+}
+
+// ServiceNode is Consul service node.
+//
+// See https://www.consul.io/api/health.html#list-nodes-for-service
+type ServiceNode struct {
+	Service Service
+	Node    Node
+	Checks  []Check
+}
+
+// Service is Consul service.
+//
+// See https://www.consul.io/api/health.html#list-nodes-for-service
+type Service struct {
+	ID      string
+	Service string
+	Address string
+	Port    int
+	Tags    []string
+	Meta    map[string]string
+}
+
+// Node is Consul node.
+//
+// See https://www.consul.io/api/health.html#list-nodes-for-service
+type Node struct {
+	Address         string
+	Datacenter      string
+	Node            string
+	Meta            map[string]string
+	TaggedAddresses map[string]string
+}
+
+// Check is Consul check.
+//
+// See https://www.consul.io/api/health.html#list-nodes-for-service
+type Check struct {
+	CheckID string
+	Status  string
+}
+
+func parseServiceNodes(data []byte) ([]ServiceNode, error) {
+	var sns []ServiceNode
+	if err := json.Unmarshal(data, &sns); err != nil {
+		return nil, fmt.Errorf("cannot unmarshal ServiceNodes from %q: %s", data, err)
+	}
+	return sns, nil
+}
+
+func (sn *ServiceNode) appendTargetLabels(ms []map[string]string, tagSeparator string) []map[string]string {
+	var addr string
+	if sn.Service.Address != "" {
+		addr = discoveryutils.JoinHostPort(sn.Service.Address, sn.Service.Port)
+	} else {
+		addr = discoveryutils.JoinHostPort(sn.Node.Address, sn.Service.Port)
+	}
+	m := map[string]string{
+		"__address__":                   addr,
+		"__meta_consul_address":         sn.Node.Address,
+		"__meta_consul_dc":              sn.Node.Datacenter,
+		"__meta_consul_health":          aggregatedStatus(sn.Checks),
+		"__meta_consul_node":            sn.Node.Node,
+		"__meta_consul_service":         sn.Service.Service,
+		"__meta_consul_service_address": sn.Service.Address,
+		"__meta_consul_service_id":      sn.Service.ID,
+		"__meta_consul_service_port":    strconv.Itoa(sn.Service.Port),
+	}
+	// We surround the separated list with the separator as well. This way regular expressions
+	// in relabeling rules don't have to consider tag positions.
+	m["__meta_consul_tags"] = tagSeparator + strings.Join(sn.Service.Tags, tagSeparator) + tagSeparator
+
+	for k, v := range sn.Node.Meta {
+		key := discoveryutils.SanitizeLabelName(k)
+		m["__meta_consul_metadata_"+key] = v
+	}
+	for k, v := range sn.Service.Meta {
+		key := discoveryutils.SanitizeLabelName(k)
+		m["__meta_consul_service_metadata_"+key] = v
+	}
+	for k, v := range sn.Node.TaggedAddresses {
+		key := discoveryutils.SanitizeLabelName(k)
+		m["__meta_consul_tagged_address_"+key] = v
+	}
+	ms = append(ms, m)
+	return ms
+}
+
+func aggregatedStatus(checks []Check) string {
+	// The code has been copy-pasted from HealthChecks.AggregatedStatus in Consul
+	var passing, warning, critical, maintenance bool
+	for _, check := range checks {
+		id := check.CheckID
+		if id == "_node_maintenance" || strings.HasPrefix(id, "_service_maintenance:") {
+			maintenance = true
+			continue
+		}
+
+		switch check.Status {
+		case "passing":
+			passing = true
+		case "warning":
+			warning = true
+		case "critical":
+			critical = true
+		default:
+			return ""
+		}
+	}
+	switch {
+	case maintenance:
+		return "maintenance"
+	case critical:
+		return "critical"
+	case warning:
+		return "warning"
+	case passing:
+		return "passing"
+	default:
+		return "passing"
+	}
+}

lib/promscrape/discovery/consul/service_node_test.go

@@ -0,0 +1,135 @@
+package consul
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/prompbmarshal"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape/discoveryutils"
+)
+
+func TestParseServiceNodesFailure(t *testing.T) {
+	f := func(s string) {
+		t.Helper()
+		sns, err := parseServiceNodes([]byte(s))
+		if err == nil {
+			t.Fatalf("expecting non-nil error")
+		}
+		if sns != nil {
+			t.Fatalf("unexpected non-nil ServiceNodes: %v", sns)
+		}
+	}
+	f(``)
+	f(`[1,23]`)
+	f(`{"items":[{"metadata":1}]}`)
+}
+
+func TestParseServiceNodesSuccess(t *testing.T) {
+	data := `
+[
+  {
+    "Node": {
+      "ID": "40e4a748-2192-161a-0510-9bf59fe950b5",
+      "Node": "foobar",
+      "Address": "10.1.10.12",
+      "Datacenter": "dc1",
+      "TaggedAddresses": {
+        "lan": "10.1.10.12",
+        "wan": "10.1.10.12"
+      },
+      "Meta": {
+        "instance_type": "t2.medium"
+      }
+    },
+    "Service": {
+      "ID": "redis",
+      "Service": "redis",
+      "Tags": ["primary"],
+      "Address": "10.1.10.12",
+      "TaggedAddresses": {
+        "lan": {
+          "address": "10.1.10.12",
+          "port": 8000
+        },
+        "wan": {
+          "address": "198.18.1.2",
+          "port": 80
+        }
+      },
+      "Meta": {
+        "redis_version": "4.0"
+      },
+      "Port": 8000,
+      "Weights": {
+        "Passing": 10,
+        "Warning": 1
+      },
+      "Namespace": "default"
+    },
+    "Checks": [
+      {
+        "Node": "foobar",
+        "CheckID": "service:redis",
+        "Name": "Service 'redis' check",
+        "Status": "passing",
+        "Notes": "",
+        "Output": "",
+        "ServiceID": "redis",
+        "ServiceName": "redis",
+        "ServiceTags": ["primary"],
+        "Namespace": "default"
+      },
+      {
+        "Node": "foobar",
+        "CheckID": "serfHealth",
+        "Name": "Serf Health Status",
+        "Status": "passing",
+        "Notes": "",
+        "Output": "",
+        "ServiceID": "",
+        "ServiceName": "",
+        "ServiceTags": [],
+        "Namespace": "default"
+      }
+    ]
+  }
+]
+`
+	sns, err := parseServiceNodes([]byte(data))
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+	if len(sns) != 1 {
+		t.Fatalf("unexpected length of ServiceNodes; got %d; want %d", len(sns), 1)
+	}
+	sn := sns[0]
+
+	// Check sn.appendTargetLabels()
+	tagSeparator := ","
+	labelss := sn.appendTargetLabels(nil, tagSeparator)
+	var sortedLabelss [][]prompbmarshal.Label
+	for _, labels := range labelss {
+		sortedLabelss = append(sortedLabelss, discoveryutils.GetSortedLabels(labels))
+	}
+	expectedLabelss := [][]prompbmarshal.Label{
+		discoveryutils.GetSortedLabels(map[string]string{
+			"__address__":                                  "10.1.10.12:8000",
+			"__meta_consul_address":                        "10.1.10.12",
+			"__meta_consul_dc":                             "dc1",
+			"__meta_consul_health":                         "passing",
+			"__meta_consul_metadata_instance_type":         "t2.medium",
+			"__meta_consul_node":                           "foobar",
+			"__meta_consul_service":                        "redis",
+			"__meta_consul_service_address":                "10.1.10.12",
+			"__meta_consul_service_id":                     "redis",
+			"__meta_consul_service_metadata_redis_version": "4.0",
+			"__meta_consul_service_port":                   "8000",
+			"__meta_consul_tagged_address_lan":             "10.1.10.12",
+			"__meta_consul_tagged_address_wan":             "10.1.10.12",
+			"__meta_consul_tags":                           ",primary,",
+		}),
+	}
+	if !reflect.DeepEqual(sortedLabelss, expectedLabelss) {
+		t.Fatalf("unexpected labels:\ngot\n%v\nwant\n%v", sortedLabelss, expectedLabelss)
+	}
+}

lib/promscrape/discovery/kubernetes/api.go

@@ -1,25 +1,17 @@
 package kubernetes
 
 import (
-	"crypto/tls"
 	"fmt"
 	"net"
 	"os"
-	"strings"
-	"time"
 
-	"github.com/VictoriaMetrics/VictoriaMetrics/lib/netutil"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promauth"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape/discoveryutils"
-	"github.com/VictoriaMetrics/fasthttp"
 )
 
 // apiConfig contains config for API server
 type apiConfig struct {
-	client     *fasthttp.HostClient
-	server     string
-	hostPort   string
-	authConfig *promauth.Config
+	client     *discoveryutils.Client
 	namespaces []string
 	selectors  []Selector
 }
@@ -39,67 +31,7 @@ func newAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 	if err != nil {
 		return nil, fmt.Errorf("cannot parse auth config: %s", err)
 	}
-	hcv, err := newHostClient(sdc.APIServer, ac)
-	if err != nil {
-		return nil, fmt.Errorf("cannot create HTTP client for %q: %s", sdc.APIServer, err)
-	}
-	cfg := &apiConfig{
-		client:     hcv.hc,
-		server:     hcv.apiServer,
-		hostPort:   hcv.hostPort,
-		authConfig: hcv.ac,
-		namespaces: sdc.Namespaces.Names,
-		selectors:  sdc.Selectors,
-	}
-	return cfg, nil
-}
-
-func getAPIResponse(cfg *apiConfig, role, path string) ([]byte, error) {
-	query := joinSelectors(role, cfg.namespaces, cfg.selectors)
-	if len(query) > 0 {
-		path += "?" + query
-	}
-	requestURL := cfg.server + path
-	var u fasthttp.URI
-	u.Update(requestURL)
-	var req fasthttp.Request
-	req.SetRequestURIBytes(u.RequestURI())
-	req.SetHost(cfg.hostPort)
-	req.Header.Set("Accept-Encoding", "gzip")
-	if cfg.authConfig != nil && cfg.authConfig.Authorization != "" {
-		req.Header.Set("Authorization", cfg.authConfig.Authorization)
-	}
-	var resp fasthttp.Response
-	// There is no need in calling DoTimeout, since the timeout is already set in hc.ReadTimeout above.
-	if err := cfg.client.Do(&req, &resp); err != nil {
-		return nil, fmt.Errorf("cannot fetch %q: %s", requestURL, err)
-	}
-	var data []byte
-	if ce := resp.Header.Peek("Content-Encoding"); string(ce) == "gzip" {
-		dst, err := fasthttp.AppendGunzipBytes(nil, resp.Body())
-		if err != nil {
-			return nil, fmt.Errorf("cannot ungzip response from %q: %s", requestURL, err)
-		}
-		data = dst
-	} else {
-		data = append(data[:0], resp.Body()...)
-	}
-	statusCode := resp.StatusCode()
-	if statusCode != fasthttp.StatusOK {
-		return nil, fmt.Errorf("unexpected status code returned from %q: %d; expecting %d; response body: %q",
-			requestURL, statusCode, fasthttp.StatusOK, data)
-	}
-	return data, nil
-}
-
-type hcValue struct {
-	hc        *fasthttp.HostClient
-	ac        *promauth.Config
-	apiServer string
-	hostPort  string
-}
-
-func newHostClient(apiServer string, ac *promauth.Config) (*hcValue, error) {
+	apiServer := sdc.APIServer
 	if len(apiServer) == 0 {
 		// Assume we run at k8s pod.
 		// Discover apiServer and auth config according to k8s docs.
@@ -124,36 +56,22 @@ func newHostClient(apiServer string, ac *promauth.Config) (*hcValue, error) {
 		}
 		ac = acNew
 	}
-
-	var u fasthttp.URI
-	u.Update(apiServer)
-	hostPort := string(u.Host())
-	isTLS := string(u.Scheme()) == "https"
-	var tlsCfg *tls.Config
-	if isTLS && ac != nil {
-		tlsCfg = ac.NewTLSConfig()
+	client, err := discoveryutils.NewClient(apiServer, ac)
+	if err != nil {
+		return nil, fmt.Errorf("cannot create HTTP client for %q: %s", apiServer, err)
 	}
-	if !strings.Contains(hostPort, ":") {
-		port := "80"
-		if isTLS {
-			port = "443"
-		}
-		hostPort = net.JoinHostPort(hostPort, port)
+	cfg := &apiConfig{
+		client:     client,
+		namespaces: sdc.Namespaces.Names,
+		selectors:  sdc.Selectors,
 	}
-	hc := &fasthttp.HostClient{
-		Addr:                hostPort,
-		Name:                "vm_promscrape/discovery",
-		DialDualStack:       netutil.TCP6Enabled(),
-		IsTLS:               isTLS,
-		TLSConfig:           tlsCfg,
-		ReadTimeout:         time.Minute,
-		WriteTimeout:        10 * time.Second,
-		MaxResponseBodySize: 300 * 1024 * 1024,
-	}
-	return &hcValue{
-		hc:        hc,
-		ac:        ac,
-		apiServer: apiServer,
-		hostPort:  hostPort,
-	}, nil
+	return cfg, nil
+}
+
+func getAPIResponse(cfg *apiConfig, role, path string) ([]byte, error) {
+	query := joinSelectors(role, cfg.namespaces, cfg.selectors)
+	if len(query) > 0 {
+		path += "?" + query
+	}
+	return cfg.client.GetAPIResponse(path)
 }

lib/promscrape/discoveryutils/client.go

@@ -1,8 +1,16 @@
 package discoveryutils
 
 import (
+	"crypto/tls"
+	"fmt"
+	"net"
 	"net/http"
+	"strings"
 	"time"
+
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/netutil"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promauth"
+	"github.com/VictoriaMetrics/fasthttp"
 )
 
 var defaultClient = &http.Client{
@@ -13,3 +21,81 @@ var defaultClient = &http.Client{
 func GetHTTPClient() *http.Client {
 	return defaultClient
 }
+
+// Client is http client, which talks to the given apiServer.
+type Client struct {
+	hc        *fasthttp.HostClient
+	ac        *promauth.Config
+	apiServer string
+	hostPort  string
+}
+
+// NewClient returns new Client for the given apiServer and the given ac.
+func NewClient(apiServer string, ac *promauth.Config) (*Client, error) {
+	var u fasthttp.URI
+	u.Update(apiServer)
+	hostPort := string(u.Host())
+	isTLS := string(u.Scheme()) == "https"
+	var tlsCfg *tls.Config
+	if isTLS && ac != nil {
+		tlsCfg = ac.NewTLSConfig()
+	}
+	if !strings.Contains(hostPort, ":") {
+		port := "80"
+		if isTLS {
+			port = "443"
+		}
+		hostPort = net.JoinHostPort(hostPort, port)
+	}
+	hc := &fasthttp.HostClient{
+		Addr:                hostPort,
+		Name:                "vm_promscrape/discovery",
+		DialDualStack:       netutil.TCP6Enabled(),
+		IsTLS:               isTLS,
+		TLSConfig:           tlsCfg,
+		ReadTimeout:         time.Minute,
+		WriteTimeout:        10 * time.Second,
+		MaxResponseBodySize: 300 * 1024 * 1024,
+	}
+	return &Client{
+		hc:        hc,
+		ac:        ac,
+		apiServer: apiServer,
+		hostPort:  hostPort,
+	}, nil
+}
+
+// GetAPIResponse returns response for the given absolute path.
+func (c *Client) GetAPIResponse(path string) ([]byte, error) {
+	requestURL := c.apiServer + path
+	var u fasthttp.URI
+	u.Update(requestURL)
+	var req fasthttp.Request
+	req.SetRequestURIBytes(u.RequestURI())
+	req.SetHost(c.hostPort)
+	req.Header.Set("Accept-Encoding", "gzip")
+	if c.ac != nil && c.ac.Authorization != "" {
+		req.Header.Set("Authorization", c.ac.Authorization)
+	}
+	var resp fasthttp.Response
+	// There is no need in calling DoTimeout, since the timeout is already set in c.hc.ReadTimeout above.
+	if err := c.hc.Do(&req, &resp); err != nil {
+		return nil, fmt.Errorf("cannot fetch %q: %s", requestURL, err)
+	}
+	var data []byte
+	if ce := resp.Header.Peek("Content-Encoding"); string(ce) == "gzip" {
+		dst, err := fasthttp.AppendGunzipBytes(nil, resp.Body())
+		if err != nil {
+			return nil, fmt.Errorf("cannot ungzip response from %q: %s", requestURL, err)
+		}
+		data = dst
+	} else {
+		data = append(data[:0], resp.Body()...)
+	}
+	statusCode := resp.StatusCode()
+	if statusCode != fasthttp.StatusOK {
+		return nil, fmt.Errorf("unexpected status code returned from %q: %d; expecting %d; response body: %q",
+			requestURL, statusCode, fasthttp.StatusOK, data)
+	}
+	return data, nil
+}

lib/promscrape/scraper.go

@@ -23,6 +23,9 @@ var (
 	kubernetesSDCheckInterval = flag.Duration("promscrape.kubernetesSDCheckInterval", 30*time.Second, "Interval for checking for changes in Kubernetes API server. "+
 		"This works only if `kubernetes_sd_configs` is configured in '-promscrape.config' file. "+
 		"See https://prometheus.io/docs/prometheus/latest/configuration/configuration/#kubernetes_sd_config for details")
+	consulSDCheckInterval = flag.Duration("promscrape.consulSDCheckInterval", 30*time.Second, "Interval for checking for changes in consul. "+
+		"This works only if `consul_sd_configs` is configured in '-promscrape.config' file. "+
+		"See https://prometheus.io/docs/prometheus/latest/configuration/configuration/#consul_sd_config for details")
 	ec2SDCheckInterval = flag.Duration("promscrape.ec2SDCheckInterval", time.Minute, "Interval for checking for changes in ec2. "+
 		"This works only if `ec2_sd_configs` is configured in '-promscrape.config' file. "+
 		"See https://prometheus.io/docs/prometheus/latest/configuration/configuration/#ec2_sd_config for details")
@@ -72,6 +75,7 @@ func runScraper(configFile string, pushData func(wr *prompbmarshal.WriteRequest)
 	scs.add("static_configs", 0, func(cfg *Config, swsPrev []ScrapeWork) []ScrapeWork { return cfg.getStaticScrapeWork() })
 	scs.add("file_sd_configs", *fileSDCheckInterval, func(cfg *Config, swsPrev []ScrapeWork) []ScrapeWork { return cfg.getFileSDScrapeWork(swsPrev) })
 	scs.add("kubernetes_sd_configs", *kubernetesSDCheckInterval, func(cfg *Config, swsPrev []ScrapeWork) []ScrapeWork { return cfg.getKubernetesSDScrapeWork() })
+	scs.add("consul_sd_configs", *consulSDCheckInterval, func(cfg *Config, swsPrev []ScrapeWork) []ScrapeWork { return cfg.getConsulSDScrapeWork() })
 	scs.add("ec2_sd_configs", *ec2SDCheckInterval, func(cfg *Config, swsPrev []ScrapeWork) []ScrapeWork { return cfg.getEC2SDScrapeWork() })
 	scs.add("gce_sd_configs", *gceSDCheckInterval, func(cfg *Config, swsPrev []ScrapeWork) []ScrapeWork { return cfg.getGCESDScrapeWork() })