GraphQL Yoga in Lambda with DB connection

lambdaHandler.ts

import { APIGatewayEvent, APIGatewayProxyResult, Context } from 'aws-lambda'
import { createYoga } from 'graphql-yoga'

import { getDb, dbSchema } from '@_models'
import { schema } from './schema'
import { ResolverContext } from './types'
import { NodePgDatabase } from 'drizzle-orm/node-postgres'

const yoga = createYoga<ResolverContext>({
  schema,
})

let hotDb: NodePgDatabase<typeof dbSchema>

export const handler = async (event: APIGatewayEvent, lambdaContext: Context): Promise<APIGatewayProxyResult> => {
  if (!hotDb) {
    const { db } = await getDb()
    hotDb = db
  }

  const response = await yoga.fetch(
    '/graphql',
    {
      method: 'POST',
      headers: event.headers as HeadersInit,
      body: event.body ? Buffer.from(event.body, event.isBase64Encoded ? 'base64' : 'utf8') : undefined,
    },
    {
      event,
      lambdaContext,
      db: hotDb,
      me: {
        id: '1',
        token: '123',
      },
    },
  )

  const responseHeaders = Object.fromEntries(response.headers.entries())

  return {
    statusCode: response.status,
    headers: { 'Access-Control-Allow-Origin': '*', 'Access-Control-Allow-Credentials': 'true' },
    body: await response.text(),
    isBase64Encoded: false,
  }
}