Summary
This article outlines some uses of preconditions.
Solution
Whereas a Runcondition will check a specified logic condition to determine whether or not to skip a procedure step, a Precondtion will determine whether the step should wait for a condition to become true before allowing that step to be consider being started.
Preconditions are evaluated, and if false, they are stored to a precondition list which will be regularly checked to determine if the underlying condition has been met, thus allowing the step to move forward and be scheduled.
NOTE - if a step contains both a precondition and a runcondition, the Precondition must pass first before any runCondition will be evaluated to determine if the step should actually be skipped.
Example and Explanation: Usage of precondition in parallel steps.
In this example step1 is configured without a precondition and to run in parallel.
Step2 is configured without q precondition and in parallel, when it is completed it sets property "step2Completed" - ectool setProperty /myJob/step2Completed complete
Step3 is configured with a precondition and also in parallel. In precondition it checks for "step2Completed" property before run and waits for it to become "true".
After running such configuration we will see next:
Once dependent conditions will be met step3 will start running.
Additional Examples:
Use case |
JavaScript condition |
Nested property check(at first evaluates if NewEnvironment is ready and after check for precondition property) |
$[/javascript (getProperty("/myProject/NewEnvironment") == "True") ? myJob.InstallerCompleted : " " ] |
Simple property check |
$[/javascript getProperty("/myJob/status")=="complete"] |