Quit Datasette if it has not received traffic for a specified time period

Some hosting providers such as Fly offer a scale to zero mechanism, where servers can shut down and will be automatically started when new traffic arrives.

This plugin can be used to configure Datasette to quit X minutes (or seconds, or hours) after the last request it received. It can also cause the Datasette server to exit after a configured maximum time whether or not it is receiving traffic.

Install this plugin in the same environment as Datasette.

datasette install datasette-scale-to-zero

This plugin will only take effect if it has been configured.

Add the following to your metadata.json or metadata.yml configuration file:

{
    "plugins": {
        "datasette-scale-to-zero": {
            "duration": "10m"
        }
    }
}

This will cause Datasette to quit if it has not received any HTTP traffic for 10 minutes.

You can set this value using a suffix of m for minutes, h for hours or s for seconds.

To cause Datasette to exit if the server has been running for longer than a specific time, use "max_age":

{
    "plugins": {
        "datasette-scale-to-zero": {
            "max_age": "10h"
        }
    }
}

This example will exit the Datasette server if it has been running for more than ten hours.

You can use "duration" and "max_age" together in the same configuration file:

{
    "plugins": {
        "datasette-scale-to-zero": {
            "max_age": "10h",
            "duration": "5m"
        }
    }
}

This example will quit if no traffic has been received in five minutes, or if the server has been running for ten hours.

You can also configure the plugin to send an HTTP request somewhere right before it quits, using the "shutdown_url" option:

{
    "plugins": {
        "datasette-scale-to-zero": {
            "duration": "10m",
            "shutdown_url": "https://example.com/shutdown"
        }
    }
}

You can add additional headers to the GET request - for example to send Authorization headers - using "shutdown_headers":

{
    "plugins": {
        "datasette-scale-to-zero": {
            "duration": "10m",
            "shutdown_url": "https://example.com/shutdown",
            "shutdown_headers": {
                "Authorization": "Bearer secret"
            }
        }
    }
}

Use "shutdown_method" to set a different HTTP method, e.g. for POST. You can also set shutdown_body to specify the body that should be sent with the request:

{
    "plugins": {
        "datasette-scale-to-zero": {
            "duration": "10m",
            "shutdown_url": "https://example.com/shutdown",
            "shutdown_method": "POST",
            "shutdown_headers": {
                "Authorization": "Bearer secret",
                "Content-Type": "application/json"
            },
            "shutdown_body": "{\"message\": \"shutting down\"}"
        }
    }
}

To set up this plugin locally, first checkout the code. Then create a new virtual environment:

cd datasette-scale-to-zero
python3 -m venv venv
source venv/bin/activate

Now install the dependencies and test dependencies:

pip install -e '.[test]'

To run the tests:

pytest