PLT-5705 Created a single source of http.Client creation logic with internet proxy support, reasonable timeouts and optional insecure connections (#6503)

utils/httpclient.go

@@ -0,0 +1,60 @@
+// Copyright (c) 2017-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package utils
+
+import (
+	"crypto/tls"
+	"net"
+	"net/http"
+	"time"
+)
+
+const (
+	connectTimeout = 3 * time.Second
+	requestTimeout = 5 * time.Second
+)
+
+// HttpClient returns a variation the default implementation of Client.
+// It uses a Transport with the same settings as the default Transport
+// but with the following modifications:
+// - shorter timeout for dial and TLS handshake (defined as constant
+//   "connectTimeout")
+// - timeout for the end-to-end request (defined as constant
+//   "requestTimeout")
+// - skipping server certificate check if specified in "config.json"
+//   via "ServiceSettings.EnableInsecureOutgoingConnections"
+func HttpClient() *http.Client {
+	if Cfg.ServiceSettings.EnableInsecureOutgoingConnections != nil && *Cfg.ServiceSettings.EnableInsecureOutgoingConnections {
+		return insecureHttpClient
+	}
+	return secureHttpClient
+}
+
+var (
+	secureHttpClient   = createHttpClient(false)
+	insecureHttpClient = createHttpClient(true)
+)
+
+func createHttpClient(enableInsecureConnections bool) *http.Client {
+	client := &http.Client{
+		Transport: &http.Transport{
+			Proxy: http.ProxyFromEnvironment,
+			DialContext: (&net.Dialer{
+				Timeout:   connectTimeout,
+				KeepAlive: 30 * time.Second,
+				DualStack: true,
+			}).DialContext,
+			MaxIdleConns:          100,
+			IdleConnTimeout:       90 * time.Second,
+			TLSHandshakeTimeout:   connectTimeout,
+			ExpectContinueTimeout: 1 * time.Second,
+			TLSClientConfig: &tls.Config{
+				InsecureSkipVerify: enableInsecureConnections,
+			},
+		},
+		Timeout: requestTimeout,
+	}
+
+	return client
+}

utils/httpclient_test.go

@@ -0,0 +1,42 @@
+// Copyright (c) 2017-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package utils
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"testing"
+)
+
+func TestHttpClientWithProxy(t *testing.T) {
+	proxy := createProxyServer()
+	defer proxy.Close()
+	os.Setenv("HTTP_PROXY", proxy.URL)
+
+	client := HttpClient()
+	resp, err := client.Get("http://acme.com")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer resp.Body.Close()
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(body) != "proxy" {
+		t.FailNow()
+	}
+}
+
+func createProxyServer() *httptest.Server {
+	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(200)
+		w.Header().Set("Content-Type", "text/plain; charset=us-ascii")
+		fmt.Fprint(w, "proxy")
+	}))
+}