Logging
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)
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",
},
],
});To use event-based logging:
- Set
emittoeventfor 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");
});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 $5
Params: [2, 7, 18, 29]
Duration: 2msconst prisma = new PrismaClient({
log: [
{
emit: "event",
level: "query",
},
{
emit: "stdout",
level: "error",
},
{
emit: "stdout",
level: "info",
},
{
emit: "stdout",
level: "warn",
},
],
});
prisma.$on("query", (e) => {
console.log("Query: " + e.query);
});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.