lib/promscrape: add filters option to dockerswarm_sd_config like Prometheus did in v2.23.0

docs/CHANGELOG.md

@@ -11,6 +11,7 @@
 * FEATURE: vminsert: export `vm_rpc_vmstorage_is_reachable` metric, which can be used for monitoring reachability of vmstorage nodes from vminsert nodes.
 * FEATURE: vmagent: add Netflix Eureka service discovery (aka [eureka_sd_config](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#eureka_sd_config)).
 See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/851
+* FEATURE: add `filters` option to `dockerswarm_sd_config` like Prometheus did in v2.23.0 - see https://github.com/prometheus/prometheus/pull/8074
 * FEATURE: add `-loggerWarnsPerSecondLimit` command-line flag for rate limiting of WARN messages in logs. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/905
 * FEATURE: apply `loggerErrorsPerSecondLimit` and `-loggerWarnsPerSecondLimit` rate limit per caller. I.e. log messages are suppressed if the same caller logs the same message
   at the rate exceeding the given limit. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/905#issuecomment-729395855

lib/promscrape/discovery/dockerswarm/api.go

@@ -1,8 +1,12 @@
 package dockerswarm
 
 import (
+	"encoding/json"
 	"fmt"
+	"net/url"
+	"strings"
 
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promauth"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape/discoveryutils"
 )
@@ -12,6 +16,9 @@ var configMap = discoveryutils.NewConfigMap()
 type apiConfig struct {
 	client *discoveryutils.Client
 	port   int
+
+	// filtersQueryArg contains escaped `filters` query arg to add to each request to Docker Swarm API.
+	filtersQueryArg string
 }
 
 func getAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
@@ -25,6 +32,7 @@ func getAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 func newAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 	cfg := &apiConfig{
 		port:            sdc.Port,
+		filtersQueryArg: getFiltersQueryArg(sdc.Filters),
 	}
 	ac, err := promauth.NewConfig(baseDir, sdc.BasicAuth, sdc.BearerToken, sdc.BearerTokenFile, sdc.TLSConfig)
 	if err != nil {
@@ -37,3 +45,36 @@ func newAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 	cfg.client = client
 	return cfg, nil
 }
+
+func (cfg *apiConfig) getAPIResponse(path string) ([]byte, error) {
+	if len(cfg.filtersQueryArg) > 0 {
+		separator := "?"
+		if strings.Contains(path, "?") {
+			separator = "&"
+		}
+		path += separator + "filters=" + cfg.filtersQueryArg
+	}
+	return cfg.client.GetAPIResponse(path)
+}
+
+func getFiltersQueryArg(filters []Filter) string {
+	if len(filters) == 0 {
+		return ""
+	}
+	m := make(map[string]map[string]bool)
+	for _, f := range filters {
+		x := m[f.Name]
+		if x == nil {
+			x = make(map[string]bool)
+			m[f.Name] = x
+		}
+		for _, value := range f.Values {
+			x[value] = true
+		}
+	}
+	buf, err := json.Marshal(m)
+	if err != nil {
+		logger.Panicf("BUG: unexpected error in json.Marshal: %s", err)
+	}
+	return url.QueryEscape(string(buf))
+}

lib/promscrape/discovery/dockerswarm/api_test.go

@@ -0,0 +1,26 @@
+package dockerswarm
+
+import (
+	"testing"
+)
+
+func TestGetFiltersQueryArg(t *testing.T) {
+	f := func(filters []Filter, queryArgExpected string) {
+		t.Helper()
+		queryArg := getFiltersQueryArg(filters)
+		if queryArg != queryArgExpected {
+			t.Fatalf("unexpected query arg; got %s; want %s", queryArg, queryArgExpected)
+		}
+	}
+	f(nil, "")
+	f([]Filter{
+		{
+			Name: "name",
+			Values: []string{"foo", "bar"},
+		},
+		{
+			Name: "xxx",
+			Values: []string{"aa"},
+		},
+	}, "%7B%22name%22%3A%7B%22bar%22%3Atrue%2C%22foo%22%3Atrue%7D%2C%22xxx%22%3A%7B%22aa%22%3Atrue%7D%7D")
+}

lib/promscrape/discovery/dockerswarm/dockerswarm.go

@@ -11,16 +11,24 @@ import (
 // See https://prometheus.io/docs/prometheus/latest/configuration/configuration/#dockerswarm_sd_config
 type SDConfig struct {
 	Host    string   `yaml:"host"`
-	// TODO: add support for proxy_url
-	TLSConfig *promauth.TLSConfig `yaml:"tls_config,omitempty"`
 	Role    string   `yaml:"role"`
 	Port    int      `yaml:"port,omitempty"`
+	Filters []Filter `yaml:"filters,omitempty"`
+
+	// TODO: add support for proxy_url
+	TLSConfig *promauth.TLSConfig `yaml:"tls_config,omitempty"`
 	// refresh_interval is obtained from `-promscrape.dockerswarmSDCheckInterval` command-line option
 	BasicAuth       *promauth.BasicAuthConfig `yaml:"basic_auth,omitempty"`
 	BearerToken     string                    `yaml:"bearer_token,omitempty"`
 	BearerTokenFile string                    `yaml:"bearer_token_file,omitempty"`
 }
 
+// Filter is a filter, which can be passed to SDConfig.
+type Filter struct {
+	Name   string   `yaml:"name"`
+	Values []string `yaml:"values"`
+}
+
 // GetLabels returns dockerswarm labels according to sdc.
 func GetLabels(sdc *SDConfig, baseDir string) ([]map[string]string, error) {
 	cfg, err := getAPIConfig(sdc, baseDir)

lib/promscrape/discovery/dockerswarm/network.go

@@ -27,7 +27,7 @@ func getNetworksLabelsByNetworkID(cfg *apiConfig) (map[string]map[string]string,
 }
 
 func getNetworks(cfg *apiConfig) ([]network, error) {
-	resp, err := cfg.client.GetAPIResponse("/networks")
+	resp, err := cfg.getAPIResponse("/networks")
 	if err != nil {
 		return nil, fmt.Errorf("cannot query dockerswarm api for networks: %w", err)
 	}

lib/promscrape/discovery/dockerswarm/nodes.go

@@ -46,7 +46,7 @@ func getNodesLabels(cfg *apiConfig) ([]map[string]string, error) {
 }
 
 func getNodes(cfg *apiConfig) ([]node, error) {
-	resp, err := cfg.client.GetAPIResponse("/nodes")
+	resp, err := cfg.getAPIResponse("/nodes")
 	if err != nil {
 		return nil, fmt.Errorf("cannot query dockerswarm api for nodes: %w", err)
 	}

lib/promscrape/discovery/dockerswarm/services.go

@@ -59,7 +59,7 @@ func getServicesLabels(cfg *apiConfig) ([]map[string]string, error) {
 }
 
 func getServices(cfg *apiConfig) ([]service, error) {
-	data, err := cfg.client.GetAPIResponse("/services")
+	data, err := cfg.getAPIResponse("/services")
 	if err != nil {
 		return nil, fmt.Errorf("cannot query dockerswarm api for services: %w", err)
 	}

lib/promscrape/discovery/dockerswarm/tasks.go

@@ -58,7 +58,7 @@ func getTasksLabels(cfg *apiConfig) ([]map[string]string, error) {
 }
 
 func getTasks(cfg *apiConfig) ([]task, error) {
-	resp, err := cfg.client.GetAPIResponse("/tasks")
+	resp, err := cfg.getAPIResponse("/tasks")
 	if err != nil {
 		return nil, fmt.Errorf("cannot query dockerswarm api for tasks: %w", err)
 	}