forked from kyma-project/kyma
/
message_handler.go
211 lines (172 loc) · 7.25 KB
/
message_handler.go
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package handlers
import (
"bytes"
"crypto/tls"
"encoding/json"
"fmt"
"log"
"net/http"
"time"
api "github.com/kyma-project/kyma/components/event-bus/api/publish"
"github.com/kyma-project/kyma/components/event-bus/api/push/eventing.kyma.cx/v1alpha1"
"github.com/kyma-project/kyma/components/event-bus/internal/common"
"github.com/kyma-project/kyma/components/event-bus/internal/push/opts"
trc "github.com/kyma-project/kyma/components/event-bus/internal/trace"
"github.com/nats-io/go-nats-streaming"
"github.com/opentracing/opentracing-go"
"github.com/opentracing/opentracing-go/ext"
)
const (
// push request headers to endpoint
headerSourceNamespace = "KYMA-Source-Namespace"
headerSourceType = "KYMA-Source-Type"
headerSourceEnvironment = "KYMA-Source-Environment"
headerEventType = "KYMA-Event-Type"
headerEventTypeVersion = "KYMA-Event-Type-Version"
headerEventID = "KYMA-Event-ID"
headerEventTime = "KYMA-Event-Time"
)
type MessageHandlerFactory struct {
tr *http.Transport
tracer *trc.Tracer
}
func NewMessageHandlerFactory(opts *opts.Options, tracer *trc.Tracer) *MessageHandlerFactory {
tr := initHTTPTransport(opts)
return &MessageHandlerFactory{
tr: tr,
tracer: tracer,
}
}
func initHTTPTransport(opts *opts.Options) *http.Transport {
return &http.Transport{
MaxIdleConns: opts.MaxIdleConns,
IdleConnTimeout: opts.IdleConnTimeout,
DisableCompression: true,
TLSClientConfig: &tls.Config{InsecureSkipVerify: opts.TLSSkipVerify},
}
}
func (mhf *MessageHandlerFactory) NewMsgHandler(sub *v1alpha1.Subscription, opts *opts.Options) func(msg *stan.Msg) {
client := &http.Client{
Transport: mhf.tr,
Timeout: time.Duration(sub.PushRequestTimeoutMS) * time.Millisecond,
}
msgHandler := func(msg *stan.Msg) {
var payload []byte
cloudEvent, err := convertToCloudEvent(&msg.Data)
if err == nil { // message is cloud event compliant, send the data field as the payload if possible
var marshallError error
payload, marshallError = json.Marshal(cloudEvent.Data)
if marshallError != nil { // data is not valid JSON type value, send the message as it is
payload = msg.Data
}
} else { // message is not cloud event compliant, send the message as it is
payload = msg.Data
}
req, err := http.NewRequest(http.MethodPost, sub.Endpoint, bytes.NewBuffer(payload))
if err != nil {
panic(fmt.Sprintf("push HTTP request creation failed: %v", err))
}
req.Header.Add("Content-Type", "application/json")
subNameSupplier := func() string { return sub.Name }
addOptionalHeader(req, sub.IncludeSubscriptionNameHeader, opts.SubscriptionNameHeader, subNameSupplier)
topicNameSupplier := func() string { return common.FromSubscriptionSpec(sub.SubscriptionSpec).Encode() }
addOptionalHeader(req, sub.IncludeTopicHeader, opts.TopicHeader, topicNameSupplier)
var pushSpan *opentracing.Span
if cloudEvent != nil {
if traceContext := getTraceContext(cloudEvent); traceContext != nil && (*mhf.tracer).Started() {
pushSpan = mhf.createPushSpan(traceContext, cloudEvent, sub)
defer trc.FinishSpan(pushSpan)
addTraceContext(pushSpan, req)
}
annotateCloudEventHeaders(req, cloudEvent)
}
resp, err := client.Do(req)
if resp != nil {
trc.TagSpanWithHttpStatusCode(pushSpan, uint16(resp.StatusCode))
}
if err != nil { // failed to send push request
// TODO introduce a metric, counter of message send failure, and update it here
log.Printf("MsgHandler :: Error send push request failed: %v\n", err)
trc.TagSpanAsError(pushSpan, "failed to send push request", err.Error())
// just return from this delivery attempt, message delivery will be retried by NATS Streaming
return
}
defer resp.Body.Close()
if resp.StatusCode < 200 || resp.StatusCode >= 300 { // subscriber failed to receive or process the message, returned non-2xx status code
// TODO introduce a metric, counter of delivery failure per response code, and update it here
trc.TagSpanAsError(pushSpan, "subscriber failed to receive or process the message, returned non-2xx status code", "")
// just return from this delivery attempt, message delivery will be retried by NATS Streaming
return
}
if err := msg.Ack(); err != nil { // failed to ACK message to NATS Streaming
// TODO introduce a metric, counter of ACK to NATS Streaming failures, and update it here
log.Printf("MsgHandler :: Error ACK failed: %v\n", err)
trc.TagSpanAsError(pushSpan, "failed to ACK message to NATS Streaming", err.Error())
// just return from this delivery attempt, message delivery will be retried by NATS Streaming
return
}
// TODO introduce a metric, counter of successful deliveries, and update it here
}
return msgHandler
}
func annotateCloudEventHeaders(req *http.Request, cloudEvent *api.CloudEvent) {
// add cloud event properties as request headers except the data field
req.Header.Add(headerSourceNamespace, cloudEvent.Source.SourceNamespace)
req.Header.Add(headerSourceType, cloudEvent.Source.SourceType)
req.Header.Add(headerSourceEnvironment, cloudEvent.Source.SourceEnvironment)
req.Header.Add(headerEventType, cloudEvent.EventType)
req.Header.Add(headerEventTypeVersion, cloudEvent.EventTypeVersion)
req.Header.Add(headerEventID, cloudEvent.EventID)
req.Header.Add(headerEventTime, cloudEvent.EventTime)
}
func (mhf *MessageHandlerFactory) createPushSpan(traceContext *api.TraceContext, cloudEvent *api.CloudEvent, sub *v1alpha1.Subscription) *opentracing.Span {
spanContext := trc.ReadTraceContext(traceContext)
pushSpan := trc.StartSpan(spanContext, &(*mhf.tracer).Options().OperationName, ext.SpanKindConsumer)
addSpanTagsForCloudEventAndSubscription(pushSpan, cloudEvent, sub)
return pushSpan
}
func addSpanTagsForCloudEventAndSubscription(pushSpan *opentracing.Span, cloudEvent *api.CloudEvent, sub *v1alpha1.Subscription) {
tags := trc.CreateTraceTagsFromCloudEvent(cloudEvent)
tags[trc.SubscriptionName] = sub.Name
tags[trc.SubscriptionEnvironment] = sub.Namespace
trc.SetSpanTags(pushSpan, &tags)
}
func addTraceContext(span *opentracing.Span, req *http.Request) error {
carrier := opentracing.HTTPHeadersCarrier(req.Header)
return opentracing.GlobalTracer().Inject((*span).Context(), opentracing.HTTPHeaders, carrier)
}
func addOptionalHeader(request *http.Request, includeHeader bool, key string, valueSupplier func() string) {
if includeHeader {
value := valueSupplier()
request.Header.Add(key, value)
}
}
func convertToCloudEvent(payload *[]byte) (*api.CloudEvent, error) {
if payload == nil {
return nil, fmt.Errorf("payload is null")
}
var cloudEvent *api.CloudEvent
err := json.Unmarshal(*payload, &cloudEvent)
if err != nil {
return nil, err
}
if err := api.ValidatePublish(&cloudEvent.PublishRequest); err != nil {
return nil, fmt.Errorf("payload is not valid: %v", string(*payload))
}
return cloudEvent, nil
}
func getTraceContext(cloudEvent *api.CloudEvent) *api.TraceContext {
if cloudEvent == nil {
return nil
}
if traceContextWrapper, present := cloudEvent.Extensions[api.FieldTraceContext]; present {
if traceContextMap, ok := traceContextWrapper.(map[string]interface{}); ok {
traceContext := api.TraceContext{}
for key, value := range traceContextMap {
traceContext[key] = fmt.Sprint(value)
}
return &traceContext
}
}
return nil
}