Merge pull request #14666 from bergquist/close_body

Closes the body properly on successful webhooks

devenv/docker/blocks/alert_webhook_listener/Dockerfile

+
+FROM golang:latest 
+ADD main.go /
+WORKDIR /
+RUN go build -o main . 
+EXPOSE 3010
+ENTRYPOINT ["/main"]

devenv/docker/blocks/alert_webhook_listener/docker-compose.yaml

+  alert_webhook_listener:
+    build: docker/blocks/alert_webhook_listener
+    network_mode: host
+    ports:
+      - "3010:3010"

devenv/docker/blocks/alert_webhook_listener/main.go

+package main
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+)
+
+func hello(w http.ResponseWriter, r *http.Request) {
+	body, err := ioutil.ReadAll(r.Body)
+	if err != nil {
+		return
+	}
+
+	line := fmt.Sprintf("webbhook: -> %s", string(body))
+	fmt.Println(line)
+	io.WriteString(w, line)
+}
+
+func main() {
+	http.HandleFunc("/", hello)
+	http.ListenAndServe(":3010", nil)
+}

pkg/services/notifications/webhook.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"net"
 	"net/http"
@@ -69,11 +70,14 @@ func (ns *NotificationService) sendWebRequestSync(ctx context.Context, webhook *
 		return err
 	}
 
+	defer resp.Body.Close()
+
 	if resp.StatusCode/100 == 2 {
+		// flushing the body enables the transport to reuse the same connection
+		io.Copy(ioutil.Discard, resp.Body)
 		return nil
 	}
 
-	defer resp.Body.Close()
 	body, err := ioutil.ReadAll(resp.Body)
 	if err != nil {
 		return err