Parse switch config in directories as well as files

Currently only --config-file arguments are considered when parsing
genericswitch groups, and any --config-dir arguments are ignored. Some
deployment tools only use --config-dir. This change discovers config
files in directories in a similar manner to oslo_config[1].

[1] https://opendev.org/openstack/oslo.config/src/branch/master/oslo_config/cfg.py#L3170-L3172

Change-Id: I56aa22602a41f959255abd69337da13ab89df00d

Author: steveb

networking_generic_switch/config.py

@@ -12,6 +12,9 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import glob
+import os
+
 from oslo_config import cfg
 from oslo_log import log as logging
 
@@ -39,13 +42,24 @@
 CONF.register_opts(ngs_opts, group='ngs')
 
 
+def config_files():
+    """Generate which yields all config files in the required order"""
+    for config_file in CONF.config_file:
+        yield config_file
+    for config_dir in CONF.config_dir:
+        config_dir_glob = os.path.join(config_dir, '*.conf')
+        for config_file in sorted(glob.glob(config_dir_glob)):
+            yield config_file
+
+
 def get_devices():
     """Parse supplied config files and fetch defined supported devices."""
 
     device_tag = 'genericswitch:'
     devices = {}
 
-    for filename in CONF.config_file:
+    for filename in config_files():
+        LOG.debug(f'Searching for genericswitch config in: {filename}')
         sections = {}
         parser = cfg.ConfigParser(filename, sections)
         try:
@@ -54,6 +68,7 @@ def get_devices():
             continue
         for parsed_item, parsed_value in sections.items():
             if parsed_item.startswith(device_tag):
+                LOG.debug(f'Found genericswitch config: {parsed_item}')
                 dev_id = parsed_item.partition(device_tag)[2]
                 device_cfg = {k: v[0] for k, v
                               in parsed_value.items()}

networking_generic_switch/tests/unit/test_config.py

@@ -12,7 +12,9 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from unittest import mock
+import os
+import shutil
+import tempfile
 
 import fixtures
 from oslo_config import fixture as config_fixture
@@ -24,34 +26,52 @@
 [genericswitch:foo]
 device_type = foo_device
 spam = eggs
+"""
 
+fake_config_bar = """
 [genericswitch:bar]
 device_type = bar_device
 ham = vikings
 """
 
+fake_config_baz = """
+[genericswitch:baz]
+device_type = baz_device
+truffle = brandy
+"""
+
 
 class TestConfig(fixtures.TestWithFixtures):
     def setUp(self):
         super(TestConfig, self).setUp()
+
+        config_file_foo = tempfile.NamedTemporaryFile(
+            suffix=".conf", prefix="ngs-", delete=False).name
+        self.addCleanup(os.remove, config_file_foo)
+
+        config_dir = tempfile.mkdtemp('-ngs', 'bar-')
+        self.addCleanup(shutil.rmtree, config_dir)
+
+        config_file_bar = os.path.join(config_dir, 'bar.conf')
+        config_file_baz = os.path.join(config_dir, 'baz.conf')
+
+        with open(config_file_foo, 'w') as f:
+            f.write(fake_config)
+        with open(config_file_bar, 'w') as f:
+            f.write(fake_config_bar)
+        with open(config_file_baz, 'w') as f:
+            f.write(fake_config_baz)
+
         self.cfg = self.useFixture(config_fixture.Config())
-        self._patch_open()
-        self.cfg.conf(args=["--config-file=/some/config/path"])
-
-    def _patch_open(self):
-        m = mock.mock_open(read_data=fake_config)
-        # NOTE(pas-ha) mocks and iterators work differently in Py2 and Py3
-        # http://bugs.python.org/issue21258
-        m.return_value.__iter__ = lambda self: self
-        m.return_value.__next__ = lambda self: next(iter(self.readline, ''))
-        patcher = mock.patch('oslo_config.cfg.open', m)
-        patcher.start()
-        self.addCleanup(patcher.stop)
+        self.cfg.conf(args=[f"--config-file={config_file_foo}",
+                            f"--config-dir={config_dir}"])
 
     def test_get_devices(self):
         device_list = config.get_devices()
-        self.assertEqual(set(device_list), set(['foo', 'bar']))
+        self.assertEqual(set(device_list), set(['foo', 'bar', 'baz']))
         self.assertEqual({"device_type": "foo_device", "spam": "eggs"},
                          device_list['foo'])
         self.assertEqual({"device_type": "bar_device", "ham": "vikings"},
                          device_list['bar'])
+        self.assertEqual({"device_type": "baz_device", "truffle": "brandy"},
+                         device_list['baz'])

releasenotes/notes/config-dir-d5f59b536c110841.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Switch configuration groups were only found in files specified by
+    `--config-file` arguments. Configuration files in `--config-dir`
+    directories are now also included.