vercel__workflow/packages/world-postgres

@workflow/world-postgres

An embedded worker/workflow system backed by PostgreSQL for multi-host self-hosted solutions. This is a reference implementation - a production-ready solution might run workers in separate processes with a more robust queuing system.

Installation

npm install @workflow/world-postgres
# or
pnpm add @workflow/world-postgres
# or
yarn add @workflow/world-postgres

Usage

Basic Setup

The postgres world can be configured by setting the WORKFLOW_TARGET_WORLD environment variable to the package name:

export WORKFLOW_TARGET_WORLD="@workflow/world-postgres"

Configuration

Configure the PostgreSQL world using environment variables:

# Required: PostgreSQL connection string
export WORKFLOW_POSTGRES_URL="postgres://username:password@localhost:5432/database"

# Optional: Job prefix for queue operations
export WORKFLOW_POSTGRES_JOB_PREFIX="myapp"

# Optional: Worker concurrency (default: 10)
export WORKFLOW_POSTGRES_WORKER_CONCURRENCY="10"

# Optional: Internal pg.Pool max size (default: 10)
export WORKFLOW_POSTGRES_MAX_POOL_SIZE="10"

Programmatic Usage

You can also create a PostgreSQL world directly in your code:

import { createWorld } from "@workflow/world-postgres";

const world = createWorld({
  connectionString: "postgres://username:password@localhost:5432/database",
  jobPrefix: "myapp", // optional
  queueConcurrency: 50, // optional
  maxPoolSize: 10, // optional, overrides WORKFLOW_POSTGRES_MAX_POOL_SIZE when `pool` is omitted
});

// Or pass an existing pg.Pool (shared with your app Drizzle, etc.); `world.close()` will not end it.
import { Pool } from "pg";
const pool = new Pool({ connectionString: process.env.DATABASE_URL });
const worldFromPool = createWorld({ pool });

Configuration Options

Option	Type	Default	Description
connectionString	string	process.env.WORKFLOW_POSTGRES_URL or 'postgres://world:world@localhost:5432/world'	Used only when pool is omitted, to construct an internal pool
maxPoolSize	number	process.env.WORKFLOW_POSTGRES_MAX_POOL_SIZE or pg.Pool default (10)	Optional. Sets the internal pg.Pool max size when createWorld() creates the pool
pool	pg.Pool	—	Optional. When set, used for Drizzle, Graphile Worker, and stream writes. world.close() does not end it.
jobPrefix	string	process.env.WORKFLOW_POSTGRES_JOB_PREFIX	Optional prefix for queue job names
queueConcurrency	number	50	Number of concurrent active step executions per process. Must be high enough to cover any parent→child workflow polling in flight — each Run#returnValue await holds a worker slot until the child run terminates.

Environment Variables

Variable	Description	Default
WORKFLOW_TARGET_WORLD	Set to "@workflow/world-postgres" to use this world	-
WORKFLOW_POSTGRES_URL	PostgreSQL connection string	'postgres://world:world@localhost:5432/world'
WORKFLOW_POSTGRES_JOB_PREFIX	Prefix for queue job names	-
WORKFLOW_POSTGRES_WORKER_CONCURRENCY	Number of concurrent workers	50
WORKFLOW_POSTGRES_MAX_POOL_SIZE	Internal pg.Pool max size	10

When pool is omitted, maxPoolSize precedence is: createWorld({ maxPoolSize }), then WORKFLOW_POSTGRES_MAX_POOL_SIZE, then the pg.Pool default.

For higher worker concurrency, Graphile Worker recommends setting maxPoolSize to 10 or queueConcurrency + 2, whichever is larger.

Database Setup

This package uses PostgreSQL with the following components:

• graphile-worker: For queue processing and job management
• Drizzle ORM: For database operations and schema management
• pg (node-postgres): For PostgreSQL client connections. Drizzle and Graphile Worker share a pg.Pool, while LISTEN uses a dedicated pg.Client created from the same connection options.

Quick Setup with CLI

The easiest way to set up your database is using the included CLI tool:

pnpm exec workflow-postgres-setup
# or
npm exec workflow-postgres-setup

The CLI automatically loads .env files and will use the connection string from:

1. WORKFLOW_POSTGRES_URL environment variable
2. DATABASE_URL environment variable
3. Default: postgres://world:world@localhost:5432/world

Database Schema

The setup creates the following tables:

• workflow_runs - Stores workflow execution runs
• workflow_events - Stores workflow events
• workflow_steps - Stores individual workflow steps
• workflow_hooks - Stores webhook hooks
• workflow_stream_chunks - Stores streaming data chunks

You can also access the schema programmatically:

import { runs, events, steps, hooks, streams } from '@workflow/world-postgres';
// or
import * as schema from '@workflow/world-postgres/schema';

Make sure your PostgreSQL database is accessible and the user has sufficient permissions to create tables and manage jobs.

Features

• Durable Storage: Stores workflow runs, events, steps, hooks, and webhooks in PostgreSQL
• Queue Processing: Uses graphile-worker as the durable queue and executes jobs over the workflow HTTP routes
• Durable Delays: Re-schedules waits and retries in PostgreSQL
• Streaming: Real-time event streaming capabilities
• Health Checks: Built-in connection health monitoring
• Configurable Concurrency: Adjustable worker concurrency for queue processing

Queue Behavior

• Graphile jobs are acknowledged only after the workflow or step execution finishes, or after the worker durably schedules a delayed follow-up job
• Backlog stays in PostgreSQL when all execution slots are busy
• Retry and sleep-style delays use Graphile runAt scheduling
• Workflow and step execution is sent through /.well-known/workflow/v1/flow and /.well-known/workflow/v1/step

Development

For local development, you can use the included Docker Compose configuration:

# Start PostgreSQL database
docker-compose up -d

# Create and run migrations
pnpm drizzle-kit generate
pnpm drizzle-kit migrate

# Set environment variables for local development
export WORKFLOW_POSTGRES_URL="postgres://world:world@localhost:5432/world"
export WORKFLOW_TARGET_WORLD="@workflow/world-postgres"

Testing

Integration tests use Testcontainers to start a PostgreSQL container. Docker must be installed and running before you run tests.

• Linux/macOS: Start the Docker daemon (e.g. sudo systemctl start docker or Docker Desktop).
• WSL2: Use Docker Desktop with WSL2 integration, or run the Docker engine inside WSL and ensure the daemon is started. Verify with docker info.

Then from the package directory:

pnpm build
pnpm test

World Selection

To use the PostgreSQL world, set the WORKFLOW_TARGET_WORLD environment variable to the package name:

export WORKFLOW_TARGET_WORLD="@workflow/world-postgres"