Compile lists of retry/task atoms at runtime compile time

Instead of recompiling and rebuilding this list every iteration
of the ``iterate_retries`` function we can just locally cache this
information in the runtime compile function and later just use
it directly.

Change-Id: I70e8409391d655730da61413300db05b25843350

taskflow/engines/action_engine/analyzer.py

@@ -14,12 +14,12 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import functools
 import itertools
 
 from networkx.algorithms import traversal
 import six
 
-from taskflow import retry as retry_atom
 from taskflow import states as st
 
 
@@ -92,6 +92,8 @@ class Analyzer(object):
         self._execution_graph = runtime.compilation.execution_graph
         self._check_atom_transition = runtime.check_atom_transition
         self._fetch_edge_deciders = runtime.fetch_edge_deciders
+        self._fetch_retries = functools.partial(
+            runtime.fetch_atoms_by_kind, 'retry')
 
     def get_next_nodes(self, node=None):
         """Get next nodes to run (originating from node or all nodes)."""
@@ -207,14 +209,13 @@ class Analyzer(object):
             yield dst
 
     def iterate_retries(self, state=None):
-        """Iterates retry controllers that match the provided state.
+        """Iterates retry atoms that match the provided state.
 
-        If no state is provided it will yield back all retry controllers.
+        If no state is provided it will yield back all retry atoms.
         """
-        for node in self._execution_graph.nodes_iter():
-            if isinstance(node, retry_atom.Retry):
-                if not state or self.get_state(node) == state:
-                    yield node
+        for atom in self._fetch_retries():
+            if not state or self.get_state(atom) == state:
+                yield atom
 
     def iterate_all_nodes(self):
         """Yields back all nodes in the execution graph."""

taskflow/engines/action_engine/runtime.py

@@ -43,6 +43,7 @@ class Runtime(object):
         self._storage = storage
         self._compilation = compilation
         self._atom_cache = {}
+        self._atoms_by_kind = {}
 
     def compile(self):
         """Compiles & caches frequently used execution helper objects.
@@ -63,6 +64,8 @@ class Runtime(object):
             'task': self.task_scheduler,
         }
         execution_graph = self._compilation.execution_graph
+        all_retry_atoms = []
+        all_task_atoms = []
         for atom in self.analyzer.iterate_all_nodes():
             metadata = {}
             walker = sc.ScopeWalker(self.compilation, atom, names_only=True)
@@ -70,10 +73,12 @@ class Runtime(object):
                 check_transition_handler = st.check_task_transition
                 change_state_handler = change_state_handlers['task']
                 scheduler = schedulers['task']
+                all_task_atoms.append(atom)
             else:
                 check_transition_handler = st.check_retry_transition
                 change_state_handler = change_state_handlers['retry']
                 scheduler = schedulers['retry']
+                all_retry_atoms.append(atom)
             edge_deciders = {}
             for previous_atom in execution_graph.predecessors(atom):
                 # If there is any link function that says if this connection
@@ -89,6 +94,8 @@ class Runtime(object):
             metadata['scheduler'] = scheduler
             metadata['edge_deciders'] = edge_deciders
             self._atom_cache[atom.name] = metadata
+        self._atoms_by_kind['retry'] = all_retry_atoms
+        self._atoms_by_kind['task'] = all_task_atoms
 
     @property
     def compilation(self):
@@ -150,6 +157,15 @@ class Runtime(object):
         metadata = self._atom_cache[atom.name]
         return metadata['edge_deciders']
 
+    def fetch_atoms_by_kind(self, kind):
+        """Fetches all the atoms of a given kind.
+
+        NOTE(harlowja): Currently only ``task`` or ``retry`` are valid
+                        kinds of atoms (requesting other kinds will just
+                        return empty lists).
+        """
+        return self._atoms_by_kind.get(kind, [])
+
     def fetch_scheduler(self, atom):
         """Fetches the cached specific scheduler for the given atom."""
         # This does not check if the name exists (since this is only used