Compose multiple objects
Compose multiple objects into a single object in a Cloud Storage bucket.
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Code sample
C++
For more information, see theCloud StorageC++ API reference documentation.
To authenticate to Cloud Storage, set up Application Default Credentials. For more information, seeSet up authentication for client libraries.
namespacegcs=::google::cloud::storage;using::google::cloud::StatusOr;[](gcs::Clientclient,std::stringconst&bucket_name,std::stringconst&destination_object_name,std::vector<gcs::ComposeSourceObject>const&compose_objects){StatusOr<gcs::ObjectMetadata>composed_object=client.ComposeObject(bucket_name,compose_objects,destination_object_name);if(!composed_object)throwstd::move(composed_object).status();std::cout <<"Composed new object " <<composed_object->name() <<" in bucket " <<composed_object->bucket() <<"\nFull metadata: " <<*composed_object <<"\n";}C#
For more information, see theCloud StorageC# API reference documentation.
To authenticate to Cloud Storage, set up Application Default Credentials. For more information, seeSet up authentication for client libraries.
usingGoogle.Apis.Storage.v1.Data;usingGoogle.Cloud.Storage.V1;usingSystem;usingSystem.Collections.Generic;publicclassComposeObjectSample{publicvoidComposeObject(stringbucketName="your-bucket-name",stringfirstObjectName="your-first-object-name",stringsecondObjectName="your-second-object-name",stringtargetObjectName="new-composite-object-name"){varstorage=StorageClient.Create();varsourceObjects=newList<ComposeRequest.SourceObjectsData>{newComposeRequest.SourceObjectsData{Name=firstObjectName},newComposeRequest.SourceObjectsData{Name=secondObjectName}};//You could add as many sourceObjects as you want here, up to the max of 32.storage.Service.Objects.Compose(newComposeRequest{SourceObjects=sourceObjects,Destination=newGoogle.Apis.Storage.v1.Data.Object{ContentType="text/plain"}},bucketName,targetObjectName).Execute();Console.WriteLine($"New composite file {targetObjectName} was created in bucket {bucketName}"+$" by combining {firstObjectName} and {secondObjectName}.");}}Go
For more information, see theCloud StorageGo API reference documentation.
To authenticate to Cloud Storage, set up Application Default Credentials. For more information, seeSet up authentication for client libraries.
import("context""fmt""io""time""cloud.google.com/go/storage")// composeFile composes source objects to create a composite object.funccomposeFile(wio.Writer,bucket,object1,object2,toObjectstring)error{// bucket := "bucket-name"// object1 := "object-name-1"// object2 := "object-name-2"// toObject := "object-name-3"ctx:=context.Background()client,err:=storage.NewClient(ctx)iferr!=nil{returnfmt.Errorf("storage.NewClient: %w",err)}deferclient.Close()ctx,cancel:=context.WithTimeout(ctx,time.Second*10)defercancel()src1:=client.Bucket(bucket).Object(object1)src2:=client.Bucket(bucket).Object(object2)dst:=client.Bucket(bucket).Object(toObject)// ComposerFrom takes varargs, so you can put as many objects here// as you want._,err=dst.ComposerFrom(src1,src2).Run(ctx)iferr!=nil{returnfmt.Errorf("ComposerFrom: %w",err)}fmt.Fprintf(w,"New composite object %v was created by combining %v and %v\n",toObject,object1,object2)returnnil}Java
For more information, see theCloud StorageJava API reference documentation.
To authenticate to Cloud Storage, set up Application Default Credentials. For more information, seeSet up authentication for client libraries.
importcom.google.cloud.storage.Blob;importcom.google.cloud.storage.BlobInfo;importcom.google.cloud.storage.Storage;importcom.google.cloud.storage.StorageOptions;publicclassComposeObject{publicstaticvoidcomposeObject(StringbucketName,StringfirstObjectName,StringsecondObjectName,StringtargetObjectName,StringprojectId){// The ID of your GCP project// String projectId = "your-project-id";// The ID of your GCS bucket// String bucketName = "your-unique-bucket-name";// The ID of the first GCS object to compose// String firstObjectName = "your-first-object-name";// The ID of the second GCS object to compose// String secondObjectName = "your-second-object-name";// The ID to give the new composite object// String targetObjectName = "new-composite-object-name";Storagestorage=StorageOptions.newBuilder().setProjectId(projectId).build().getService();// 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.BlobTargetOptionprecondition;if(storage.get(bucketName,targetObjectName)==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(storage.get(bucketName,targetObjectName).getGeneration());}Storage.ComposeRequestcomposeRequest=Storage.ComposeRequest.newBuilder()// addSource takes varargs, so you can put as many objects here as you want, up to the// max of 32.addSource(firstObjectName,secondObjectName).setTarget(BlobInfo.newBuilder(bucketName,targetObjectName).build()).setTargetOptions(precondition).build();BlobcompositeObject=storage.compose(composeRequest);System.out.println("New composite object "+compositeObject.getName()+" was created by combining "+firstObjectName+" and "+secondObjectName);}}Node.js
For more information, see theCloud StorageNode.js API reference documentation.
To authenticate to Cloud Storage, set up Application Default Credentials. For more information, seeSet up authentication for client libraries.
/** * TODO(developer): Uncomment the following lines before running the sample. */// The ID of your GCS bucket// const bucketName = 'your-unique-bucket-name';// The ID of the first GCS file to compose// const firstFileName = 'your-first-file-name';// The ID of the second GCS file to compose// const secondFileName = 'your-second-file-name';// The ID to give the new composite file// const destinationFileName = 'new-composite-file-name';// Imports the Google Cloud client libraryconst{Storage}=require('@google-cloud/storage');// Creates a clientconststorage=newStorage();asyncfunctioncomposeFile(){constbucket=storage.bucket(bucketName);constsources=[firstFileName,secondFileName];// Optional:// Set a generation-match precondition to avoid potential race conditions// and data corruptions. The request to compose is aborted if the object's// generation number does not match your precondition. For a destination// object that does not yet exist, set the ifGenerationMatch precondition to 0// If the destination object already exists in your bucket, set instead a// generation-match precondition using its generation number.constcombineOptions={ifGenerationMatch:destinationGenerationMatchPrecondition,};awaitbucket.combine(sources,destinationFileName,combineOptions);console.log(`New composite file${destinationFileName} was created by combining${firstFileName} and${secondFileName}`);}composeFile().catch(console.error);PHP
For more information, see theCloud StoragePHP API reference documentation.
To authenticate to Cloud Storage, set up Application Default Credentials. For more information, seeSet up authentication for client libraries.
use Google\Cloud\Storage\StorageClient;/** * Compose two objects into a single target object. * * @param string $bucketName The name of your Cloud Storage bucket. * (e.g. 'my-bucket') * @param string $firstObjectName The name of the first GCS object to compose. * (e.g. 'my-object-1') * @param string $secondObjectName The name of the second GCS object to compose. * (e.g. 'my-object-2') * @param string $targetObjectName The name of the object to be created. * (e.g. 'composed-my-object-1-my-object-2') */function compose_file(string $bucketName, string $firstObjectName, string $secondObjectName, string $targetObjectName): void{ $storage = new StorageClient(); $bucket = $storage->bucket($bucketName); // In this example, we are composing only two objects, but Cloud Storage supports // composition of up to 32 objects. $objectsToCompose = [$firstObjectName, $secondObjectName]; $targetObject = $bucket->compose($objectsToCompose, $targetObjectName, [ 'destination' => [ 'contentType' => 'application/octet-stream' ] ]); if ($targetObject->exists()) { printf( 'New composite object %s was created by combining %s and %s', $targetObject->name(), $firstObjectName, $secondObjectName ); }}Python
For more information, see theCloud StoragePython API reference documentation.
To authenticate to Cloud Storage, set up Application Default Credentials. For more information, seeSet up authentication for client libraries.
fromgoogle.cloudimportstoragedefcompose_file(bucket_name,first_blob_name,second_blob_name,destination_blob_name):"""Concatenate source blobs into destination blob."""# bucket_name = "your-bucket-name"# first_blob_name = "first-object-name"# second_blob_name = "second-blob-name"# destination_blob_name = "destination-object-name"storage_client=storage.Client()bucket=storage_client.bucket(bucket_name)destination=bucket.blob(destination_blob_name)destination.content_type="text/plain"# Note sources is a list of Blob instances, up to the max of 32 instances per requestsources=[bucket.blob(first_blob_name),bucket.blob(second_blob_name)]# Optional: set a generation-match precondition to avoid potential race conditions# and data corruptions. The request to compose is aborted if the object's# generation number does not match your precondition. For a destination# object that does not yet exist, set the if_generation_match precondition to 0.# If the destination object already exists in your bucket, set instead a# generation-match precondition using its generation number.# There is also an `if_source_generation_match` parameter, which is not used in this example.destination_generation_match_precondition=0destination.compose(sources,if_generation_match=destination_generation_match_precondition)print("New composite object{} in the bucket{} was created by combining{} and{}".format(destination_blob_name,bucket_name,first_blob_name,second_blob_name))returndestinationRuby
For more information, see theCloud StorageRuby API reference documentation.
To authenticate to Cloud Storage, set up Application Default Credentials. For more information, seeSet up authentication for client libraries.
defcompose_filebucket_name:,first_file_name:,second_file_name:,destination_file_name:# The ID of your GCS bucket# bucket_name = "your-unique-bucket-name"# The ID of the first GCS object to compose# first_file_name = "your-first-file-name"# The ID of the second GCS object to compose# second_file_name = "your-second-file-name"# The ID to give the new composite object# destination_file_name = "new-composite-file-name"require"google/cloud/storage"storage=Google::Cloud::Storage.newbucket=storage.bucketbucket_name,skip_lookup:truedestination=bucket.compose[first_file_name,second_file_name],destination_file_namedo|f|f.content_type="text/plain"endputs"Composed new file#{destination.name} in the bucket#{bucket_name} "\"by combining#{first_file_name} and#{second_file_name}"endWhat's next
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