Add hook to download Fuchsia SDK

build/fuchsia/update_sdk.py

Index: build/fuchsia/update_sdk.py
diff --git a/build/fuchsia/update_sdk.py b/build/fuchsia/update_sdk.py
new file mode 100755
index 0000000000000000000000000000000000000000..2302629c01cb5add3718e13ecd801f7370241925
--- /dev/null
+++ b/build/fuchsia/update_sdk.py
@@ -0,0 +1,65 @@
+#!/usr/bin/env python
+# Copyright 2017 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.
+
+"""Updates the Fuchsia SDK to the given revision. Should be used in a 'hooks_os'
+entry so that it only runs when .gclient's target_os includes 'fuchsia'."""
+
+import os
+import shutil
+import subprocess
+import sys
+import tarfile
+import tempfile
+
+REPOSITORY_ROOT = os.path.abspath(os.path.join(
+    os.path.dirname(__file__), '..', '..'))
+sys.path.append(os.path.join(REPOSITORY_ROOT, 'build'))
+
+import find_depot_tools
+
+
+def EnsureDirExists(path):
+  if not os.path.exists(path):
+    print 'Creating directory %s' % path
+    os.makedirs(path)
+
+
+def main():
+  if len(sys.argv) != 2:
+    print >>sys.stderr, 'usage: %s <sdk_hash>' % sys.argv[0]
+    return 1
+
+  sdk_hash = sys.argv[1]
+  output_dir = os.path.join(REPOSITORY_ROOT, 'third_party', 'fuchsia-sdk')
+
+  hash_filename = os.path.join(output_dir, '.hash')
+  if os.path.exists(hash_filename):
+    with open(hash_filename, 'r') as f:
+      if f.read().strip() == sdk_hash:
+        # Nothing to do.
+        return 0
+
+  print 'Downloading SDK %s...' % sdk_hash
+
+  if os.path.isdir(output_dir):
+    shutil.rmtree(output_dir)
+
+  bucket = 'gs://fuchsia-build/fuchsia/sdk/linux64/'
+  with tempfile.NamedTemporaryFile() as f:
+    cmd = [os.path.join(find_depot_tools.DEPOT_TOOLS_PATH, 'gsutil.py'),
+           'cp', bucket + sdk_hash, f.name]
+    subprocess.check_call(cmd)
+    f.seek(0)
+    EnsureDirExists(output_dir)
+    tarfile.open(mode='r:gz', fileobj=f).extractall(path=output_dir)
+
+  with open(hash_filename, 'w') as f:
+    f.write(sdk_hash)
+
+  return 0
+
+
+if __name__ == '__main__':
+  sys.exit(main())