Add MongoDB scaler

go.mod

@@ -36,6 +36,7 @@ require (
 	github.com/stretchr/testify v1.6.1
 	github.com/tidwall/gjson v1.6.7
 	github.com/xdg/scram v0.0.0-20180814205039-7eeb5667e42c
+	go.mongodb.org/mongo-driver v1.1.2
 	golang.org/x/crypto v0.0.0-20201016220609-9e8e0b390897 // indirect
 	google.golang.org/api v0.36.0
 	google.golang.org/genproto v0.0.0-20200904004341-0bd0a958aa1d

go.sum

@@ -550,6 +550,7 @@ github.com/go-sql-driver/mysql v1.4.0/go.mod h1:zAC/RDZ24gD3HViQzih4MyKcchzm+sOG
 github.com/go-sql-driver/mysql v1.4.1/go.mod h1:zAC/RDZ24gD3HViQzih4MyKcchzm+sOG5ZlKdlhCg5w=
 github.com/go-sql-driver/mysql v1.5.0 h1:ozyZYNQW3x3HtqT1jira07DN2PArx2v7/mN66gGcHOs=
 github.com/go-sql-driver/mysql v1.5.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
+github.com/go-stack/stack v1.8.0 h1:5SgMzNM5HxrEjV0ww2lTmX6E2Izsfxas4+YHWRs3Lsk=
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
 github.com/go-test/deep v1.0.2-0.20181118220953-042da051cf31/go.mod h1:wGDj63lr65AM2AQyKZd/NYHGb0R+1RLqB8NKt3aSFNA=
 github.com/go-test/deep v1.0.4/go.mod h1:wGDj63lr65AM2AQyKZd/NYHGb0R+1RLqB8NKt3aSFNA=
@@ -1395,6 +1396,7 @@ go.etcd.io/etcd v0.0.0-20191023171146-3cf2f69b5738 h1:VcrIfasaLFkyjk6KNlXQSzO+B0
 go.etcd.io/etcd v0.0.0-20191023171146-3cf2f69b5738/go.mod h1:dnLIgRNXwCJa5e+c6mIZCrds/GIG4ncV9HhK5PX7jPg=
 go.mongodb.org/mongo-driver v1.0.3/go.mod h1:u7ryQJ+DOzQmeO7zB6MHyr8jkEQvC8vH7qLUO4lqsUM=
 go.mongodb.org/mongo-driver v1.1.1/go.mod h1:u7ryQJ+DOzQmeO7zB6MHyr8jkEQvC8vH7qLUO4lqsUM=
+go.mongodb.org/mongo-driver v1.1.2 h1:jxcFYjlkl8xaERsgLo+RNquI0epW6zuy/ZRQs6jnrFA=
 go.mongodb.org/mongo-driver v1.1.2/go.mod h1:u7ryQJ+DOzQmeO7zB6MHyr8jkEQvC8vH7qLUO4lqsUM=
 go.opencensus.io v0.15.0/go.mod h1:UffZAU+4sDEINUGP/B7UfBBkq4fqLu9zXAX7ke6CHW0=
 go.opencensus.io v0.17.0/go.mod h1:mp1VrMQxhlqqDpKvH4UcQUa4YwlzNmymAjPrDdfxNpI=

pkg/scalers/mongo_scaler.go

@@ -0,0 +1,286 @@
+package scalers
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strconv"
+	"time"
+
+	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/mongo"
+	"go.mongodb.org/mongo-driver/mongo/options"
+	"go.mongodb.org/mongo-driver/mongo/readpref"
+	"go.mongodb.org/mongo-driver/x/bsonx"
+	"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"
+	logf "sigs.k8s.io/controller-runtime/pkg/log"
+
+	kedautil "github.com/kedacore/keda/v2/pkg/util"
+)
+
+// mongoDBScaler is support for mongoDB in keda.
+type mongoDBScaler struct {
+	metadata *mongoDBMetadata
+	client   *mongo.Client
+}
+
+// mongoDBMetadata specify mongoDB scaler params.
+type mongoDBMetadata struct {
+	// The string is used by connected with mongoDB.
+	// +optional
+	connectionString string
+	// Specify the host to connect to the mongoDB server,if the connectionString be provided, don't need specify this param.
+	// +optional
+	host string
+	// Specify the port to connect to the mongoDB server,if the connectionString be provided, don't need specify this param.
+	// +optional
+	port string
+	// Specify the username to connect to the mongoDB server,if the connectionString be provided, don't need specify this param.
+	// +optional
+	username string
+	// Specify the password to connect to the mongoDB server,if the connectionString be provided, don't need specify this param.
+	// +optional
+	password string
+
+	// The name of the database to be queried.
+	// +required
+	dbName string
+	// The name of the collection to be queried.
+	// +required
+	collection string
+	// A mongoDB filter doc,used by specify DB.
+	// +required
+	query string
+	// A threshold that is used as targetAverageValue in HPA
+	// +required
+	queryValue int
+
+	metricName string
+}
+
+// Default variables and settings
+const (
+	mongoDBDefaultTimeOut = 10 * time.Second
+	defaultCollection     = "default"
+	defaultDB             = "test"
+	defaultQueryValue     = 1
+)
+
+var mongoDBLog = logf.Log.WithName("mongodb_scaler")
+
+// NewMongoDBScaler creates a new mongoDB scaler
+func NewMongoDBScaler(config *ScalerConfig) (Scaler, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), mongoDBDefaultTimeOut)
+	defer cancel()
+
+	meta, connStr, err := parseMongoDBMetadata(config)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parsing mongoDB metadata, because of %v", err)
+	}
+
+	opt := options.Client().ApplyURI(connStr)
+	client, err := mongo.Connect(ctx, opt)
+	if err != nil {
+		return nil, fmt.Errorf("failed to establish connection with mongoDB, because of %v", err)
+	}
+
+	if err = client.Ping(ctx, readpref.Primary()); err != nil {
+		return nil, fmt.Errorf("failed to ping mongoDB, because of %v", err)
+	}
+
+	return &mongoDBScaler{
+		metadata: meta,
+		client:   client,
+	}, nil
+}
+
+func parseMongoDBMetadata(config *ScalerConfig) (*mongoDBMetadata, string, error) {
+	var connStr string
+	// setting default metadata
+	meta := mongoDBMetadata{
+		collection: defaultCollection,
+		query:      "",
+		queryValue: defaultQueryValue,
+		dbName:     defaultDB,
+	}
+
+	// parse metaData from ScaledJob config
+	if val, ok := config.TriggerMetadata["collection"]; ok {
+		meta.collection = val
+	} else {
+		return nil, "", fmt.Errorf("no collection given")
+	}
+
+	if val, ok := config.TriggerMetadata["query"]; ok {
+		meta.query = val
+	} else {
+		return nil, "", fmt.Errorf("no query given")
+	}
+
+	if val, ok := config.TriggerMetadata["queryValue"]; ok {
+		queryValue, err := strconv.Atoi(val)
+		if err != nil {
+			return nil, "", fmt.Errorf("failed to convert %v to int, because of %v", queryValue, err.Error())
+		}
+		meta.queryValue = queryValue
+	} else {
+		return nil, "", fmt.Errorf("no queryValue given")
+	}
+
+	if val, ok := config.TriggerMetadata["dbName"]; ok {
+		meta.dbName = val
+	} else {
+		return nil, "", fmt.Errorf("no dbName given")
+	}
+
+	// Resolve connectionString
+	if c, ok := config.AuthParams["connectionString"]; ok {
+		meta.connectionString = c
+	} else if v, ok := config.TriggerMetadata["connectionStringFromEnv"]; ok {
+		meta.connectionString = config.ResolvedEnv[v]
+	} else {
+		meta.connectionString = ""
+		if val, ok := config.TriggerMetadata["host"]; ok {
+			meta.host = val
+		} else {
+			return nil, "", fmt.Errorf("no host given")
+		}
+		if val, ok := config.TriggerMetadata["port"]; ok {
+			meta.port = val
+		} else {
+			return nil, "", fmt.Errorf("no port given")
+		}
+
+		if val, ok := config.TriggerMetadata["username"]; ok {
+			meta.username = val
+		} else {
+			return nil, "", fmt.Errorf("no username given")
+		}
+		// get password from env or authParams
+		if v, ok := config.AuthParams["password"]; ok {
+			meta.password = v
+		} else if v, ok := config.TriggerMetadata["passwordFromEnv"]; ok {
+			meta.password = config.ResolvedEnv[v]
+		}
+
+		if len(meta.password) == 0 {
+			return nil, "", fmt.Errorf("no password given")
+		}
+	}
+
+	if meta.connectionString != "" {
+		connStr = meta.connectionString
+	} else {
+		// Build connection str
+		addr := fmt.Sprintf("%s:%s", meta.host, meta.port)
+		auth := fmt.Sprintf("%s:%s", meta.username, meta.password)
+		connStr = "mongodb://" + auth + "@" + addr
+	}
+
+	if val, ok := config.TriggerMetadata["metricName"]; ok {
+		meta.metricName = kedautil.NormalizeString(fmt.Sprintf("mongodb-%s", val))
+	} else {
+		maskedURL, err := kedautil.MaskPartOfURL(connStr, kedautil.Hostname)
+		if err != nil {
+			return nil, "", fmt.Errorf("failure masking part of url")
+		}
+		meta.metricName = kedautil.NormalizeString(fmt.Sprintf("mongodb-%s-%s", maskedURL, meta.collection))
+	}
+	return &meta, connStr, nil
+}
+
+func (s *mongoDBScaler) IsActive(ctx context.Context) (bool, error) {
+	result, err := s.getQueryResult()
+	if err != nil {
+		mongoDBLog.Error(err, fmt.Sprintf("failed to get query result by mongoDB, because of %v", err))
+		return false, err
+	}
+	return result > 0, nil
+}
+
+// Close disposes of mongoDB connections
+func (s *mongoDBScaler) Close() error {
+	if s.client != nil {
+		err := s.client.Disconnect(context.TODO())
+		if err != nil {
+			mongoDBLog.Error(err, fmt.Sprintf("failed to close mongoDB connection, because of %v", err))
+			return err
+		}
+	}
+
+	return nil
+}
+
+// getQueryResult query mongoDB by meta.query
+func (s *mongoDBScaler) getQueryResult() (int, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), mongoDBDefaultTimeOut)
+	defer cancel()
+
+	filter, err := json2BsonDoc(s.metadata.query)
+	if err != nil {
+		mongoDBLog.Error(err, fmt.Sprintf("failed to convert query param to bson.Doc, because of %v", err))
+		return 0, err
+	}
+
+	docsNum, err := s.client.Database(s.metadata.dbName).Collection(s.metadata.collection).CountDocuments(ctx, filter)
+	if err != nil {
+		mongoDBLog.Error(err, fmt.Sprintf("failed to query %v in %v, because of %v", s.metadata.dbName, s.metadata.collection, err))
+		return 0, err
+	}
+
+	return int(docsNum), nil
+}
+
+// GetMetrics query from mongoDB,and return to external metrics
+func (s *mongoDBScaler) GetMetrics(ctx context.Context, metricName string, metricSelector labels.Selector) ([]external_metrics.ExternalMetricValue, error) {
+	num, err := s.getQueryResult()
+	if err != nil {
+		return []external_metrics.ExternalMetricValue{}, fmt.Errorf("failed to inspect momgoDB, because of %v", err)
+	}
+
+	metric := external_metrics.ExternalMetricValue{
+		MetricName: metricName,
+		Value:      *resource.NewQuantity(int64(num), resource.DecimalSI),
+		Timestamp:  metav1.Now(),
+	}
+
+	return append([]external_metrics.ExternalMetricValue{}, metric), nil
+}
+
+// GetMetricSpecForScaling get the query value for scaling
+func (s *mongoDBScaler) GetMetricSpecForScaling() []v2beta2.MetricSpec {
+	targetQueryValue := resource.NewQuantity(int64(s.metadata.queryValue), resource.DecimalSI)
+
+	externalMetric := &v2beta2.ExternalMetricSource{
+		Metric: v2beta2.MetricIdentifier{
+			Name: s.metadata.metricName,
+		},
+		Target: v2beta2.MetricTarget{
+			Type:         v2beta2.AverageValueMetricType,
+			AverageValue: targetQueryValue,
+		},
+	}
+	metricSpec := v2beta2.MetricSpec{
+		External: externalMetric, Type: externalMetricType,
+	}
+	return []v2beta2.MetricSpec{metricSpec}
+}
+
+// json2BsonDoc convert Json to Bson.Doc
+func json2BsonDoc(js string) (doc bsonx.Doc, err error) {
+	doc = bsonx.Doc{}
+	err = bson.UnmarshalExtJSON([]byte(js), true, &doc)
+	if err != nil {
+		return nil, err
+	}
+
+	if len(doc) == 0 {
+		return nil, errors.New("empty bson document")
+	}
+
+	return doc, nil
+}

pkg/scalers/mongo_scaler_test.go

@@ -0,0 +1,87 @@
+package scalers
+
+import (
+	"testing"
+
+	"go.mongodb.org/mongo-driver/mongo"
+)
+
+var testMongoDBResolvedEnv = map[string]string{
+	"MongoDB_CONN_STR": "test_conn_str",
+	"MongoDB_PASSWORD": "test",
+}
+
+type parseMongoDBMetadataTestData struct {
+	metadata    map[string]string
+	resolvedEnv map[string]string
+	raisesError bool
+}
+
+type mongoDBMetricIdentifier struct {
+	metadataTestData *parseMongoDBMetadataTestData
+	name             string
+}
+
+var testMONGODBMetadata = []parseMongoDBMetadataTestData{
+	// No metadata
+	{
+		metadata:    map[string]string{},
+		resolvedEnv: testMongoDBResolvedEnv,
+		raisesError: true,
+	},
+	// connectionStringFromEnv
+	{
+		metadata:    map[string]string{"query": `{"name":"John"}`, "collection": "demo", "queryValue": "12", "connectionStringFromEnv": "Mongo_CONN_STR", "dbName": "test"},
+		resolvedEnv: testMongoDBResolvedEnv,
+		raisesError: false,
+	},
+	// with metric name
+	{
+		metadata:    map[string]string{"query": `{"name":"John"}`, "metricName": "hpa", "collection": "demo", "queryValue": "12", "connectionStringFromEnv": "Mongo_CONN_STR", "dbName": "test"},
+		resolvedEnv: testMongoDBResolvedEnv,
+		raisesError: false,
+	},
+}
+
+var mongoDBMetricIdentifiers = []mongoDBMetricIdentifier{
+	{metadataTestData: &testMONGODBMetadata[2], name: "mongodb-hpa"},
+}
+
+func TestParseMongoDBMetadata(t *testing.T) {
+	for _, testData := range testMONGODBMetadata {
+		_, _, err := parseMongoDBMetadata(&ScalerConfig{TriggerMetadata: testData.metadata})
+		if err != nil && !testData.raisesError {
+			t.Error("Expected success but got error:", err)
+		}
+		if err == nil && testData.raisesError {
+			t.Error("Expected error but got success")
+		}
+	}
+}
+
+func TestMongoDBGetMetricSpecForScaling(t *testing.T) {
+	for _, testData := range mongoDBMetricIdentifiers {
+		meta, _, err := parseMongoDBMetadata(&ScalerConfig{ResolvedEnv: testData.metadataTestData.resolvedEnv, TriggerMetadata: testData.metadataTestData.metadata})
+		if err != nil {
+			t.Fatal("Could not parse metadata:", err)
+		}
+		mockMongoDBScaler := mongoDBScaler{meta, &mongo.Client{}}
+
+		metricSpec := mockMongoDBScaler.GetMetricSpecForScaling()
+		metricName := metricSpec[0].External.Metric.Name
+		if metricName != testData.name {
+			t.Error("Wrong External metric source name:", metricName)
+		}
+	}
+}
+
+func TestJson2BsonDoc(t *testing.T) {
+	var testJSON = `{"name":"carson"}`
+	doc, err := json2BsonDoc(testJSON)
+	if err != nil {
+		t.Error("convert testJson to Bson.Doc err:", err)
+	}
+	if doc == nil {
+		t.Error("the doc is nil")
+	}
+}