Systemstate

Systemstate is a special type of protocol that lets you listen for state change events on all of the Connectware resources. For any object that can be addressed by a Resource ID, the current state can be queried by read or be subscribed by subscribe.

Commissioning File Specifics

The following describes the general format of the commissioning file you will need to assemble to configure this protocol.

You can find a fully working example below: Sample Commissioning file:

Connection Settings

The service using this protocol does not create a connection to somewhere outside of the Connectware but rather an internal connection that taps into the internal state of the Connectware. So you will need to configure the connection object the following way:

eventsConnection:
    type: Cybus::Connection
    properties:
        protocol: Systemstate
        connection: {}

protocol

Required. Must be Systemstate.

Connection Properties

Endpoint settings

Each connection can have multiple endpoints. These define the operations that are supported. For the Systemstate protocol, read and subscribe are available as operations.

You define an endpoint by adding a resource of type Cybus::Endpoint and protocol Systemstate.

The only property you need to configure for read or subscribe is a Resource ID that identifies the component you want to receive updates from. This Resource ID is constructed from the Service ID and the Resource ID, separated by a hyphen character (a minus character: -).

On a subscribe endpoint, a message with the state notification will be sent on each state change of the respective resource.

With a read endpoint, on the other hand, it is possible to query the current status by sending any message to the topic with suffix req, then receiving the response on the topic with the suffix res.

Endpoint Properties

Examples

The examples are using the example commissioning file below. Thus, the MQTT topics might differ in your application but the payload needs to be the same (as long as no JSONata rules are being used).

The protocol produce the following output messages:

When enabling an endpoint:

{ 'state': 'enabling', 'resourceId': 'samplesystemstateservice-someEndpoint', 'timestamp': 1621256032226 }

When the endpoint is enabled:

{ 'state': 'enabled', 'resourceId': 'samplesystemstateservice-someEndpoint', 'timestamp': 1621256032233 }

When the initial subscribe operation was completed:

{ 'state': 'subscribed', 'resourceId': 'samplesystemstateservice-someConnection', 'timestamp': 1621256032230 }

Sample Commissioning file:

Download:

1KB

systemstate-example.yml

description: >
    Sample SystemState service commissioning file

metadata:
    name: Sample SystemState service
    provider: cybus
    homepage: https://www.cybus.io
    version: 1.0.0

resources:
    someConnection:
        type: Cybus::Connection
        properties:
            protocol: Systemstate
            connection: {}

    someEndpoint:
        type: Cybus::Endpoint
        properties:
            protocol: Systemstate
            connection: !ref someConnection
            subscribe:
                resourceId: !sub '${Cybus::ServiceId}-someConnection'

    anotherEndpoint:
        type: Cybus::Endpoint
        properties:
            protocol: Systemstate
            connection: !ref someConnection
            subscribe:
                resourceId: !sub '${Cybus::ServiceId}-someEndpoint'

    serviceEndpoint:
        type: Cybus::Endpoint
        properties:
            protocol: Systemstate
            connection: !ref someConnection
            subscribe:
                resourceId: !sub '${Cybus::ServiceId}'