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

third_party/gsutil/gslib/cat_helper.py

+# -*- 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.
+"""Helper for cat and cp streaming download."""
+
+from __future__ import absolute_import
+
+import sys
+
+from gslib.exception import CommandException
+from gslib.wildcard_iterator import StorageUrlFromString
+
+
+class CatHelper(object):
+
+  def __init__(self, command_obj):
+    """Initializes the helper object.
+
+    Args:
+      command_obj: gsutil command instance of calling command.
+    """
+    self.command_obj = command_obj
+
+  def CatUrlStrings(self, url_strings, show_header=False, start_byte=0,
+                    end_byte=None):
+    """Prints each of the url strings to stdout.
+
+    Args:
+      url_strings: String iterable.
+      show_header: If true, print a header per file.
+      start_byte: Starting byte of the file to print, used for constructing
+                  range requests.
+      end_byte: Ending byte of the file to print; used for constructing range
+                requests. If this is negative, the start_byte is ignored and
+                and end range is sent over HTTP (such as range: bytes -9)
+    Returns:
+      0 on success.
+
+    Raises:
+      CommandException if no URLs can be found.
+    """
+    printed_one = False
+    # We manipulate the stdout so that all other data other than the Object
+    # contents go to stderr.
+    cat_outfd = sys.stdout
+    sys.stdout = sys.stderr
+    try:
+      for url_str in url_strings:
+        did_some_work = False
+        # TODO: Get only the needed fields here.
+        for blr in self.command_obj.WildcardIterator(url_str).IterObjects():
+          did_some_work = True
+          if show_header:
+            if printed_one:
+              print
+            print '==> %s <==' % blr
+            printed_one = True
+          cat_object = blr.root_object
+          storage_url = StorageUrlFromString(blr.url_string)
+          if storage_url.IsCloudUrl():
+            self.command_obj.gsutil_api.GetObjectMedia(
+                cat_object.bucket, cat_object.name, cat_outfd,
+                start_byte=start_byte, end_byte=end_byte,
+                object_size=cat_object.size, generation=storage_url.generation,
+                provider=storage_url.scheme)
+          else:
+            cat_outfd.write(open(storage_url.object_name, 'rb').read())
+        if not did_some_work:
+          raise CommandException('No URLs matched %s' % url_str)
+      sys.stdout = cat_outfd
+    finally:
+      sys.stdout = cat_outfd
+
+    return 0