Set up a network service bootstrap.

services/network/download_network_service.py

+#!/usr/bin/env python
+# Copyright 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import argparse
+import os
+import sys
+import tempfile
+import zipfile
+
+_PLATFORMS = ["linux-x64", "android-arm"]
+
+if not sys.platform.startswith("linux"):
+  print "Not supported for your platform"
+  sys.exit(0)
+
+# Add //tools to the system path so that we can import the gs helper.
+script_dir = os.path.dirname(os.path.realpath(__file__))
+tools_path = os.path.join(script_dir, os.pardir, os.pardir, "tools")
+sys.path.insert(0, tools_path)
+# pylint: disable=F0401
+import gs
+
+
+def download_binary(version, platform, prebuilt_directory):
+  gs_path = "gs://mojo/network/%s/%s.zip" % (version, platform)
+  output_directory = os.path.join(prebuilt_directory, platform)
+  binary_name = "network_service.mojo"
+
+  with tempfile.NamedTemporaryFile() as temp_zip_file:
+    gs.download_from_public_bucket(gs_path, temp_zip_file.name)
+    with zipfile.ZipFile(temp_zip_file.name) as z:
+      zi = z.getinfo(binary_name)
+      mode = zi.external_attr >> 16
+      z.extract(zi, output_directory)
+      os.chmod(os.path.join(output_directory, binary_name), mode)
+
+
+def main():
+  parser = argparse.ArgumentParser(
+      description="Download prebuilt network service binaries from google " +
+                  "storage")
+  parser.parse_args()
+
+  prebuilt_directory_path = os.path.join(script_dir, "prebuilt")
+  stamp_path = os.path.join(prebuilt_directory_path, "STAMP")
+  version_path = os.path.join(script_dir, "VERSION")
+  with open(version_path) as version_file:
+    version = version_file.read().strip()
+
+  try:
+    with open(stamp_path) as stamp_file:
+      current_version = stamp_file.read().strip()
+      if current_version == version:
+        return 0  # Already have the right version.
+  except IOError:
+    pass  # If the stamp file does not exist we need to download a new binary.
+
+  for platform in _PLATFORMS:
+    download_binary(version, platform, prebuilt_directory_path)
+
+  with open(stamp_path, 'w') as stamp_file:
+    stamp_file.write(version)
+  return 0
+
+
+if __name__ == "__main__":
+  sys.exit(main())