Moved configuration options of dragonflow

Change-Id: I92c08efc65bfea552af7817a577689afa4a0a3a1
Implements: blueprint centralize-config-options

dragonflow/conf/__init__.py

@@ -16,9 +16,9 @@ from dragonflow.conf import df_active_port_detection
 from dragonflow.conf import df_common_params
 from dragonflow.conf import df_dhcp
 from dragonflow.conf import df_dnat
+from dragonflow.conf import df_l2
 from dragonflow.conf import df_metadata_service
 from dragonflow.conf import df_ryu
-from dragonflow.conf import l2_ml2
 
 
 CONF = cfg.CONF
@@ -28,6 +28,6 @@ df_common_params.register_opts()
 df_dhcp.register_opts()
 df_metadata_service.register_opts()
 df_active_port_detection.register_opts()
-l2_ml2.register_opts()
+df_l2.register_opts()
 df_dnat.register_opts()
 df_ryu.register_opts()

dragonflow/conf/df_common_params.py

@@ -164,3 +164,7 @@ df_opts = [
 
 def register_opts():
     cfg.CONF.register_opts(df_opts, 'df')
+
+
+def list_opts():
+    return {'df': df_opts}

dragonflow/conf/df_dhcp.py

@@ -35,3 +35,7 @@ df_dhcp_opts = [
 
 def register_opts():
     cfg.CONF.register_opts(df_dhcp_opts, 'df_dhcp_app')
+
+
+def list_opts():
+    return {'df_dhcp_app': df_dhcp_opts}

dragonflow/conf/df_dnat.py

@@ -32,3 +32,7 @@ df_dnat_app_opts = [
 
 def register_opts():
     cfg.CONF.register_opts(df_dnat_app_opts, group='df_dnat_app')
+
+
+def list_opts():
+    return {'df_dnat_app': df_dnat_app_opts}

dragonflow/conf/df_l2.py

@@ -39,3 +39,7 @@ df_l2_app_opts = [
 
 def register_opts():
     cfg.CONF.register_opts(df_l2_app_opts, group='df_l2_app')
+
+
+def list_opts():
+    return {'df_l2_app': df_l2_app_opts}

dragonflow/conf/df_ryu.py

@@ -28,3 +28,7 @@ df_ryu_opts = [
 
 def register_opts():
     cfg.CONF.register_opts(df_ryu_opts, 'df_ryu')
+
+
+def list_opts():
+    return {'df_ryu': df_ryu_opts}

dragonflow/conf/opts.py

@@ -10,22 +10,58 @@
 #  License for the specific language governing permissions and limitations
 #  under the License.
 
-from dragonflow.conf import df_active_port_detection
-from dragonflow.conf import df_common_params
-from dragonflow.conf import df_dhcp
-from dragonflow.conf import df_dnat
-from dragonflow.conf import df_metadata_service
-from dragonflow.conf import df_ryu
-from dragonflow.conf import l2_ml2
+"""
+This is the single point of entry to generate the sample configuration
+file for dragonflow. It collects all the necessary info from the other modules
+in this package. It is assumed that:
+
+* every other module in this package has a 'list_opts' function which
+  return a dict where
+  * the keys are strings which are the group names
+  * the value of each key is a list of config options for that group
+* the dragonflow.conf package doesn't have further packages with config options
+* this module is only used in the context of sample file generation
+"""
+
+import collections
+import imp
+import os
+import pkgutil
+
+from dragonflow._i18n import _ as _i18
+
+LIST_OPTS_FUNC_NAME = "list_opts"
 
 
 def list_opts():
-    return [
-        ('df', df_common_params.df_opts),
-        ('df_ryu', df_ryu.df_ryu_opts),
-        ('df_dhcp_app', df_dhcp.df_dhcp_opts),
-        ('df_dnat_app', df_dnat.df_dnat_app_opts),
-        ('df_l2_app', l2_ml2.df_l2_app_opts),
-        ('df_metadata', df_metadata_service.df_metadata_opts),
-        ('df_active_port_detection',
-         df_active_port_detection.df_active_port_detection_opts)]
+    opts = collections.defaultdict(list)
+    imported_modules = _import_modules()
+    _append_config_options(imported_modules, opts)
+    return [(key, val) for key, val in opts.items()]
+
+
+def _import_modules():
+    imported_modules = []
+    package_path = os.path.dirname(os.path.abspath(__file__))
+    for _, modname, ispkg in pkgutil.iter_modules(path=[package_path]):
+        if modname == __name__.split('.')[-1] or ispkg:
+            continue
+
+        path = ('%s/%s.py' % (package_path, modname))
+        mod = imp.load_source(modname, path)
+        if not hasattr(mod, LIST_OPTS_FUNC_NAME):
+            msg = _i18("The module '%s' should have a '%s' function which "
+                       "returns the config options." % (mod.__name__,
+                       LIST_OPTS_FUNC_NAME))
+            raise Exception(msg)
+        else:
+            imported_modules.append(mod)
+
+    return imported_modules
+
+
+def _append_config_options(imported_modules, config_options):
+    for mod in imported_modules:
+        configs = mod.list_opts()
+        for key, val in configs.items():
+            config_options[key].extend(val)