How to Add an External Package to n8n for PostgreSQL Connections in a Code Node workflow

By adding the external pg package to a custom n8n Docker image, you can easily use a Code node to interact with PostgreSQL. Here’s a step-by-step guide to achieve this.

Dockerfile

The Dockerfile adds the PostgreSQL package (pg) globally to the n8n image.

# Use the latest official n8n image
FROM n8nio/n8n:latest

# Switch to root user to install additional packages
USER root

# Install the pg package globally
RUN npm install -g pg

# Revert back to the node user for security reasons
USER node

Build the Docker Image

To create a Docker image from the Dockerfile, run the following commands in the same directory as the Dockerfile:

# Build the Docker image
docker build -t n8n-with-pg .

# Verify the image creation
docker image ls

Docker Compose Configuration

Create a docker-compose.yml file to manage your n8n container. This example assumes you are using an external volume named n8n_data for persistent storage.

volumes:
  n8n_data:
    external: true

services:
  n8n:
    container_name: n8n
    image: n8n-with-pg
    restart: always
    ports:
      - "port:port"
    environment:
      - ... your custom environments
      - NODE_FUNCTION_ALLOW_EXTERNAL=pg
    volumes:
      - n8n_data:/home/node/.n8n

Run the Container

Start your container using Docker Compose:

sudo docker compose up -d

Now your n8n container is set up with the pg package pre-installed, ready to use for your workflows requiring PostgreSQL integration.

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Extra:

Here's an example of how to use a Code node in n8n to connect to a PostgreSQL database using the pg package: