Fix FakeService for Thrift tests (#200)

Do not set FakeService as the proxy if the target URI points
directly to the corresponding WireMock server.

Author: jayantsing-db

src/main/java/com/databricks/jdbc/client/http/DatabricksHttpClient.java

@@ -2,6 +2,7 @@
 
 import static com.databricks.jdbc.driver.DatabricksJdbcConstants.FAKE_SERVICE_URI_PROP_SUFFIX;
 import static com.databricks.jdbc.driver.DatabricksJdbcConstants.IS_FAKE_SERVICE_TEST_PROP;
+import static io.netty.util.NetUtil.LOCALHOST;
 
 import com.databricks.jdbc.client.DatabricksHttpException;
 import com.databricks.jdbc.client.IDatabricksHttpClient;
@@ -192,9 +193,6 @@ public static void setProxyDetailsInHttpClient(
   static void setFakeServiceRouteInHttpClient(HttpClientBuilder builder) {
     builder.setRoutePlanner(
         (host, request, context) -> {
-          // Get the fake service URI for the target URI and set it as proxy
-          final HttpHost proxy =
-              HttpHost.create(System.getProperty(host.toURI() + FAKE_SERVICE_URI_PROP_SUFFIX));
           final HttpHost target;
           try {
             target =
@@ -205,6 +203,16 @@ static void setFakeServiceRouteInHttpClient(HttpClientBuilder builder) {
           } catch (UnsupportedSchemeException e) {
             throw new HttpException(e.getMessage());
           }
+
+          if (LOCALHOST.getHostName().equalsIgnoreCase(host.getHostName())) {
+            // If the target host is localhost, then no need to set proxy
+            return new HttpRoute(target, null, false);
+          }
+
+          // Get the fake service URI for the target URI and set it as proxy
+          final HttpHost proxy =
+              HttpHost.create(System.getProperty(host.toURI() + FAKE_SERVICE_URI_PROP_SUFFIX));
+
           return new HttpRoute(target, null, proxy, false);
         });
   }

src/test/java/com/databricks/jdbc/client/http/DatabricksHttpClientTest.java

@@ -43,6 +43,8 @@ public class DatabricksHttpClientTest {
 
   @Mock CloseableHttpResponse closeableHttpResponse;
 
+  @Mock HttpClientBuilder httpClientBuilder;
+
   private static final String CLUSTER_JDBC_URL =
       "jdbc:databricks://e2-dogfood.staging.cloud.databricks.com:443/default;transportMode=http;ssl=1;httpPath=sql/protocolv1/o/6051921418418893/1115-130834-ms4m0yv;AuthMech=3;UserAgentEntry=MyApp";
   private static final String DBSQL_JDBC_URL =
@@ -77,7 +79,6 @@ public void testSetFakeServiceRouteInHttpClient() throws HttpException {
     final String testFakeServiceURI = "http://localhost:8080";
     System.setProperty(testTargetURI + FAKE_SERVICE_URI_PROP_SUFFIX, testFakeServiceURI);
 
-    HttpClientBuilder httpClientBuilder = Mockito.mock(HttpClientBuilder.class);
     ArgumentCaptor<HttpRoutePlanner> routePlannerCaptor =
         ArgumentCaptor.forClass(HttpRoutePlanner.class);
 
@@ -101,11 +102,29 @@ public void testSetFakeServiceRouteInHttpClient() throws HttpException {
     System.clearProperty(testTargetURI + FAKE_SERVICE_URI_PROP_SUFFIX);
   }
 
+  @Test
+  public void testSetFakeServiceRouteInHttpClientWithLocalhostTarget() throws HttpException {
+    ArgumentCaptor<HttpRoutePlanner> routePlannerCaptor =
+        ArgumentCaptor.forClass(HttpRoutePlanner.class);
+
+    DatabricksHttpClient.setFakeServiceRouteInHttpClient(httpClientBuilder);
+
+    Mockito.verify(httpClientBuilder).setRoutePlanner(routePlannerCaptor.capture());
+    HttpRoutePlanner capturedRoutePlanner = routePlannerCaptor.getValue();
+
+    HttpGet request = new HttpGet("http://localhost:53423");
+    HttpRoute route =
+        capturedRoutePlanner.determineRoute(
+            HttpHost.create(request.getURI().toString()), request, null);
+
+    // Verify the route has no proxy host set as the target URI directly points to fake service
+    assertNull(route.getProxyHost());
+  }
+
   @Test
   public void testSetFakeServiceRouteInHttpClientThrowsError() {
     final String testTargetURI = "https://example.com";
 
-    HttpClientBuilder httpClientBuilder = Mockito.mock(HttpClientBuilder.class);
     ArgumentCaptor<HttpRoutePlanner> routePlannerCaptor =
         ArgumentCaptor.forClass(HttpRoutePlanner.class);
 
@@ -131,7 +150,6 @@ public void testSetFakeServiceRouteInHttpClientThrowsHTTPError() {
     final String testFakeServiceURI = "http://localhost:8080";
     System.setProperty(testTargetURI + FAKE_SERVICE_URI_PROP_SUFFIX, testFakeServiceURI);
 
-    HttpClientBuilder httpClientBuilder = Mockito.mock(HttpClientBuilder.class);
     ArgumentCaptor<HttpRoutePlanner> routePlannerCaptor =
         ArgumentCaptor.forClass(HttpRoutePlanner.class);