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..2cc321604c58bee1f95554e10f3a0ec94fd5dbd6
--- /dev/null
+++ b/build/fuchsia/update_sdk.py
@@ -0,0 +1,68 @@
+#!/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. Checks .gclient target_os
+so that it doesn't download unnecessarily."""
+
+import os
+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'))
+sys.path.append(os.path.join(REPOSITORY_ROOT, 'tools', 'cr'))
+
+import cr.base
+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
+
+  # Check whether we're targeting Fuchsia.
+  user_path = os.path.expanduser(os.path.join('~', '.config', 'cr'))
+  cr.auto.user.__path__.append(user_path)
+  cr.loader.Scan()
+  with cr.base.context.Create(
+      description='Fuchsia SDK update tool',
+      epilog='') as context:
+
+    cr.base.client.DetectClient()
+    target_os = cr.context.gclient.get('target_os', [])
+    if 'fuchsia' not in target_os:
+      # Nothing to do.
+      return 0

[Dirk Pranke, 2017/05/11 22:31:30]

Why use CR for this, rather than just loading .gclient directly? 

[scottmg, 2017/05/11 22:38:17]

No good reason. I'll do that if the hooks_os thing doesn't pan out.

+
+  sdk_hash = sys.argv[1]
+  output_dir = os.path.join(REPOSITORY_ROOT, 'third_party', 'fuchsia-sdk')
+  bucket = 'gs://fuchsia-build/fuchsia/sdk/linux64/'
+  print 'Downloading SDK %s...' % sdk_hash
+
+  if os.path.isdir(output_dir):
+    os.removedirs(output_dir)
+
+  with tempfile.NamedTemporaryFile() as f:
+    cmd = [os.path.join(find_depot_tools.DEPOT_TOOLS_PATH, 'gsutil.py'),
+           'cp', bucket + sdk_hash, f.name]
+    print cmd
+    subprocess.check_call(cmd)
+    f.seek(0)
+    EnsureDirExists(output_dir)
+    tarfile.open(mode='r:gz', fileobj=f).extractall(path=output_dir)
+
+
+if __name__ == '__main__':
+  sys.exit(main())