This specification is currently a draft under development. |
Subscription Event Protocol
The CloudOS Subscription Event Protocol provides an event based model for managing subscriptions between Personal Clouds. The current implementation of the protocol will create a symmetric relationship between both Personal Clouds. In order to used the Subscription Event Protocol the CloudOS ruleset must be installed in the Personal Cloud for both the originating and target.
Subscribe
The system:subscribe event is used to create a Personal Channel between two Personal Clouds.
- domain: cloudos
- type: subscribe
- attributes:
- channelName
- namespace
- relationship
- targetChannel
- The channelName attribute is a label associated with the subscription that should convey meaning to developer. The channelName is only used as a component in the creation of the channel token. If no channelName is specified the value of "orphan" will be used.
- The namespace attribute is provided as a means for the developer to group subscriptions within a single, or group, or applications. The namespace is used to filter the list of subscriptions returned by the subscriptionList() function. If not namespace is specified the value of "shared" will be used.
- The relationship attribute is provided as a means for the developer to characterize the relationship between the originating and target Personal Cloud. The relationship attribute should be specified as a pair of values separated by a dash (e.g. parent-child, peer-peer, master-slave). The first value of the relationship attribute will be stored with the originating Personal Cloud subscription, the second value will be stored with the target Personal Cloud subscription. The relationship attribute values are used to filter the list of subscriptions returned by the subscriptionList() function. If not relationship is specified the value of "peer-peer" will be used.
- The targetChannel attribute is the Personal Channel token for the target Personal Cloud to which the subscription is to be made.
The sending Personal Cloud will have the following event raised to signal that the subscription request has been received:
- domain: cloudos
- type: subscriptionRequestAdded
- attributes: targetChannel, backChannel, namespace, relationship, channelName
fired {
raise cloudos event subscribe
with channelName = "Coworkers Bob+Ted"
and namespace = "MyFriends"
and relationship = "friend-friend"
and targetChannel = "3f15b820-af7f-012f-4c6e-00163ebczzzz"
and _api = "sky";
} |
The Personal Cloud receiving the subscription request will have the following event raised to signal the receipt of a pending subscription request:
- domain: cloudos
- type: subscriptionRequestPending
- attributes: eventChannel, namespace, relationship, channelName
rule receive_subscriptionRequestAdded
select when cloudos subscriptionRequestAdded
namespace re/MyFriends"
channelName re/Coworkers Bob+Ted/
relationship re/friend-friend/ |
Subscription Approval or Rejection
With the subscription request pending approval, the Personal Cloud which received the request can either approve or reject the request. To approve the subscription request the following event should be raised:
- domain: cloudos
- type: subscriptionRequestApproved
- attributes: eventChannel
fired {
raise cloudos event subscriptionRequestApproved
with eventChannel = "3f15b820-af7f-012f-4c6e-00163ebcaaaa"
and _api = "sky";
} |
Once the subscription request is approved both Personal Clouds will receive a callback events raised within each respective Personal Cloud. These events are raised to enable the developer to take additional actions when the Personal Channels are actually created.
- domain: cloudos
- type: CloudOS_subscriptionAdded
- attributes: eventChannel, backChannel, namespace, relationship, channelName
rule receive_subscriptionRequestAdded
select when cloudos subscriptionRequestAdded
namespace re/MyFriends/
channelName re/Coworkers Bob+Ted/
relationship re/friend-friend/ |
To reject the subscription request the following event should be raised:
- domain: cloudos
- type: subscriptionRequestRejected
- attributes: eventChannel
fired {
raise cloudos event subscriptionRequestRejected
with eventChannel = "3f15b820-af7f-012f-4c6e-00163ebcaaaa"
and _api = "sky";
} |
When the subscription request is rejected the following event will be raised with the Personal Cloud:
- domain: cloudos
- type: subscriptionRejected
- attributes: eventChannel, namespace, relationship, channelName
rule receive_subscriptionRejected
select when cloudos subscriptionRejected
namespace re/MyFriends/
channelName re/Coworkers Bob+Ted/
relationship re/friend-friend/ |
And the following event will be raised in the Personal Cloud which made the subscription request:
- domain: cloudos
- type: subscriptionRejected
- attributes: backChannel, namespace, relationship, channelName
rule receive_subscriptionRejected
select when cloudos subscriptionRejected
namespace re/MyFriends/
channelName re/Coworkers Bob+Ted/
relationship re/friend-friend/ |
Unsubscribe
The system:unsubscribe event is used to remove the Personal Channels between two Personal Clouds.
- domain: cloudos
- type: unsubscribe
- attribute: backChannel
fired {
raise cloudos event unsubscribe
with eventChannel = "3f15b820-af7f-012f-4c6e-00163ebcfddfd"
and _api = "sky";
} |
The backChannel attribute uniquely identifies the Personal Channel within the Personal Cloud, and provided to the target Personal Cloud for raising events into the current Personal Cloud. The backChannel is one of the attributes provided by the subscriptionList() function.
During the processing of removing the Personal Channels bewteen the two Personal Clouds callback events are raised within each respective Personal Cloud. These events are raised to enable the developer to take additional actions when the Personal Channels are actually being removed.
- domain: cloudos
- type: CloudOS_subscriptionRemoved
- attributes: eventChannel, backChannel, namespace, relationship, channelName
rule receive_CloudOS_subscriptionRemoved
select when cloudos CloudOS_subscriptionRemoved
namespace re/MyFriends/
channelName re/Coworkers Bob+Ted/
relationship re/friend-friend/ |
Functions
subscriptionList(namespace, relationship)
The subscriptionList() function will return a map of the subscriptions within the specified namespace and relationship. In order to use the function you must include the CloudOS module as a pragma in the meta section of your ruleset:
use module a169x625 alias CloudOS