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preswald run

The preswald run command launches a local development server for your application, enabling you to test and interact with your app in a browser. The command will run the script defined in the entrypoint in the preswald.toml.

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Options

  • port (int):
    The port on which to run the Preswald server. Default is 8501
  • log-level (str):
    The log level for the Preswald server. Options are DEBUG, INFO, WARNING, ERROR, CRITICAL. Default is INFO
  • disable-new-tab (bool):
    Flag which controls whether or not a new browser window pops up to show the rendered data app. Default is false, which means that a new window will pop up.

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Example Usage

To launch the development server for your app: 
preswald run
or 
preswald run --port 8504 --log-level DEBUG --disable-new-tab
After running the command, your application will be available locally at: 
http://localhost:8501

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Detailed Explanation

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1. Launching the Server

When you run the command, preswald starts a local development server using the specified Python script. This allows you to quickly preview and debug your app in a controlled environment.

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2. Supported Script Format

Any Python file containing valid application logic can be used.

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3. Localhost Access

The app is hosted on localhost, which is a local server accessible only from your machine. Use the provided URL to interact with your app through a browser.

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4. Stopping the Server

To stop the server, press Ctrl+C in the terminal where the command is running.

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5. Error Handling

If the script cannot be executed (e.g., due to missing dependencies or syntax errors), preswald will provide helpful error messages to guide you.
Use the preswald run command to test, iterate, and debug your app effortlessly in a local environment.