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diff --git a/docs/clamp/controlloop/api-protocol/controlloop-participant-protocol.rst b/docs/clamp/controlloop/api-protocol/controlloop-participant-protocol.rst new file mode 100644 index 00000000..2fa5336f --- /dev/null +++ b/docs/clamp/controlloop/api-protocol/controlloop-participant-protocol.rst @@ -0,0 +1,472 @@ +.. This work is licensed under a Creative Commons Attribution 4.0 International License. + +.. _controlloop-participant-protocol-label: + +The CLAMP Control Loop Participant Protocol +########################################### + +The CLAMP Control Loop Participant protocol is an asynchronous protocol that is used by the +CLAMP runtime to coordinate life cycle management of Control Loop instances. The protocol +supports the functions described in the sections below. + + +Protocol Dialogues +================== + +The protocol supports the dialogues described below. + +Participant Registration and De-Registration +-------------------------------------------- + +Registration when a participant comes up and update of participant with control loop type +information and common parameter values for its control loop types. + +.. image:: ../images/clamp-cl-participants/participant-registering.png + + +De-registration is executed as a participant goes down. + +.. image:: ../images/clamp-cl-participants/participant-deregistration.png + + +Control Loop Priming and De-Priming +----------------------------------- + +When a control loop is primed, the portion of the Control Loop Type Definition and Common +Property values for the participants of each participant type mentioned in the Control Loop +Definition are sent to the participants. + +.. image:: ../images/clamp-cl-participants/controlloop-priming.png + +When a control loop is de-primed, the portion of the Control Loop Type Definition and Common +Property values for the participants of each participant type mentioned in the Control Loop +Definition are deleted on participants. + +.. image:: ../images/clamp-cl-participants/controlloop-depriming.png + + +Control Loop Update +------------------- + +Control Loop Update handles creation, change, and deletion of control loops on participants. +Change of control loops uses a semantic versioning approach and follow the semantics described +on the page `4.1 Management of Control Loop Instance Configurations <management-cl-instance-configs>`. + +.. image:: ../images/clamp-cl-participants/controlloop-update.png + +The handling of a ControlLoopUpdate message in each participant is as shown below. + +.. image:: ../images/clamp-cl-participants/controlloop-update-msg.png + +Control Loop State Change +------------------------- + +This dialogue is used to change the state of Control Loops and their Control Loop Elements. The +CLAMP Runtime sends a Control Loop State Change message on the control loop to all participants. +Participants that have Control Loop Elements in that Control Loop attempt an update on the state +of the control loop elements they have for that control loop, and report the result back. + +The *startPhase* in the `Definition of TOSCA fundamental Control Loop Types +<https://github.com/onap/policy-clamp/blob/master/common/src/main/resources/tosca/ControlLoopTOSCAServiceTemplateTypes.yaml>`_ +is particularly important in control loop state changes because sometime the user wishes to control +the order in which the state changes in Control Loop Elements in a control loop. In state changes +from *UNITITIALISED* → *PASSIVE* and from *PASSIVE* → *RUNNING*, control loop elements are started in +increasing order of their *startPhase*. In state changes from *RUNNING* → *PASSIVE* and from *PASSIVE* +→ *UNITITIALISED*, control loop elements are started in decreasing order of their *startPhase*. + +The CLAMP runtime controls the state change process described in the diagram below. The CLAMP runtime +sends a Control Loop State Change message on DMaaP to all participants in a particular Start Phase so, +in each state change multiple Control Loop State Change messages are sent, one for each Start Phase in +the control loop. If more than one Control Loop Element has the same Start Phase, those Control Loop +Elements receive the same Control Loop State Change message from DMaaP and start in parallel. + +The Participant reads each State Change Message it sees on DMaaP. If the Start Phase on the Control +Loop State Change message matches the Start Phase of the Control Loop Element, the participant processes +the State Change message. Otherwise the participant ignores the message. + +.. image:: ../images/clamp-cl-participants/controlloop-state-change.png + +The handling of a ControlLoopStateChange message in each participant is as shown below. + +.. image:: ../images/clamp-cl-participants/controlloop-state-change-msg.png + +Control Loop Monitoring and Reporting +------------------------------------- + +This dialogue is used as a heartbeat mechanism for participants, to monitor the status of Control Loop +Elements, and to gather statistics on control loops. The ParticipantStatus message is sent periodically +by each participant. The reporting interval for sending the message is configurable. + +.. image:: ../images/clamp-cl-participants/controlloop-monitoring.png + + +Messages +======== + +The CLAMP Control Loop Participant Protocol uses the following messages. The descriptions below give +an overview of each message. For the precise definition of the messages, see the `CLAMP code at Github +<https://github.com/onap/policy-clamp/tree/master/models/src/main/java/org/onap/policy/clamp/controlloop/models/messages/dmaap/participant>`_ +. All messages are carried on DMaaP. + + +.. list-table:: + :widths: 15 10 10 15 15 35 + :header-rows: 1 + + * - Message + - Source + - Target + - Purpose + - Important Fields |