Experiment with JavaScript as a pipeline language

[thll]

This is a prototypical implementation of JavaScript as a pipeline language. It should enable us to evaluate whether using JavaScript is generally feasible. The implementation is expected to have many rough edges and may cut corners.

How to test this:

Create a JavaScript test rule in a file called test.js:

"use strict";

const name = 'javascript test';

const when = (msg) => !!msg.json;

const then = (msg, {set_fields}) => {
    let json = JSON.parse(msg.json);
    set_fields(json, "js_", null, null, null);

    Object.assign(msg, {'js_a' : 'a', 'js_b' : 'b'});

    for (let i = 0; i < 10; i++) {
        msg[`js_field_${i}`] = i;
    }
};

export default { 'name': name, 'when': when, 'then': then };

Upload it with httpie:

http --auth admin:admin POST :9000/api/system/pipelines/rule X-Requested-By:me content_type=application/javascript+module source=@./test.js

Remember the ID of the created rule, and, if you want to modify it later, upload the changed code like this:

http --auth admin:admin PUT :9000/api/system/pipelines/rule/<rule-id> X-Requested-By:me content_type=application/javascript+module source=@./test.js

Use the Graylog UI to assign the rule to a pipeline and then send messages with a json field set. You should see the additional fields set on the message.

/nocl Not planned as a feature right now