Tango Device

Properties

Property	Type	Default Value	Example Value
`exchanges_json`	String	`""`	`'{"exchanges": []}'`
`exchanges_config_path`	String	`""`	`'/component/lmc-queueconnector-01/owner'`

Commands

Command	Args	Return Type
`IsMonitoringDB()`	Void	Bool
`Configure()`	String	Void
`Reset()`	Void	Void

Note

Additional commands Standby(), Start(), Stop(), Abort() are intended for testing purposes and may be disabled or removed in future releases.

State Model

The present implementation utilizes the following native Tango operational states that can be read using the state attribute.

INIT: the device is currently initialising.
FAULT: the device has experienced an unexpected error from which it needs to be reset.
STANDBY: the device is not configured.
OFF: the device is configured, but not currently in use.
OPEN: the device is opening stream connections.
ON: the device is streaming data.
CLOSE: the device is closing stream connections.

Note

Transition arrows are triggered by a corresponding tango command, with the exception of underlined transitions, which are triggered automatically.

Configuring

The Queue Connector Tango Device only streams data when it has been configured at runtime. This can be performed via multiple approaches.

Configure by Property

To configure via properties, set either the exchanges_json and exchanges_config_path properties in the tango database and the device will configure on initialization.

Note

If both exchanges_json and exchanges_config_path properties are provided, then exchanges_config_path will take priority.

Configuration Database Path

To configure via SDP Config, set the exchanges_config_path property to a SDP Config path (including leading slash). The device will fetch the JSON value at the given path parsed as a QueueConnectorDescriptor.

JSON

To configure via JSON, set the exchanges_json property to JSON that will be parsed as a QueueConnectorDescriptor.

Configure by Command

Configuration may be performed post initialization using the Configure() command.

JSON

Pass a raw JSON string of the QueueConnectorDescriptor to the Configure() when in the STANDBY state. Configuring the device successfully will transition the device to the OFF state.

Configuration Database Path

Pass a configuration database path string to the Configure() command.

Note

The command will check for a leading ‘/’ as a heuristic for detecting a config_path to configure from, otherwise attempting to parse the string as JSON.

Note

Configure by command is deprecated and estimated for remove in version 4.0.0