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""" |
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Downloads a file using s3transfer. You can also chose how type of file that |
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is downloaded (i.e. filename, seekable, nonseekable). |
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Usage |
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===== |
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NOTE: Make sure you run ``pip install -r requirements-dev.txt`` before running. |
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To download a file:: |
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./download-file --file-name myfilename --file-type filename \\ |
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--s3-bucket mybucket --s3-key mykey |
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""" |
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import argparse |
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from botocore.session import get_session |
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from s3transfer.manager import TransferManager |
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class NonSeekableWriter: |
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"""A wrapper to hide the ability to seek for a fileobj""" |
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def __init__(self, fileobj): |
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self._fileobj = fileobj |
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def write(self, b): |
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return self._fileobj.write(b) |
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class Downloader: |
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def download(self, args): |
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session = get_session() |
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client = session.create_client('s3') |
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file_type = args.file_type |
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if args.debug: |
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session.set_debug_logger('') |
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with TransferManager(client) as manager: |
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getattr(self, 'download_' + file_type)( |
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manager, args.file_name, args.s3_bucket, args.s3_key |
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) |
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def download_filename(self, manager, filename, bucket, s3_key): |
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manager.download(bucket, s3_key, filename) |
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def download_seekable(self, manager, filename, bucket, s3_key): |
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with open(filename, 'wb') as f: |
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future = manager.download(bucket, s3_key, f) |
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future.result() |
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def download_nonseekable(self, manager, filename, bucket, s3_key): |
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with open(filename, 'wb') as f: |
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future = manager.download(bucket, s3_key, NonSeekableWriter(f)) |
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future.result() |
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def main(): |
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parser = argparse.ArgumentParser(usage=__doc__) |
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parser.add_argument('--file-name', required=True, help='The name of file') |
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parser.add_argument( |
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'--file-type', |
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choices=['filename', 'seekable', 'nonseekable'], |
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required=True, |
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help='The way to represent the file when downloading', |
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) |
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parser.add_argument( |
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'--s3-bucket', |
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required=True, |
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help='The S3 bucket to download the file to', |
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) |
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parser.add_argument( |
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'--s3-key', required=True, help='The key to download to' |
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) |
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parser.add_argument( |
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'--debug', |
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action='store_true', |
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help='Whether to turn debugging on. This will get printed to stderr', |
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) |
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args = parser.parse_args() |
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Downloader().download(args) |
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if __name__ == '__main__': |
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main() |
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