@startuml r5-1_proposed_policy_update_flow
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skinparam component {
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skinparam note {
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title = R5-1 El Alto proposal for \n policy flows between the new PDP and DCAE component \n PDP does the pub-sub for policies per component \n %date[yyyy-MM-dd HH:mm]%

package "<&dollar> Policy-Engine" as policy_engine #88ff88 {
    component "<&dollar> new Policy-Access-Point (<b>new PAP</b>)" as PAP
    component "<&dollar> new Policy-Decision-Point (<b>new PDP</b>)\n==pub-sub==\n maintains the table of policy-update subscribers \nwith <&crop> policy-filters and subscriber_topic\n--subscribe--\n[0.3.2] insert-update the record for the <b>subscriber_topic</b>\n[0.3.3] notify the subscriber_topic \nwith the latest snapshot of policies that match to any of policy-filters\n--unsubscribe--\n[99.2] delete the record for the <b>subscriber_topic</b>\n==[1] on policy push/delete from PAP==\n[1.0] select all  subscribers that match to the pushed/deleted policies \n by any <&crop> policy-filter\n[1.1] for each affected subscriber retrieve all the latest snapshot of policies \n[1.2] notify each subscriber_topic separately \nwith the latest snapshot of policies" as PDP

    database "<&list> <b>policy-update subscribers</b> (table in database)\n..unique topic per each component instance..\n<b>subscriber_topic</b> TEXT <&key> PK -- "policies_DCAE_tca_<service-component-name>"\n..\n action TEXT -- "configure"\nONAPName TEXT -- "DCAE"\nONAPComponent TEXT -- "tca"\nONAPInstance TEXT -- "<service-component-name>"\n..list of policy-filters on subscriber_topic (component)..\n<&list> <&crop> <b>policy-filters</b> JSON -- list of the <b>"resource"</b> objects of /decision/v1: \n[{"policy-id": ["onap.scaleout.tca", "onap.restart.tca"]}, ...]" as policy_update_subscribers
}

package "<&dollar> DCAE" as DCAE {
    package "<&signpost> DCAE-Controller" as DCAE_Controller #eeffee {
        package "<&cog> deployment" #eeeeff {
            component "<&aperture> <b>deployment_handler</b>\n--\n[0] install component through cloudify for the blueprint+inputs\n--\n[99] uninstall component through cloudify" as deployment_handler

            component "<&aperture> <b>policy_handler</b>\n--[0.3] on startup of component - /subscribe--\n[0.3.1] get <b>subscriber_topic</b> and all policy-filters from req from plugin\n[0.3.2] subscribe with PDP for policy-updates on all <&crop> policy-filters and \n<b>subscriber_topic</b>="policies_DCAE_tca_<service-component-name>"\n--\n==[99.2] on shutdown of component - /unsubscribe==\n[99.2] unsubscribe <b>subscriber_topic</b> from PDP" as policy_handler

            package "<b>cloudify</b>" as cloudify_server #00ffff {
                control cloudify
                component "<&aperture> <b>k8s_plugin decorated with @policies_gather</b>\n--[0] install component--\n[0.0] <b>k8s_plugin</b>: save config for component into consul-kv under <service-component-name>\n[0.1] <b>@policies_gather</b>: gather policy-filters assigned to component in blueprint+inputs\n[0.2] <b>@policies_gather</b>: save <service-component-name>:<b>subscriber_topic</b>='policies_DCAE_tca_<service-component-name>' into consul-kv\n[0.3] <b>@policies_gather</b>: subscribe the component for policy-updates through policy_handler\n pass <b>subscriber_topic</b>="policies_DCAE_tca_<service-component-name>" \nand multiple policy-filters for component as [{"policy-id": ["onap.scaleout.tca", "onap.restart.tca"]}]\n[0.4] <b>k8s_plugin</b>: install and start component\n--[99] uninstall component--\n[99.0] <b>@policies_gather</b>: delete records from consul-kv\n[99.1] <b>k8s_plugin</b>: delete records from consul-kv\n[99.2] <b>k8s_plugin</b>: stop and uninstall component" as k8s_plugin
            }
        }
        database "<&target> <b>consul-kv</b>\n--config for component--\n<service-component-name>={...config...}\n<service-component-name>:<b>subscriber_topic</b>='policies_DCAE_tca_<service-component-name>'" as consul_kv
        component "<&aperture> <b>config_binding_service</b>" as config_binding_service

    }
    component "<&target> <b>DCAE component like TCA</b>\n--[0.4] on startup - run policy-update receiver--\n[0.4.1] get subscriber_topic along with the config from CBS\n[0.4.2] listen for policy-update notifications from <b>MR of DMaaP</b> on \n<b>subscriber_topic</b>="policies_DCAE_tca_<service-component-name>"\n with long-collect-polling time like 15 seconds to grab the push notification\n--\n[0.3.3] and [1.2] on receiving the push-notification of policy-update, \n[1.3] calculate the delta - compare the collection of existing policies \n versus the latest snapshot of policies and figure out \nwhat policies are added/updated/removed \n[1.4] handle and consume the added/updated/removed policies" as dcae_component #eeeeff
}

component "<&rss> <b>Message Router of DMaaP</b>\n--\n [0.3.3] and [1.2] persistently delivers \nthe policy-update notification \nto each <b>subscriber_topic</b> \nwith the latest snapshot of policies" as DMaaP #ff8888

PAP .down.> PDP : [1] push/delete policies
PDP .down.> policy_update_subscribers : [0.3.2] subscribe\n insert/update \nsubscriber record
PDP .down.> policy_update_subscribers : [1.0] iterate through \nall subscribers
PDP ..> policy_update_subscribers : [99.2] unsubscribe \n delete <b>subscriber_topic</b>

PDP .down.> DMaaP : [0.3.3] and [1.2] push policy-update \n for DCAE component instance
DMaaP .up.> dcae_component : [0.3.3] and [1.2] push policy-update for DCAE component instance

dcae_component .right.> config_binding_service : [0.4.1] get subscriber_topic along with the config
config_binding_service .right.> consul_kv : [0.4.1] get config and subscriber_topic

policy_handler ..> PDP :     [0.3.2] POST /v1/decision/<b>subscription</b>/<<b>subscriber_topic</b>>
policy_handler ..> PDP : [99.2] DELETE /v1/decision/<b>subscription</b>/<<b>subscriber_topic</b>>

deployment_handler .down.> cloudify : [0] install component
deployment_handler .down.> cloudify : [99] uninstall \ncomponent
cloudify .down.> k8s_plugin : [0] install \ncomponent
cloudify .down.> k8s_plugin : [99] uninstall \ncomponent
k8s_plugin .down.> consul_kv : [0.0] and [0.2] save config and <b>subscriber_topic</b> for component
k8s_plugin .down.> consul_kv : [99.0] and [99.1] delete records

k8s_plugin .up.> policy_handler : [0.3] subscribe
k8s_plugin .up.> policy_handler : [99.2] unsubscribe

k8s_plugin .left.> dcae_component : [0.4]  start  component
k8s_plugin .left.> dcae_component : [99.2] stop component

' note "[99.2] http DELETE /decision/<b>subscription</b>/v1/<<b>subscriber_topic</b>>" as message_unsub_to_PDP
' dcae_component .down.> message_unsub_to_PDP
' message_unsub_to_PDP ..> PDP



left footer
    <&thumb-up> no middleman (DCAE-Control) for policy update flow
    <&thumb-up> minimal number of messages and volume of data
    <&thumb-up> Message Router of DMaaP persistently delivers the push-notification of the policy-update per each component instance globally identified by subscriber_topic

    <b>requirements on new PDP -- see the diagram</b>
    <&task> maintain pub-sub table per subscriber_topic with policy-filters
    <&task> notify about the policy added/updated/removed through Message Router of DMaaP

    <b>requirements on DCAE Component -- see the diagram</b>
    <&task> on start, get
        + subscriber_topic (globally unique for the component instance like "policies_DCAE_tca_<service-component-name>")
    <&task> provide handler for the push-notification of the polciy-update received from Message Router of DMaaP
    <&task> listen for the policy-update notification on subscriber_topic coming through the Message Router of DMaaP with long polling collect-time
    <&task> calc delta of policy-update and consume it

    <b>requirements on Config-Binding-Service - new data from consul-kv</b>
    <&task> get from consul-kv and return the
        + subscriber_topic (globally unique for the component instance like "policies_DCAE_tca_<service-component-name>")

    <b>requirements on @policies_gather -- see the diagram</b>
    <b>requirements on k8s_plugin -- see the diagram</b>
    <b>requirements on policy_handler -- see the diagram</b>
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@enduml