/
event_receiver.go
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/
event_receiver.go
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/*
Copyright 2020 The Knative Authors
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package kncloudevents
import (
"context"
"crypto/tls"
"fmt"
"net"
"net/http"
"time"
"go.opencensus.io/plugin/ochttp"
"knative.dev/pkg/network/handlers"
"knative.dev/pkg/tracing/propagation/tracecontextb3"
)
const (
DefaultShutdownTimeout = time.Minute * 1
)
type HTTPEventReceiver struct {
port int
server *http.Server
listener net.Listener
checker http.HandlerFunc
drainQuietPeriod time.Duration
// Used to signal when receiver is listening
Ready chan interface{}
}
// HTTPEventReceiverOption enables further configuration of a HTTPEventReceiver.
type HTTPEventReceiverOption func(*HTTPEventReceiver)
func NewHTTPEventReceiver(port int, o ...HTTPEventReceiverOption) *HTTPEventReceiver {
h := &HTTPEventReceiver{
port: port,
}
h.Ready = make(chan interface{})
for _, opt := range o {
opt(h)
}
return h
}
// WithChecker takes a handler func which will run as an additional health check in Drainer.
// kncloudevents HTTPEventReceiver uses Drainer to perform health check.
// By default, Drainer directly writes StatusOK to kubelet probe if the Pod is not draining.
// Users can configure customized liveness and readiness check logic by defining checker here.
func WithChecker(checker http.HandlerFunc) HTTPEventReceiverOption {
return func(h *HTTPEventReceiver) {
h.checker = checker
}
}
// WithDrainQuietPeriod configures the QuietPeriod for the Drainer.
func WithDrainQuietPeriod(duration time.Duration) HTTPEventReceiverOption {
return func(h *HTTPEventReceiver) {
h.drainQuietPeriod = duration
}
}
// WithTLSConfig configures the TLS config for the receiver.
func WithTLSConfig(cfg *tls.Config) HTTPEventReceiverOption {
return func(h *HTTPEventReceiver) {
if h.server == nil {
h.server = newServer()
}
h.server.TLSConfig = cfg
}
}
// WithWriteTimeout sets the HTTP server's WriteTimeout. It covers the time between end of reading
// Request Header to end of writing response.
func WithWriteTimeout(duration time.Duration) HTTPEventReceiverOption {
return func(h *HTTPEventReceiver) {
if h.server == nil {
h.server = newServer()
}
h.server.WriteTimeout = duration
}
}
// WithReadTimeout sets the HTTP server's ReadTimeout. It covers the duration from reading the entire request
// (Headers + Body)
func WithReadTimeout(duration time.Duration) HTTPEventReceiverOption {
return func(h *HTTPEventReceiver) {
if h.server == nil {
h.server = newServer()
}
h.server.ReadTimeout = duration
}
}
func (recv *HTTPEventReceiver) GetAddr() string {
if recv.server != nil {
return recv.server.Addr
}
return ""
}
// Blocking
func (recv *HTTPEventReceiver) StartListen(ctx context.Context, handler http.Handler) error {
var err error
if recv.listener, err = net.Listen("tcp", fmt.Sprintf(":%d", recv.port)); err != nil {
return err
}
drainer := &handlers.Drainer{
Inner: CreateHandler(handler),
HealthCheck: recv.checker,
QuietPeriod: recv.drainQuietPeriod,
}
if recv.server == nil {
recv.server = newServer()
}
recv.server.Addr = recv.listener.Addr().String()
recv.server.Handler = drainer
errChan := make(chan error, 1)
go func() {
close(recv.Ready)
if recv.server.TLSConfig == nil {
errChan <- recv.server.Serve(recv.listener)
} else {
errChan <- recv.server.ServeTLS(recv.listener, "", "")
}
}()
// wait for the server to return or ctx.Done().
select {
case <-ctx.Done():
// As we start to shutdown, disable keep-alives to avoid clients hanging onto connections.
recv.server.SetKeepAlivesEnabled(false)
drainer.Drain()
ctx, cancel := context.WithTimeout(context.Background(), getShutdownTimeout(ctx))
defer cancel()
err := recv.server.Shutdown(ctx)
<-errChan // Wait for server goroutine to exit
return err
case err := <-errChan:
return err
}
}
type shutdownTimeoutKey struct{}
func getShutdownTimeout(ctx context.Context) time.Duration {
v := ctx.Value(shutdownTimeoutKey{})
if v == nil {
return DefaultShutdownTimeout
}
return v.(time.Duration)
}
func WithShutdownTimeout(ctx context.Context, timeout time.Duration) context.Context {
return context.WithValue(ctx, shutdownTimeoutKey{}, timeout)
}
func CreateHandler(handler http.Handler) http.Handler {
return &ochttp.Handler{
Propagation: tracecontextb3.TraceContextEgress,
Handler: handler,
}
}
func newServer() *http.Server {
return &http.Server{
ReadTimeout: 10 * time.Second,
}
}