151 lines
5.4 KiB
Python
151 lines
5.4 KiB
Python
# -*- coding: utf-8 -*- #
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# Copyright 2021 Google LLC. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Implementation of Unix-like cat command for cloud storage providers."""
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from __future__ import absolute_import
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from __future__ import division
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from __future__ import unicode_literals
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import textwrap
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from googlecloudsdk.api_lib.storage import cloud_api
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from googlecloudsdk.calliope import arg_parsers
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from googlecloudsdk.calliope import base
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from googlecloudsdk.command_lib.storage import encryption_util
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from googlecloudsdk.command_lib.storage import errors
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from googlecloudsdk.command_lib.storage import flags
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from googlecloudsdk.command_lib.storage import name_expansion
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from googlecloudsdk.command_lib.storage import storage_url
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from googlecloudsdk.command_lib.storage.tasks import task_executor
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from googlecloudsdk.command_lib.storage.tasks.cat import cat_task_iterator
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def _range_parser(string_value):
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"""Creates Range object out of given string value.
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Args:
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string_value (str): The range the user entered.
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Returns:
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Range(int, int|None): The Range object from the given string value.
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"""
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if string_value == '-':
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return arg_parsers.Range(start=0, end=None)
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range_start, _, range_end = string_value.partition('-')
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if not range_start:
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# Checking to see if the user entered -y for the range.
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return arg_parsers.Range(start=-1 * int(range_end), end=None)
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if not range_end:
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# Checking to see if the user entered x- for the range.
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return arg_parsers.Range(start=int(range_start), end=None)
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return arg_parsers.Range.Parse(string_value)
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@base.UniverseCompatible
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class Cat(base.Command):
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"""Outputs the contents of one or more URLs to stdout."""
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detailed_help = {
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'DESCRIPTION':
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"""
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The cat command outputs the contents of one or more URLs to stdout. While
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the cat command does not compute a checksum, it is otherwise equivalent to
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doing:
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$ {parent_command} cp url... -
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(The final '-' causes gcloud to stream the output to stdout.)
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""",
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'EXAMPLES':
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"""
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The following command writes all text files in a bucket to stdout:
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$ {command} gs://bucket/*.txt
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The following command outputs a short header describing file.txt, along
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with its contents:
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$ {command} -d gs://my-bucket/file.txt
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The following command outputs bytes 256-939 of file.txt:
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$ {command} -r 256-939 gs://my-bucket/file.txt
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The following command outputs the last 5 bytes of file.txt:
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$ {command} -r -5 gs://my-bucket/file.txt
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""",
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}
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@staticmethod
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def Args(parser):
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parser.add_argument('url', nargs='+', help='The url of objects to list.')
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parser.add_argument(
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'-d',
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'--display-url',
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action='store_true',
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help='Prints the header before each object.')
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parser.add_argument(
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'-r',
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'--range',
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type=_range_parser,
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help=textwrap.dedent("""\
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Causes gcloud storage to output just the specified byte range of
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the object. In a case where "start" = 'x', and "end" = 'y',
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ranges take the form:
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`x-y` (e.g., `-r 256-5939`), `x-` (e.g., `-r 256-`),
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`-y` (e.g., `-r -5`)
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When offsets start at 0, x-y means to return bytes x
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through y (inclusive), x- means to return bytes x through
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the end of the object, and -y changes the role of y.
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If -y is present, then it returns the last y bytes of the object.
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If the bytes are out of range of the object,
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then nothing is printed"""))
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flags.add_additional_headers_flag(parser)
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flags.add_encryption_flags(parser, command_only_reads_data=True)
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def Run(self, args):
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encryption_util.initialize_key_store(args)
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if args.url:
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storage_urls = []
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for url_string in args.url:
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url_object = storage_url.storage_url_from_string(url_string)
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if not isinstance(url_object, storage_url.CloudUrl):
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raise errors.InvalidUrlError('cat only works for valid cloud URLs.'
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' {} is an invalid cloud URL.'.format(
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url_object.url_string))
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storage_urls.append(url_object)
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# Not using "FieldsScope.SHORT" because downloads always expect
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# serialization data for recovering from errors, which requires
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# the "GCS mediaLink" API field.
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source_expansion_iterator = name_expansion.NameExpansionIterator(
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args.url,
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fields_scope=cloud_api.FieldsScope.NO_ACL,
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recursion_requested=name_expansion.RecursionSetting.NO)
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task_iterator = cat_task_iterator.get_cat_task_iterator(
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source_expansion_iterator,
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args.display_url,
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start_byte=getattr(args.range, 'start', 0),
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end_byte=getattr(args.range, 'end', None))
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self.exit_code = task_executor.execute_tasks(task_iterator=task_iterator)
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