fix: close and drain the response body always (#8847)

pkg/event/target/webhook.go

@@ -142,15 +142,14 @@ func (target *WebhookTarget) send(eventData event.Event) error {
 
 	resp, err := target.httpClient.Do(req)
 	if err != nil {
+		target.Close()
 		return err
 	}
-
 	defer resp.Body.Close()
 	io.Copy(ioutil.Discard, resp.Body)
 
 	if resp.StatusCode < 200 || resp.StatusCode > 299 {
-		// close any idle connections upon any error.
-		target.httpClient.CloseIdleConnections()
+		target.Close()
 		return fmt.Errorf("sending event failed with %v", resp.Status)
 	}
 

pkg/madmin/api.go

@@ -270,6 +270,9 @@ func (adm AdminClient) do(req *http.Request) (*http.Response, error) {
 	for {
 		resp, err = adm.httpClient.Do(req)
 		if err != nil {
+			// Close idle connections upon error.
+			adm.httpClient.CloseIdleConnections()
+
 			// Handle this specifically for now until future Golang
 			// versions fix this issue properly.
 			urlErr, ok := err.(*url.Error)

pkg/net/url.go

@@ -20,6 +20,8 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
+	"io/ioutil"
 	"net"
 	"net/http"
 	"net/url"
@@ -100,6 +102,7 @@ func (u URL) DialHTTP() error {
 	if err != nil {
 		return err
 	}
+	io.Copy(ioutil.Discard, resp.Body)
 	resp.Body.Close()
 	return nil
 }