add scaler for temporal

pkg/scalers/temporal.go

@@ -0,0 +1,224 @@
+package scalers
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"time"
+
+	"github.com/go-logr/logr"
+	"github.com/kedacore/keda/v2/pkg/scalers/scalersconfig"
+	kedautil "github.com/kedacore/keda/v2/pkg/util"
+	sdk "go.temporal.io/sdk/client"
+	sdklog "go.temporal.io/sdk/log"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+	v2 "k8s.io/api/autoscaling/v2"
+	"k8s.io/metrics/pkg/apis/external_metrics"
+)
+
+var (
+	temporalDefauleQueueTypes = []sdk.TaskQueueType{
+		sdk.TaskQueueTypeActivity,
+		sdk.TaskQueueTypeWorkflow,
+		sdk.TaskQueueTypeNexus,
+	}
+)
+
+type temporalScaler struct {
+	metricType v2.MetricTargetType
+	metadata   *temporalMetadata
+	tcl        sdk.Client
+	logger     logr.Logger
+}
+
+type temporalMetadata struct {
+	ActivationTargetQueueSize int64    `keda:"name=activationTargetQueueSize, order=triggerMetadata, default=0"`
+	Endpoint                  string   `keda:"name=endpoint,       order=triggerMetadata;resolvedEnv"`
+	Namespace                 string   `keda:"name=namespace,      order=triggerMetadata, default=default"`
+	TargetQueueSize           int64    `keda:"name=targetQueueSize, order=triggerMetadata, default=5"`
+	QueueName                 string   `keda:"name=queueName,      order=triggerMetadata"`
+	QueueTypes                []string `keda:"name=queueTypes,      order=triggerMetadata, optional"`
+	BuildIDs                  []string `keda:"name=buildIds,      order=triggerMetadata, optional"`
+	AllActive                 bool     `keda:"name=selectAllActive,      order=triggerMetadata, default=true"`
+	Unversioned               bool     `keda:"name=selectUnversioned,    order=triggerMetadata, default=true"`
+	APIKey                    string   `keda:"name=apiKey,         order=authParams;triggerMetadata, optional"`
+
+	triggerIndex int
+}
+
+func (a *temporalMetadata) Validate() error {
+	if a.TargetQueueSize <= 0 {
+		return fmt.Errorf("targetQueueSize must be a positive number")
+	}
+	if a.ActivationTargetQueueSize < 0 {
+		return fmt.Errorf("activationTargetQueueSize must be a positive number")
+	}
+
+	return nil
+}
+
+func NewTemporalScaler(ctx context.Context, config *scalersconfig.ScalerConfig) (Scaler, error) {
+	logger := InitializeLogger(config, "temporal_scaler")
+
+	metricType, err := GetMetricTargetType(config)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get scaler metric type: %w", err)
+	}
+
+	meta, err := parseTemporalMetadata(config, logger)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse Temporal metadata: %w", err)
+	}
+
+	c, err := getTemporalClient(ctx, meta)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create Temporal client connection: %w", err)
+	}
+
+	return &temporalScaler{
+		metricType: metricType,
+		metadata:   meta,
+		tcl:        c,
+		logger:     logger,
+	}, nil
+}
+
+func (s *temporalScaler) Close(_ context.Context) error {
+	if s.tcl != nil {
+		s.tcl.Close()
+	}
+	return nil
+}
+
+func (s *temporalScaler) GetMetricSpecForScaling(context.Context) []v2.MetricSpec {
+	metricName := kedautil.NormalizeString(fmt.Sprintf("temporal-%s-%s", s.metadata.Namespace, s.metadata.QueueName))
+	externalMetric := &v2.ExternalMetricSource{
+		Metric: v2.MetricIdentifier{
+			Name: GenerateMetricNameWithIndex(s.metadata.triggerIndex, metricName),
+		},
+		Target: GetMetricTarget(s.metricType, s.metadata.TargetQueueSize),
+	}
+
+	metricSpec := v2.MetricSpec{
+		External: externalMetric,
+		Type:     externalMetricType,
+	}
+
+	return []v2.MetricSpec{metricSpec}
+}
+
+func (s *temporalScaler) GetMetricsAndActivity(ctx context.Context, metricName string) ([]external_metrics.ExternalMetricValue, bool, error) {
+	queueSize, err := s.getQueueSize(ctx)
+	if err != nil {
+		return nil, false, fmt.Errorf("failed to get Temporal queue size: %w", err)
+	}
+
+	metric := GenerateMetricInMili(metricName, float64(queueSize))
+
+	return []external_metrics.ExternalMetricValue{metric}, queueSize > s.metadata.ActivationTargetQueueSize, nil
+}
+
+func (s *temporalScaler) getQueueSize(ctx context.Context) (int64, error) {
+	var selection *sdk.TaskQueueVersionSelection
+	if s.metadata.AllActive || s.metadata.Unversioned || len(s.metadata.BuildIDs) > 0 {
+		selection = &sdk.TaskQueueVersionSelection{
+			AllActive:   s.metadata.AllActive,
+			Unversioned: s.metadata.Unversioned,
+			BuildIDs:    s.metadata.BuildIDs,
+		}
+	}
+
+	queueType := getQueueTypes(s.metadata.QueueTypes)
+
+	resp, err := s.tcl.DescribeTaskQueueEnhanced(ctx, sdk.DescribeTaskQueueEnhancedOptions{
+		TaskQueue:      s.metadata.QueueName,
+		ReportStats:    true,
+		Versions:       selection,
+		TaskQueueTypes: queueType,
+	})
+	if err != nil {
+		return 0, fmt.Errorf("failed to get Temporal queue size: %w", err)
+	}
+
+	return getCombinedBacklogCount(resp), nil
+}
+
+func getQueueTypes(queueTypes []string) []sdk.TaskQueueType {
+	var taskQueueTypes []sdk.TaskQueueType
+	for _, t := range queueTypes {
+		var taskQueueType sdk.TaskQueueType
+		switch t {
+		case "workflow":
+			taskQueueType = sdk.TaskQueueTypeWorkflow
+		case "activity":
+			taskQueueType = sdk.TaskQueueTypeActivity
+		case "nexus":
+			taskQueueType = sdk.TaskQueueTypeNexus
+		}
+		taskQueueTypes = append(taskQueueTypes, taskQueueType)
+	}
+
+	if len(taskQueueTypes) == 0 {
+		return temporalDefauleQueueTypes
+	}
+	return taskQueueTypes
+}
+
+func getCombinedBacklogCount(description sdk.TaskQueueDescription) int64 {
+	var count int64
+	for _, versionInfo := range description.VersionsInfo {
+		for _, typeInfo := range versionInfo.TypesInfo {
+			if typeInfo.Stats != nil {
+				count += typeInfo.Stats.ApproximateBacklogCount
+			}
+		}
+	}
+	return count
+}
+
+func getTemporalClient(ctx context.Context, meta *temporalMetadata) (sdk.Client, error) {
+	options := sdk.Options{
+		HostPort:  meta.Endpoint,
+		Namespace: meta.Namespace,
+		Logger:    sdklog.NewStructuredLogger(slog.Default()),
+	}
+
+	dialOptions := []grpc.DialOption{
+		grpc.WithConnectParams(grpc.ConnectParams{
+			MinConnectTimeout: 5 * time.Second,
+		}),
+	}
+
+	if meta.APIKey != "" {
+		dialOptions = append(dialOptions, grpc.WithUnaryInterceptor(
+			func(ctx context.Context, method string, req any, reply any,
+				cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
+				return invoker(
+					metadata.AppendToOutgoingContext(ctx, "temporal-namespace", meta.Namespace),
+					method,
+					req,
+					reply,
+					cc,
+					opts...,
+				)
+			},
+		))
+		options.Credentials = sdk.NewAPIKeyStaticCredentials(meta.APIKey)
+	}
+
+	options.ConnectionOptions = sdk.ConnectionOptions{
+		DialOptions: dialOptions,
+	}
+
+	return sdk.DialContext(ctx, options)
+}
+
+func parseTemporalMetadata(config *scalersconfig.ScalerConfig, _ logr.Logger) (*temporalMetadata, error) {
+	meta := &temporalMetadata{triggerIndex: config.TriggerIndex}
+	if err := config.TypedConfig(meta); err != nil {
+		return meta, fmt.Errorf("error parsing temporal metadata: %w", err)
+	}
+
+	return meta, nil
+}