ACM startPhase flow

How startPhase is currently implemented

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;

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

Participant	Composition Definition Element	startPhase

Participant	Composition Definition Element	startPhase
Policy	onap.policy.clamp.ac.element.Policy_AutomationCompositionElement	0
K8s	onap.policy.clamp.ac.element.K8S_StarterAutomationCompositionElement	0
K8s	onap.policy.clamp.ac.element.K8S_BridgeAutomationCompositionElement	0
K8s	onap.policy.clamp.ac.element.K8S_SinkAutomationCompositionElement	0
Http	onap.policy.clamp.ac.element.Http_StarterAutomationCompositionElement	1
Http	onap.policy.clamp.ac.element.Http_BridgeAutomationCompositionElement	1
Http	onap.policy.clamp.ac.element.Http_SinkAutomationCompositionElement	1

The diagram below shows the flow of messages:

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 stage 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]
    - update: [0]
    - undeploy: [0]
    - delete: [0]

All not defined operations will be set to 0.

Example of stage

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

Participant	Composition Definition Element	stage

Participant	Composition Definition Element	stage
SEF	A1	0, 2
SEF	A2	0, 2
CNLCM	B	1

At the migrate method will be add a new stage parameter, and it will be created a new abstract class AcElementListenerV3. The abstract class AcElementListenerV1 and AcElementListenerV2 will wrap the new method to maintain the compatibility.

Below the refactored migrate method.

    /**
     * Handle an update on a automation composition element.
     *
     * @param compositionElement the information of the Automation Composition Definition Element
     * @param compositionElementTarget the information of the Automation Composition Definition Element Target
     * @param instanceElement the information of the Automation Composition Instance Element
     * @param instanceElementMigrate the information of the Automation Composition Instance Element updated
     * @param stage the stage to perform
     * @throws PfModelException from Policy framework
     */
    void migrate(CompositionElementDto compositionElement, CompositionElementDto compositionElementTarget,
            InstanceElementDto instanceElement, InstanceElementDto instanceElementMigrate, Integer stage) throws PfModelException;

Note: instanceElement will contain the old properties only in the first call, if required we can implement old properties for each stage.

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

It will add new method "updateAutomationCompositionElementStage" as below.

Note: Participant has the control to decide what will be the next stage.

During the execution of the operation the user is able to see the stage that is executing for each instance element. "stage" field will be add in DB.