How to Initialize Prisma Client once at Build step?

[Cauen]

There is a way to initialize Prisma Client once at build step to avoid "FATAL: too many connections" at build time?
I've tried to cache using https://github.com/blitz-js/blitz/issues/485 solution, and using a singleton class.
But dont work

Cache

import { Prisma } from 'db';
import {enhancePrisma} from "blitz"
import {PrismaClient} from "@prisma/client"

declare global {
  namespace NodeJS {
    interface Global {
      prisma: PrismaType;
    }
  }
}

interface EnhancedPrismaClientAddedMethods {
  $reset: () => Promise<void>;
}

type PrismaType = PrismaClient<Prisma.PrismaClientOptions, unknown, unknown> & EnhancedPrismaClientAddedMethods

const EnhancedPrisma = enhancePrisma(PrismaClient)
let prisma: PrismaType

console.log({ globalPrisma: global.prisma })
global.prisma = global.prisma || (() => {
  console.log("CREATING PRISMA ENHANCED")
  return new EnhancedPrisma()
})()
prisma = global.prisma

export * from "@prisma/client"
export default prisma

Singleton

import { Prisma } from 'db';
import {enhancePrisma} from "blitz"
import { PrismaClient} from "@prisma/client"

interface EnhancedPrismaClientAddedMethods {
  $reset: () => Promise<void>;
}

type PrismaType = PrismaClient<Prisma.PrismaClientOptions, unknown, unknown> & EnhancedPrismaClientAddedMethods

const EnhancedPrisma = enhancePrisma(PrismaClient)

class DBClient {
  public prisma: PrismaType
  private static instance: DBClient
  static count: number = 0

  private constructor() {
    this.prisma = new EnhancedPrisma()
  }

  public static getInstance = (): DBClient => {
    if (!DBClient.instance) {
      DBClient.count = DBClient.count + 1
      DBClient.instance = new DBClient()
      console.log('INITIALIZE DBCLIENT ' + DBClient.count)
    }
    return DBClient.instance
  }
}

export default DBClient.getInstance().prisma
export * from "@prisma/client"

[flybayer]

The enhancePrisma utility already uses a singleton for you. So all you need in db/index.ts is this:

import { enhancePrisma } from "blitz"
import { PrismaClient } from "@prisma/client"

const EnhancedPrisma = enhancePrisma(PrismaClient)

export * from "@prisma/client"
export default new EnhancedPrisma()

As for your build issue, I'm guessing you have a bunch of getStaticProps that are reading the DB? That's the only thing that should read from the DB at build time. And I thought the singleton that we use internally would work for that, but maybe not? 🤔

[Cauen]

@flybayer
Yes, you correct that I'm reading database at getStaticProps
I've used the store example and a free instance at elephantsql
At start command, the singleton works correctly, but at the build command, it initialize prisma client multiple times

[flybayer]

Ok bummer. This is a behavior from Next.js itself that we'll have to look into.

For now, check out the discussion here: prisma/prisma#5537. Maybe some of the things there can help