When using EffectLogger.layer, queries are logged via Effect’s logging system. You can configure the output
format by providing a different Effect logger layer (e.g., Logger.pretty for development, Logger.json for production).
Drizzle <> Effect Postgres
- Database connection basics with Drizzle
- Effect - website
- @effect/sql-pg - A PostgreSQL toolkit for Effect - read here
Drizzle has native support for Effect PostgreSQL connections with the @effect/sql-pg driver.
Step 1 - Install packages
npm i drizzle-orm@rc effect @effect/sql-pg pg
npm i -D drizzle-kit@rc @types/pg
Step 2 - Initialize the driver and make a query
Drizzle provides an Effect-native API that integrates with Effect’s service pattern. Use PgDrizzle.makeWithDefaults()
to quickly create a Drizzle database instance with sensible defaults (no logging, no caching).
import 'dotenv/config';
import * as PgDrizzle from 'drizzle-orm/effect-postgres';
import { PgClient } from '@effect/sql-pg';
import * as Effect from 'effect/Effect';
import * as Redacted from 'effect/Redacted';
import { sql } from 'drizzle-orm';
import { types } from 'pg';
// Configure the PgClient layer with type parsers
const PgClientLive = PgClient.layer({
url: Redacted.make(process.env.DATABASE_URL!),
types: {
getTypeParser: (typeId, format) => {
// Return raw values for date/time types to let Drizzle handle parsing
if ([1184, 1114, 1082, 1186, 1231, 1115, 1185, 1187, 1182].includes(typeId)) {
return (val: any) => val;
}
return types.getTypeParser(typeId, format);
},
},
});
const program = Effect.gen(function*() {
// Create the database with default services (no logging, no caching)
const db = yield* PgDrizzle.makeWithDefaults();
// Execute queries
const result = yield* db.execute<{ id: number }>(sql`SELECT 1 as id`);
console.log(result);
});
// Run the program with the PgClient layer
Effect.runPromise(program.pipe(Effect.provide(PgClientLive)));Step 3 - Create a DB Layer for dependency injection
For larger applications, create a reusable DB layer that can be composed with other services. This follows Effect’s recommended pattern for dependency injection:
import * as PgDrizzle from 'drizzle-orm/effect-postgres';
import { PgClient } from '@effect/sql-pg';
import * as Context from 'effect/Context';
import * as Effect from 'effect/Effect';
import * as Layer from 'effect/Layer';
import * as Redacted from 'effect/Redacted';
import { types } from 'pg';
import * as relations from './schema/relations';
// Configure the PgClient layer
const PgClientLive = PgClient.layer({
url: Redacted.make(process.env.DATABASE_URL!),
types: {
getTypeParser: (typeId, format) => {
if ([1184, 1114, 1082, 1186, 1231, 1115, 1185, 1187, 1182].includes(typeId)) {
return (val: any) => val;
}
return types.getTypeParser(typeId, format);
},
},
});
// Create the DB effect with default services
const dbEffect = PgDrizzle.make({ relations }).pipe(
Effect.provide(PgDrizzle.DefaultServices)
);
// Define a DB service tag for dependency injection
class DB extends Context.Tag('DB')<DB, Effect.Effect.Success<typeof dbEffect>>() {}
// Create a layer that provides the DB service
const DBLive = Layer.effect(
DB,
Effect.gen(function*() {
return yield* dbEffect;
}),
);
// Compose all layers together
const AppLive = Layer.provideMerge(DBLive, PgClientLive);
// Use the DB service in your application
const program = Effect.gen(function*() {
const db = yield* DB;
const users = yield* db.select().from(usersTable);
return users;
});
// Run with all dependencies provided
Effect.runPromise(program.pipe(Effect.provide(AppLive)));Advanced: Custom logger and cache configuration
For more control over logging and caching, use PgDrizzle.make() directly and provide your own service implementations.
Logger configuration
By default, makeWithDefaults() uses a no-op logger (no logging). You can enable logging by providing
a different EffectLogger implementation:
import * as PgDrizzle from 'drizzle-orm/effect-postgres';
import { EffectLogger } from 'drizzle-orm/effect-postgres';
import * as Effect from 'effect/Effect';
const program = Effect.gen(function*() {
const db = yield* PgDrizzle.make({ /* schema, relations, casing */ }).pipe(
// Enable Effect-based logging (uses Effect.log with annotations)
Effect.provide(EffectLogger.layer),
// Provide remaining default services (cache)
Effect.provide(PgDrizzle.DefaultServices),
);
const users = yield* db.select().from(usersTable);
return users;
});Available logger options:
EffectLogger.Default- No-op logger (no logging occurs) - this is the defaultEffectLogger.layer- Logs queries using Effect’sEffect.log()with annotations for query SQL and parameters. Integrates with Effect’s logging infrastructure.EffectLogger.fromDrizzle(logger)- Wraps a DrizzleLoggerinstance for use with EffectEffectLogger.layerFromDrizzle(logger)- Creates an Effect Layer from a Drizzle logger
Using a Drizzle logger:
import * as PgDrizzle from 'drizzle-orm/effect-postgres';
import { EffectLogger } from 'drizzle-orm/effect-postgres';
import * as Effect from 'effect/Effect';
import { DefaultLogger } from 'drizzle-orm';
const program = Effect.gen(function*() {
const db = yield* PgDrizzle.make({ /* schema, relations, casing */ }).pipe(
// Use a Drizzle logger wrapped for Effect
Effect.provide(EffectLogger.layerFromDrizzle(new DefaultLogger())),
// Provide remaining default services (cache)
Effect.provide(PgDrizzle.DefaultServices),
);
const users = yield* db.select().from(usersTable);
return users;
});Cache configuration
Similarly, you can provide a custom cache implementation:
import * as PgDrizzle from 'drizzle-orm/effect-postgres';
import { EffectLogger } from 'drizzle-orm/effect-postgres';
import { EffectCache } from 'drizzle-orm/cache/core/cache-effect';
import * as Effect from 'effect/Effect';
import { MyCustomCache } from './cache';
const program = Effect.gen(function*() {
const db = yield* PgDrizzle.make({ /* schema, relations, casing */ }).pipe(
// Provide a custom cache wrapped for Effect
Effect.provide(EffectCache.layerFromDrizzle(new MyCustomCache())),
// Provide remaining default services (logger)
Effect.provide(PgDrizzle.DefaultServices),
);
const users = yield* db.select().from(usersTable);
return users;
});Available cache options:
EffectCache.Default- No-op cache (no caching occurs) - this is the defaultEffectCache.fromDrizzle(cache)- Wraps a DrizzleCacheinstance for use with EffectEffectCache.layerFromDrizzle(cache)- Creates an Effect Layer from a Drizzle cache (useful for composing with other layers)