Remove environment data from task inbound context

* It's redundant to keep environment data in task inbound context,
  it is immutable and we can always take it from workflow execution
  object which is more efficient from DB space consumption
  standpoint. The only case when it's allowed to modify data
  in a workflow environment is when we either resume or re-run
  a workflow and in this case we can change it for the whole
  workflow execution.

Change-Id: I244c1768aaa306f8ad41084325107a40005d874c

mistral/engine/tasks.py

@@ -14,7 +14,6 @@
 #    limitations under the License.
 
 import abc
-import copy
 import operator
 from oslo_log import log as logging
 from osprofiler import profiler
@@ -241,7 +240,7 @@ class Task(object):
         if not action_name:
             return {}
 
-        env = self.task_ex.in_context.get('__env', {})
+        env = self.wf_ex.context.get('__env', {})
 
         return env.get('__actions', {}).get(action_name, {})
 
@@ -351,12 +350,16 @@ class RegularTask(Task):
         )
 
     def _get_target(self, input_dict):
+        ctx_view = data_flow.ContextView(
+            input_dict,
+            self.ctx,
+            self.wf_ex.context,
+            self.wf_ex.input
+        )
+
         return expr.evaluate_recursively(
             self.task_spec.get_target(),
-            utils.merge_dicts(
-                copy.deepcopy(input_dict),
-                copy.deepcopy(self.ctx)
-            )
+            ctx_view
         )
 
     def _get_action_input(self, ctx=None):

mistral/engine/workflows.py

@@ -140,11 +140,6 @@ class Workflow(object):
         # Calculate commands to process next.
         cmds = wf_ctrl.continue_workflow()
 
-        if env:
-            for cmd in cmds:
-                if isinstance(cmd, commands.RunExistingTask):
-                    _update_task_environment(cmd.task_ex, env)
-
         self._continue_workflow(cmds)
 
     def rerun(self, task_ex, reset=True, env=None):
@@ -167,8 +162,6 @@ class Workflow(object):
 
         self.set_state(states.RUNNING, recursive=True)
 
-        _update_task_environment(task_ex, env)
-
         wf_ctrl = wf_base.get_controller(self.wf_ex)
 
         # Calculate commands to process next.
@@ -379,16 +372,6 @@ class Workflow(object):
         )
 
 
-def _update_task_environment(task_ex, env):
-    if env is None:
-        return
-
-    task_ex.in_context['__env'] = utils.merge_dicts(
-        task_ex.in_context['__env'],
-        env
-    )
-
-
 def _get_environment(params):
     env = params.get('env', {})
 

mistral/services/workflows.py

@@ -116,6 +116,7 @@ def update_workflow_execution_env(wf_ex, env):
         )
 
     wf_ex.params['env'] = utils.merge_dicts(wf_ex.params['env'], env)
+
     data_flow.add_environment_to_context(wf_ex)
 
     return wf_ex

mistral/workflow/base.py

@@ -16,7 +16,6 @@
 #    limitations under the License.
 
 import abc
-import copy
 
 from oslo_log import log as logging
 from osprofiler import profiler
@@ -182,19 +181,7 @@ class WorkflowController(object):
         # to cover 'split' (aka 'merge') use case.
         upstream_task_execs = self._get_upstream_task_executions(task_spec)
 
-        ctx = data_flow.evaluate_upstream_context(upstream_task_execs)
-
-        # TODO(rakhmerov): Seems like we can fully get rid of '__env' in
-        # task context if we are OK to have it only in workflow execution
-        # object (wf_ex.context). Now we can selectively modify env
-        # for some tasks if we resume or re-run a workflow.
-        if self.wf_ex.context:
-            ctx['__env'] = u.merge_dicts(
-                copy.deepcopy(ctx.get('__env', {})),
-                copy.deepcopy(self.wf_ex.context.get('__env', {}))
-            )
-
-        return ctx
+        return data_flow.evaluate_upstream_context(upstream_task_execs)
 
     @abc.abstractmethod
     def _get_upstream_task_executions(self, task_spec):