How do I enable logging with CustomPrismaModule?

[cjmyles]

I am utilising the CustomPrismaModule in order to make use of client extensions. I have a file prisma.extension.ts that has the following code:

export const extendedPrismaClient = new PrismaClient<
  Prisma.PrismaClientOptions,
  'query' | 'info' | 'warn' | 'error'
>({
  log: [
    { level: 'query', emit: 'event' },
    { level: 'info', emit: 'event' },
    { level: 'warn', emit: 'event' },
    { level: 'error', emit: 'event' },
  ],
}).$extends({
  model: {
     ...
  },
});

export type ExtendedPrismaClient = typeof extendedPrismaClient;

This is then instantiated in my app.module.ts file:

imports: [
    CustomPrismaModule.forRootAsync({
      name: 'PrismaService',
      isGlobal: true,
      useFactory: () => {
        return extendedPrismaClient;
      },
    }),

According to the docs I need to add the following to my main.ts file:

async function bootstrap() {
  const app = await NestFactory.create(AppModule);

  // log query events
  const prismaService: PrismaService = app.get(PrismaService);
  prismaService.$on('query', (event) => {
    console.log(event);
  });

However, this results in the following error:

Nest could not find PrismaService element (this provider does not exist in the current context)

[marcjulian]

Hi @cjmyles, you have full control over your PrismaClient instance with the extension. You should be able to add $on to your new PrismaClient() before calling $extends(). There was, not sure if still is, a problem with $on that it returns void so that $extends() cant be called.

export const extendedPrismaClient = new PrismaClient<
  Prisma.PrismaClientOptions,
  'query' | 'info' | 'warn' | 'error'
>({
  log: [
    { level: 'query', emit: 'event' },
    { level: 'info', emit: 'event' },
    { level: 'warn', emit: 'event' },
    { level: 'error', emit: 'event' },
  ],
})
.$on(...) // should go in here
.$extends({
  model: {
     ...
  },
});

export type ExtendedPrismaClient = typeof extendedPrismaClient;

[marcjulian]

I might have to update the docs to explain a bit more the differences between PrismaService and CustomPrismaService.

Because you use CustomPrismaModule in your app.module.ts imports you can only access CustomPrismaService with your extended PrismaClient.

The PrismaService only has access to the default PrismaClient at the default generated location.

async function bootstrap() {
  const app = await NestFactory.create(AppModule);

  // log query events
  const prismaService: PrismaService = app.get(PrismaService); // ❌ this won't work because PrismaSerivce is not provided, only CustomPrismaService. But `$on` is not a function for `CustomPrismaService` because you have full control of your PrismaClient instance
  prismaService.$on('query', (event) => {
    console.log(event);
  });

If you have any questions, please let me know.

[cjmyles]

@marcjulian Thanks for the responses. I'm with you now. Until the bug is fixed regarding $on() returning void, it looks like I can't use both logging and client functions then. I can see the FIXME comment in the prisma extension example but I can't find an issue in the issues list. Is this something we need to create?

[marcjulian]

@cjmyles yes would be good to create a Issue for $on() returning void in the prisma repo

[cjmyles]

@marcjulian Done. See prisma/prisma#25153