Revert "Add gsutil 4.13 to telemetry/third_party"

tools/telemetry/third_party/gsutil/gslib/tracker_file.py

-# -*- coding: utf-8 -*-
-# Copyright 2015 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.
-"""Helper functions for tracker file functionality."""
-
-import errno
-import hashlib
-import os
-import re
-
-from boto import config
-from gslib.exception import CommandException
-from gslib.util import CreateDirIfNeeded
-from gslib.util import GetGsutilStateDir
-from gslib.util import ResumableThreshold
-from gslib.util import UTF8
-
-# The maximum length of a file name can vary wildly between different
-# operating systems, so we always ensure that tracker files are less
-# than 100 characters in order to avoid any such issues.
-MAX_TRACKER_FILE_NAME_LENGTH = 100
-
-
-TRACKER_FILE_UNWRITABLE_EXCEPTION_TEXT = (
-    'Couldn\'t write tracker file (%s): %s. This can happen if gsutil is '
-    'configured to save tracker files to an unwritable directory)')
-
-
-class TrackerFileType(object):
-  UPLOAD = 'upload'
-  DOWNLOAD = 'download'
-  PARALLEL_UPLOAD = 'parallel_upload'
-  REWRITE = 'rewrite'
-
-
-def _HashFilename(filename):
-  """Apply a hash function (SHA1) to shorten the passed file name.
-
-  The spec for the hashed file name is as follows:
-
-      TRACKER_<hash>_<trailing>
-
-  where hash is a SHA1 hash on the original file name and trailing is
-  the last 16 chars from the original file name. Max file name lengths
-  vary by operating system so the goal of this function is to ensure
-  the hashed version takes fewer than 100 characters.
-
-  Args:
-    filename: file name to be hashed.
-
-  Returns:
-    shorter, hashed version of passed file name
-  """
-  if isinstance(filename, unicode):
-    filename = filename.encode(UTF8)
-  else:
-    filename = unicode(filename, UTF8).encode(UTF8)
-  m = hashlib.sha1(filename)
-  return 'TRACKER_' + m.hexdigest() + '.' + filename[-16:]
-
-
-def CreateTrackerDirIfNeeded():
-  """Looks up or creates the gsutil tracker file directory.
-
-  This is the configured directory where gsutil keeps its resumable transfer
-  tracker files. This function creates it if it doesn't already exist.
-
-  Returns:
-    The pathname to the tracker directory.
-  """
-  tracker_dir = config.get(
-      'GSUtil', 'resumable_tracker_dir',
-      os.path.join(GetGsutilStateDir(), 'tracker-files'))
-  CreateDirIfNeeded(tracker_dir)
-  return tracker_dir
-
-
-def GetRewriteTrackerFilePath(src_bucket_name, src_obj_name, dst_bucket_name,
-                              dst_obj_name, api_selector):
-  """Gets the tracker file name described by the arguments.
-
-  Args:
-    src_bucket_name: Source bucket (string).
-    src_obj_name: Source object (string).
-    dst_bucket_name: Destination bucket (string).
-    dst_obj_name: Destination object (string)
-    api_selector: API to use for this operation.
-
-  Returns:
-    File path to tracker file.
-  """
-  # Encode the src and dest bucket and object names into the tracker file
-  # name.
-  res_tracker_file_name = (
-      re.sub('[/\\\\]', '_', 'rewrite__%s__%s__%s__%s__%s.token' %
-             (src_bucket_name, src_obj_name, dst_bucket_name,
-              dst_obj_name, api_selector)))
-
-  return _HashAndReturnPath(res_tracker_file_name, TrackerFileType.REWRITE)
-
-
-def GetTrackerFilePath(dst_url, tracker_file_type, api_selector, src_url=None):
-  """Gets the tracker file name described by the arguments.
-
-  Args:
-    dst_url: Destination URL for tracker file.
-    tracker_file_type: TrackerFileType for this operation.
-    api_selector: API to use for this operation.
-    src_url: Source URL for the source file name for parallel uploads.
-
-  Returns:
-    File path to tracker file.
-  """
-  if tracker_file_type == TrackerFileType.UPLOAD:
-    # Encode the dest bucket and object name into the tracker file name.
-    res_tracker_file_name = (
-        re.sub('[/\\\\]', '_', 'resumable_upload__%s__%s__%s.url' %
-               (dst_url.bucket_name, dst_url.object_name, api_selector)))
-  elif tracker_file_type == TrackerFileType.DOWNLOAD:
-    # Encode the fully-qualified dest file name into the tracker file name.
-    res_tracker_file_name = (
-        re.sub('[/\\\\]', '_', 'resumable_download__%s__%s.etag' %
-               (os.path.realpath(dst_url.object_name), api_selector)))
-  elif tracker_file_type == TrackerFileType.PARALLEL_UPLOAD:
-    # Encode the dest bucket and object names as well as the source file name
-    # into the tracker file name.
-    res_tracker_file_name = (
-        re.sub('[/\\\\]', '_', 'parallel_upload__%s__%s__%s__%s.url' %
-               (dst_url.bucket_name, dst_url.object_name,
-                src_url, api_selector)))
-  elif tracker_file_type == TrackerFileType.REWRITE:
-    # Should use GetRewriteTrackerFilePath instead.
-    raise NotImplementedError()
-
-  return _HashAndReturnPath(res_tracker_file_name, tracker_file_type)
-
-
-def _HashAndReturnPath(res_tracker_file_name, tracker_file_type):
-  resumable_tracker_dir = CreateTrackerDirIfNeeded()
-  hashed_tracker_file_name = _HashFilename(res_tracker_file_name)
-  tracker_file_name = '%s_%s' % (str(tracker_file_type).lower(),
-                                 hashed_tracker_file_name)
-  tracker_file_path = '%s%s%s' % (resumable_tracker_dir, os.sep,
-                                  tracker_file_name)
-  assert len(tracker_file_name) < MAX_TRACKER_FILE_NAME_LENGTH
-  return tracker_file_path
-
-
-def DeleteTrackerFile(tracker_file_name):
-  if tracker_file_name and os.path.exists(tracker_file_name):
-    os.unlink(tracker_file_name)
-
-
-def HashRewriteParameters(
-    src_obj_metadata, dst_obj_metadata, projection, src_generation=None,
-    gen_match=None, meta_gen_match=None, canned_acl=None, fields=None,
-    max_bytes_per_call=None):
-  """Creates an MD5 hex digest of the parameters for a rewrite call.
-
-  Resuming rewrites requires that the input parameters are identical. Thus,
-  the rewrite tracker file needs to represent the input parameters. For
-  easy comparison, hash the input values. If a user does a performs a
-  same-source/same-destination rewrite via a different command (for example,
-  with a changed ACL), the hashes will not match and we will restart the
-  rewrite from the beginning.
-
-  Args:
-    src_obj_metadata: apitools Object describing source object. Must include
-      bucket, name, and etag.
-    dst_obj_metadata: apitools Object describing destination object. Must
-      include bucket and object name
-    projection: Projection used for the API call.
-    src_generation: Optional source generation.
-    gen_match: Optional generation precondition.
-    meta_gen_match: Optional metageneration precondition.
-    canned_acl: Optional canned ACL string.
-    fields: Optional fields to include in response.
-    max_bytes_per_call: Optional maximum bytes rewritten per call.
-
-  Returns:
-    MD5 hex digest Hash of the input parameters, or None if required parameters
-    are missing.
-  """
-  if (not src_obj_metadata or
-      not src_obj_metadata.bucket or
-      not src_obj_metadata.name or
-      not src_obj_metadata.etag or
-      not dst_obj_metadata or
-      not dst_obj_metadata.bucket or
-      not dst_obj_metadata.name or
-      not projection):
-    return
-  md5_hash = hashlib.md5()
-  for input_param in (
-      src_obj_metadata, dst_obj_metadata, projection, src_generation,
-      gen_match, meta_gen_match, canned_acl, fields, max_bytes_per_call):
-    md5_hash.update(str(input_param))
-  return md5_hash.hexdigest()
-
-
-def ReadRewriteTrackerFile(tracker_file_name, rewrite_params_hash):
-  """Attempts to read a rewrite tracker file.
-
-  Args:
-    tracker_file_name: Tracker file path string.
-    rewrite_params_hash: MD5 hex digest of rewrite call parameters constructed
-        by HashRewriteParameters.
-
-  Returns:
-    String rewrite_token for resuming rewrite requests if a matching tracker
-    file exists, None otherwise (which will result in starting a new rewrite).
-  """
-  # Check to see if we already have a matching tracker file.
-  tracker_file = None
-  if not rewrite_params_hash:
-    return
-  try:
-    tracker_file = open(tracker_file_name, 'r')
-    existing_hash = tracker_file.readline().rstrip('\n')
-    if existing_hash == rewrite_params_hash:
-      # Next line is the rewrite token.
-      return tracker_file.readline().rstrip('\n')
-  except IOError as e:
-    # Ignore non-existent file (happens first time a rewrite is attempted.
-    if e.errno != errno.ENOENT:
-      print('Couldn\'t read Copy tracker file (%s): %s. Restarting copy '
-            'from scratch.' %
-            (tracker_file_name, e.strerror))
-  finally:
-    if tracker_file:
-      tracker_file.close()
-
-
-def WriteRewriteTrackerFile(tracker_file_name, rewrite_params_hash,
-                            rewrite_token):
-  """Writes a rewrite tracker file.
-
-  Args:
-    tracker_file_name: Tracker file path string.
-    rewrite_params_hash: MD5 hex digest of rewrite call parameters constructed
-        by HashRewriteParameters.
-    rewrite_token: Rewrite token string returned by the service.
-  """
-  _WriteTrackerFile(tracker_file_name, '%s\n%s\n' % (rewrite_params_hash,
-                                                     rewrite_token))
-
-
-def ReadOrCreateDownloadTrackerFile(src_obj_metadata, dst_url,
-                                    api_selector):
-  """Checks for a download tracker file and creates one if it does not exist.
-
-  Args:
-    src_obj_metadata: Metadata for the source object. Must include
-                      etag and size.
-    dst_url: Destination file StorageUrl.
-    api_selector: API mode to use (for tracker file naming).
-
-  Returns:
-    True if the tracker file already exists (resume existing download),
-    False if we created a new tracker file (new download).
-  """
-  if src_obj_metadata.size < ResumableThreshold():
-    # Don't create a tracker file for a small downloads; cross-process resumes
-    # won't work, but restarting a small download is inexpensive.
-    return False
-
-  assert src_obj_metadata.etag
-  tracker_file_name = GetTrackerFilePath(
-      dst_url, TrackerFileType.DOWNLOAD, api_selector)
-  tracker_file = None
-
-  # Check to see if we already have a matching tracker file.
-  try:
-    tracker_file = open(tracker_file_name, 'r')
-    etag_value = tracker_file.readline().rstrip('\n')
-    if etag_value == src_obj_metadata.etag:
-      return True
-  except IOError as e:
-    # Ignore non-existent file (happens first time a download
-    # is attempted on an object), but warn user for other errors.
-    if e.errno != errno.ENOENT:
-      print('Couldn\'t read URL tracker file (%s): %s. Restarting '
-            'download from scratch.' %
-            (tracker_file_name, e.strerror))
-  finally:
-    if tracker_file:
-      tracker_file.close()
-
-  # Otherwise, create a new tracker file and start from scratch.
-  _WriteTrackerFile(tracker_file_name, '%s\n' % src_obj_metadata.etag)
-
-
-def _WriteTrackerFile(tracker_file_name, data):
-  """Creates a tracker file, storing the input data."""
-  try:
-    with os.fdopen(os.open(tracker_file_name,
-                           os.O_WRONLY | os.O_CREAT, 0600), 'w') as tf:
-      tf.write(data)
-    return False
-  except (IOError, OSError) as e:
-    raise RaiseUnwritableTrackerFileException(tracker_file_name, e.strerror)
-
-
-def RaiseUnwritableTrackerFileException(tracker_file_name, error_str):
-  """Raises an exception when unable to write the tracker file."""
-  raise CommandException(TRACKER_FILE_UNWRITABLE_EXCEPTION_TEXT %
-                         (tracker_file_name, error_str))