yc-serverless-live-debug

Local debug of Yandex Cloud Functions on Node.js.

• How it works
• Setup
• Usage
  • Debug single function
  • Debug several functions
  • Debug other triggers

How it works

Main components:

1. stub - cloud function that proxies requests to local code
2. store - cloud function that stores WebSocket connections info in YDB. This connection info is later used by stub to know where to proxy request
3. client - CLI app running on local machine and handling requests coming by WebSocket

The schema was inspired by SST Live Lambda Dev

Setup

Install package:

npm i -D @vitalets/live-debug

Deploy cloud components:

npx live-debug deploy

Create live-debug.config.ts (or live-debug.config.js) in project root:

import { defineConfig } from '@vitalets/live-debug';

export default defineConfig({
  handler: event => {
    console.log('got request', event);
    return {
      statusCode: 200,
      body: `Hello from local code!`,
    };
  }
});

Run live debug:

npx live-debug run

Expected output:

Reading config: /project/live-debug.config
Running local client...
WS connection opened
Local client connected
Check url: https://**********.apigw.yandexcloud.net
Waiting requests...
GET /?
Response sent

See example for more details.

Usage

On server all requests are handled by single stub function. You can setup routing for your needs in the config.

Debug single function

For single function you can just assign handler from your code:

import { defineConfig } from '@vitalets/live-debug';
import { handler } from './path/to/your/handler';

export default defineConfig({
  handler
});

Debug several functions

To debug several functions simultaneously you can setup routing by url:

import { defineConfig } from '@vitalets/live-debug';
import { Handler } from '@yandex-cloud/function-types';
import { handlerA } from './path/to/your/handler-a';
import { handlerB } from './path/to/your/handler-b';

export default defineConfig({
  handler: <Handler.Http>((event, ctx) => {
    // @ts-expect-error url is not typed
    const url = String(event.url);
    if (url.startsWith('/handler-a')) return handlerA(event, ctx);
    if (url.startsWith('/handler-b')) return handlerB(event, ctx);
    return { statusCode: 200, body: 'No handler' };
  })
});

Debug other triggers

You can debug other triggers: message queue, object storage, etc. In cloud console configure needed trigger to point to stub function.

import { defineConfig } from '@vitalets/live-debug';
import { Handler } from '@yandex-cloud/function-types';

export default defineConfig({
  handler: <Handler.MessageQueue>(event => {
    console.log(event.messages);
  })
});