Utils for auto-file-discovery

This patch creates horizon.utils.file-discovery module which provides
functionalities for automatic file-discovery.  With these infrastructural
helpers, we can build JavaScript and HTML file auto-discovery for horizon
align with th existing plug-in mechanism.

1) discover_files(base_path, sub_path='', ext='', trim_base_path=False):
   Discover all files with certain extension in given paths

2) sort_js_files(js_files):
   Sorts JavaScript files in `js_files` into source files, mock files
   and spec files based on file extension.

   Output:
   * sources: source files for production.  The order of source files
     is significant and should be listed in the below order:
     - First all the files that defines application's angular module.
       Those files have extension of `.module.js`.  The order among them
       is not significant.
     - Followed by all other source code files.  The order among them
       is not significant.

   * mocks: mock files provide mock data/services for tests.  They have
     extension of `.mock.js`. The order among them is not significant.

   * specs: spec files for testing.  They have extension of `.spec.js`.
     The order among them is not significant.

3) discover_static_files(base_path, sub_path=''):
   Discover static files in given paths, returns JavaScript sources,
   mocks, specs and HTML templates files grouped in lists.

Partially-Implements: blueprint auto-js-file-finding
Change-Id: Idd0b69451f81b2f740b10515e3e274d48b681dbe

horizon/utils/file_discovery.py

@@ -0,0 +1,108 @@
+# 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.
+
+import logging
+
+from os import path
+from os import walk
+
+LOG = logging.getLogger(__name__)
+
+MODULE_EXT = '.module.js'
+MOCK_EXT = '.mock.js'
+SPEC_EXT = '.spec.js'
+
+
+def discover_files(base_path, sub_path='', ext='', trim_base_path=False):
+    """Discovers all files with certain extension in given paths.
+    """
+    file_list = []
+    for root, dirs, files in walk(path.join(base_path, sub_path)):
+        if trim_base_path:
+            root = root.replace(base_path, '', 1)
+        file_list.extend([path.join(root, file_name)
+                          for file_name in files
+                          if file_name.endswith(ext)])
+    return file_list
+
+
+def sort_js_files(js_files):
+    """Sorts JavaScript files in `js_files` into source files, mock files
+    and spec files based on file extension.
+
+    Output:
+    * sources: source files for production.  The order of source files
+      is significant and should be listed in the below order:
+      - First, all the that defines the other application's angular module.
+        Those files have extension of `.module.js`.  The order among them is
+        not significant.
+      - Followed by all other source code files.  The order among them
+        is not significant.
+
+    * mocks: mock files provide mock data/services for tests.  They have
+      extension of `.mock.js`. The order among them is not significant.
+
+    * specs: spec files for testing.  They have extension of `.spec.js`.
+      The order among them is not significant.
+    """
+    modules = [f for f in js_files if f.endswith(MODULE_EXT)]
+    mocks = [f for f in js_files if f.endswith(MOCK_EXT)]
+    specs = [f for f in js_files if f.endswith(SPEC_EXT)]
+
+    other_sources = [f for f in js_files if
+                     not f.endswith(MODULE_EXT)
+                     and not f.endswith(MOCK_EXT)
+                     and not f.endswith(SPEC_EXT)]
+
+    sources = modules + other_sources
+    return sources, mocks, specs
+
+
+def discover_static_files(base_path, sub_path=''):
+    """Discovers static files in given paths, returning JavaScript sources,
+    mocks, specs and HTML templates, all grouped in lists.
+    """
+    js_files = discover_files(base_path, sub_path=sub_path,
+                              ext='.js', trim_base_path=True)
+    sources, mocks, specs = sort_js_files(js_files)
+    html_files = discover_files(base_path, sub_path=sub_path,
+                                ext='.html', trim_base_path=True)
+
+    p = path.join(base_path, sub_path)
+    _log(sources, 'JavaScript source', p)
+    _log(mocks, 'JavaScript mock', p)
+    _log(specs, 'JavaScript spec', p)
+    _log(html_files, 'HTML template', p)
+
+    return sources, mocks, specs, html_files
+
+
+def populate_horizon_config(horizon_config, base_path,
+                            sub_path='', prepend=False):
+    sources, mocks, specs, template = discover_static_files(
+        base_path, sub_path=sub_path)
+    if prepend:
+        horizon_config.setdefault('js_files', [])[:0] = sources
+        horizon_config.setdefault('js_spec_files', [])[:0] = mocks + specs
+        horizon_config.setdefault('external_templates', [])[:0] = template
+    else:
+        horizon_config.setdefault('js_files', []).extend(sources)
+        horizon_config.setdefault('js_spec_files', []).extend(mocks + specs)
+        horizon_config.setdefault('external_templates', []).extend(template)
+
+
+def _log(file_list, list_name, in_path):
+    """Logs result at debug level
+    """
+    file_names = '\n'.join(file_list)
+    LOG.debug("\nDiscovered {0} {1} file(s) in {2}:\n{3}\n"
+              .format(len(file_list), list_name, in_path, file_names))