Trigger actions include starting a process instance, sending a BPMN signal or any connector action. An action contains a payload that is sent from the trigger to the action being started.
The values for action payloads can be set in different ways depending on the action being sent and the source event type that generated the action. For example, if the Slack MESSAGE_RECEIVED event is used, then the value of an action can use the value of the slackChannelId the message was received from or an expression based on the event model.
The ways in which an action can be set are as:
| Variables | Variables from the source event. For example, using a BPMN engine activity as an event will allow variables such as the processDefinitionKey as a value. |
| Expressions | Entered using a JSON editor to create more complex mappings from JSON objects. For example ${temperature.celsius} will use the value for the object celsius. |
| Values | Static values that can be entered when the trigger action is modeled. |