[controller] Log remote address in the controller audit log (#1507)

Sometimes it's necessary to identify the source of requests to the Venice controller.  
Without logging the remote address, debugging can be difficult. This change adds  
the client IP to the audit log, to make troubleshooting easier.

services/venice-controller/src/main/java/com/linkedin/venice/controller/AuditInfo.java

@@ -10,6 +10,7 @@ public class AuditInfo {
   private String url;
   private Map<String, String> params;
   private String method;
+  private String clientIp;
 
   public AuditInfo(Request request) {
     this.url = request.url();
@@ -18,49 +19,31 @@ public AuditInfo(Request request) {
       this.params.put(param, request.queryParams(param));
     }
     this.method = request.requestMethod();
+    this.clientIp = request.ip() + ":" + request.raw().getRemotePort();
   }
 
-  /**
-   * @return a string representation of {@link AuditInfo} object.
-   */
   @Override
   public String toString() {
-    StringJoiner joiner = new StringJoiner(" ");
-    joiner.add("[AUDIT]");
-    joiner.add(method);
-    joiner.add(url);
-    joiner.add(params.toString());
-    return joiner.toString();
+    return formatAuditMessage("[AUDIT]", null);
   }
 
-  /**
-   * @return a audit-successful string.
-   */
   public String successString() {
-    return toString(true, null);
+    return formatAuditMessage("[AUDIT]", "SUCCESS");
   }
 
-  /**
-   * @return a audit-failure string.
-   */
   public String failureString(String errMsg) {
-    return toString(false, errMsg);
+    return formatAuditMessage("[AUDIT]", "FAILURE: " + (errMsg != null ? errMsg : ""));
   }
 
-  private String toString(boolean success, String errMsg) {
-    StringJoiner joiner = new StringJoiner(" ");
-    joiner.add("[AUDIT]");
-    if (success) {
-      joiner.add("SUCCESS");
-    } else {
-      joiner.add("FAILURE: ");
-      if (errMsg != null) {
-        joiner.add(errMsg);
-      }
+  private String formatAuditMessage(String prefix, String status) {
+    StringJoiner joiner = new StringJoiner(" ").add(prefix);
+
+    if (status != null) {
+      joiner.add(status);
     }
-    joiner.add(method);
-    joiner.add(url);
-    joiner.add(params.toString());
+
+    joiner.add(method).add(url).add(params.toString()).add("ClientIP: " + clientIp);
+
     return joiner.toString();
   }
 }

services/venice-controller/src/test/java/com/linkedin/venice/controller/AuditInfoTest.java

@@ -0,0 +1,94 @@
+package com.linkedin.venice.controller;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+import static org.testng.Assert.assertFalse;
+import static org.testng.Assert.assertTrue;
+
+import java.util.HashSet;
+import java.util.Set;
+import javax.servlet.http.HttpServletRequest;
+import org.testng.annotations.BeforeMethod;
+import org.testng.annotations.Test;
+import spark.Request;
+
+
+public class AuditInfoTest {
+  private static final String TEST_URL = "http://localhost/test";
+  private static final String METHOD_GET = "GET";
+  private static final String CLIENT_IP = "127.0.0.1";
+  private static final int CLIENT_PORT = 8080;
+  private static final String PARAM_1 = "param1";
+  private static final String PARAM_2 = "param2";
+  private static final String VALUE_1 = "value1";
+  private static final String VALUE_2 = "value2";
+  private static final String AUDIT_PREFIX = "[AUDIT]";
+  private static final String SUCCESS = "SUCCESS";
+  private static final String FAILURE = "FAILURE";
+  private static final String ERROR_MESSAGE = "Some error";
+
+  private Request request;
+  private AuditInfo auditInfo;
+  private HttpServletRequest httpServletRequest;
+
+  @BeforeMethod
+  public void setUp() {
+    request = mock(Request.class);
+    when(request.url()).thenReturn(TEST_URL);
+    when(request.requestMethod()).thenReturn(METHOD_GET);
+    when(request.ip()).thenReturn(CLIENT_IP);
+
+    Set<String> queryParams = new HashSet<>();
+    queryParams.add(PARAM_1);
+    queryParams.add(PARAM_2);
+
+    when(request.queryParams()).thenReturn(queryParams);
+    when(request.queryParams(PARAM_1)).thenReturn(VALUE_1);
+    when(request.queryParams(PARAM_2)).thenReturn(VALUE_2);
+
+    httpServletRequest = mock(HttpServletRequest.class);
+    when(httpServletRequest.getRemotePort()).thenReturn(CLIENT_PORT);
+    when(request.raw()).thenReturn(httpServletRequest);
+
+    auditInfo = new AuditInfo(request);
+  }
+
+  @Test
+  public void testToStringReturnsExpectedFormat() {
+    String result = auditInfo.toString();
+    assertTrue(result.contains(AUDIT_PREFIX));
+    assertTrue(result.contains(METHOD_GET));
+    assertTrue(result.contains(TEST_URL));
+    assertTrue(result.contains(PARAM_1 + "=" + VALUE_1));
+    assertTrue(result.contains(PARAM_2 + "=" + VALUE_2));
+    assertTrue(result.contains("ClientIP: " + CLIENT_IP + ":" + CLIENT_PORT));
+  }
+
+  @Test
+  public void testSuccessStringReturnsExpectedFormat() {
+    String result = auditInfo.successString();
+    assertTrue(result.contains(AUDIT_PREFIX));
+    assertTrue(result.contains(SUCCESS));
+    assertTrue(result.contains(METHOD_GET));
+    assertTrue(result.contains(TEST_URL));
+    assertTrue(result.contains("ClientIP: " + CLIENT_IP));
+  }
+
+  @Test
+  public void testFailureStringReturnsExpectedFormat() {
+    String result = auditInfo.failureString(ERROR_MESSAGE);
+    assertTrue(result.contains(AUDIT_PREFIX));
+    assertTrue(result.contains(FAILURE));
+    assertTrue(result.contains(ERROR_MESSAGE));
+    assertTrue(result.contains(METHOD_GET));
+    assertTrue(result.contains(TEST_URL));
+    assertTrue(result.contains("ClientIP: " + CLIENT_IP));
+  }
+
+  @Test
+  public void testFailureStringHandlesNullErrorMessage() {
+    String result = auditInfo.failureString(null);
+    assertTrue(result.contains(AUDIT_PREFIX));
+    assertFalse(result.contains("null"));
+  }
+}