Query Logger

Durcno supports query logging through a configurable logger option. When set, after every SQL query is executed the logger's info() method is called with the SQL string, bound arguments, and the query duration in milliseconds.

Interface

Any object implementing the QueryLogger interface can be used:

interface QueryLogger {
  info(message: string, meta?: Record<string, unknown>): void;
}

This interface is intentionally minimal so that any logger — Winston, Pino, a custom object — can be used without additional adapters.

Built-in Winston Logger

Durcno ships a pre-configured Winston logger via the durcno/logger sub-path export. It uses a [durcno] label, an ISO timestamp, and a box-drawing format that renders the SQL and bound arguments in a readable style.

Installation

Winston is a peer dependency. Install it alongside Durcno:

npm

npm install winston

pnpm

pnpm add winston

Bun

bun add winston

Yarn

yarn add winston

Usage

// durcno.config.ts
import { defineConfig } from "durcno";
import { pg } from "durcno/connectors/pg";
import { createQueryLogger } from "durcno/logger";

export default defineConfig({
  schema: "db/schema.ts",
  out: "migrations",
  connector: pg({
    dbCredentials: {
      url: process.env.DATABASE_URL!,
    },
    logger: createQueryLogger(),
  }),
});

Output Format

Each logged query is printed in a box-drawing style:

2026-04-23T10:00:00.000Z [durcno] INFO: Query
  ┌ SQL
  │ SELECT "id", "name", "email"
  │ FROM "public"."users"
  │ WHERE "id" = $1
  ├ Arguments
  │ $1 = 42
  ├ Duration
  │ 3.21ms
  └

If a query has no bound arguments the Arguments section is omitted. The Duration section shows how long the query took to execute.

Custom Logger

Pass any object with a compatible info() method. The metadata object will always contain:

Key	Type	Description
sql	string	The SQL string sent to the DB
arguments	(string | number | null)[] | undefined	The bound parameter values
durationMs	number	Query execution time in milliseconds

// durcno.config.ts
import { defineConfig } from "durcno";
import { pg } from "durcno/connectors/pg";

export default defineConfig({
  schema: "db/schema.ts",
  connector: pg({
    dbCredentials: {
      url: process.env.DATABASE_URL!,
    },
    logger: {
      info(message, meta) {
        console.log(`[db] ${message}`, meta);
      },
    },
  }),
});

Using Pino

import pino from "pino";

const log = pino();

export default defineConfig({
  schema: "db/schema.ts",
  connector: pg({
    dbCredentials: { url: process.env.DATABASE_URL! },
    logger: {
      info: (message, meta) => log.info(meta ?? {}, message),
    },
  }),
});

Disabling the Logger

Omit the logger option (or set it to undefined) to disable query logging entirely. No queries will be logged and there is no performance overhead.