List support for known servers and script-exporter targets

api/v0/api.go

@@ -32,6 +32,7 @@ type DeleteResponse struct {
 type ListResponse struct {
 	Error        *v2.Error                `json:",omitempty"`
 	StaticConfig []discovery.StaticConfig `json:",omitempty"`
+	Servers      []string                 `json:",omitempty"`
 }
 
 // Network contains IPv4 and IPv6 addresses.

handler/handler.go

@@ -347,32 +347,56 @@ func (s *Server) List(rw http.ResponseWriter, req *http.Request) {
 		return
 	}
 
+	format := req.URL.Query().Get("format")
+
 	// Create a prometheus StaticConfig for each known host.
 	for i := range hosts {
 		h, err := host.Parse(hosts[i])
 		if err != nil {
 			continue
 		}
+		if format == "script-exporter" {
+			// NOTE: do not assign any ports for script exporter.
+			ports[i] = []string{""}
+		} else {
+			// Convert port strings to ":<port>".
+			p := []string{}
+			for j := range ports[i] {
+				p = append(p, ":"+ports[i][j])
+			}
+			ports[i] = p
+		}
 		for _, port := range ports[i] {
+			labels := map[string]string{
+				"machine":    hosts[i],
+				"type":       "virtual",
+				"deployment": "byos",
+				"managed":    "none",
+				"org":        h.Org,
+			}
+			if req.URL.Query().Get("service") != "" {
+				labels["service"] = req.URL.Query().Get("service")
+			}
 			// We create one record per host to add a unique "machine" label to each one.
 			configs = append(configs, discovery.StaticConfig{
-				Targets: []string{hosts[i] + ":" + port},
-				Labels: map[string]string{
-					"machine":    hosts[i],
-					"type":       "virtual",
-					"deployment": "byos",
-					"managed":    "none",
-					"org":        h.Org,
-				},
+				Targets: []string{hosts[i] + port},
+				Labels:  labels,
 			})
 		}
 	}
 
 	var results interface{}
-	format := req.URL.Query().Get("format")
-	if format == "prometheus" {
+	switch format {
+	case "script-exporter":
+		fallthrough
+	case "blackbox":
+		fallthrough
+	case "prometheus": // TODO(soltesz): retire this name.
 		results = configs
-	} else {
+	case "servers":
+		resp.Servers = hosts
+		results = resp
+	default:
 		// NOTE: default format is not valid for prometheus StaticConfig format.
 		resp.StaticConfig = configs
 		results = resp

handler/handler_test.go

@@ -576,11 +576,31 @@ func TestServer_List(t *testing.T) {
 			params: "?format=prometheus",
 			lister: &fakeStatusTracker{
 				nodes: []string{"test1"},
-				ports: [][]string{[]string{}},
+				ports: [][]string{{}},
 			},
 			wantCode:   http.StatusOK,
 			wantLength: 0,
 		},
+		{
+			name:   "success-servers",
+			params: "?format=servers",
+			lister: &fakeStatusTracker{
+				nodes: []string{"ndt-lga3356-040e9f4b.mlab.autojoin.measurement-lab.org"},
+				ports: [][]string{{"9990"}},
+			},
+			wantCode:   http.StatusOK,
+			wantLength: 1,
+		},
+		{
+			name:   "success-script-exporter",
+			params: "?format=script-exporter&service=ndt7_client_byos",
+			lister: &fakeStatusTracker{
+				nodes: []string{"ndt-lga3356-040e9f4b.mlab.autojoin.measurement-lab.org"},
+				ports: [][]string{{"9990"}},
+			},
+			wantCode:   http.StatusOK,
+			wantLength: 1,
+		},
 		{
 			name:   "error-internal",
 			params: "",
@@ -606,17 +626,24 @@ func TestServer_List(t *testing.T) {
 			var err error
 			raw := rw.Body.Bytes()
 			configs := []discovery.StaticConfig{}
-			if strings.Contains(tt.params, "prometheus") {
+			length := 0
+			if strings.Contains(tt.params, "prometheus") || strings.Contains(tt.params, "script-exporter") {
 				err = json.Unmarshal(raw, &configs)
+				length = len(configs)
+			} else if strings.Contains(tt.params, "servers") {
+				resp := v0.ListResponse{}
+				err = json.Unmarshal(raw, &resp)
+				length = len(resp.Servers)
 			} else {
 				resp := v0.ListResponse{}
 				err = json.Unmarshal(raw, &resp)
 				configs = resp.StaticConfig
+				length = len(configs)
 			}
 			testingx.Must(t, err, "failed to unmarshal response")
 
-			if len(configs) != tt.wantLength {
-				t.Errorf("List() returned wrong length; got %d, want %d", len(configs), tt.wantLength)
+			if length != tt.wantLength {
+				t.Errorf("List() returned wrong length; got %d, want %d", length, tt.wantLength)
 			}
 		})
 	}