[catapult] - Copy Telemetry's gsutilz over to third_party.

third_party/gsutil/gslib/addlhelp/retries.py

Index: third_party/gsutil/gslib/addlhelp/retries.py
diff --git a/third_party/gsutil/gslib/addlhelp/retries.py b/third_party/gsutil/gslib/addlhelp/retries.py
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+++ b/third_party/gsutil/gslib/addlhelp/retries.py
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+# -*- coding: utf-8 -*-
+# Copyright 2014 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 text about retry handling."""
+
+from gslib.help_provider import HelpProvider
+
+_DETAILED_HELP_TEXT = ("""
+<B>RETRY STRATEGY</B>
+  There are a number of reasons that gsutil operations can fail; some are not
+  retryable, and require that the user take some action, for example:
+    - Invalid credentials
+    - Network unreachable because of a proxy configuration problem
+    - Access denied, because the bucket or object you are trying to use has an
+      ACL that doesn't permit the action you're trying to perform.
+
+  In other cases errors are retryable - basically, the HTTP 429 and 5xx error
+  codes. For these cases, gsutil will retry using a truncated binary exponential
+  backoff strategy:
+
+    - Wait a random period between [0..1] seconds and retry;
+    - If that fails, wait a random period between [0..2] seconds and retry;
+    - If that fails, wait a random period between [0..4] seconds and retry;
+    - And so on, up to a configurable maximum number of retries (default = 6),
+    with each retry period bounded by a configurable maximum period of time
+    (default = 60 seconds).
+
+  Thus, by default, gsutil will retry 6 times over 1+2+4+8+16+32=63 seconds.
+  You can adjust the number of retries and maximum delay of any individual retry
+  by editing the num_retries and max_retry_delay configuration variables in the
+  "[Boto]" section of the .boto config file. Most users shouldn't need to change
+  these values.
+
+  For data transfers (the gsutil cp and rsync commands), gsutil provides
+  additional retry functionality, in the form of resumable transfers.
+  Essentially, a transfer that was interrupted because of a transient error
+  can be restarted without starting over from scratch. For more details
+  about this, see the "RESUMABLE TRANSFERS" section of "gsutil help cp".
+""")
+
+
+class CommandOptions(HelpProvider):
+  """Additional help text about retry handling."""
+
+  # Help specification. See help_provider.py for documentation.
+  help_spec = HelpProvider.HelpSpec(
+      help_name='retries',
+      help_name_aliases=['retry', 'backoff', 'reliability'],
+      help_type='additional_help',
+      help_one_line_summary='Retry Handling Strategy',
+      help_text=_DETAILED_HELP_TEXT,
+      subcommand_help_text={},
+  )