Feature/add sqs scaler (#191)

* Initial sqs scaler

* Update aws_sqs_queue_scaler.go

* Add AWS SQS scaler.

* Add example AwsSqsQueue Scaled Object.

* Update Aws Sqs Scaler test.

* Add vedored libraries


Former-commit-id: 33ff409

Gopkg.toml

@@ -86,3 +86,7 @@
   version = "0.2.0"
 
 
+
+[[constraint]]
+  name = "github.com/aws/aws-sdk-go"
+  version = "1.19.27"

examples/awssqsqueue_scaledobject.yaml

@@ -0,0 +1,40 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: nginx-deployment
+  labels:
+    app: nginx
+spec:
+  replicas: 0
+  selector:
+    matchLabels:
+      app: nginx
+  template:
+    metadata:
+      labels:
+        app: nginx
+    spec:
+      containers:
+      - name: nginx
+        image: nginx:1.7.9
+        ports:
+        - containerPort: 80
+---
+apiVersion: keda.k8s.io/v1alpha1
+kind: ScaledObject
+metadata:
+  name: aws-sqs-queue-scaledobject
+  namespace: default
+  labels:
+    deploymentName: nginx-deployment
+    test: nginx-deployment
+spec:
+  scaleTargetRef:
+    deploymentName: nginx-deployment
+  triggers:
+  - type: aws-sqs-queue
+    metadata:
+      # Required: queueURL
+      queueURL: https://sqs.eu-west-1.amazonaws.com/<acccount_id>/testQueue
+      # Optional
+      queueLength: "5" # default 5

pkg/handler/scale_handler.go

@@ -497,6 +497,8 @@ func (h *ScaleHandler) getScaler(trigger keda_v1alpha1.ScaleTriggers, resolvedEn
 		return scalers.NewAzureQueueScaler(resolvedEnv, trigger.Metadata)
 	case "azure-servicebus":
 		return scalers.NewAzureServiceBusScaler(resolvedEnv, trigger.Metadata)
+	case "aws-sqs-queue":
+		return scalers.NewAwsSqsQueueScaler(resolvedEnv, trigger.Metadata)
 	case "kafka":
 		return scalers.NewKafkaScaler(resolvedEnv, trigger.Metadata)
 	case "rabbitmq":

pkg/scalers/aws_sqs_queue.go

@@ -0,0 +1,37 @@
+package scalers
+
+import (
+	"context"
+	"errors"
+	"strconv"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/session"
+	"github.com/aws/aws-sdk-go/service/sqs"
+)
+
+func GetAwsSqsQueueLength(ctx context.Context, queueURL string) (int32, error) {
+	sess, err := session.NewSession(aws.NewConfig().WithRegion("eu-west-1"))
+	sqsClient := sqs.New(sess)
+
+	if len(queueURL) == 0 {
+		return -1, errors.New("empty queueURL is not valid")
+	}
+
+	input := &sqs.GetQueueAttributesInput{
+		AttributeNames: aws.StringSlice([]string{"All"}),
+		QueueUrl:       aws.String(queueURL),
+	}
+
+	output, err := sqsClient.GetQueueAttributes(input)
+	if err != nil {
+		return -1, nil
+	}
+
+	approximateNumberOfMessages, err := strconv.Atoi(*output.Attributes["ApproximateNumberOfMessages"])
+	if err != nil {
+		return -1, nil
+	}
+
+	return int32(approximateNumberOfMessages), nil
+}

pkg/scalers/aws_sqs_queue_scaler.go

@@ -0,0 +1,107 @@
+package scalers
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strconv"
+
+	log "github.com/Sirupsen/logrus"
+	v2beta1 "k8s.io/api/autoscaling/v2beta1"
+	"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"
+)
+
+const (
+	awsSqsQueueMetricName = "ApproximateNumberOfMessages"
+)
+
+type awsSqsQueueScaler struct {
+	metadata *awsSqsQueueMetadata
+}
+
+type awsSqsQueueMetadata struct {
+	targetQueueLength int
+	queueURL          string
+}
+
+// NewawsSqsQueueScaler creates a new awsSqsQueueScaler
+func NewAwsSqsQueueScaler(resolvedEnv, metadata map[string]string) (Scaler, error) {
+	meta, err := parseAwsSqsQueueMetadata(metadata, resolvedEnv)
+	if err != nil {
+		return nil, fmt.Errorf("Error parsing SQS queue metadata: %s", err)
+	}
+
+	return &awsSqsQueueScaler{
+		metadata: meta,
+	}, nil
+}
+
+func parseAwsSqsQueueMetadata(metadata, resolvedEnv map[string]string) (*awsSqsQueueMetadata, error) {
+	meta := awsSqsQueueMetadata{}
+	meta.targetQueueLength = defaultTargetQueueLength
+
+	if val, ok := metadata["queueLength"]; ok {
+		queueLength, err := strconv.Atoi(val)
+		if err != nil {
+			log.Errorf("Error parsing SQS queue metadata %s: %s", "queueLength", err)
+		} else {
+			meta.targetQueueLength = queueLength
+		}
+	}
+
+	if val, ok := metadata["queueURL"]; ok {
+		queueURL := val
+
+		if len(val) <= 0 {
+			log.Errorf("Error parsing SQS queue metadata %s: %s", "queueURL", errors.New("Empty queueURL is not valid"))
+		} else {
+			meta.queueURL = queueURL
+		}
+	}
+
+	return &meta, nil
+}
+
+// GetScaleDecision is a func
+func (s *awsSqsQueueScaler) IsActive(ctx context.Context) (bool, error) {
+	length, err := GetAwsSqsQueueLength(ctx, s.metadata.queueURL)
+
+	if err != nil {
+		log.Errorf("Error %s", err)
+		return false, err
+	}
+
+	return length > 0, nil
+}
+
+func (s *awsSqsQueueScaler) Close() error {
+	return nil
+}
+
+func (s *awsSqsQueueScaler) GetMetricSpecForScaling() []v2beta1.MetricSpec {
+	targetQueueLengthQty := resource.NewQuantity(int64(s.metadata.targetQueueLength), resource.DecimalSI)
+	externalMetric := &v2beta1.ExternalMetricSource{MetricName: awsSqsQueueMetricName, TargetAverageValue: targetQueueLengthQty}
+	metricSpec := v2beta1.MetricSpec{External: externalMetric, Type: externalMetricType}
+	return []v2beta1.MetricSpec{metricSpec}
+}
+
+//GetMetrics returns value for a supported metric and an error if there is a problem getting the metric
+func (s *awsSqsQueueScaler) GetMetrics(ctx context.Context, metricName string, metricSelector labels.Selector) ([]external_metrics.ExternalMetricValue, error) {
+	queuelen, err := GetAwsSqsQueueLength(ctx, s.metadata.queueURL)
+
+	if err != nil {
+		log.Errorf("Error getting queue length %s", err)
+		return []external_metrics.ExternalMetricValue{}, err
+	}
+
+	metric := external_metrics.ExternalMetricValue{
+		MetricName: metricName,
+		Value:      *resource.NewQuantity(int64(queuelen), resource.DecimalSI),
+		Timestamp:  metav1.Now(),
+	}
+
+	return append([]external_metrics.ExternalMetricValue{}, metric), nil
+}

pkg/scalers/aws_sqs_queue_test.go

@@ -0,0 +1,26 @@
+package scalers
+
+import (
+	"context"
+	"os"
+	"testing"
+)
+
+func TestGetQueueLengthReal(t *testing.T) {
+	queueURL := os.Getenv("AWS_SQS_QUEUE_URL")
+
+	t.Log("This test will use the environment variable AWS_SQS_QUEUE_URL if it is set")
+	t.Log("Ensure that AWS credentials are configured to be able to access the queue")
+	t.Log("If set, it will connect to the specified SQS Queue & check:")
+	t.Logf("\tQueue '%s' has 0 message\n", queueURL)
+
+	length, err := GetAwsSqsQueueLength(context.TODO(), queueURL)
+	if err != nil {
+		t.Error(err)
+	}
+	t.Log("QueueLength = ", length)
+
+	if length != 0 {
+		t.Error("Expected length to be 0, but got", length)
+	}
+}