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Add Ports

Ports are connection points on nodes where data enters (input ports) or exits (output ports). This guide shows you how to add and configure ports on your nodes.

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Prerequisites

Before you begin, make sure you have:

Node Created

A node created in your graph. See Quickstart if needed.

Schemas Defined

Schemas created for the data types you want to use. See Create a Schema if needed.

Node Selected

The node you want to add ports to is selected on the canvas.

Graph Editor Open

Cerulion Graph Editor running with your graph open.

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What You’ll Do

You’ll add input and output ports to a node, configure their types, and set up triggers. Ports enable nodes to receive and send data.

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Step-by-Step Guide

1

Select the node

Click on the node you want to add ports to.
The node should be highlighted, and the properties panel (right sidebar) should show the node’s properties.
2

Open port configuration

In the properties panel, find the Ports section:
  • Input Ports - List of input ports (on the left side of the node)
  • Output Ports - List of output ports (on the right side of the node)
Click Add Input Port or Add Output Port button.
A new port should appear in the list with default settings.
3

Configure port name

Enter a descriptive name for the port:
  • Use camelCase or snake_case (e.g., temperatureIn, sensor_data)
  • Be descriptive: temperature_in is better than input1
  • Match the data it carries: temperature_readings for temperature data
For this example, if adding an input port, enter: temperature_in
The port name should appear in the list.
4

Set port type

From the Type dropdown, select the schema type for this port:
  • Only schemas from your project are shown
  • The type determines what data this port can receive/send
  • Ports can only connect if their types match
For this example, select: TemperatureReading
The schema type should be selected and shown in the dropdown.
If you don’t see the schema you need, create it first. See Create a Schema.
5

Configure trigger (input ports only)

For input ports, you can configure whether it’s a trigger:
  • Trigger - Node executes when data arrives on this port
  • Not a trigger - Port is read but doesn’t cause execution
By default, all inputs are triggers. You only need to change this if you want specific control over when nodes execute.
The trigger checkbox should reflect your choice. Trigger ports appear red with a ★ star.
6

Add more ports (optional)

Repeat steps 2-5 to add more ports:
  • Multiple inputs - Node can receive data from multiple sources
  • Multiple outputs - Node can send data to multiple destinations
Most nodes have 1-3 inputs and 1-3 outputs. Add ports as needed for your use case.
7

Save changes

Click Save or press Ctrl+S / Cmd+S to save the node configuration.
The ports should appear on the node:
  • Input ports on the left side (blue circles, or red if triggers)
  • Output ports on the right side (green circles)

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Understanding Ports

After adding ports, they:
  • Appear visually on the node (left for inputs, right for outputs)
  • Have types that ensure type-safe connections
  • Can be connected to other nodes or topics
  • Are configured with names and trigger settings

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Port Configuration Details

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Input Ports

Input ports receive data:
  • Location: Left side of the node
  • Color: Blue (normal) or red (trigger)
  • Trigger: Determines if data arrival causes node execution
  • Type: Schema type that defines what data it accepts

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Output Ports

Output ports send data:
  • Location: Right side of the node
  • Color: Green
  • Type: Schema type that defines what data it sends

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Port Best Practices

Descriptive Names

Use clear port names. “temperature_in” is better than “input1” or “port0”.

Match Data Purpose

Port names should indicate what data they carry. Match the schema name or purpose.

Reasonable Count

Most nodes need 1-3 inputs and 1-3 outputs. Too many ports make nodes hard to understand.

Type Safety

Always set port types. This prevents connection errors and ensures type safety.

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Editing Ports

To edit an existing port:
1

Select the node

Click on the node with the port you want to edit.
2

Find the port

In the properties panel, find the port in the Input Ports or Output Ports list.
3

Edit properties

Click the port to expand its properties, then edit:
  • Name - Change the port name
  • Type - Change the schema type (may break connections)
  • Trigger - Toggle trigger setting (input ports only)
Changing a port type may break existing connections. Update connected nodes or recreate connections.
4

Save changes

Click Save to apply changes.

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Removing Ports

To remove a port:
1

Select the node

Click on the node with the port you want to remove.
2

Find the port

In the properties panel, find the port in the Input Ports or Output Ports list.
3

Delete the port

Click the Delete button (trash icon) next to the port.
Deleting a port will also delete any connections to that port. Make sure you want to remove those connections.
4

Confirm deletion

Confirm that you want to delete the port and its connections.
The port should be removed from the node and from the canvas.

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Troubleshooting

Problem: Add port button is disabled or doesn’t work.Solutions:
  • Ensure a node is selected
  • Check that the node is not locked or read-only
  • Try refreshing the editor
  • Verify you have write permissions for the project
Problem: Can’t find the schema type you need.Solutions:
  • Verify the schema exists in your project
  • Check that the schema file is valid (no errors)
  • Refresh the project to reload schemas
  • Create the schema first if it doesn’t exist
Problem: Added port but don’t see it on the canvas.Solutions:
  • Ensure you saved the node configuration
  • Try zooming in/out or panning the canvas
  • Check that the node is fully visible
  • Refresh the graph view

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Next Steps

Now that you can add ports, learn how to use them:

Connect Nodes

Learn how to connect nodes together using their ports.

Ports and Links

Understand how ports and links work together.

Triggers

Learn about trigger configuration for input ports.

Write Node Code

Learn how to write code that uses these ports.