Middleware sample: logging

The following example logs the time taken for a Prisma Client query to run:

const prisma = new PrismaClient()

prisma.$use(async (params, next) => {
  const before = Date.now()

  const result = await next(params)

  const after = Date.now()

  console.log(`Query ${params.model}.${params.action} took ${after - before}ms`)

  return result
})

const create = await prisma.post.create({
  data: {
    title: 'Welcome to Prisma Day 2020',
  },
})

const createAgain = await prisma.post.create({
  data: {
    title: 'All about database collation',
  },
})

Example output:

Query Post.create took 92ms
Query Post.create took 15ms

The example is based on the following sample schema:

generator client {
  provider = "prisma-client-js"
}

datasource db {
  provider = "mysql"
  url      = env("DATABASE_URL")
}

model Post {
  authorId  Int?
  content   String?
  id        Int     @id @default(autoincrement())
  published Boolean @default(false)
  title     String
  user      User?   @relation(fields: [authorId], references: [id])
  language  String?

  @@index([authorId], name: "authorId")
}

model User {
  email           String  @unique
  id              Int     @id @default(autoincrement())
  name            String?
  posts           Post[]
  extendedProfile Json?
  role            Role    @default(USER)
}

enum Role {
  ADMIN
  USER
  MODERATOR
}

Going further

You can also use Prisma Client extensions to log the time it takes to perform a query. A functional example can be found in this GitHub repository.