Triggers define a dependency on a task or family . There can be only one trigger dependency per node, but that can be a complex boolean expression of the status of several nodes. Triggers can not be added to the suite node. A node with a trigger can only be activated when its trigger has expired. A trigger holds the node as long as the trigger’s expression evaluation returns false.
Trigger evaluation occurs whenever the child command communicates with the server. i.e. whenever there is a state change in the suite definition and at least once every 60 seconds. The keywords in trigger expressions are: unknown , suspended , complete , queued , submitted , active , aborted and clear and set for event status. Triggers can also reference Node attributes like event , meter , variable , repeat and generated variables and limits. Triggers can also reference the late flag on a node. Trigger evaluation for node attributes uses integer arithmetic. See Glossary
from ecflow import Defs,Suite,Task,Trigger,Complete defs = Defs( Suite("s1", Task("t1"), Task("t2", Trigger("t1 == active and t3 == aborted"), Complete("t3 == complete")), Task("t3")))
The following examples show alternative styles that produce the same definition:
defs = Defs() s1 = defs.add_suite("s1") t1 = s1.add_task("t1") t2 = s1.add_task("t2") t2.add_trigger( "t1 == active and t3 == aborted" ) t2.add_complete( "t3 == complete" ) t3 = s1.add_task("t3") | defs = Defs().add( Suite("s1").add( Task("t1"), Task("t2").add( Trigger("t1 == active and t3 == aborted"), Complete("t3 == complete")), Task("t3"))) | defs = Defs(Suite("s1")) defs.s1 += [ Task("t{}".format(i)) for i in range(1,4) ] defs.s1.t2 += [ Trigger("t1 == active and t3 == aborted"), Complete("t3 == complete") ] |
Adding triggers like '<nodepath> == complete' is extremely common. Hence there are a few short cuts;
task = Task("task") # Using a trigger with a 'list' argument, each string/node element converted to <name> == complete t = Trigger(["a","b",task]) # because Task("task") does *NOT* have a parent, we will use the name assert str(t) == "a == complete AND b == complete AND task == complete","Trigger not as expected: " + str(t)) defs = Defs() task = defs.add_suite("s").add_family("f").add_task("task") t = Trigger(["a","b",task]) # Task('task') has a parent hierarchy, hence we use full path in trigger expression assert str(t) == "a == complete AND b == complete AND /s/f/task == complete", "Trigger not as expected: " + str(t))
Chaining Tasks
There are many times where we want to add a chain of tasks, i.e. where tasks must be run sequentially one after the other. The following examples show different styles of chaining tasks which are identical:
from ecflow import * defs = Defs( Suite("s1", Task("t1"), Task("t2",Trigger( "t1 == complete" )), Task("t3",Trigger( "t2 == complete" )), Task("t4",Trigger( "t3 == complete" )))) | from ecflow import * defs = Defs() + Suite("s1") defs.s1 += [ Task("t1"),Task("t2"), Task("t3"),Task("t4") ] defs.s1.t2 += Trigger( ["t1"] ) defs.s1.t3 += Trigger( ["t2"] ) defs.s1.t4 += Trigger( ["t3"] ) | from ecflow import * defs = Defs() + Suite("s1") defs.s1 >> Task("t1") >> Task("t2") >> Task("t3") >> Task("t4") # >> relies on the leading node to be a Family or Suite |
Reverse Chaining
It is also possible to << to reverse chain task.
The following suites are identical:
defs = Defs() + Suite("s1") defs.s1 += [ Task("t1"),Task("t2"),Task("t3"),Task("t4") ] defs.s1.t1 += Trigger( "t2 == complete" ) defs.s1.t2 += Trigger( "t3 == complete" ) defs.s1.t3 += Trigger( "t4 == complete" ) | defs = Defs() + Suite("s1") defs.s1 << Task("t1") << Task("t2") << Task("t3") << Task("t4") # << relies on the leading node to be a Suite or Family |
In the examples above we use 'defs.s1.*' to reference a node by name. This is useful in small designs but will produce maintenance issues in large designs IF the node names are changed.