ACM startPhase flow

How startPhase is currently implemented

Example using the Demo. The table below shows the startPhase for each Composition Definition Element

The diagram below shows the flow of messages:Note:

• startPhase is configured in composition definition element and defines the order of execution of instance elements;
• Any instance element is executed only once;
• All instance elements whit same startPhase are executed at same time in parallel;
• startPhase is used by deploy and unlock; startPhase in reverse order is used by lock, undeploy and delete;

Alternative flow with "stage"

To maintain the backward compatibility, we are introducing a new property stage.

Minimal support for stage:

• Still valid the startPhase definition for backward compatibility;
• stage is configured in composition definition element;
• stage  is applied only for migrate operation;
• Any instance element could be executed more then one time; 
• All instance elements whit same stage are executed at same time in parallel;

Example of composition definition element stage property:

properties:
  stage: [0,2]

Default value set to 0.

Full support for stage:

• Still valid the startPhase definition for backward compatibility;
• Using startPhase and stage in a composition definition is not valid;
• stage is configured in composition definition element;
• Any composition definition element could have different sptePhase for each operation: for example the order for deploy could different for migrate;
• Any instance element could be executed more then one time; 
• All instance elements whit same stage are executed at same time in parallel;
• stage has not reversal order.

Example of composition definition element stage property:

properties:
  stage:
    - deploy: [0,1]
    - migrate: [0,2]
    - undeploy: [1]
    - delete: [1]

All not defined operations will be set to 0.

Example of stage

The table below shows the stage for each Composition Definition Element:

When an instance element has completed a step, not means that the full implementation is completed (DEPLOYED state).

During the execution of the operation how the user is able to see the steps executed by the instance element? Same issue for monitoring, it needs new filed into Instance Element to store what step is executed.