Add a run_eslint wrapper script

common/eslint/eslint/__init__.py

Index: common/eslint/eslint/__init__.py
diff --git a/common/eslint/eslint/__init__.py b/common/eslint/eslint/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..28860deb6a090942294a57ddfa1886767443b64e
--- /dev/null
+++ b/common/eslint/eslint/__init__.py
@@ -0,0 +1,61 @@
+# Copyright 2016 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 os
+import subprocess
+import sys
+
+
+_CATAPULT_PATH = os.path.join(
+    os.path.dirname(os.path.abspath(__file__)),
+    os.path.pardir, os.path.pardir, os.path.pardir)
+
+
+def _AddToPathIfNeeded(path):
+  if path not in sys.path:
+    sys.path.insert(0, path)
+
+
+def _UpdateSysPathIfNeeded():
+  _AddToPathIfNeeded(os.path.join(_CATAPULT_PATH, 'common', 'node_runner'))
+  _AddToPathIfNeeded(os.path.join(_CATAPULT_PATH, 'common', 'py_utils'))
+
+
+_UpdateSysPathIfNeeded()
+
+
+import py_utils
+from node_runner import node_util
+
+
+ESLINT_CMD = [
+  node_util.GetNodePath(),
+  os.path.join(node_util.GetNodeModulesPath(), 'eslint', 'bin', 'eslint.js'),
+  '--color',
+  '--config',
+  os.path.join(py_utils.GetCatapultDir(), 'common', 'eslint', '.eslintrc'),

[nednguyen, 2016/10/05 16:13:33]

I would make the "config" path & rules configurable. So you add eslintrc_path &
rulesdir as parameters in RunEslintOnDirs & RunEslintOnFiles with values default
to these

[charliea (OOO until 10-5), 2016/10/05 17:24:43]

Done.

+  '--rulesdir',
+  os.path.join(py_utils.GetCatapultDir(), 'common', 'eslint', 'rules'),
+]
+
+
+def RunEslintOnDirs(dirs):
+  try:
+    find_cmd = ['find'] + dirs + ['-name', '*.html']
+    p1 = subprocess.Popen(find_cmd, stdout=subprocess.PIPE)
+    output = subprocess.check_output(['xargs'] + ESLINT_CMD, stdin=p1.stdout)
+    p1.wait()
+    return output
+  except subprocess.CalledProcessError as e:
+    return e.output
+
+
+def RunEslintOnFiles(filenames=None):

[nednguyen, 2016/10/05 16:13:33]

Why bother having a default value for filenames as it should throw exception in
the default case?

[charliea (OOO until 10-5), 2016/10/05 17:24:43]

Good point. I started raising an error when filenames is none or []. I also did
the same thing above for RunEslintOnDirs().

+  if filenames is None:
+    filenames = []
+  try:
+    return subprocess.check_output(ESLINT_CMD + filenames,
+                                   stderr=subprocess.STDOUT)
+  except subprocess.CalledProcessError as e:
+    return e.output