Skip to content

PgMigrator

Runs database migrations for PostgreSQL projects that use Effect SQL.

This module reuses the shared SQL migrator and connects it to PostgreSQL. It exposes the common migration helpers and adds run and layer functions that apply pending migration files with the current SQL client. When schema dumps are requested, it uses pg_dump and the usual process and filesystem services.

12 exports Added in v4.0.0 Source

Constructors

make

Added in v4.0.0

Creates a migrator that ensures the migrations table exists, runs pending migrations in a transaction, and optionally dumps the schema after successful migrations.

Signature

declare const make: <RD = never>({
  dumpSchema,
}: {
  dumpSchema?: (path: string, migrationsTable: string) => Effect.Effect<void, MigrationError, RD>;
}) => <R2 = never>({
  loader,
  schemaDirectory,
  table,
}: MigratorOptions<R2>) => Effect.Effect<
  ReadonlyArray<readonly [id: number, name: string]>,
  MigrationError | SqlError,
  Client.SqlClient | RD | R2
>;

Errors

MigrationError

Added in v4.0.0

Error raised while loading, validating, locking, or running SQL migrations.

Signature

declare class MigrationError extends MigrationError_base<{
  readonly _tag: "MigrationError";
  readonly cause?: unknown;
  readonly kind: "BadState" | "ImportError" | "Failed" | "Duplicates" | "Locked";
  readonly message: string;
}> {
  constructor(args: {
    readonly cause?: unknown;
    readonly kind: "BadState" | "ImportError" | "Failed" | "Duplicates" | "Locked";
    readonly message: string;
  });
}

Layers

layer

Added in v4.0.0 Source

Creates a layer that runs PostgreSQL migrations during layer construction, including pg_dump-based schema dump support when requested.

Signature

declare function layer<R>(
  options: MigratorOptions<R>,
): Layer<
  never,
  SqlError | MigrationError,
  PgClient | SqlClient | ChildProcessSpawner | FileSystem | Path | R
>;

Loaders

fromBabelGlob

Added in v4.0.0

Creates a migration loader from a Babel-style glob record, parsing keys such as _<id>_<name>Js, _<id>_<name>Ts, _<id>_<name>Mjs, or _<id>_<name>Mts and sorting migrations by id.

Signature

declare const fromBabelGlob: (migrations: Record<string, any>) => Loader;

fromFileSystem

Added in v4.0.0

Creates a migration loader that reads a directory with FileSystem, imports files named <id>_<name>.js, <id>_<name>.ts, <id>_<name>.mjs, or <id>_<name>.mts, and sorts migrations by id.

Signature

declare const fromFileSystem: (directory: string) => Loader<FileSystem>;

fromGlob

Added in v4.0.0

Creates a migration loader from a glob record of dynamic import functions, parsing files named <id>_<name>.js, <id>_<name>.ts, <id>_<name>.mjs, or <id>_<name>.mts and sorting migrations by id.

Signature

declare const fromGlob: (migrations: Record<string, () => Promise<any>>) => Loader;

fromRecord

Added in v4.0.0

Creates a migration loader from a record of migration effects keyed by <id>_<name>, sorted by migration id.

Signature

declare const fromRecord: (
  migrations: Record<string, Effect.Effect<void, unknown, Client.SqlClient>>,
) => Loader;

Models

Loader type

Added in v4.0.0

Effect that resolves the available migrations for the migrator or fails with a MigrationError.

Signature

type Loader<R = never> = Effect.Effect<ReadonlyArray<ResolvedMigration>, MigrationError, R>;

Migration interface

Added in v4.0.0

Metadata for a migration recorded in the migrations table, including its id, name, and creation timestamp.

Signature

interface Migration {
  readonly createdAt: Date;
  readonly id: number;
  readonly name: string;
}

ResolvedMigration type

Added in v4.0.0

Tuple produced by a migration loader, containing the migration id, migration name, and an effect that loads the migration implementation.

Signature

type ResolvedMigration = readonly [
  id: number,
  name: string,
  load: Effect.Effect<any, any, Client.SqlClient>,
];

Options

MigratorOptions interface

Added in v4.0.0

Options for running SQL migrations, including the migration loader, optional schema dump directory, and migrations table name.

Signature

interface MigratorOptions<R = never> {
  readonly loader: Loader<R>;
  readonly schemaDirectory?: string;
  readonly table?: string;
}

Running

run

Added in v4.0.0 Source

Runs PostgreSQL SQL migrations using the configured clients. Schema dumps use pg_dump and require child process, filesystem, and path services.

Signature

declare const run: <R2 = never>(
  options: Migrator.MigratorOptions<R2>,
) => Effect.Effect<
  ReadonlyArray<readonly [id: number, name: string]>,
  Migrator.MigrationError | SqlError,
  | SqlClient
  | PgClient
  | ChildProcessSpawner.ChildProcessSpawner
  | FileSystem.FileSystem
  | Path.Path
  | R2
>;