Add script to pack npm_binary tarballs with dependencies

Contrary to our experience with bower, not all packages on
registry.npmjs.org come with dependencies bundled. This script
produces a tarball with bundled dependencies which can be hosted on
the Gerrit GCS bucket and used as an npm_binary.

Change-Id: I2403c7f0acf759be2508b845d1f359cdf6a65e4e

tools/js/npm_pack.py

@@ -0,0 +1,74 @@
+#!/usr/bin/env python
+# Copyright (C) 2015 The Android Open Source Project
+#
+# 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.
+
+from __future__ import print_function
+
+import atexit
+import json
+import os
+import shutil
+import subprocess
+import sys
+import tarfile
+import tempfile
+
+
+def is_bundled(tar):
+  # No entries for directories, so scan for a matching prefix.
+  for entry in tar.getmembers():
+    if entry.name.startswith('package/node_modules/'):
+      return True
+  return False
+
+
+def bundle_dependencies():
+  with open('package.json') as f:
+    package = json.load(f)
+  package['bundledDependencies'] = package['dependencies'].keys()
+  with open('package.json', 'w') as f:
+    json.dump(package, f)
+
+
+def main(args):
+  if len(args) != 2:
+    print('Usage: %s <package> <version>' % sys.argv[0], file=sys.stderr)
+    return 1
+
+  name, version = args
+  filename = '%s-%s.tgz' % (name, version)
+  url = 'http://registry.npmjs.org/%s/-/%s' % (name, filename)
+
+  tmpdir = tempfile.mkdtemp();
+  tgz = os.path.join(tmpdir, filename)
+  atexit.register(lambda: shutil.rmtree(tmpdir))
+
+  subprocess.check_call(['curl', '--proxy-anyauth', '-ksfo', tgz, url])
+  with tarfile.open(tgz, 'r:gz') as tar:
+    if is_bundled(tar):
+      print('%s already has bundled node_modules' % filename)
+      return 1
+    tar.extractall(path=tmpdir)
+
+  oldpwd = os.getcwd()
+  os.chdir(os.path.join(tmpdir, 'package'))
+  bundle_dependencies()
+  subprocess.check_call(['npm', 'install'])
+  subprocess.check_call(['npm', 'pack'])
+  shutil.copy(filename, os.path.join(oldpwd, filename))
+  return 0
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv[1:]))