User-Defined Functions (UDF) Management API

Besides defining function in plugins, user-defined functions (UDF) are also supported independently. Currently, we only support JavaScript UDF. We can use REST API or CLI to manage JavaScript functions. You can create, list, describe, delete, and update functions.

Create a UDF

Use this endpoint to create a new function.

POST http://localhost:9081/udf/javascript

The request body should be a JSON object with the following fields:

• id: A unique name for the function. This name must also be defined as a function in the script field.
• description: A brief description of the function.
• script: The function implementation in JavaScript.
• isAgg: A boolean indicating whether the function is an aggregate function.

Here's an example:

{
   "id": "area",
   "description": "calculate area",
   "script": "function area(x, y) { return x * y; }",
   "isAgg": false
}

List UDFs

Use this endpoint to display all JavaScript functions defined in the server.

GET http://localhost:9081/udf/javascript

The response will be a list of function names. For example:

["area"]

Describe a UDF

Use this endpoint to get the detailed definition of a function.

GET http://localhost:9081/udf/javascript/{id}

Replace {id} with the name of the function you want to describe. The response will be a JSON object with the function's details. For example:

{
   "id": "area",
   "description": "calculate area",
   "script": "function area(x, y) { return x * y; }",
   "isAgg": false
}

Delete a UDF

Use this endpoint to delete a function.

DELETE http://localhost:9081/udf/javascript/{id}

Replace {id} with the name of the function you want to delete. Note that you need to manually stop or delete any rules using the UDF before deleting it. A running rule will not be affected by the deletion of a UDF.

Update a UDF

The JavaScript UDF can be updated and hot reload. Notice that, a running rule must be restarted to load the updated function.

PUT http://localhost:9081/udf/javascript/{id}

Replace {id} with the name of the function you want to update. The request body should be the same as when creating a UDF. If the function of the id does not exist, it will be created. Otherwise, it will be updated.