#!/usr/bin/env python

# Copyright 2020 Google LLC. 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.

import sys

# [START storage_compose_file]

from google.cloud import storage

def compose_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 request

sources = [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 = 0

destination.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

)

)

return destination

# [END storage_compose_file]

if __name__ == "__main__":

compose_file(

bucket_name=sys.argv[1],

first_blob_name=sys.argv[2],

second_blob_name=sys.argv[3],

destination_blob_name=sys.argv[4],

)