migrate-from-v2-and-v3.md

Migrate from v2 and v3

With Fastify v4, we've changed some of the API for the PubSubHandler and bumped node to v16. Most of the changes aren't an issue for most users.

• Bumped node to v16
• Bumped fastify to v4
• The address attribute is changed to host to align with Fastify
• With ajv version 7 and above, ajvTypeBoxPlugin is required. (only required when using the Fastify plugin)
• Added pino logger to Cloud Functions
• Added log to handler (see example down below)

Using pubSubFastifyPlugin in v4

import Fastify from 'fastify';
import { TypeBoxTypeProvider } from '@fastify/type-provider-typebox';
import { pubSubFastifyPlugin } from 'pubsub-http-handler';

interface MyHandler {
  hello: string;
  world: string;
}

const server = async () => {
  const handler: PubSubHandler<MyHandler> = ({ message, data }) => {
    // `message` contains attributes, data (as string), messageId
    // `data` contains a base64 decoded JSON serialized object (type is MyHandler in the example)

    ...
  };

  const fastify = Fastify().withTypeProvider<TypeBoxTypeProvider>()

  fastify.register(pubSubFastifyPlugin)
  fastify.listen();
};

Improved logging

The handler now comes with a log attribute which contains a pino instance.

import { TypeBoxTypeProvider } from '@fastify/type-provider-typebox';
import Fastify from 'fastify';
import { PubSubHandler, pubSubFastifyPlugin } from '../src';

interface HandlerArguments {
  name: string;
  party: {
    name: string;
  };
  bookingId: string;
}

const server = () => {
  const fastify = Fastify().withTypeProvider<TypeBoxTypeProvider>();

  const handler: PubSubHandler<HandlerArguments> = ({ data, log }) => {
    const { name, party, bookingId } = data;
    log.info(`${name} from ${party.name} had a booking with id ${bookingId}`);
  };

  fastify.register(pubSubFastifyPlugin, { handler });

  fastify.server.listen(8000);
};

server();