Overview
Connections define the execution paths of a workflow template. By connecting elements on the canvas, the user guides the decision logic and defines the sequence of events for the execution. Any element type can be connected to any other element type; there is no restriction based on the type of element.
Element Connection Constraints
The ports available on an element dictate how connections can be established, but only the Rule node and the Outcome node accept multiple inbound paths. This is the defining constraint of the workflow canvas. Furthermore, outbound ports on tasks and rules are generated by configuring resolution paths or condition paths within the element, rather than dragging free-form connections out of the node.
| Element | Inbound Paths | Outbound Paths |
| Starting Rule | None. It is the entry point. | One per condition path or one default path. |
| Task | One | One per resolution path. |
| Rule | Multiple | One per condition path or one default path. |
| Delay | One | One |
| Nested automation | One | One |
| Schedule | One | One |
| Outcome node | Multiple | None. It is terminal. |
Technical Considerations and Exclusivity
When designing connections, adhere to the following principles:
- Path Exclusivity: Paths coming out of any task or any rule are always exclusive. Only one of them fires on a given execution.
- No Direct Convergence: Two outputs of the same element can never converge on the same inbound port.
- Convergence Validation: Because paths out of a task or rule are exclusive, they cannot feed into a Rule configured with ALL convergence. Neostella initially allows the connection , marks it as invalid with a red line, and removes it from the canvas after approximately three seconds.
- Closed Schedule Containers: Connections cannot cross the boundary of a schedule container. Elements inside connect only to each other, and the inbound and outbound ports of the schedule container are the only way in and out.
Configuration Steps
How to Create a Connection
To configure a connection between elements:
- Locate the output port of the first element and hover over it.
- Click and hold. Then, drag the connection to the input port of the subsequent element.
- A line connecting the elements appears and the Connection was created successfully. message is displayed.
How to Create Parallel Connections
Parallel branches allow a workflow to follow multiple paths simultaneously. To create parallel connections, click and drag from a single output port of an element to the input ports of several subsequent elements.
How to Create Merged Connections
Merged connections combine multiple execution paths into a single downstream step. To create merged connections connect the output ports of different elements to the input port of a single subsequent element. Ensure the destination element is a Rule or an Outcome node, as these are the only elements that accept multiple inbound paths.
How to Delete Connections
To remove an existing path:
- Locate the connection to delete and click on the line.
- Press the Backspace key.
- The Connection was deleted successfully message is displayed.
Validation & Troubleshooting
- Successful Connection: A solid line connects the elements and a green success banner is displayed at the bottom of the interface.
- Invalid Connection: If a connection violates platform constraints, a red line with a warning icon is displayed between the elements, along with a Connection is not valid. message. Verify that the connection does not violate the path exclusivity principle or route exclusive paths into an ALL rule.
- Dead Ends: A path does not have to lead anywhere. If a connection is omitted intentionally, the branch stops silently at runtime without producing an error. If every branch reaches a dead end, the execution remains in the Running status indefinitely.