| Index: tools/telemetry/third_party/gsutil/gslib/addlhelp/subdirs.py
|
| diff --git a/tools/telemetry/third_party/gsutil/gslib/addlhelp/subdirs.py b/tools/telemetry/third_party/gsutil/gslib/addlhelp/subdirs.py
|
| new file mode 100644
|
| index 0000000000000000000000000000000000000000..69bcda430467eb43bffd8f5e2ac4eee416997f55
|
| --- /dev/null
|
| +++ b/tools/telemetry/third_party/gsutil/gslib/addlhelp/subdirs.py
|
| @@ -0,0 +1,115 @@
|
| +# -*- coding: utf-8 -*-
|
| +# Copyright 2012 Google Inc. 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.
|
| +"""Additional help about subdirectory handling in gsutil."""
|
| +
|
| +from __future__ import absolute_import
|
| +
|
| +from gslib.help_provider import HelpProvider
|
| +
|
| +_DETAILED_HELP_TEXT = ("""
|
| +<B>OVERVIEW</B>
|
| + This section provides details about how subdirectories work in gsutil.
|
| + Most users probably don't need to know these details, and can simply use
|
| + the commands (like cp -r) that work with subdirectories. We provide this
|
| + additional documentation to help users understand how gsutil handles
|
| + subdirectories differently than most GUI / web-based tools (e.g., why
|
| + those other tools create "dir_$folder$" objects), and also to explain cost and
|
| + performance implications of the gsutil approach, for those interested in such
|
| + details.
|
| +
|
| + gsutil provides the illusion of a hierarchical file tree atop the "flat"
|
| + name space supported by the Google Cloud Storage service. To the service,
|
| + the object gs://your-bucket/abc/def/ghi.txt is just an object that happens to
|
| + have "/" characters in its name. There are no "abc" or "abc/def" directories;
|
| + just a single object with the given name. This
|
| + `diagram <https://cloud.google.com/storage/images/gsutil-subdirectories-thumb.png>`
|
| + illustrates how gsutil provides a hierarchical view of objects in a bucket.
|
| +
|
| + gsutil achieves the hierarchical file tree illusion by applying a variety of
|
| + rules, to try to make naming work the way users would expect. For example, in
|
| + order to determine whether to treat a destination URI as an object name or the
|
| + root of a directory under which objects should be copied gsutil uses these
|
| + rules:
|
| +
|
| + 1. If the destination object ends with a "/" gsutil treats it as a directory.
|
| + For example, if you run the command:
|
| +
|
| + gsutil cp your-file gs://your-bucket/abc/
|
| +
|
| + gsutil will create the object gs://your-bucket/abc/file.
|
| +
|
| + 2. If the destination object is XYZ and an object exists called XYZ_$folder$
|
| + gsutil treats XYZ as a directory. For example, if you run the command:
|
| +
|
| + gsutil cp your-file gs://your-bucket/abc
|
| +
|
| + and there exists an object called abc_$folder$, gsutil will create the
|
| + object gs://your-bucket/abc/file.
|
| +
|
| + 3. If you attempt to copy multiple source files to a destination URI, gsutil
|
| + treats the destination URI as a directory. For example, if you run
|
| + the command:
|
| +
|
| + gsutil cp -r your-dir gs://your-bucket/abc
|
| +
|
| + gsutil will create objects like gs://your-bucket/abc/your-dir/file1, etc.
|
| + (assuming file1 is a file under the source directory).
|
| +
|
| + 4. If none of the above rules applies, gsutil performs a bucket listing to
|
| + determine if the target of the operation is a prefix match to the
|
| + specified string. For example, if you run the command:
|
| +
|
| + gsutil cp your-file gs://your-bucket/abc
|
| +
|
| + gsutil will make a bucket listing request for the named bucket, using
|
| + delimiter="/" and prefix="abc". It will then examine the bucket listing
|
| + results and determine whether there are objects in the bucket whose path
|
| + starts with gs://your-bucket/abc/, to determine whether to treat the target
|
| + as an object name or a directory name. In turn this impacts the name of the
|
| + object you create: If the above check indicates there is an "abc" directory
|
| + you will end up with the object gs://your-bucket/abc/file; otherwise you
|
| + will end up with the object gs://your-bucket/abc. (See
|
| + "HOW NAMES ARE CONSTRUCTED" under "gsutil help cp" for more details.)
|
| +
|
| + This rule-based approach stands in contrast to the way many tools work, which
|
| + create objects to mark the existence of folders (such as "dir_$folder$").
|
| + gsutil understands several conventions used by such tools but does not
|
| + require such marker objects to implement naming behavior consistent with
|
| + UNIX commands.
|
| +
|
| + A downside of the gsutil approach is it requires an extra bucket listing
|
| + before performing the needed cp or mv command. However those listings are
|
| + relatively inexpensive, because they use delimiter and prefix parameters to
|
| + limit result data. Moreover, gsutil makes only one bucket listing request
|
| + per cp/mv command, and thus amortizes the bucket listing cost across all
|
| + transferred objects (e.g., when performing a recursive copy of a directory
|
| + to the cloud).
|
| +""")
|
| +
|
| +
|
| +class CommandOptions(HelpProvider):
|
| + """Additional help about subdirectory handling in gsutil."""
|
| +
|
| + # Help specification. See help_provider.py for documentation.
|
| + help_spec = HelpProvider.HelpSpec(
|
| + help_name='subdirs',
|
| + help_name_aliases=[
|
| + 'dirs', 'directory', 'directories', 'folder', 'folders', 'hierarchy',
|
| + 'subdir', 'subdirectory', 'subdirectories'],
|
| + help_type='additional_help',
|
| + help_one_line_summary='How Subdirectories Work',
|
| + help_text=_DETAILED_HELP_TEXT,
|
| + subcommand_help_text={},
|
| + )
|
|
|