Cancel the plan if some of its prerequisites failed

Author: adamruzicka

examples/execution_plan_chaining.rb

@@ -4,23 +4,34 @@
 require_relative 'example_helper'
 
 class DelayedAction < Dynflow::Action
-  def plan
-    plan_self
+  def plan(should_fail = false)
+    plan_self :should_fail => should_fail
   end
 
   def run
     sleep 5
+    raise "Controlled failure" if input[:should_fail]
+  end
+
+  def rescue_strategy
+    Dynflow::Action::Rescue::Fail
   end
 end
 
 if $PROGRAM_NAME == __FILE__
-  ExampleHelper.world.action_logger.level = 1
-  ExampleHelper.world.logger.level = 0
+  world = ExampleHelper.create_world do |config|
+    config.auto_rescue = true
+  end
+  world.action_logger.level = 1
+  world.logger.level = 0
 
-  plan1 = ExampleHelper.world.trigger(DelayedAction)
-  plan2 = ExampleHelper.world.chain(plan1.execution_plan_id, DelayedAction)
-  plan3 = ExampleHelper.world.chain(plan2.execution_plan_id, DelayedAction)
-  plan4 = ExampleHelper.world.chain(plan2.execution_plan_id, DelayedAction)
+  plan1 = world.trigger(DelayedAction)
+  plan2 = world.chain(plan1.execution_plan_id, DelayedAction)
+  plan3 = world.chain(plan2.execution_plan_id, DelayedAction)
+  plan4 = world.chain(plan2.execution_plan_id, DelayedAction)
+
+  plan5 = world.trigger(DelayedAction, true)
+  plan6 = world.chain(plan5.execution_plan_id, DelayedAction)
 
   puts <<-MSG.gsub(/^.*\|/, '')
     |
@@ -34,9 +45,12 @@ def run
     |    #{plan2.id} is delayed and should run once #{plan1.id} finishes.
     |    #{plan3.id} and #{plan4.id} are delayed and should run once #{plan2.id} finishes.
     |
+    |    #{plan5.id} runs immediately and is expected to fail.
+    |    #{plan6.id} should not run at all as its prerequisite failed.
+    |
     |  Visit #{ExampleHelper::DYNFLOW_URL} to see their status.
     |
   MSG
 
-  ExampleHelper.run_web_console
+  ExampleHelper.run_web_console(world)
 end

lib/dynflow/delayed_plan.rb

@@ -31,6 +31,12 @@ def timeout
       error("Execution plan could not be started before set time (#{@start_before})", 'timeout')
     end
 
+    def failed_dependencies(uuids)
+      bullets = uuids.map { |u| "- #{u}" }.join("\n")
+      msg = "Execution plan could not be started because some of its preqrequisite execution plans failed:\n#{bullets}"
+      error(msg, 'failed-dependency')
+    end
+
     def error(message, history_entry = nil)
       execution_plan.root_plan_step.state = :error
       execution_plan.root_plan_step.error = ::Dynflow::ExecutionPlan::Steps::Error.new(message)

lib/dynflow/director.rb

@@ -114,7 +114,15 @@ def execute
         plan = world.persistence.load_delayed_plan(execution_plan_id)
         return if plan.nil? || plan.execution_plan.state != :scheduled
 
-        if !plan.start_before.nil? && plan.start_before < Time.now.utc()
+        if plan.start_before.nil?
+          blocker_ids = world.persistence.find_execution_plan_dependencies(execution_plan_id)
+          statuses = world.persistence.find_execution_plan_statuses({ filters: { uuid: blocker_ids } })
+          failed = statuses.select { |_uuid, status| status[:state] == 'stopped' && status[:result] == 'error' }
+          if failed.any?
+            plan.failed_dependencies(failed.keys)
+            return
+          end
+        elsif plan.start_before < Time.now.utc()
           plan.timeout
           return
         end