The CLAMP Automation Composition Runtime 

Contents

This article explains how CLAMP Automation Composition Runtime is implemented.

Terminology 

Broadcast message: a message for all participants (participantId=null and participantType=null)
Message to a participant: a message only for a participant (participantId and participantType properly filled)
ThreadPoolExecutor: ThreadPoolExecutor executes the given task, into SupervisionAspect class is configured to execute tasks in ordered manner, one by one
Spring Scheduling: into SupervisionAspect class, the @Scheduled annotation invokes “schedule()” method every “runtime.participantParameters.heartBeatMs” milliseconds with a fixed delay
MessageIntercept: “@MessageIntercept” annotation is used into SupervisionHandler class to intercept “handleParticipantMessage” method calls using spring aspect oriented programming
GUI: swagger-ui, Postman or policy-gui

Design of Rest Api 

Create of a Automation Composition Type 

GUI calls POST “/commission” endpoint with a Automation Composition Type Definition (Tosca Service Template) as body
runtime-ACM receives the call by Rest-Api (CommissioningController)
It saves to DB the Tosca Service Template using PolicyModelsProvider
if there are participants registered, it triggers the execution to send a broadcast PARTICIPANT_UPDATE message
the message is built by ParticipantUpdatePublisher using Tosca Service Template data (to fill the list of ParticipantDefinition)

Delete of a Automation Composition Type 

GUI calls DELETE “/commission” endpoint
runtime-ACM receives the call by Rest-Api (CommissioningController)
if there are participants registered, runtime-ACM triggers the execution to send a broadcast PARTICIPANT_UPDATE message
the message is built by ParticipantUpdatePublisher with an empty list of ParticipantDefinition
It deletes the Automation Composition Type from DB

Create of a Automation Composition 

GUI calls POST “/instantiation” endpoint with a Automation Composition as body
runtime-ACM receives the call by Rest-Api (InstantiationController)
It validates the Automation Composition
It saves the Automation Composition to DB
Design of an update of a Automation Composition
GUI calls PUT “/instantiation” endpoint with a Automation Composition as body
runtime-ACM receives the call by Rest-Api (InstantiationController)
It validates the Automation Composition
It saves the Automation Composition to DB

Delete of a Automation Composition 

GUI calls DELETE “/instantiation” endpoint
runtime-ACM receives the call by Rest-Api (InstantiationController)
It checks that Automation Composition is in UNINITIALISED status
It deletes the Automation Composition from DB

“issues Automation Composition commands to Automation Compositions”

case UNINITIALISED to PASSIVE

GUI calls “/instantiation/command” endpoint with PASSIVE as orderedState
runtime-ACM checks if participants registered are matching with the list of Automation Composition Element
It updates Automation Composition and Automation Composition elements to DB (orderedState = PASSIVE)
It validates the status order issued
It triggers the execution to send a broadcast AUTOMATION_COMPOSITION_UPDATE message
the message is built by AutomationCompositionUpdatePublisher using Tosca Service Template data and AutomationComposition data. (with startPhase = 0)
It updates Automation Composition and Automation Composition elements to DB (state = UNINITIALISED2PASSIVE)

case PASSIVE to UNINITIALISED

GUI calls “/instantiation/command” endpoint with UNINITIALISED as orderedState
runtime-ACM checks if participants registered are matching with the list of Automation Composition Element
It updates Automation Composition and Automation Composition elements to DB (orderedState = UNINITIALISED)
It validates the status order issued
It triggers the execution to send a broadcast AUTOMATION_COMPOSITION_STATE_CHANGE message
the message is built by AutomationCompositionStateChangePublisher with automationcompositionId
It updates Automation Composition and Automation Composition elements to DB (state = PASSIVE2UNINITIALISED)

case PASSIVE to RUNNING

GUI calls “/instantiation/command” endpoint with RUNNING as orderedState
runtime-ACM checks if participants registered are matching with the list of Automation Composition Element.
It updates Automation Composition and Automation Composition elements to DB (orderedState = RUNNING)
It validates the status order issued
It triggers the execution to send a broadcast AUTOMATION_COMPOSITION_STATE_CHANGE message
the message is built by AutomationCompositionStateChangePublisher with automationcompositionId
It updates Automation Composition and Automation Composition elements to DB (state = PASSIVE2RUNNING)

case RUNNING to PASSIVE

GUI calls “/instantiation/command” endpoint with UNINITIALISED as orderedState
runtime-ACM checks if participants registered are matching with the list of Automation Composition Element
It updates Automation Composition and Automation Composition elements to db (orderedState = RUNNING)
It validates the status order issued
It triggers the execution to send a broadcast AUTOMATION_COMPOSITION_STATE_CHANGE message
the message is built by AutomationCompositionStateChangePublisher with automationcompositionId
It updates Automation Composition and Automation Composition elements to db (state = RUNNING2PASSIVE)

The startPhase is particularly important in Automation Composition update and Automation Composition state changes because sometime the user wishes to control the order in which the state changes in Automation Composition Elements in a Automation Composition.

How to define StartPhase 

StartPhase is defined as shown below in the Definition of TOSCA fundamental Automation Composition Types yaml file.

startPhase:
  type: integer
  required: false
  constraints:
  - greater-or-equal: 0
  description: A value indicating the start phase in which this Automation Composition element will be started, the
               first start phase is zero. Automation Composition Elements are started in their start_phase order and stopped
               in reverse start phase order. Automation Composition Elements with the same start phase are started and
               stopped simultaneously
  metadata:
    common: true

The “common: true” value in the metadata of the startPhase property identifies that property as being a common property. This property will be set on the CLAMP GUI during Automation Composition commissioning. Example where it could be used:

org.onap.domain.database.Http_PMSHMicroserviceAutomationCompositionElement:
  # Consul http config for PMSH.
  version: 1.2.3
  type: org.onap.policy.clamp.acm.HttpAutomationCompositionElement
  type_version: 1.0.1
  description: Automation Composition element for the http requests of PMSH microservice
  properties:
    provider: ONAP
    participant_id:
      name: HttpParticipant0
      version: 1.0.0
    participantType:
      name: org.onap.acm.HttpAutomationCompositionParticipant
      version: 2.3.4
    uninitializedToPassiveTimeout: 180
    startPhase: 1

How StartPhase works 

In state changes from UNITITIALISED → PASSIVE, Automation Composition elements are started in increasing order of their startPhase.

Example with Http_PMSHMicroserviceAutomationCompositionElement with startPhase to 1 and PMSH_K8SMicroserviceAutomationCompositionElement with startPhase to 0

runtime-ACM sends a broadcast AUTOMATION_COMPOSITION_UPDATE message to all participants with startPhase = 0
participant receives the AUTOMATION_COMPOSITION_UPDATE message and runs to PASSIVE state (only CL elements defined as startPhase = 0)
runtime-ACM receives AUTOMATION_COMPOSITION_UPDATE_ACT messages from participants and set the state (from the CL element of the message) to PASSIVE
runtime-ACM calculates that all CL elements with startPhase = 0 are set to proper state and sends a broadcast AUTOMATION_COMPOSITION_UPDATE message with startPhase = 1
participant receives the AUTOMATION_COMPOSITION_UPDATE message and runs to PASSIVE state (only CL elements defined as startPhase = 1)
runtime-ACM calculates that all CL elements are set to proper state and set CL to PASSIVE

In that scenario the message AUTOMATION_COMPOSITION_UPDATE has been sent two times.

Design of managing messages 

PARTICIPANT_REGISTER 

A participant starts and send a PARTICIPANT_REGISTER message
ParticipantRegisterListener collects the message from DMaap
if not present, it saves participant reference with status UNKNOWN to DB
if is present a Automation Composition Type, it triggers the execution to send a PARTICIPANT_UPDATE message to the participant registered (message of Priming)
the message is built by ParticipantUpdatePublisher using Tosca Service Template data (to fill the list of ParticipantDefinition)
It triggers the execution to send a PARTICIPANT_REGISTER_ACK message to the participant registered
MessageIntercept intercepts that event, if PARTICIPANT_UPDATE message has been sent, it will be add a task to handle PARTICIPANT_REGISTER in SupervisionScanner
SupervisionScanner starts the monitoring for participantUpdate

PARTICIPANT_UPDATE_ACK 

A participant sends PARTICIPANT_UPDATE_ACK message in response to a PARTICIPANT_UPDATE message
ParticipantUpdateAckListener collects the message from DMaap
MessageIntercept intercepts that event and adds a task to handle PARTICIPANT_UPDATE_ACK in SupervisionScanner
SupervisionScanner removes the monitoring for participantUpdate
It updates the status of the participant to DB

PARTICIPANT_STATUS 

A participant sends a scheduled PARTICIPANT_STATUS message
ParticipantStatusListener collects the message from DMaap
MessageIntercept intercepts that event and adds a task to handle PARTICIPANT_STATUS in SupervisionScanner
SupervisionScanner clears and starts the monitoring for participantStatus

AUTOMATION_COMPOSITION_UPDATE_ACK 

A participant sends AUTOMATION_COMPOSITION_UPDATE_ACK message in response to a AUTOMATION_COMPOSITION_UPDATE message. It will send a AUTOMATION_COMPOSITION_UPDATE_ACK - for each CL-elements moved to the ordered state as indicated by the AUTOMATION_COMPOSITION_UPDATE
AutomationCompositionUpdateAckListener collects the message from DMaap
It checks the status of all Automation Composition elements and checks if the Automation Composition is primed
It updates the CL to DB if it is changed
MessageIntercept intercepts that event and adds a task to handle a monitoring execution in SupervisionScanner

AUTOMATION_COMPOSITION_STATECHANGE_ACK 

Design of a AUTOMATION_COMPOSITION_STATECHANGE_ACK is similar to the design for AUTOMATION_COMPOSITION_UPDATE_ACK

Design of monitoring execution in SupervisionScanner 

Monitoring is designed to process the follow operations:

to determine the next startPhase in a AUTOMATION_COMPOSITION_UPDATE message
to update CL state: in a scenario that “AutomationComposition.state” is in a kind of transitional state (example UNINITIALISED2PASSIVE), if all - CL-elements are moved properly to the specific state, the “AutomationComposition.state” will be updated to that and saved to DB
to retry AUTOMATION_COMPOSITION_UPDATE/AUTOMATION_COMPOSITION_STATE_CHANGE messages. if there is a CL Element not in the proper state, it will retry a broadcast message
to retry PARTICIPANT_UPDATE message to the participant in a scenario that runtime-ACM do not receive PARTICIPANT_UPDATE_ACT from it
to send PARTICIPANT_STATUS_REQ to the participant in a scenario that runtime-ACM do not receive PARTICIPANT_STATUS from it

The solution Design of retry, timeout, and reporting for all Participant message dialogues are implemented into the monitoring execution.

Spring Scheduling inserts the task to monitor retry execution into ThreadPoolExecutor
ThreadPoolExecutor executes the task
a message will be retry if runtime-ACM do no receive Act message before MaxWaitMs milliseconds

Design of Exception handling 

GlobalControllerExceptionHandler 

If error occurred during the Rest Api call, runtime-ACM responses with a proper status error code and a JSON message error. This class is implemented to intercept and handle AutomationCompositionException, PfModelException and PfModelRuntimeException if they are thrown during the Rest Ali calls. All of those classes must implement ErrorResponseInfo that contains message error and status response code. So the Exception is converted in JSON message.

RuntimeErrorController 

If wrong end-point is called or an Exception not intercepted by GlobalControllerExceptionHandler, runtime-ACM responses with a proper status error code and a JSON message error. This class is implemented to redirect the standard Web error page to a JSON message error. Typically that happen when a wrong end-point is called, but also could be happen for not authorized call, or any other Exception not intercepted by GlobalControllerExceptionHandler.