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docs: update storage_copy_file to include MegabytesCopiedPerChunk #2910

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Merged
BenWhitehead merged 1 commit into from
Feb 5, 2025
+43 −33
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docs: update storage_copy_file to include MegabytesCopiedPerChunk #2910

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74 changes: 42 additions & 32 deletions samples/snippets/src/main/java/com/example/storage/object/CopyObject.java
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Original file line number Diff line number Diff line change
Expand Up @@ -19,12 +19,16 @@
// [START storage_copy_file]

import com.google.cloud.storage.BlobId;
import com.google.cloud.storage.BlobInfo;
import com.google.cloud.storage.CopyWriter;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.Storage.CopyRequest;
import com.google.cloud.storage.StorageOptions;

public class CopyObject {
public static void copyObject(
String projectId, String sourceBucketName, String objectName, String targetBucketName) {
String projectId, String sourceBucketName, String objectName, String targetBucketName)
throws Exception {
// The ID of your GCP project
// String projectId = "your-project-id";

Expand All @@ -37,40 +41,46 @@ public static void copyObject(
// The ID of the bucket to copy the object to
// String targetBucketName = "target-object-bucket";

Storage storage = StorageOptions.newBuilder().setProjectId(projectId).build().getService();
BlobId source = BlobId.of(sourceBucketName, objectName);
BlobId target =
BlobId.of(
targetBucketName, objectName); // you could change "objectName" to rename the object
try (Storage storage =
StorageOptions.newBuilder().setProjectId(projectId).build().getService()) {
BlobId sourceId = BlobId.of(sourceBucketName, objectName);
// you could change "objectName" to rename the object
BlobId targetId = BlobId.of(targetBucketName, objectName);

// Optional: set a generation-match precondition to avoid potential race
// conditions and data corruptions. The request returns a 412 error if the
// preconditions are not met.
Storage.BlobTargetOption precondition;
if (storage.get(targetBucketName, objectName) == null) {
// For a target object that does not yet exist, set the DoesNotExist precondition.
// This will cause the request to fail if the object is created before the request runs.
precondition = Storage.BlobTargetOption.doesNotExist();
// Recommended: set a generation-match precondition to avoid potential race
// conditions and data corruptions. The request returns a 412 error if the
// preconditions are not met.
Storage.BlobTargetOption precondition;
BlobInfo existingTarget = storage.get(targetBucketName, objectName);
if (existingTarget == null) {
// For a target object that does not yet exist, set the DoesNotExist precondition.
// This will cause the request to fail if the object is created before the request runs.
precondition = Storage.BlobTargetOption.doesNotExist();
} else {
// If the destination already exists in your bucket, instead set a generation-match
// precondition. This will cause the request to fail if the existing object's generation
// changes before the request runs.
precondition = Storage.BlobTargetOption.generationMatch(existingTarget.getGeneration());
}

} else {
// If the destination already exists in your bucket, instead set a generation-match
// precondition. This will cause the request to fail if the existing object's generation
// changes before the request runs.
precondition =
Storage.BlobTargetOption.generationMatch(
storage.get(targetBucketName, objectName).getGeneration());
}

storage.copy(
Storage.CopyRequest.newBuilder().setSource(source).setTarget(target, precondition).build());
CopyRequest copyRequest =
CopyRequest.newBuilder()
.setSource(sourceId)
.setTarget(targetId, precondition)
// limit the number of bytes Cloud Storage will attempt to copy before responding to
// an individual request.
// If you see Read Timeout errors, try reducing this value.
.setMegabytesCopiedPerChunk(2048L) // 2GiB
.build();
CopyWriter copyWriter = storage.copy(copyRequest);
BlobInfo successfulCopyResult = copyWriter.getResult();

System.out.println(
"Copied object "
+ objectName
+ " from bucket "
+ sourceBucketName
+ " to "
+ targetBucketName);
System.out.printf(
"Copied object gs://%s/%s to %s%n",
sourceBucketName,
objectName,
successfulCopyResult.getBlobId().toGsUtilUriWithGeneration());
}
}
}
// [END storage_copy_file]
2 changes: 1 addition & 1 deletion samples/snippets/src/test/java/com/example/storage/ITObjectSnippets.java
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Original file line number Diff line number Diff line change
Expand Up @@ -134,7 +134,7 @@ public void testChangeObjectStorageClass() {
}

@Test
public void testCopyObject() {
public void testCopyObject() throws Exception {
String newBucket = RemoteStorageHelper.generateBucketName();
storage.create(BucketInfo.newBuilder(newBucket).build());
try {
Expand Down