Run Code

Controlled node

Overview

The Run Code node executes Python code in a sandboxed serverless environment. This node is useful for performing custom data processing, calculations, or transformations that aren't covered by other built-in nodes.

Passing Variables

To pass data into your Python code, use #define variableName at the top of your code. The node will automatically create input sockets for each variable you define, allowing you to connect data from other nodes.

Inputs

Input	Type	Description	Default
Run	Event	Triggers the execution of the Python code.	-
Code	Code	The Python code to execute. Access this via the properties panel.	See example below
Dynamic Inputs	Data	Additional inputs are automatically generated based on #define macros in your code.	-

Dynamic Input Generation

The node scans your code for lines starting with #define and creates corresponding input sockets. For example:

#define inputData
#define multiplier

This creates two input sockets named inputData and multiplier that you can connect to other nodes.

Outputs

Output	Type	Description
Done	Event	Fires when the code execution completes successfully.
Output	Data	Contains the return value from your Python code. If the code returns an error object, it will be passed through.

Runtime Behavior and Defaults

Execution Environment

• Language: Python 3.x
• Timeout: 30 seconds (configurable via MAX_CODE_EXECUTE_TIME_S). If your code exceeds this limit, a RunCodeError is thrown.
• Sandbox: Code runs in an isolated environment with access to standard Python libraries.

Error Handling

If your code raises an exception or times out:

• The node throws a RunCodeError with details about the failure
• Execution stops and the workflow can handle the error via an Assert node or error handling connections

Return Values

Your Python code should return a value that will be passed to the Output socket. Supported return types include:

• Primitives (strings, numbers, booleans)
• Lists and dictionaries
• None (for operations that don't need to return data)

Example

Basic Calculation

#define price
#define tax_rate

# Calculate total with tax
total = price * (1 + tax_rate)

return total

Processing Input Data

#define raw_text

# Process the input text
words = raw_text.split()
word_count = len(words)

return {
    "original_text": raw_text,
    "word_count": word_count,
    "words": words
}

Error Handling Pattern

Connect the Done event to an Assert node to check if the output contains an error:

#define data

try:
    result = int(data) * 2
    return result
except Exception as e:
    return {"error": str(e)}

Then use an Assert node to check if the output is an error object and handle accordingly.