Add checks to see if stream endpoints exist before calling them (#174)

* Add checks to see if stream endpoints exist before calling them

* Add unit tests

* Renamed functions

---------

Co-authored-by: Donal Hurley <d.hurley@f5.com>

Author: dhurley

client/nginx.go

@@ -11,6 +11,8 @@ import (
 	"reflect"
 	"strings"
 	"time"
+
+	"golang.org/x/exp/slices"
 )
 
 const (
@@ -1149,6 +1151,11 @@ func determineStreamUpdates(updatedServers []StreamUpstreamServer, nginxServers
 
 // GetStats gets process, slab, connection, request, ssl, zone, stream zone, upstream and stream upstream related stats from the NGINX Plus API.
 func (client *NginxClient) GetStats() (*Stats, error) {
+	endpoints, err := client.GetAvailableEndpoints()
+	if err != nil {
+		return nil, fmt.Errorf("failed to get stats: %w", err)
+	}
+
 	info, err := client.GetNginxInfo()
 	if err != nil {
 		return nil, fmt.Errorf("failed to get stats: %w", err)
@@ -1194,21 +1201,6 @@ func (client *NginxClient) GetStats() (*Stats, error) {
 		return nil, fmt.Errorf("failed to get stats: %w", err)
 	}
 
-	streamZones, err := client.GetStreamServerZones()
-	if err != nil {
-		return nil, fmt.Errorf("failed to get stats: %w", err)
-	}
-
-	streamUpstreams, err := client.GetStreamUpstreams()
-	if err != nil {
-		return nil, fmt.Errorf("failed to get stats: %w", err)
-	}
-
-	streamZoneSync, err := client.GetStreamZoneSync()
-	if err != nil {
-		return nil, fmt.Errorf("failed to get stats: %w", err)
-	}
-
 	locationZones, err := client.GetLocationZones()
 	if err != nil {
 		return nil, fmt.Errorf("failed to get stats: %w", err)
@@ -1229,14 +1221,49 @@ func (client *NginxClient) GetStats() (*Stats, error) {
 		return nil, fmt.Errorf("failed to get stats: %w", err)
 	}
 
-	limitConnsStream, err := client.GetStreamConnectionsLimit()
+	workers, err := client.GetWorkers()
 	if err != nil {
 		return nil, fmt.Errorf("failed to get stats: %w", err)
 	}
 
-	workers, err := client.GetWorkers()
-	if err != nil {
-		return nil, fmt.Errorf("failed to get stats: %w", err)
+	streamZones := &StreamServerZones{}
+	streamUpstreams := &StreamUpstreams{}
+	limitConnsStream := &StreamLimitConnections{}
+	streamZoneSync := &StreamZoneSync{}
+
+	if slices.Contains(endpoints, "stream") {
+		streamEndpoints, err := client.GetAvailableStreamEndpoints()
+		if err != nil {
+			return nil, fmt.Errorf("failed to get stats: %w", err)
+		}
+
+		if slices.Contains(streamEndpoints, "server_zones") {
+			streamZones, err = client.GetStreamServerZones()
+			if err != nil {
+				return nil, fmt.Errorf("failed to get stats: %w", err)
+			}
+		}
+
+		if slices.Contains(streamEndpoints, "upstreams") {
+			streamUpstreams, err = client.GetStreamUpstreams()
+			if err != nil {
+				return nil, fmt.Errorf("failed to get stats: %w", err)
+			}
+		}
+
+		if slices.Contains(streamEndpoints, "limit_conns") {
+			limitConnsStream, err = client.GetStreamConnectionsLimit()
+			if err != nil {
+				return nil, fmt.Errorf("failed to get stats: %w", err)
+			}
+		}
+
+		if slices.Contains(streamEndpoints, "zone_sync") {
+			streamZoneSync, err = client.GetStreamZoneSync()
+			if err != nil {
+				return nil, fmt.Errorf("failed to get stats: %w", err)
+			}
+		}
 	}
 
 	return &Stats{
@@ -1261,6 +1288,26 @@ func (client *NginxClient) GetStats() (*Stats, error) {
 	}, nil
 }
 
+// GetAvailableEndpoints returns available endpoints in the API.
+func (client *NginxClient) GetAvailableEndpoints() ([]string, error) {
+	var endpoints []string
+	err := client.get("", &endpoints)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get endpoints: %w", err)
+	}
+	return endpoints, nil
+}
+
+// GetAvailableStreamEndpoints returns available stream endpoints in the API.
+func (client *NginxClient) GetAvailableStreamEndpoints() ([]string, error) {
+	var endpoints []string
+	err := client.get("stream", &endpoints)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get endpoints: %w", err)
+	}
+	return endpoints, nil
+}
+
 // GetNginxInfo returns Nginx stats.
 func (client *NginxClient) GetNginxInfo() (*NginxInfo, error) {
 	var info NginxInfo

client/nginx_test.go

@@ -4,6 +4,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"reflect"
+	"strings"
 	"testing"
 )
 
@@ -589,3 +590,54 @@ func TestClientWithHTTPClient(t *testing.T) {
 		t.Fatalf("expected client to be nil, but got %v", client)
 	}
 }
+
+func TestGetStats_NoStreamEndpoint(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.RequestURI == "/" {
+			_, err := w.Write([]byte(`[4, 5, 6, 7]`))
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+		} else if r.RequestURI == "/7/" {
+			_, err := w.Write([]byte(`["nginx","processes","connections","slabs","http","resolvers","ssl"]`))
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+		} else if strings.HasPrefix(r.RequestURI, "/7/stream") {
+			t.Fatal("Stream endpoint should not be called since it does not exist.")
+		} else {
+			_, err := w.Write([]byte(`{}`))
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+		}
+	}))
+	defer ts.Close()
+
+	// Test creating a new client with a supported API version on the server
+	client, err := NewNginxClient(ts.URL, WithAPIVersion(7), WithCheckAPI())
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if client == nil {
+		t.Fatalf("client is nil")
+	}
+
+	stats, err := client.GetStats()
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if !reflect.DeepEqual(stats.StreamServerZones, StreamServerZones{}) {
+		t.Fatalf("StreamServerZones: expected %v, actual %v", StreamServerZones{}, stats.StreamServerZones)
+	}
+	if !reflect.DeepEqual(stats.StreamLimitConnections, StreamLimitConnections{}) {
+		t.Fatalf("StreamLimitConnections: expected %v, actual %v", StreamLimitConnections{}, stats.StreamLimitConnections)
+	}
+	if !reflect.DeepEqual(stats.StreamUpstreams, StreamUpstreams{}) {
+		t.Fatalf("StreamUpstreams: expected %v, actual %v", StreamUpstreams{}, stats.StreamUpstreams)
+	}
+	if !reflect.DeepEqual(stats.StreamZoneSync, &StreamZoneSync{}) {
+		t.Fatalf("StreamZoneSync: expected %v, actual %v", &StreamZoneSync{}, stats.StreamZoneSync)
+	}
+}

go.mod

@@ -1,3 +1,5 @@
 module github.com/nginxinc/nginx-plus-go-client
 
 go 1.19
+
+require golang.org/x/exp v0.0.0-20230905200255-921286631fa9

go.sum

@@ -0,0 +1,2 @@
+golang.org/x/exp v0.0.0-20230905200255-921286631fa9 h1:GoHiUyI/Tp2nVkLI2mCxVkOjsbSXD66ic0XW0js0R9g=
+golang.org/x/exp v0.0.0-20230905200255-921286631fa9/go.mod h1:S2oDrQGGwySpoQPVqRShND87VCbxmc6bL1Yd2oYrm6k=