Improved flow by defining httpClient only once

Signed-off-by: Tim de Pater <[email protected]>

main.go

@@ -128,27 +128,27 @@ func main() {
 	// returns nil if not provided and falls back to simple TCP.
 	tlsConfig := createTLSConfig(*esCA, *esClientCert, *esClientPrivateKey, *esInsecureSkipVerify)
 
-	httpTransport := &http.Transport{
+	var httpTransport http.RoundTripper
+
+	httpTransport = &http.Transport{
 		TLSClientConfig: tlsConfig,
 		Proxy:           http.ProxyFromEnvironment,
 	}
 
-	httpClient := &http.Client{
-		Timeout:   *esTimeout,
-		Transport: httpTransport,
-	}
-
 	if *esApiKey != "" {
 		apiKey := *esApiKey
-		httpClient = &http.Client{
-			Timeout: *esTimeout,
-			Transport: &transportWithApiKey{
-				underlyingTransport: httpTransport,
-				apiKey:              apiKey,
-			},
+
+		httpTransport = &transportWithApiKey{
+			underlyingTransport: httpTransport,
+			apiKey:              apiKey,
 		}
 	}
 
+	httpClient := &http.Client{
+		Timeout:   *esTimeout,
+		Transport: httpTransport,
+	}
+
 	// version metric
 	versionMetric := version.NewCollector(Name)
 	prometheus.MustRegister(versionMetric)