Make plugins easier to use

This removes the need for editing mistral.conf and
makes the naming of the plugin more obvious.

Change-Id: Ie6e043eacfd0e413d81690f7c5978fd7bbec171d

doc/source/writing_a_plugin_action.rst

@@ -21,22 +21,11 @@ How to write an Action Plugin
 ::
 
  [entry_points]
- myproject.plugins.example =
-    runner = solum.mistral_plugins.somefile:RunnerAction
+ mistral.actions =
+    example.runner = my.mistral_plugins.somefile:RunnerAction
 
-3. Add the namespace into /etc/mistral/mistral.conf
-   (don't overwrite "mistral.plugins.std")
+3. Use your plugin
 
-::
-
- action_plugins = mistral.plugins.std,myproject.plugins.example
-
-4. Use your plugin
-
-Note on naming the plugin.
-
- * The namespace is "myproject.plugins.example"
- * The class is named "runner"
  * Now you can call the action "example.runner"
 
 ::

etc/mistral.conf.sample

@@ -198,9 +198,6 @@
 # Options defined in mistral.config
 #
 
-# List of namespaces to search for plug-ins. (list value)
-#action_plugins=mistral.actions.std
-
 # Specifies which mistral server to start by the launch
 # script. Valid options are all or any combination of api,
 # engine, and executor. (list value)

mistral/actions/action_factory.py

@@ -15,7 +15,7 @@
 #    limitations under the License.
 
 import inspect
-from oslo.config import cfg
+from stevedore import extension
 
 from mistral.actions import base
 from mistral.actions import std_actions
@@ -30,12 +30,11 @@ _ACTION_CTX_PARAM = 'action_context'
 _NAMESPACES = {}
 
 
-def _find_or_create_namespace(full_name):
-    name = full_name.split('.')[-1]
+def _find_or_create_namespace(name):
     ns = _NAMESPACES.get(name)
 
     if not ns:
-        ns = base.Namespace(full_name)
+        ns = base.Namespace(name)
         _NAMESPACES[name] = ns
 
     return ns
@@ -46,10 +45,16 @@ def get_registered_namespaces():
 
 
 def _register_action_classes():
-    cfg.CONF.import_opt('action_plugins', 'mistral.config')
-    for py_ns in cfg.CONF.action_plugins:
-        ns = _find_or_create_namespace(py_ns)
-        ns.log()
+    mgr = extension.ExtensionManager(
+        namespace='mistral.actions',
+        invoke_on_load=False)
+
+    for name in mgr.names():
+        ns = _find_or_create_namespace(name.split('.')[0])
+        ns.add(name.split('.')[1], mgr[name].plugin)
+
+    for ns in _NAMESPACES:
+        _NAMESPACES[ns].log()
 
 
 def get_action_class(action_full_name):

mistral/actions/base.py

@@ -15,7 +15,6 @@
 #    limitations under the License.
 
 import abc
-from stevedore import extension
 
 from mistral.openstack.common import log as logging
 
@@ -87,25 +86,22 @@ class Namespace(object):
     """Action namespace."""
 
     def __init__(self, namespace):
-        self.name = namespace.split('.')[-1]
-        self.mgr = extension.ExtensionManager(
-            namespace=namespace,
-            invoke_on_load=False)
+        self.name = namespace
+        self.actions = {}
 
     def contains_action_name(self, name):
-        return name in self.mgr.names()
+        return name in self.actions
 
     def get_action_class(self, name):
-        # ExtensionManager has no "get"
-        if self.contains_action_name(name):
-            return self.mgr[name].plugin
-        else:
-            return None
+        return self.actions.get(name)
 
     def __len__(self):
-        # ExtensionManager has no len()
-        return len(self.mgr.names())
+        return len(self.actions)
 
     def log(self):
-        for ext in self.mgr:
-            LOG.debug('%s:%s' % (self.name, ext.name))
+        for ext in self.actions:
+            LOG.debug('%s:%s' % (self.name, ext))
+
+    def add(self, name, action):
+        if name not in self.actions:
+            self.actions[name] = action

mistral/config.py

@@ -87,12 +87,6 @@ launch_opt = cfg.ListOpt(
          'api, engine, and executor.'
 )
 
-action_plugins_opt = cfg.ListOpt(
-    'action_plugins',
-    default=['mistral.actions.std'],
-    help='List of namespaces to search for plug-ins.')
-
-
 wf_trace_log_name_opt = cfg.StrOpt('workflow_trace_log_name',
                                    default='workflow_trace',
                                    help='Logger name for pretty '
@@ -106,7 +100,6 @@ CONF.register_opts(pecan_opts, group='pecan')
 CONF.register_opts(db_opts, group='database')
 CONF.register_opts(executor_opts, group='executor')
 CONF.register_opt(wf_trace_log_name_opt)
-CONF.register_opt(action_plugins_opt)
 
 CONF.register_cli_opt(use_debugger)
 CONF.register_cli_opt(launch_opt)

setup.cfg

@@ -39,9 +39,9 @@ mistral.engine.drivers =
 mistral.executor.drivers =
     default = mistral.engine.drivers.default.executor:DefaultExecutor
 
-mistral.actions.std =
-    echo = mistral.actions.std_actions:EchoAction
-    http = mistral.actions.std_actions:HTTPAction
-    mistral_http = mistral.actions.std_actions:MistralHTTPAction
-    ssh = mistral.actions.std_actions:SSHAction
-    email = mistral.actions.std_actions:SendEmailAction
+mistral.actions =
+    std.echo = mistral.actions.std_actions:EchoAction
+    std.http = mistral.actions.std_actions:HTTPAction
+    std.mistral_http = mistral.actions.std_actions:MistralHTTPAction
+    std.ssh = mistral.actions.std_actions:SSHAction
+    std.email = mistral.actions.std_actions:SendEmailAction