Add Selenium Grid scaler

pkg/scalers/selenium_grid_scaler.go

@@ -0,0 +1,201 @@
+package scalers
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+
+	kedautil "github.com/kedacore/keda/v2/pkg/util"
+	v2beta2 "k8s.io/api/autoscaling/v2beta2"
+	"k8s.io/apimachinery/pkg/api/resource"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/labels"
+	"k8s.io/metrics/pkg/apis/external_metrics"
+)
+
+type seleniumGridScaler struct {
+	metadata *seleniumGridScalerMetadata
+	client   *http.Client
+}
+
+type seleniumGridScalerMetadata struct {
+	url         string
+	browserName string
+	targetValue int64
+}
+
+type seleniumResponse struct {
+	Data data `json:"data"`
+}
+
+type data struct {
+	SessionsInfo sessionsInfo `json:"sessionsInfo"`
+}
+
+type sessionsInfo struct {
+	SessionQueueRequests []string          `json:"sessionQueueRequests"`
+	Sessions             []seleniumSession `json:"sessions"`
+}
+
+type seleniumSession struct {
+	Id           string `json:"id"`
+	Capabilities string `json:"capabilities"`
+	NodeId       string `json:"nodeId"`
+}
+
+type capability struct {
+	BrowserName string `json:"browserName"`
+}
+
+func NewSeleniumGridScaler(config *ScalerConfig) (Scaler, error) {
+	meta, err := parseSeleniumGridScalerMetadata(config)
+
+	if err != nil {
+		return nil, fmt.Errorf("error parsing selenium grid metadata: %s", err)
+	}
+
+	httpClient := kedautil.CreateHTTPClient(config.GlobalHTTPTimeout)
+
+	return &seleniumGridScaler{
+		metadata: meta,
+		client:   httpClient,
+	}, nil
+}
+
+func parseSeleniumGridScalerMetadata(config *ScalerConfig) (*seleniumGridScalerMetadata, error) {
+	meta := seleniumGridScalerMetadata{
+		targetValue: 1,
+	}
+
+	if val, ok := config.TriggerMetadata["url"]; ok {
+		meta.url = val
+	} else {
+		return nil, fmt.Errorf("no selenium grid url given in metadata")
+	}
+
+	if val, ok := config.TriggerMetadata["browserName"]; ok {
+		meta.browserName = val
+	} else {
+		return nil, fmt.Errorf("no browser name given in metadata")
+	}
+
+	return &meta, nil
+}
+
+// No cleanup required for selenium grid scaler
+func (s *seleniumGridScaler) Close() error {
+	return nil
+}
+
+func (s *seleniumGridScaler) GetMetrics(ctx context.Context, metricName string, metricSelector labels.Selector) ([]external_metrics.ExternalMetricValue, error) {
+	v, err := s.getSessionsCount()
+	if err != nil {
+		return []external_metrics.ExternalMetricValue{}, fmt.Errorf("error requesting selenium grid endpoint: %s", err)
+	}
+
+	metric := external_metrics.ExternalMetricValue{
+		MetricName: metricName,
+		Value:      *v,
+		Timestamp:  metav1.Now(),
+	}
+
+	return append([]external_metrics.ExternalMetricValue{}, metric), nil
+}
+
+func (s *seleniumGridScaler) GetMetricSpecForScaling() []v2beta2.MetricSpec {
+	targetValue := resource.NewQuantity(s.metadata.targetValue, resource.DecimalSI)
+	metricName := kedautil.NormalizeString(fmt.Sprintf("%s-%s", "seleniumgrid", s.metadata.browserName))
+	externalMetric := &v2beta2.ExternalMetricSource{
+		Metric: v2beta2.MetricIdentifier{
+			Name: metricName,
+		},
+		Target: v2beta2.MetricTarget{
+			Type:         v2beta2.AverageValueMetricType,
+			AverageValue: targetValue,
+		},
+	}
+	metricSpec := v2beta2.MetricSpec{
+		External: externalMetric, Type: externalMetricType,
+	}
+	return []v2beta2.MetricSpec{metricSpec}
+}
+
+func (s *seleniumGridScaler) IsActive(ctx context.Context) (bool, error) {
+	v, err := s.getSessionsCount()
+	if err != nil {
+		return false, err
+	}
+
+	return v.AsApproximateFloat64() > 0.0, nil
+}
+
+func (s *seleniumGridScaler) getSessionsCount() (*resource.Quantity, error) {
+	body, err := json.Marshal(map[string]string{
+		"query": "{ sessionsInfo { sessionQueueRequests, sessions { id, capabilities, nodeId } } }",
+	})
+
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequest("POST", s.metadata.url, bytes.NewBuffer(body))
+	if err != nil {
+		return nil, err
+	}
+
+	res, err := s.client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+
+	if res.StatusCode != http.StatusOK {
+		msg := fmt.Sprintf("selenium grid returned %d", res.StatusCode)
+		return nil, errors.New(msg)
+	}
+
+	defer res.Body.Close()
+	b, err := ioutil.ReadAll(res.Body)
+	if err != nil {
+		return nil, err
+	}
+	v, err := getCountFromSeleniumResponse(b, s.metadata.browserName)
+	if err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+func getCountFromSeleniumResponse(b []byte, browserName string) (*resource.Quantity, error) {
+	var count int64 = 0
+	var seleniumResponse seleniumResponse = seleniumResponse{}
+
+	if err := json.Unmarshal(b, &seleniumResponse); err != nil {
+		return nil, err
+	}
+
+	var sessionQueueRequests = seleniumResponse.Data.SessionsInfo.SessionQueueRequests
+	for _, sessionQueueRequest := range sessionQueueRequests {
+		var capability = capability{}
+		if err := json.Unmarshal([]byte(sessionQueueRequest), &capability); err == nil {
+			if capability.BrowserName == browserName {
+				count = count + 1
+			}
+		}
+	}
+
+	var sessions = seleniumResponse.Data.SessionsInfo.Sessions
+	for _, session := range sessions {
+		var capability = capability{}
+		if err := json.Unmarshal([]byte(session.Capabilities), &capability); err == nil {
+			if capability.BrowserName == browserName {
+				count = count + 1
+			}
+		}
+	}
+
+	return resource.NewQuantity(count, resource.DecimalSI), nil
+}

pkg/scalers/selenium_grid_scaler_test.go

@@ -0,0 +1,190 @@
+package scalers
+
+import (
+	"reflect"
+	"testing"
+
+	"k8s.io/apimachinery/pkg/api/resource"
+)
+
+func Test_getCountFromSeleniumResponse(t *testing.T) {
+	type args struct {
+		b           []byte
+		browserName string
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    *resource.Quantity
+		wantErr bool
+	}{
+		{
+			name: "nil response body should through error",
+			args: args{
+				b:           []byte(nil),
+				browserName: "",
+			},
+			// want:    resource.NewQuantity(0, resource.DecimalSI),
+			wantErr: true,
+		},
+		{
+			name: "empty response body should through error",
+			args: args{
+				b:           []byte(""),
+				browserName: "",
+			},
+			// want:    resource.NewQuantity(0, resource.DecimalSI),
+			wantErr: true,
+		},
+		{
+			name: "no active sessions should return count as 0",
+			args: args{
+				b: []byte(`{
+					"data": {
+						"sessionsInfo": {
+							"sessionQueueRequests": [],
+							"sessions": []
+						}
+					}
+				}`),
+				browserName: "",
+			},
+			want:    resource.NewQuantity(0, resource.DecimalSI),
+			wantErr: false,
+		},
+		{
+			name: "active sessions with no matching browsername should return count as 0",
+			args: args{
+				b: []byte(`{
+					"data": {
+						"sessionsInfo": {
+							"sessionQueueRequests": ["{\n  \"browserName\": \"chrome\"\n}","{\n  \"browserName\": \"chrome\"\n}"],
+							"sessions": [
+								{
+									"id": "0f9c5a941aa4d755a54b84be1f6535b1",
+									"capabilities": "{\n  \"acceptInsecureCerts\": false,\n  \"browserName\": \"chrome\",\n  \"browserVersion\": \"91.0.4472.114\",\n  \"chrome\": {\n    \"chromedriverVersion\": \"91.0.4472.101 (af52a90bf87030dd1523486a1cd3ae25c5d76c9b-refs\\u002fbranch-heads\\u002f4472@{#1462})\",\n    \"userDataDir\": \"\\u002ftmp\\u002f.com.google.Chrome.DMqx9m\"\n  },\n  \"goog:chromeOptions\": {\n    \"debuggerAddress\": \"localhost:35839\"\n  },\n  \"networkConnectionEnabled\": false,\n  \"pageLoadStrategy\": \"normal\",\n  \"platformName\": \"linux\",\n  \"proxy\": {\n  },\n  \"se:cdp\": \"http:\\u002f\\u002flocalhost:35839\",\n  \"se:cdpVersion\": \"91.0.4472.114\",\n  \"se:vncEnabled\": true,\n  \"se:vncLocalAddress\": \"ws:\\u002f\\u002flocalhost:7900\\u002fwebsockify\",\n  \"setWindowRect\": true,\n  \"strictFileInteractability\": false,\n  \"timeouts\": {\n    \"implicit\": 0,\n    \"pageLoad\": 300000,\n    \"script\": 30000\n  },\n  \"unhandledPromptBehavior\": \"dismiss and notify\",\n  \"webauthn:extension:largeBlob\": true,\n  \"webauthn:virtualAuthenticators\": true\n}",
+									"nodeId": "d44dcbc5-0b2c-4d5e-abf4-6f6aa5e0983c"
+								}
+							]
+						}
+					}
+				}`),
+				browserName: "",
+			},
+			want:    resource.NewQuantity(0, resource.DecimalSI),
+			wantErr: false,
+		},
+		{
+			name: "active sessions with matching browsername should return count as 2",
+			args: args{
+				b: []byte(`{
+					"data": {
+						"sessionsInfo": {
+							"sessionQueueRequests": ["{\n  \"browserName\": \"chrome\"\n}","{\n  \"browserName\": \"chrome\"\n}"],
+							"sessions": []
+						}
+					}
+				}`),
+				browserName: "chrome",
+			},
+			want:    resource.NewQuantity(2, resource.DecimalSI),
+			wantErr: false,
+		},
+		{
+			name: "active sessions with matching browsername should return count as 3",
+			args: args{
+				b: []byte(`{
+					"data": {
+						"sessionsInfo": {
+							"sessionQueueRequests": ["{\n  \"browserName\": \"chrome\"\n}","{\n  \"browserName\": \"chrome\"\n}"],
+							"sessions": [
+								{
+									"id": "0f9c5a941aa4d755a54b84be1f6535b1",
+									"capabilities": "{\n  \"acceptInsecureCerts\": false,\n  \"browserName\": \"chrome\",\n  \"browserVersion\": \"91.0.4472.114\",\n  \"chrome\": {\n    \"chromedriverVersion\": \"91.0.4472.101 (af52a90bf87030dd1523486a1cd3ae25c5d76c9b-refs\\u002fbranch-heads\\u002f4472@{#1462})\",\n    \"userDataDir\": \"\\u002ftmp\\u002f.com.google.Chrome.DMqx9m\"\n  },\n  \"goog:chromeOptions\": {\n    \"debuggerAddress\": \"localhost:35839\"\n  },\n  \"networkConnectionEnabled\": false,\n  \"pageLoadStrategy\": \"normal\",\n  \"platformName\": \"linux\",\n  \"proxy\": {\n  },\n  \"se:cdp\": \"http:\\u002f\\u002flocalhost:35839\",\n  \"se:cdpVersion\": \"91.0.4472.114\",\n  \"se:vncEnabled\": true,\n  \"se:vncLocalAddress\": \"ws:\\u002f\\u002flocalhost:7900\\u002fwebsockify\",\n  \"setWindowRect\": true,\n  \"strictFileInteractability\": false,\n  \"timeouts\": {\n    \"implicit\": 0,\n    \"pageLoad\": 300000,\n    \"script\": 30000\n  },\n  \"unhandledPromptBehavior\": \"dismiss and notify\",\n  \"webauthn:extension:largeBlob\": true,\n  \"webauthn:virtualAuthenticators\": true\n}",
+									"nodeId": "d44dcbc5-0b2c-4d5e-abf4-6f6aa5e0983c"
+								}
+							]
+						}
+					}
+				}`),
+				browserName: "chrome",
+			},
+			want:    resource.NewQuantity(3, resource.DecimalSI),
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := getCountFromSeleniumResponse(tt.args.b, tt.args.browserName)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("getCountFromSeleniumResponse() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("getCountFromSeleniumResponse() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func Test_parseSeleniumGridScalerMetadata(t *testing.T) {
+	type args struct {
+		config *ScalerConfig
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    *seleniumGridScalerMetadata
+		wantErr bool
+	}{
+		{
+			name: "invalid url string should throw error",
+			args: args{
+				config: &ScalerConfig{
+					TriggerMetadata: map[string]string{},
+				},
+			},
+			wantErr: true,
+		},
+		{
+			name: "invalid browsername string should throw error",
+			args: args{
+				config: &ScalerConfig{
+					TriggerMetadata: map[string]string{
+						"url": "",
+					},
+				},
+			},
+			wantErr: true,
+		},
+		{
+			name: "valid url and browsername should return metadata",
+			args: args{
+				config: &ScalerConfig{
+					TriggerMetadata: map[string]string{
+						"url":         "http://selenium-hub:4444/graphql",
+						"browserName": "chrome",
+					},
+				},
+			},
+			wantErr: false,
+			want: &seleniumGridScalerMetadata{
+				url:         "http://selenium-hub:4444/graphql",
+				browserName: "chrome",
+				targetValue: 1,
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := parseSeleniumGridScalerMetadata(tt.args.config)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("parseSeleniumGridScalerMetadata() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("parseSeleniumGridScalerMetadata() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}