Logging - Prisma — ContextQMD

Use the PrismaClient log parameter to configure log levels , including warnings, errors, and information about the queries sent to the database.

Prisma Client supports two types of logging:

Logging to stdout (default)
Event-based logging (use $on() method to subscribe to events)

:::info

You can also use the DEBUG environment variable to enable debugging output in Prisma Client. See Debugging for more information.

:::

:::info

If you want a detailed insight into your Prisma Client's performance at the level of individual operations, see Tracing.

:::

Log to stdout

The simplest way to print all log levels to stdout is to pass in an array LogLevel objects:

const prisma = new PrismaClient({
  log: ["query", "info", "warn", "error"],
});

This is the short form of passing in an array of LogDefinition objects where the value of emit is always stdout:

const prisma = new PrismaClient({
  log: [
    {
      emit: "stdout",
      level: "query",
    },
    {
      emit: "stdout",
      level: "error",
    },
    {
      emit: "stdout",
      level: "info",
    },
    {
      emit: "stdout",
      level: "warn",
    },
  ],
});

Event-based logging

To use event-based logging:

Set emit to event for a specific log level, such as query
Use the $on() method to subscribe to the event

The following example subscribes to all query events and write the duration and query to console:

const prisma = new PrismaClient({
  log: [
    {
      emit: "event",
      level: "query",
    },
    {
      emit: "stdout",
      level: "error",
    },
    {
      emit: "stdout",
      level: "info",
    },
    {
      emit: "stdout",
      level: "warn",
    },
  ],
});

prisma.$on("query", (e) => {
  console.log("Query: " + e.query);
  console.log("Params: " + e.params);
  console.log("Duration: " + e.duration + "ms");
});

sql

Query: SELECT "public"."User"."id", "public"."User"."email", "public"."User"."name" FROM "public"."User" WHERE 1=1 OFFSET $1
Params: [0]
Duration: 3ms
Query: SELECT "public"."Post"."id", "public"."Post"."title", "public"."Post"."authorId" FROM "public"."Post" WHERE "public"."Post"."authorId" IN ($1,$2,$3,$4) OFFSET $5
Params: [2, 7, 18, 29]
Duration: 2ms

const prisma = new PrismaClient({
  log: [
    {
      emit: "event",
      level: "query",
    },
    {
      emit: "stdout",
      level: "error",
    },
    {
      emit: "stdout",
      level: "info",
    },
    {
      emit: "stdout",
      level: "warn",
    },
  ],
});

prisma.$on("query", (e) => {
  console.log("Query: " + e.query);
});

bash

Query: db.User.aggregate([ { $project: { _id: 1, email: 1, name: 1, }, }, ])
Query: db.Post.aggregate([ { $match: { userId: { $in: [ "622f0bbbdf635a42016ee325", ], }, }, }, { $project: { _id: 1, slug: 1, title: 1, body: 1, userId: 1, }, }, ])

The exact event (e) type and the properties available depends on the log level.