/
redis_streams_scaler.go
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/
redis_streams_scaler.go
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package scalers
import (
"context"
"crypto/tls"
"fmt"
"strconv"
"github.com/go-redis/redis"
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"
logf "sigs.k8s.io/controller-runtime/pkg/log"
)
const (
pendingEntriesCountMetricName = "RedisStreamPendingEntriesCount"
// defaults
defaultTargetPendingEntriesCount = 5
defaultAddress = "redis-master.default.svc.cluster.local:6379"
defaultPassword = ""
defaultDbIndex = 0
defaultTLS = false
defaultRedisHost = ""
defaultRedisPort = ""
// metadata names
pendingEntriesCountMetadata = "pendingEntriesCount"
streamNameMetadata = "stream"
consumerGroupNameMetadata = "consumerGroup"
addressMetadata = "address"
hostMetadata = "host"
portMetadata = "port"
passwordMetadata = "password"
databaseIndexMetadata = "databaseIndex"
enableTLSMetadata = "enableTLS"
// error
missingRedisAddressOrHostPortInfo = "address or host missing. please provide redis address should in host:port format or set the host/port values"
)
type redisStreamsScaler struct {
metadata *redisStreamsMetadata
conn *redis.Client
}
type redisStreamsMetadata struct {
targetPendingEntriesCount int
streamName string
consumerGroupName string
address string
password string
host string
port string
databaseIndex int
enableTLS bool
}
var redisStreamsLog = logf.Log.WithName("redis_streams_scaler")
// NewRedisStreamsScaler creates a new redisStreamsScaler
func NewRedisStreamsScaler(resolvedEnv, metadata, authParams map[string]string) (Scaler, error) {
meta, err := parseRedisStreamsMetadata(metadata, resolvedEnv, authParams)
if err != nil {
return nil, fmt.Errorf("error parsing redis streams metadata: %s", err)
}
c, err := getRedisConnection(meta)
if err != nil {
return nil, fmt.Errorf("redis connection failed: %s", err)
}
return &redisStreamsScaler{
metadata: meta,
conn: c,
}, nil
}
func getRedisConnection(metadata *redisStreamsMetadata) (*redis.Client, error) {
options := &redis.Options{
Addr: metadata.address,
Password: metadata.password,
DB: metadata.databaseIndex,
}
if metadata.enableTLS == true {
options.TLSConfig = &tls.Config{
InsecureSkipVerify: true,
}
}
// this does not guarentee successful connection
c := redis.NewClient(options)
// confirm if connected
err := c.Ping().Err()
if err != nil {
return nil, err
}
return c, nil
}
func parseRedisStreamsMetadata(metadata, resolvedEnv, authParams map[string]string) (*redisStreamsMetadata, error) {
meta := redisStreamsMetadata{}
meta.targetPendingEntriesCount = defaultTargetPendingEntriesCount
if val, ok := metadata[pendingEntriesCountMetadata]; ok {
pendingEntriesCount, err := strconv.Atoi(val)
if err != nil {
return nil, fmt.Errorf("error parsing pending entries count %v", err)
}
meta.targetPendingEntriesCount = pendingEntriesCount
} else {
return nil, fmt.Errorf("missing pending entries count")
}
if val, ok := metadata[streamNameMetadata]; ok {
meta.streamName = val
} else {
return nil, fmt.Errorf("missing redis stream name")
}
if val, ok := metadata[consumerGroupNameMetadata]; ok {
meta.consumerGroupName = val
} else {
return nil, fmt.Errorf("missing redis stream consumer group name")
}
address := defaultAddress
host := defaultRedisHost
port := defaultRedisPort
if val, ok := metadata[addressMetadata]; ok && val != "" {
address = val
} else {
if val, ok := metadata[hostMetadata]; ok && val != "" {
host = val
} else {
return nil, fmt.Errorf(missingRedisAddressOrHostPortInfo)
}
if val, ok := metadata[portMetadata]; ok && val != "" {
port = val
} else {
return nil, fmt.Errorf(missingRedisAddressOrHostPortInfo)
}
}
if val, ok := resolvedEnv[address]; ok {
meta.address = val
} else {
if val, ok := resolvedEnv[host]; ok {
meta.host = val
} else {
return nil, fmt.Errorf(missingRedisAddressOrHostPortInfo)
}
if val, ok := resolvedEnv[port]; ok {
meta.port = val
} else {
return nil, fmt.Errorf(missingRedisAddressOrHostPortInfo)
}
meta.address = fmt.Sprintf("%s:%s", meta.host, meta.port)
}
meta.password = defaultPassword
if val, ok := authParams[passwordMetadata]; ok {
meta.password = val
} else if val, ok := metadata[passwordMetadata]; ok && val != "" {
if passd, ok := resolvedEnv[val]; ok {
meta.password = passd
}
}
meta.databaseIndex = defaultDbIndex
if val, ok := metadata[databaseIndexMetadata]; ok {
dbIndex, err := strconv.ParseInt(val, 10, 64)
if err != nil {
return nil, fmt.Errorf("error parsing redis database index %v", err)
}
meta.databaseIndex = int(dbIndex)
}
meta.enableTLS = defaultTLS
if val, ok := metadata[enableTLSMetadata]; ok {
tls, err := strconv.ParseBool(val)
if err != nil {
return nil, fmt.Errorf("error parsing enableTLS %v", err)
}
meta.enableTLS = tls
}
return &meta, nil
}
// IsActive checks if there are pending entries in the 'Pending Entries List' for consumer group of a stream
func (s *redisStreamsScaler) IsActive(ctx context.Context) (bool, error) {
count, err := s.getPendingEntriesCount()
if err != nil {
redisStreamsLog.Error(err, "error")
return false, err
}
return count > 0, nil
}
func (s *redisStreamsScaler) Close() error {
return s.conn.Close()
}
// GetMetricSpecForScaling returns the metric spec for the HPA
func (s *redisStreamsScaler) GetMetricSpecForScaling() []v2beta1.MetricSpec {
targetPendingEntriesCount := resource.NewQuantity(int64(s.metadata.targetPendingEntriesCount), resource.DecimalSI)
externalMetric := &v2beta1.ExternalMetricSource{MetricName: pendingEntriesCountMetricName, TargetAverageValue: targetPendingEntriesCount}
metricSpec := v2beta1.MetricSpec{External: externalMetric, Type: externalMetricType}
return []v2beta1.MetricSpec{metricSpec}
}
// GetMetrics fetches the number of pending entries for a consumer group in a stream
func (s *redisStreamsScaler) GetMetrics(ctx context.Context, metricName string, metricSelector labels.Selector) ([]external_metrics.ExternalMetricValue, error) {
pendingEntriesCount, err := s.getPendingEntriesCount()
if err != nil {
redisStreamsLog.Error(err, "error fetching pending entries count")
return []external_metrics.ExternalMetricValue{}, err
}
metric := external_metrics.ExternalMetricValue{
MetricName: metricName,
Value: *resource.NewQuantity(pendingEntriesCount, resource.DecimalSI),
Timestamp: metav1.Now(),
}
return append([]external_metrics.ExternalMetricValue{}, metric), nil
}
func (s *redisStreamsScaler) getPendingEntriesCount() (int64, error) {
pendingEntries, err := s.conn.XPending(s.metadata.streamName, s.metadata.consumerGroupName).Result()
if err != nil {
return -1, err
}
return pendingEntries.Count, nil
}