Search by labels and prefixes

Implemented in API and ctl.

README.md

@@ -179,13 +179,13 @@ It uses Go client library also located in this repository.
 So far the REST API is super simple and it has only two endpoints:
 
 ```
-GET /                                # Same as /v1/discoveries
+GET /                                                  # Same as /v1/discoveries
-GET /v1/discovery                    # Returns current local discovery packet
+GET /v1/discovery                                      # Returns current local discovery packet
-GET /v1/discoveries                  # Returns list of all discovered servers and their labels.
+GET /v1/discoveries                                    # Returns list of all discovered servers and their labels.
-GET /v1/discoveries?labels=LABELS    # output will be filtered based on one or multiple labels separated by comma
+GET /v1/discoveries?labels=LABELS&prefixes=PREFIXES    # output will be filtered based on one or multiple labels separated by comma or it can search for given prefixes, only one of those will be used
-GET /v1/prometheus/:name             # Generates output for Prometheus's SD config, name is group of the monitoring services described above.
+GET /v1/prometheus/:name                               # Generates output for Prometheus's SD config, name is group of the monitoring services described above.
-POST /v1/labels                      # Add runtime labels that will persist over daemon restarts. Labels should be in the body of the request, one line per one label.
+POST /v1/labels                                        # Add runtime labels that will persist over daemon restarts. Labels should be in the body of the request, one line per one label.
-DELETE /v1/labels                    # Delete runtime labels. One label per line. Can't affect the labels from environment variables or labels added from the LabelPath.
+DELETE /v1/labels                                      # Delete runtime labels. One label per line. Can't affect the labels from environment variables or labels added from the LabelPath.
 ```
 
 If there is an error the error message is returned as plain text.

client/main.go

@@ -115,13 +115,38 @@ func (l *LobbyClient) GetDiscoveries() ([]server.Discovery, error) {
 }
 
 // Find discoveries by their labels
-func (l *LobbyClient) FindByLabels(labels server.Labels) (server.Discoveries, error) {
+func (l *LobbyClient) FindByLabels(labels server.Labels) ([]server.Discovery, error) {
 	l.init()
 
 	path := fmt.Sprintf("/v1/discoveries?labels=%s", strings.Join(labels.StringSlice(), ","))
 	method := "GET"
 
-	var discoveries server.Discoveries
+	var discoveries []server.Discovery
+
+	status, body, err := l.call(method, path, "")
+	if err != nil {
+		return discoveries, err
+	}
+	if status != 200 {
+		return discoveries, fmt.Errorf("non-200 response: %s", body)
+	}
+
+	err = json.Unmarshal([]byte(body), &discoveries)
+	if err != nil {
+		return discoveries, fmt.Errorf("response parsing error: %v", err)
+	}
+
+	return discoveries, nil
+}
+
+// Find discoveries by label prefixes
+func (l *LobbyClient) FindByPrefixes(prefixes []string) ([]server.Discovery, error) {
+	l.init()
+
+	path := fmt.Sprintf("/v1/discoveries?prefixes=%s", strings.Join(prefixes, ","))
+	method := "GET"
+
+	var discoveries []server.Discovery
 
 	status, body, err := l.call(method, path, "")
 	if err != nil {

ctl/main.go

@@ -14,10 +14,12 @@ func Usage() {
 	flag.Usage()
 	fmt.Println("")
 	fmt.Println("Commands:")
-	fmt.Println("  discovery                      returns discovery packet of the server where the client is connected to")
+	fmt.Println("  discovery                        returns discovery packet of the server where the client is connected to")
-	fmt.Println("  discoveries                    returns list of all registered discovery packets")
+	fmt.Println("  discoveries                      returns list of all registered discovery packets")
-	fmt.Println("  labels add LABEL [LABEL] ...   adds new runtime labels")
+	fmt.Println("  discoveries labels [LABEL] ...   returns list of all registered discovery packets with given labels (OR)")
-	fmt.Println("  labels del LABEL [LABEL] ...   deletes runtime labels")
+	fmt.Println("  discoveries search [LABEL] ...   returns list of all registered discovery packets with given label prefixes (OR)")
+	fmt.Println("  labels add LABEL [LABEL] ...     adds new runtime labels")
+	fmt.Println("  labels del LABEL [LABEL] ...     deletes runtime labels")
 }
 
 func main() {
@@ -66,10 +68,41 @@ func main() {
 
 	switch flag.Args()[0] {
 	case "discoveries":
-		discoveries, err := client.GetDiscoveries()
+		var discoveries []server.Discovery
-		if err != nil {
+		var err error
-			fmt.Println(err)
+
+		if len(flag.Args()) > 2 {
+			if flag.Arg(1) == "labels" {
+				labels := []server.Label{}
+				for _, label := range flag.Args()[2:] {
+					labels = append(labels, server.Label(label))
+				}
+
+				discoveries, err = client.FindByLabels(labels)
+				if err != nil {
+					fmt.Println(err)
+					os.Exit(1)
+				}
+			} else if flag.Arg(1) == "search" {
+				discoveries, err = client.FindByPrefixes(flag.Args()[2:])
+				if err != nil {
+					fmt.Println(err)
+					os.Exit(1)
+				}
+			} else {
+				fmt.Println("ERROR: unknown usage of discoveries arguments")
+				fmt.Println("")
+				Usage()
+				os.Exit(0)
+			}
+		} else {
+			discoveries, err = client.GetDiscoveries()
+			if err != nil {
+				fmt.Println(err)
+				os.Exit(1)
+			}
 		}
+
 		printDiscoveries(discoveries)
 	case "discovery":
 		discovery, err := client.GetDiscovery()

daemon/handlers.go

@@ -12,12 +12,15 @@ import (
 
 func listHandler(c echo.Context) error {
 	labels := c.QueryParam("labels")
+	prefixes := c.QueryParam("prefixes")
 
 	var discoveries []server.Discovery
 
 	if len(labels) > 0 {
 		labelsFilterSlice := strings.Split(labels, ",")
 		discoveries = discoveryStorage.Filter(labelsFilterSlice)
+	} else if len(prefixes) > 0 {
+		discoveries = discoveryStorage.FilterPrefix(strings.Split(prefixes, ","))
 	} else {
 		discoveries = discoveryStorage.GetAll()
 	}

server/discovery.go

@@ -148,6 +148,7 @@ func (d *Discoveries) GetAll() []Discovery {
 	return d.activeServers
 }
 
+// Filter returns list of discoveries based on given labels
 func (d *Discoveries) Filter(labelsFilter []string) []Discovery {
 	newSet := []Discovery{}
 
@@ -174,6 +175,33 @@ func (d *Discoveries) Filter(labelsFilter []string) []Discovery {
 	return newSet
 }
 
+// Filter returns list of discoveries based on given label prefixes.
+func (d *Discoveries) FilterPrefix(prefixes []string) []Discovery {
+	newSet := []Discovery{}
+
+	var found bool
+	if len(prefixes) > 0 {
+		for _, discovery := range d.activeServers {
+			found = false
+			for _, label := range discovery.Labels {
+				for _, prefix := range prefixes {
+					if strings.HasPrefix(label.String(), prefix) {
+						newSet = append(newSet, discovery)
+						found = true
+						break
+					}
+				}
+				if found {
+					break
+				}
+			}
+		}
+
+	}
+
+	return newSet
+}
+
 // Clean checks loops over last check values for each discovery object and removes it if it's passed
 func (d *Discoveries) Clean() {
 	newSet := []Discovery{}