HADOOP-19575. ABFS: [FNSOverBlob] Add Distinct String In User Agent to Get Telemetry for FNS-Blob (#7713)

Contributed by Manika Joshi.

hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/services/AbfsClient.java

@@ -127,6 +127,7 @@ import static org.apache.hadoop.fs.azurebfs.constants.AbfsHttpConstants.PLUS_ENC
 import static org.apache.hadoop.fs.azurebfs.constants.AbfsHttpConstants.SEMICOLON;
 import static org.apache.hadoop.fs.azurebfs.constants.AbfsHttpConstants.SINGLE_WHITE_SPACE;
 import static org.apache.hadoop.fs.azurebfs.constants.AbfsHttpConstants.UTF_8;
+import static org.apache.hadoop.fs.azurebfs.constants.AbfsServiceType.BLOB;
 import static org.apache.hadoop.fs.azurebfs.constants.ConfigurationKeys.FS_AZURE_IDENTITY_TRANSFORM_CLASS;
 import static org.apache.hadoop.fs.azurebfs.constants.FileSystemConfigurations.DEFAULT_DELETE_CONSIDERED_IDEMPOTENT;
 import static org.apache.hadoop.fs.azurebfs.constants.FileSystemConfigurations.ONE_MB;
@@ -152,6 +153,7 @@ public abstract class AbfsClient implements Closeable {
   public static final Logger LOG = LoggerFactory.getLogger(AbfsClient.class);
   public static final String HUNDRED_CONTINUE_USER_AGENT = SINGLE_WHITE_SPACE + HUNDRED_CONTINUE + SEMICOLON;
   public static final String ABFS_CLIENT_TIMER_THREAD_NAME = "abfs-timer-client";
+  public static final String FNS_BLOB_USER_AGENT_IDENTIFIER = "FNS";
 
   private final URL baseUrl;
   private final SharedKeyCredentials sharedKeyCredentials;
@@ -1319,6 +1321,14 @@ public abstract class AbfsClient implements Closeable {
     sb.append(FORWARD_SLASH);
     sb.append(abfsConfiguration.getClusterType());
 
+    // Add a unique identifier in FNS-Blob user agent string
+    if (!getIsNamespaceEnabled()
+        && abfsConfiguration.getFsConfiguredServiceType() == BLOB) {
+      sb.append(SEMICOLON)
+          .append(SINGLE_WHITE_SPACE)
+          .append(FNS_BLOB_USER_AGENT_IDENTIFIER);
+    }
+
     sb.append(")");
 
     appendIfNotEmpty(sb, abfsConfiguration.getCustomUserAgentPrefix(), false);

hadoop-tools/hadoop-azure/src/test/java/org/apache/hadoop/fs/azurebfs/services/ITestAbfsClient.java

@@ -106,6 +106,7 @@ public final class ITestAbfsClient extends AbstractAbfsIntegrationTest {
 
   private static final String ACCOUNT_NAME = "bogusAccountName.dfs.core.windows.net";
   private static final String FS_AZURE_USER_AGENT_PREFIX = "Partner Service";
+  private static final String FNS_BLOB_USER_AGENT_IDENTIFIER = "FNS";
   private static final String HUNDRED_CONTINUE_USER_AGENT = SINGLE_WHITE_SPACE + HUNDRED_CONTINUE + SEMICOLON;
   private static final String TEST_PATH = "/testfile";
   public static final int REDUCED_RETRY_COUNT = 2;
@@ -355,6 +356,42 @@ public final class ITestAbfsClient extends AbstractAbfsIntegrationTest {
       .contains(DEFAULT_VALUE_UNKNOWN);
   }
 
+  @Test
+  // Test to verify the unique identifier in user agent string for FNS-Blob accounts
+  public void verifyUserAgentForFNSBlob() throws Exception {
+    assumeHnsDisabled();
+    assumeBlobServiceType();
+    final AzureBlobFileSystem fs = getFileSystem();
+    final AbfsConfiguration configuration = fs.getAbfsStore()
+        .getAbfsConfiguration();
+
+    String userAgentStr = getUserAgentString(configuration, false);
+    verifyBasicInfo(userAgentStr);
+    Assertions.assertThat(userAgentStr)
+        .describedAs(
+            "User-Agent string for FNS accounts on Blob endpoint should contain "
+                + FNS_BLOB_USER_AGENT_IDENTIFIER)
+        .contains(FNS_BLOB_USER_AGENT_IDENTIFIER);
+  }
+
+  @Test
+  // Test to verify that the user agent string for non-FNS-Blob accounts
+  // does not contain the FNS identifier.
+  public void verifyUserAgentForDFS() throws Exception {
+    assumeDfsServiceType();
+    final AzureBlobFileSystem fs = getFileSystem();
+    final AbfsConfiguration configuration = fs.getAbfsStore()
+        .getAbfsConfiguration();
+
+    String userAgentStr = getUserAgentString(configuration, false);
+    verifyBasicInfo(userAgentStr);
+    Assertions.assertThat(userAgentStr)
+        .describedAs(
+            "User-Agent string for non-FNS-Blob accounts should not contain"
+                + FNS_BLOB_USER_AGENT_IDENTIFIER)
+        .doesNotContain(FNS_BLOB_USER_AGENT_IDENTIFIER);
+  }
+
   public static AbfsClient createTestClientFromCurrentContext(
       AbfsClient baseAbfsClientInstance,
       AbfsConfiguration abfsConfig) throws IOException, URISyntaxException {