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main.go
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main.go
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package main
import (
"context"
"crypto/tls"
"crypto/x509"
"fmt"
"io"
"log"
"net/http"
"os"
"os/signal"
"strings"
"sync"
"syscall"
"unicode/utf8"
"github.com/IBM/sarama"
"github.com/pkg/errors"
"go.uber.org/zap"
"github.com/fission/keda-connectors/common"
)
// Following code snippet is from KEDA project and adapted for Fission.
// Copyright 2020 The KEDA Authors.
// and others that have contributed code to the public domain.
// Licensed under the Apache License, Version 2.0 (the "License");
// https://github.com/kedacore/keda/blob/v1.5.0/LICENSE
// https://github.com/kedacore/keda/blob/v1.5.0/pkg/scalers/kafka_scaler.go#L28
type kafkaMetadata struct {
bootstrapServers []string
consumerGroup string
offsetResetPolicy string
// SASL
saslType string
username string
password string
// TLS
tls string
cert string
key string
ca string
}
const (
kafkaAuthModeNone string = ""
kafkaAuthModeSaslPlaintext string = "plaintext"
kafkaAuthModeSaslScramSha256 string = "scram_sha256"
kafkaAuthModeSaslScramSha512 string = "scram_sha512"
)
// https://github.com/kedacore/keda/blob/v1.5.0/pkg/scalers/kafka_scaler.go#L83
func parseKafkaMetadata(logger *zap.Logger) (kafkaMetadata, error) {
meta := kafkaMetadata{}
// brokerList marked as deprecated, bootstrapServers is the new one to use
if os.Getenv("BROKER_LIST") != "" && os.Getenv("BOOTSTRAP_SERVERS") != "" {
return meta, errors.New("cannot specify both bootstrapServers and brokerList (deprecated)")
}
if os.Getenv("BROKER_LIST") == "" && os.Getenv("BOOTSTRAP_SERVERS") == "" {
return meta, errors.New("no bootstrapServers or brokerList (deprecated) given")
}
if os.Getenv("BOOTSTRAP_SERVERS") != "" {
meta.bootstrapServers = strings.Split(os.Getenv("BOOTSTRAP_SERVERS"), ",")
}
if os.Getenv("BROKER_LIST") != "" {
logger.Info("WARNING: usage of brokerList is deprecated. use bootstrapServers instead.")
meta.bootstrapServers = strings.Split(os.Getenv("BROKER_LIST"), ",")
}
if os.Getenv("CONSUMER_GROUP") == "" {
return meta, errors.New("No consumerGroup given")
}
meta.consumerGroup = os.Getenv("CONSUMER_GROUP")
offsetResetPolicy := os.Getenv("OFFSET_RESET_POLICY")
// If offsetResetPolicy is not set, use latest by default
if offsetResetPolicy == "" {
offsetResetPolicy = "latest"
}
// Check offsetResetPolicy is valid
if offsetResetPolicy != "earliest" && offsetResetPolicy != "latest" {
return meta, errors.Errorf("offsetResetPolicy %s not support. It should be one of earliest or latest", offsetResetPolicy)
}
meta.offsetResetPolicy = offsetResetPolicy
meta.tls = os.Getenv("TLS")
if meta.tls == "" {
meta.tls = "disabled"
}
meta.saslType = os.Getenv("SASL")
if meta.saslType != kafkaAuthModeSaslPlaintext && meta.saslType != kafkaAuthModeNone && meta.saslType != kafkaAuthModeSaslScramSha256 && meta.saslType != kafkaAuthModeSaslScramSha512 {
return meta, fmt.Errorf("incorrect value for sasl authentication %s given", meta.saslType)
}
if meta.saslType != kafkaAuthModeNone {
if os.Getenv("USERNAME") == "" {
return meta, errors.New("no username given")
}
meta.username = strings.TrimSpace(os.Getenv("USERNAME"))
if os.Getenv("PASSWORD") == "" {
return meta, errors.New("no password given")
}
meta.password = strings.TrimSpace(os.Getenv("PASSWORD"))
}
if meta.tls == "enable" {
// if either CERT or KEY are provided, both must be provided
if os.Getenv("CERT") != "" && os.Getenv("KEY") == "" {
return meta, errors.New("cert given but no key, both required")
}
if os.Getenv("KEY") != "" && os.Getenv("CERT") == "" {
return meta, errors.New("key given but no cert, both required")
}
// CA is optional
meta.ca = os.Getenv("CA")
// CERT and KEY must be provided as a pair, but both are optional
meta.cert = os.Getenv("CERT")
meta.key = os.Getenv("KEY")
}
return meta, nil
}
// End of code snippet from KEDA project.
func getConfig(metadata kafkaMetadata) (*sarama.Config, error) {
config := sarama.NewConfig()
config.Version = sarama.V2_0_0_0
// When offsetResetPolicy is earliest, set Consumer.Offsets.Initial to OffsetOldest.
// Otherwise, set Consumer.Offsets.Initial to OffsetNewest.
// Ref: https://github.com/Shopify/sarama/issues/803#issuecomment-269215508
if metadata.offsetResetPolicy == "earliest" {
config.Consumer.Offsets.Initial = sarama.OffsetOldest
} else {
config.Consumer.Offsets.Initial = sarama.OffsetNewest
}
if ok := metadata.saslType == kafkaAuthModeSaslPlaintext || metadata.saslType == kafkaAuthModeSaslScramSha256 || metadata.saslType == kafkaAuthModeSaslScramSha512; ok {
config.Net.SASL.Enable = true
config.Net.SASL.User = metadata.username
config.Net.SASL.Password = metadata.password
}
if metadata.saslType == kafkaAuthModeSaslPlaintext {
config.Net.SASL.Mechanism = sarama.SASLMechanism(sarama.SASLTypePlaintext)
}
if metadata.saslType == kafkaAuthModeSaslScramSha256 {
config.Net.SASL.SCRAMClientGeneratorFunc = func() sarama.SCRAMClient { return &XDGSCRAMClient{HashGeneratorFcn: SHA256} }
config.Net.SASL.Mechanism = sarama.SASLMechanism(sarama.SASLTypeSCRAMSHA256)
}
if metadata.saslType == kafkaAuthModeSaslScramSha512 {
config.Net.SASL.SCRAMClientGeneratorFunc = func() sarama.SCRAMClient { return &XDGSCRAMClient{HashGeneratorFcn: SHA512} }
config.Net.SASL.Mechanism = sarama.SASLMechanism(sarama.SASLTypeSCRAMSHA512)
}
if metadata.tls == "enable" {
config.Net.TLS.Enable = true
tlsConfig, err := NewTLSConfig(metadata.cert, metadata.key, metadata.ca)
if err != nil {
return nil, err
}
config.Net.TLS.Config = tlsConfig
}
return config, nil
}
// kafkaConnector represents a Sarama consumer group consumer
type kafkaConnector struct {
ready chan bool
logger *zap.Logger
producer sarama.SyncProducer
connectorData common.ConnectorMetadata
}
// Setup is run at the beginning of a new session, before ConsumeClaim
func (conn *kafkaConnector) Setup(sarama.ConsumerGroupSession) error {
close(conn.ready)
return nil
}
// Cleanup is run at the end of a session, once all ConsumeClaim goroutines have exited
func (conn *kafkaConnector) Cleanup(sarama.ConsumerGroupSession) error {
return nil
}
// ConsumeClaim must start a consumer loop of ConsumerGroupClaim's Messages()
func (conn *kafkaConnector) ConsumeClaim(session sarama.ConsumerGroupSession, claim sarama.ConsumerGroupClaim) error {
// NOTE:
// Do not move the code below to a goroutine.
// The `ConsumeClaim` itself is called within a goroutine, see:
// https://github.com/Shopify/sarama/blob/master/consumer_group.go#L27-L29
for message := range claim.Messages() {
conn.logger.Info(fmt.Sprintf("Message claimed: value = %s, timestamp = %v, topic = %s", string(message.Value), message.Timestamp, message.Topic))
msg := string(message.Value)
headers := http.Header{
"KEDA-Topic": {conn.connectorData.Topic},
"KEDA-Response-Topic": {conn.connectorData.ResponseTopic},
"KEDA-Error-Topic": {conn.connectorData.ErrorTopic},
"Content-Type": {conn.connectorData.ContentType},
"KEDA-Source-Name": {conn.connectorData.SourceName},
}
// Set the headers came from Kafka record
for _, h := range message.Headers {
if utf8.ValidString(string(h.Value)) {
headers.Add(string(h.Key), string(h.Value))
}
}
resp, err := common.HandleHTTPRequest(msg, headers, conn.connectorData, conn.logger)
if err != nil {
conn.errorHandler(err)
} else {
body, err := io.ReadAll(resp.Body)
if err != nil {
conn.errorHandler(err)
} else {
// Generate Kafka record headers
var kafkaRecordHeaders []sarama.RecordHeader
for k, v := range resp.Header {
// One key may have multiple values
for _, v := range v {
kafkaRecordHeaders = append(kafkaRecordHeaders, sarama.RecordHeader{Key: []byte(k), Value: []byte(v)})
}
}
if success := conn.responseHandler(string(body), kafkaRecordHeaders); success {
session.MarkMessage(message, "")
}
}
err = resp.Body.Close()
if err != nil {
conn.logger.Error(err.Error())
}
}
}
return nil
}
func (conn *kafkaConnector) errorHandler(err error) {
if len(conn.connectorData.ErrorTopic) > 0 {
_, _, e := conn.producer.SendMessage(&sarama.ProducerMessage{
Topic: conn.connectorData.ErrorTopic,
Value: sarama.StringEncoder(err.Error()),
})
if e != nil {
conn.logger.Error("failed to publish message to error topic",
zap.Error(e),
zap.String("source", conn.connectorData.SourceName),
zap.String("message", err.Error()),
zap.String("topic", conn.connectorData.ErrorTopic))
}
} else {
conn.logger.Error("message received to publish to error topic, but no error topic was set",
zap.String("message", err.Error()),
zap.String("source", conn.connectorData.SourceName),
zap.String("http endpoint", conn.connectorData.HTTPEndpoint),
)
}
}
func (conn *kafkaConnector) responseHandler(msg string, headers []sarama.RecordHeader) bool {
if len(conn.connectorData.ResponseTopic) > 0 {
_, _, err := conn.producer.SendMessage(&sarama.ProducerMessage{
Topic: conn.connectorData.ResponseTopic,
Value: sarama.StringEncoder(msg),
Headers: headers,
})
if err != nil {
conn.logger.Warn("failed to publish response body from http request to topic",
zap.Error(err),
zap.String("topic", conn.connectorData.ResponseTopic),
zap.String("source", conn.connectorData.SourceName),
zap.String("http endpoint", conn.connectorData.HTTPEndpoint))
return false
}
}
return true
}
func getProducer(metadata kafkaMetadata) (sarama.SyncProducer, error) {
config, err := getConfig(metadata)
if err != nil {
return nil, err
}
config.Producer.RequiredAcks = sarama.WaitForLocal
config.Producer.Retry.Max = 10
config.Producer.Return.Successes = true
producer, err := sarama.NewSyncProducer(metadata.bootstrapServers, config)
if err != nil {
return nil, err
}
return producer, nil
}
func main() {
logger, err := zap.NewProduction()
if err != nil {
log.Fatalf("can't initialize zap logger: %v", err)
}
defer logger.Sync()
metadata, err := parseKafkaMetadata(logger)
if err != nil {
logger.Error("Failed to fetch kafka metadata", zap.Error(err))
return
}
connData, err := common.ParseConnectorMetadata()
if err != nil {
logger.Error("Failed to parse connector meta data", zap.Error(err))
return
}
config, err := getConfig(metadata)
if err != nil {
logger.Error("Failed to create kafka config", zap.Error(err))
return
}
producer, err := getProducer(metadata)
if err != nil {
logger.Error("Failed to create kafka producer", zap.Error(err))
return
}
defer producer.Close()
conn := kafkaConnector{
ready: make(chan bool),
logger: logger,
producer: producer,
connectorData: connData,
}
ctx, cancel := context.WithCancel(context.Background())
client, err := sarama.NewConsumerGroup(metadata.bootstrapServers, metadata.consumerGroup, config)
if err != nil {
logger.Error("Error creating consumer group client", zap.Error(err))
return
}
wg := &sync.WaitGroup{}
wg.Add(1)
go func() {
defer wg.Done()
for {
if err := client.Consume(ctx, []string{connData.Topic}, &conn); err != nil {
logger.Error("Error from consumer", zap.Error(err))
}
// check if context was cancelled, signaling that the consumer should stop
if ctx.Err() != nil {
return
}
conn.ready = make(chan bool)
}
}()
<-conn.ready // Await till the consumer has been set up
logger.Info("Sarama consumer up and running!...")
sigterm := make(chan os.Signal, 1)
signal.Notify(sigterm, syscall.SIGINT, syscall.SIGTERM)
select {
case <-ctx.Done():
logger.Info("terminating: context cancelled")
case <-sigterm:
logger.Info("terminating: via signal")
}
cancel()
wg.Wait()
if err = client.Close(); err != nil {
logger.Error("Error closing client", zap.Error(err))
}
}
// NewTLSConfig returns a *tls.Config using the given ceClient cert, ceClient key,
// and CA certificate. If none are appropriate, a nil *tls.Config is returned.
// Ref: https://github.com/kedacore/keda/blob/154364276402783c08fa24e7968fd31b9f89b6a6/pkg/util/tls_config.go
// TODO: Move this to common package as other connectors might need this
func NewTLSConfig(clientCert, clientKey, caCert string) (*tls.Config, error) {
valid := false
config := &tls.Config{}
if clientCert != "" && clientKey != "" {
cert, err := tls.X509KeyPair([]byte(clientCert), []byte(clientKey))
if err != nil {
return nil, fmt.Errorf("error parse X509KeyPair: %s", err)
}
config.Certificates = []tls.Certificate{cert}
valid = true
}
if caCert != "" {
caCertPool := x509.NewCertPool()
caCertPool.AppendCertsFromPEM([]byte(caCert))
config.RootCAs = caCertPool
config.InsecureSkipVerify = true
valid = true
}
if !valid {
config = nil
}
return config, nil
}