Put provides and requires code to basic Flow

Code that calculates provides and requires for flow is almost
identical for all patterns, so this change makes it completely
identical and puts it to the base class. Other patterns are
still allowed to override these properties for sake of customization
or optimization.

Change-Id: I6e875e863047b5287ec727fc9a491f252f144ecf

taskflow/flow.py

@@ -43,16 +43,10 @@ class Flow(object):
     def __init__(self, name, retry=None):
         self._name = six.text_type(name)
         self._retry = retry
-        # If retry doesn't have a name,
+        # NOTE(akarpinska): if retry doesn't have a name,
         # the name of its owner will be assigned
-        if self._retry:
+        if self._retry and self._retry.name is None:
-            self._retry_provides = self.retry.provides
-            self._retry_requires = self.retry.requires
-            if not self._retry.name:
                 self._retry.set_name(self.name + "_retry")
-        else:
-            self._retry_provides = set()
-            self._retry_requires = set()
 
     @property
     def name(self):
@@ -66,6 +60,10 @@ class Flow(object):
         """
         return self._retry
 
+    @abc.abstractmethod
+    def add(self, *items):
+        """Adds a given item/items to this flow."""
+
     @abc.abstractmethod
     def __len__(self):
         """Returns how many items are in this flow."""
@@ -90,14 +88,29 @@ class Flow(object):
         lines.append("%s" % (len(self)))
         return "; ".join(lines)
 
-    @abc.abstractmethod
+    @property
-    def add(self, *items):
-        """Adds a given item/items to this flow."""
-
-    @abc.abstractproperty
-    def requires(self):
-        """Browse argument requirement names this flow requires to run."""
-
-    @abc.abstractproperty
     def provides(self):
-        """Browse argument names provided by the flow."""
+        """Set of result names provided by the flow.
+
+        Includes names of all the outputs provided by atoms of this flow.
+        """
+        provides = set()
+        if self._retry:
+            provides.update(self._retry.provides)
+        for subflow in self:
+            provides.update(subflow.provides)
+        return provides
+
+    @property
+    def requires(self):
+        """Set of argument names required by the flow.
+
+        Includes names of all the inputs required by atoms of this
+        flow, but not provided within the flow itself.
+        """
+        requires = set()
+        if self._retry:
+            requires.update(self._retry.requires)
+        for subflow in self:
+            requires.update(subflow.requires)
+        return requires - self.provides

taskflow/patterns/graph_flow.py

@@ -104,8 +104,8 @@ class Flow(flow.Flow):
 
         if self.retry:
             update_requirements(self.retry)
-            provided.update(dict((k,
+            provided.update(dict((k, self.retry)
-                                  self.retry) for k in self._retry_provides))
+                                 for k in self.retry.provides))
 
         # NOTE(harlowja): Add items and edges to a temporary copy of the
         # underlying graph and only if that is successful added to do we then
@@ -123,7 +123,7 @@ class Flow(flow.Flow):
                         % dict(item=item.name,
                                flow=provided[value].name,
                                value=value))
-                if value in self._retry_requires:
+                if self.retry and value in self.retry.requires:
                     raise exc.DependencyFailure(
                         "Flows retry controller %(retry)s requires %(value)s "
                         "but item %(item)s being added to the flow produces "
@@ -167,22 +167,6 @@ class Flow(flow.Flow):
         for (u, v, e_data) in self._get_subgraph().edges_iter(data=True):
             yield (u, v, e_data)
 
-    @property
-    def provides(self):
-        provides = set()
-        provides.update(self._retry_provides)
-        for subflow in self:
-            provides.update(subflow.provides)
-        return provides
-
-    @property
-    def requires(self):
-        requires = set()
-        requires.update(self._retry_requires)
-        for subflow in self:
-            requires.update(subflow.requires)
-        return requires - self.provides
-
 
 class TargetedFlow(Flow):
     """Graph flow with a target.

taskflow/patterns/linear_flow.py

@@ -78,22 +78,3 @@ class Flow(flow.Flow):
         for src, dst in zip(self._children[:-1],
                             self._children[1:]):
             yield (src, dst, _LINK_METADATA.copy())
-
-    @property
-    def provides(self):
-        provides = set()
-        provides.update(self._retry_provides)
-        for subflow in self._children:
-            provides.update(subflow.provides)
-        return provides
-
-    @property
-    def requires(self):
-        requires = set()
-        provides = set()
-        requires.update(self._retry_requires)
-        provides.update(self._retry_provides)
-        for subflow in self._children:
-            requires.update(subflow.requires - provides)
-            provides.update(subflow.provides)
-        return requires

taskflow/patterns/unordered_flow.py

@@ -41,12 +41,9 @@ class Flow(flow.Flow):
         if not items:
             return self
 
-        # NOTE(harlowja): check that items to be added are actually
+        # check that items don't provide anything that other
-        # independent.
+        # part of flow provides or requires
-        provides = set()
+        provides = self.provides
-        for subflow in self:
-            provides.update(subflow.provides)
-
         old_requires = self.requires
         for item in items:
             item_provides = item.provides
@@ -57,7 +54,7 @@ class Flow(flow.Flow):
                     "by other item(s) of unordered flow %(flow)s"
                     % dict(item=item.name, flow=self.name,
                            oo=sorted(bad_provs)))
-            same_provides = (provides | self._retry_provides) & item.provides
+            same_provides = provides & item.provides
             if same_provides:
                 raise exceptions.DependencyFailure(
                     "%(item)s provides %(value)s but is already being"
@@ -67,6 +64,11 @@ class Flow(flow.Flow):
                            value=sorted(same_provides)))
             provides |= item.provides
 
+        # check that items don't require anything other children provides
+        if self.retry:
+            # NOTE(imelnikov): it is allowed to depend on value provided
+            # by retry controller of the flow
+            provides -= self.retry.provides
         for item in items:
             bad_reqs = provides & item.requires
             if bad_reqs:
@@ -79,23 +81,6 @@ class Flow(flow.Flow):
         self._children.update(items)
         return self
 
-    @property
-    def provides(self):
-        provides = set()
-        provides.update(self._retry_provides)
-        for subflow in self:
-            provides.update(subflow.provides)
-        return provides
-
-    @property
-    def requires(self):
-        requires = set()
-        for subflow in self:
-            requires.update(subflow.requires)
-        requires.update(self._retry_requires)
-        requires -= self._retry_provides
-        return requires
-
     def __len__(self):
         return len(self._children)