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gcp_pub_sub_scaler.go
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gcp_pub_sub_scaler.go
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package scalers
import (
"context"
"errors"
"fmt"
"regexp"
"strconv"
"strings"
"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"
kedav1alpha1 "github.com/kedacore/keda/v2/apis/keda/v1alpha1"
kedautil "github.com/kedacore/keda/v2/pkg/util"
)
const (
compositeSubscriptionIDPrefix = "projects/[a-z][a-zA-Z0-9-]*[a-zA-Z0-9]/subscriptions/[a-zA-Z][a-zA-Z0-9-_~%\\+\\.]*"
defaultTargetSubscriptionSize = 5
defaultTargetOldestUnackedMessageAge = 10
pubSubStackDriverSubscriptionSizeMetricName = "pubsub.googleapis.com/subscription/num_undelivered_messages"
pubSubStackDriverOldestUnackedMessageAgeMetricName = "pubsub.googleapis.com/subscription/oldest_unacked_message_age"
pubsubModeSubscriptionSize = "SubscriptionSize"
pubsubModeOldestUnackedMessageAge = "OldestUnackedMessageAge"
)
var regexpCompositeSubscriptionIDPrefix = regexp.MustCompile(compositeSubscriptionIDPrefix)
type gcpAuthorizationMetadata struct {
GoogleApplicationCredentials string
podIdentityOwner bool
podIdentityProviderEnabled bool
}
type pubsubScaler struct {
client *StackDriverClient
metadata *pubsubMetadata
}
type pubsubMetadata struct {
mode string
value int
subscriptionName string
gcpAuthorization gcpAuthorizationMetadata
scalerIndex int
}
var gcpPubSubLog = logf.Log.WithName("gcp_pub_sub_scaler")
// NewPubSubScaler creates a new pubsubScaler
func NewPubSubScaler(config *ScalerConfig) (Scaler, error) {
meta, err := parsePubSubMetadata(config)
if err != nil {
return nil, fmt.Errorf("error parsing PubSub metadata: %s", err)
}
return &pubsubScaler{
metadata: meta,
}, nil
}
func parsePubSubMetadata(config *ScalerConfig) (*pubsubMetadata, error) {
meta := pubsubMetadata{}
meta.mode = pubsubModeSubscriptionSize
mode, modePresent := config.TriggerMetadata["mode"]
value, valuePresent := config.TriggerMetadata["value"]
if subSize, subSizePresent := config.TriggerMetadata["subscriptionSize"]; subSizePresent {
if modePresent || valuePresent {
return nil, errors.New("you can use either mode and value fields or subscriptionSize field")
}
gcpPubSubLog.Info("subscriptionSize field is deprecated. Use mode and value fields instead")
meta.mode = pubsubModeSubscriptionSize
subSizeValue, err := strconv.Atoi(subSize)
if err != nil {
return nil, fmt.Errorf("value parsing error %s", err.Error())
}
meta.value = subSizeValue
} else {
if modePresent {
meta.mode = mode
}
switch meta.mode {
case pubsubModeSubscriptionSize:
meta.value = defaultTargetSubscriptionSize
case pubsubModeOldestUnackedMessageAge:
meta.value = defaultTargetOldestUnackedMessageAge
default:
return nil, fmt.Errorf("trigger mode %s must be one of %s, %s", meta.mode, pubsubModeSubscriptionSize, pubsubModeOldestUnackedMessageAge)
}
if valuePresent {
triggerValue, err := strconv.Atoi(value)
if err != nil {
return nil, fmt.Errorf("value parsing error %s", err.Error())
}
meta.value = triggerValue
}
}
if val, ok := config.TriggerMetadata["subscriptionName"]; ok {
if val == "" {
return nil, fmt.Errorf("no subscription name given")
}
meta.subscriptionName = val
} else {
return nil, fmt.Errorf("no subscription name given")
}
auth, err := getGcpAuthorization(config, config.ResolvedEnv)
if err != nil {
return nil, err
}
meta.gcpAuthorization = *auth
meta.scalerIndex = config.ScalerIndex
return &meta, nil
}
// IsActive checks if there are any messages in the subscription
func (s *pubsubScaler) IsActive(ctx context.Context) (bool, error) {
switch s.metadata.mode {
case pubsubModeSubscriptionSize:
size, err := s.getMetrics(ctx, pubSubStackDriverSubscriptionSizeMetricName)
if err != nil {
gcpPubSubLog.Error(err, "error getting Active Status")
return false, err
}
return size > 0, nil
case pubsubModeOldestUnackedMessageAge:
_, err := s.getMetrics(ctx, pubSubStackDriverOldestUnackedMessageAgeMetricName)
if err != nil {
gcpPubSubLog.Error(err, "error getting Active Status")
return false, err
}
return true, nil
default:
return false, errors.New("unknown mode")
}
}
func (s *pubsubScaler) Close(context.Context) error {
if s.client != nil {
err := s.client.metricsClient.Close()
s.client = nil
if err != nil {
gcpPubSubLog.Error(err, "error closing StackDriver client")
}
}
return nil
}
// GetMetricSpecForScaling returns the metric spec for the HPA
func (s *pubsubScaler) GetMetricSpecForScaling(context.Context) []v2beta2.MetricSpec {
// Construct the target value as a quantity
targetValueQty := resource.NewQuantity(int64(s.metadata.value), resource.DecimalSI)
externalMetric := &v2beta2.ExternalMetricSource{
Metric: v2beta2.MetricIdentifier{
Name: GenerateMetricNameWithIndex(s.metadata.scalerIndex, kedautil.NormalizeString(fmt.Sprintf("gcp-ps-%s", s.metadata.subscriptionName))),
},
Target: v2beta2.MetricTarget{
Type: v2beta2.AverageValueMetricType,
AverageValue: targetValueQty,
},
}
// Create the metric spec for the HPA
metricSpec := v2beta2.MetricSpec{
External: externalMetric,
Type: externalMetricType,
}
return []v2beta2.MetricSpec{metricSpec}
}
// GetMetrics connects to Stack Driver and finds the size of the pub sub subscription
func (s *pubsubScaler) GetMetrics(ctx context.Context, metricName string, metricSelector labels.Selector) ([]external_metrics.ExternalMetricValue, error) {
var value int64
var err error
switch s.metadata.mode {
case pubsubModeSubscriptionSize:
value, err = s.getMetrics(ctx, pubSubStackDriverSubscriptionSizeMetricName)
if err != nil {
gcpPubSubLog.Error(err, "error getting subscription size")
return []external_metrics.ExternalMetricValue{}, err
}
case pubsubModeOldestUnackedMessageAge:
value, err = s.getMetrics(ctx, pubSubStackDriverOldestUnackedMessageAgeMetricName)
if err != nil {
gcpPubSubLog.Error(err, "error getting oldest unacked message age")
return []external_metrics.ExternalMetricValue{}, err
}
}
metric := external_metrics.ExternalMetricValue{
MetricName: metricName,
Value: *resource.NewQuantity(value, resource.DecimalSI),
Timestamp: metav1.Now(),
}
return append([]external_metrics.ExternalMetricValue{}, metric), nil
}
func (s *pubsubScaler) setStackdriverClient(ctx context.Context) error {
var client *StackDriverClient
var err error
if s.metadata.gcpAuthorization.podIdentityProviderEnabled {
client, err = NewStackDriverClientPodIdentity(ctx)
} else {
client, err = NewStackDriverClient(ctx, s.metadata.gcpAuthorization.GoogleApplicationCredentials)
}
if err != nil {
return err
}
s.client = client
return nil
}
// getMetrics gets metric type value from stackdriver api
func (s *pubsubScaler) getMetrics(ctx context.Context, metricType string) (int64, error) {
if s.client == nil {
err := s.setStackdriverClient(ctx)
if err != nil {
return -1, err
}
}
subscriptionID, projectID := getSubscriptionData(s)
filter := `metric.type="` + metricType + `" AND resource.labels.subscription_id="` + subscriptionID + `"`
return s.client.GetMetrics(ctx, filter, projectID)
}
func getSubscriptionData(s *pubsubScaler) (string, string) {
var subscriptionID string
var projectID string
if regexpCompositeSubscriptionIDPrefix.MatchString(s.metadata.subscriptionName) {
subscriptionID = strings.Split(s.metadata.subscriptionName, "/")[3]
projectID = strings.Split(s.metadata.subscriptionName, "/")[1]
} else {
subscriptionID = s.metadata.subscriptionName
}
return subscriptionID, projectID
}
func getGcpAuthorization(config *ScalerConfig, resolvedEnv map[string]string) (*gcpAuthorizationMetadata, error) {
metadata := config.TriggerMetadata
authParams := config.AuthParams
meta := gcpAuthorizationMetadata{}
if metadata["identityOwner"] == "operator" {
meta.podIdentityOwner = false
} else if metadata["identityOwner"] == "" || metadata["identityOwner"] == "pod" {
meta.podIdentityOwner = true
switch {
case config.PodIdentity == kedav1alpha1.PodIdentityProviderGCP:
// do nothing, rely on underneath metadata google
meta.podIdentityProviderEnabled = true
case authParams["GoogleApplicationCredentials"] != "":
meta.GoogleApplicationCredentials = authParams["GoogleApplicationCredentials"]
default:
if metadata["credentialsFromEnv"] != "" {
meta.GoogleApplicationCredentials = resolvedEnv[metadata["credentialsFromEnv"]]
} else {
return nil, fmt.Errorf("GoogleApplicationCredentials not found")
}
}
}
return &meta, nil
}