add checksum failure metrics (#1549)

gcs/src/main/java/com/google/cloud/hadoop/fs/gcs/GhfsGlobalStorageStatistics.java

@@ -35,6 +35,7 @@
 import static com.google.cloud.hadoop.gcsio.GoogleCloudStorageStatistics.GCS_API_SERVER_SERVICE_UNAVAILABLE_COUNT;
 import static com.google.cloud.hadoop.gcsio.GoogleCloudStorageStatistics.GCS_API_SERVER_SIDE_ERROR_COUNT;
 import static com.google.cloud.hadoop.gcsio.GoogleCloudStorageStatistics.GCS_API_SERVER_TIMEOUT_COUNT;
+import static com.google.cloud.hadoop.gcsio.GoogleCloudStorageStatistics.WRITE_CHECKSUM_FAILURE_COUNT;
 import static com.google.cloud.hadoop.gcsio.StatisticTypeEnum.TYPE_DURATION;
 import static com.google.cloud.hadoop.gcsio.StatisticTypeEnum.TYPE_DURATION_TOTAL;
 import static com.google.common.base.Preconditions.checkArgument;
@@ -303,6 +304,10 @@ void incrementGcsExceptionCount() {
     increment(EXCEPTION_COUNT);
   }
 
+  void incrementWriteChecksumFailureCount() {
+    increment(WRITE_CHECKSUM_FAILURE_COUNT);
+  }
+
   void incrementGcsTotalRequestCount() {
     increment(GCS_API_REQUEST_COUNT);
   }

gcs/src/main/java/com/google/cloud/hadoop/fs/gcs/GoogleCloudStorageEventSubscriber.java

@@ -21,6 +21,7 @@
 
 import com.google.cloud.hadoop.gcsio.GoogleCloudStorageStatistics;
 import com.google.cloud.hadoop.gcsio.StatisticTypeEnum;
+import com.google.cloud.hadoop.util.GCSChecksumFailureEvent;
 import com.google.cloud.hadoop.util.GcsJsonApiEvent;
 import com.google.cloud.hadoop.util.GcsJsonApiEvent.EventType;
 import com.google.cloud.hadoop.util.GcsJsonApiEvent.RequestType;
@@ -141,6 +142,11 @@ private void subscriberOnException(IOException exception) {
     storageStatistics.incrementGcsExceptionCount();
   }
 
+  @Subscribe
+  private void onGcsChecksumFailure(GCSChecksumFailureEvent exception) {
+    storageStatistics.incrementWriteChecksumFailureCount();
+  }
+
   /**
    * Updating the required gcs specific statistics based on httpresponse.
    *

gcs/src/test/java/com/google/cloud/hadoop/fs/gcs/GoogleCloudStorageStatisticsTest.java

@@ -31,6 +31,7 @@
 import static com.google.cloud.hadoop.gcsio.GoogleCloudStorageStatistics.GCS_API_SERVER_SIDE_ERROR_COUNT;
 import static com.google.cloud.hadoop.gcsio.GoogleCloudStorageStatistics.GCS_API_SERVER_TIMEOUT_COUNT;
 import static com.google.cloud.hadoop.gcsio.GoogleCloudStorageStatistics.GCS_METADATA_REQUEST;
+import static com.google.cloud.hadoop.gcsio.GoogleCloudStorageStatistics.WRITE_CHECKSUM_FAILURE_COUNT;
 import static com.google.common.truth.Truth.assertThat;
 
 import com.google.cloud.hadoop.util.GcsJsonApiEvent;
@@ -184,6 +185,14 @@ public void gcs_clientBadRequestCount() throws IOException {
     verifyStatistics(verifyCounterStats);
   }
 
+  @Test
+  public void gcs_writeChecksumFailureCount() throws IOException {
+    GoogleCloudStorageEventBus.postWriteChecksumFailure();
+    GhfsGlobalStorageStatistics verifyCounterStats = new GhfsGlobalStorageStatistics();
+    verifyCounterStats.incrementCounter(WRITE_CHECKSUM_FAILURE_COUNT, 1);
+    verifyStatistics(verifyCounterStats);
+  }
+
   private class TestGcsApiEvent implements IGcsJsonApiEvent {
     private final int statusCode;
 

gcsio/src/main/java/com/google/cloud/hadoop/gcsio/GoogleCloudStorageStatistics.java

@@ -27,6 +27,10 @@
 /** Statistics which are collected in GCS Connector. */
 public enum GoogleCloudStorageStatistics {
   EXCEPTION_COUNT("exception_count", "Counts the number of exceptions encountered", TYPE_COUNTER),
+  WRITE_CHECKSUM_FAILURE_COUNT(
+      "write_checksum_failure_count",
+      "Counts the number of checksum failures during write",
+      TYPE_COUNTER),
 
   /** Status Code Counters for JSON Path */
   GCS_API_REQUEST_COUNT(

gcsio/src/main/java/com/google/cloud/hadoop/gcsio/GoogleCloudStorageWriteChannel.java

@@ -130,6 +130,7 @@ private void verifyChecksums(String serverProvidedCrc32c) throws IOException {
     String srcCrc =
         BaseEncoding.base64().encode(Ints.toByteArray(cumulativeCrc32cHasher.hash().asInt()));
     if (!srcCrc.equals(serverProvidedCrc32c)) {
+      GoogleCloudStorageEventBus.postWriteChecksumFailure();
       throw new IOException(
           String.format(
               "Data integrity check failed for resource '%s'. Client-calculated CRC32C (%s) did not match server-provided CRC32C (%s).",

util/src/main/java/com/google/cloud/hadoop/util/GCSChecksumFailureEvent.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2025 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.cloud.hadoop.util;
+
+/** A thin class to emit checksum failure event for EventBus notification. */
+public class GCSChecksumFailureEvent extends Exception {}

util/src/main/java/com/google/cloud/hadoop/util/GoogleCloudStorageEventBus.java

@@ -27,6 +27,7 @@ public class GoogleCloudStorageEventBus {
   private static EventBus eventBus = new EventBus();
 
   private static IOException exception = new IOException();
+  private static GCSChecksumFailureEvent checksumFailureEvent = new GCSChecksumFailureEvent();
 
   /**
    * Method to register an obj to event bus
@@ -76,4 +77,8 @@ public static void onGrpcStatus(Status status) {
   public static void postGcsJsonApiEvent(IGcsJsonApiEvent gcsJsonApiEvent) {
     eventBus.post(gcsJsonApiEvent);
   }
+
+  public static void postWriteChecksumFailure() {
+    eventBus.post(checksumFailureEvent);
+  }
 }