HDDS-13943. Improve error message for malformed input in DirstreamClientHandler

hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/stream/DirstreamClientHandler.java

@@ -44,6 +44,10 @@
  */
 public class DirstreamClientHandler extends ChannelInboundHandlerAdapter {
 
+  private static final String INVALID_FORMAT_MESSAGE =
+      "Expected format: <size> <filename> where <size> is a number and <filename> "
+          + "is a string separated by a single space. Example: '1024 myfile.txt'";
+
   private final StreamingDestination destination;
   private boolean headerMode = true;
   private String currentFileName = "";
@@ -80,7 +84,16 @@ public void doRead(ChannelHandlerContext ctx, ByteBuf buffer)
         name.release();
         buffer.skipBytes(1);
         String[] parts = currentFileName.split(" ", 2);
-        remaining = Long.parseLong(parts[0]);
+        if (parts.length < 2 || parts[1].isEmpty()) {
+          throw new IllegalArgumentException("Invalid file name format: " + currentFileName + ". "
+              + INVALID_FORMAT_MESSAGE);
+        }
+        try {
+          remaining = Long.parseLong(parts[0]);
+        } catch (NumberFormatException e) {
+          throw new IllegalArgumentException("Invalid file name format: " + currentFileName + ". "
+              + INVALID_FORMAT_MESSAGE, e);
+        }
         Path destFilePath = destination.mapToDestination(parts[1]);
         final Path destfileParent = destFilePath.getParent();
         if (destfileParent == null) {

hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/stream/TestDirstreamClientHandler.java

@@ -17,7 +17,9 @@
 
 package org.apache.hadoop.ozone.container.stream;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import io.netty.buffer.ByteBuf;
@@ -27,8 +29,12 @@
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.stream.Stream;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 /**
  * Test streaming client.
@@ -113,6 +119,32 @@ public void splitContent() throws IOException {
     assertEquals("yyy", getContent("bsd.txt"));
   }
 
+  @ParameterizedTest(name = "Invalid format: {0}")
+  @MethodSource("provideInvalidFormatTestCases")
+  public void testInvalidFormat(String testCaseName, String invalidInput) {
+    final DirstreamClientHandler handler = new DirstreamClientHandler(
+        new DirectoryServerDestination(tmpDir));
+
+    IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> {
+      handler.doRead(null, wrap(invalidInput));
+    });
+    assertThat(exception)
+        .hasMessageContaining("Invalid file name format");
+  }
+
+  private static Stream<Arguments> provideInvalidFormatTestCases() {
+    return Stream.of(
+        // Test case: Missing space between size and filename
+        Arguments.of("Missing space", "123File.txt\n"),
+        // Test case: Empty filename after space
+        Arguments.of("Empty filename", "123 \n"),
+        // Test case: Only size number, no filename
+        Arguments.of("Only size", "12345\n"),
+        // Test case: Size is not a number
+        Arguments.of("Invalid size (non-numeric)", "oops filename.txt\n")
+    );
+  }
+
   @Nonnull
   private String getContent(String name) throws IOException {
     return new String(Files.readAllBytes(tmpDir.resolve(name)),