I’m trying to integrate Drizzle ORM into my Fastify application as a plugin using TypeScript. Despite following the provided documentation and examples, I’m encountering issues accessing the Drizzle instance within my request handlers. Here’s my plugin implementation:

import fp from "fastify-plugin";
import { FastifyInstance, FastifyPluginOptions } from "fastify";
import { drizzle } from "drizzle-orm/postgres-js";
import postgres from "postgres";

const drizzlePlugin = fp(
  async (fastify: FastifyInstance, options: FastifyPluginOptions) => {
    const databaseUrl = fastify.config.DATABASE_URL;

    const queryClient = postgres(databaseUrl);
    const Drizzle = drizzle(queryClient);

    fastify.decorate("drizzle", Drizzle);

    try {
      await queryClient`SELECT 1`; // Simple query to check the connection
      fastify.log.info("Database connected successfully.");
    } catch (error) {
      fastify.log.error("Failed to connect to the database: ", error);
      throw error; // Optionally rethrow to handle the error further or fail the plugin registration
    }

    fastify.addHook("onClose", (instance, done) => {
      instance.drizzle.close(); // Adjust based on actual API to close connections
      done();
    });
  },
  { name: "drizzle-orm", dependencies: [] }
);

export default drizzlePlugin;

That’s my fastify.d.ts file:

import "fastify";
import { Drizzle } from "@drizzle-orm/core";

declare module "fastify" {
  interface FastifyInstance {
    authenticate: (
      request: FastifyRequest,
      reply: FastifyReply
    ) => Promise<void>;
    config: {
      JWT_SECRET: string;
      COOKIE_NAME: string;
      PORT: number;
      HOST: string;
      COOKIE_SECRET: string;
      DATABASE_URL: string;
    };
    drizzle: Drizzle;
  }

  interface FastifyRequest {
    user?: { id: string; email: string };
  }
}