How do I resolve connectivity issues between Supabase and n8n on Docker?

Below is some troubleshooting advice for connecting to Supabase from n8n when using Docker:

Possible Issue: Incorrect Network Reference

When n8n runs in its own Docker container, using "localhost" in your credentials will reference that container—not your Supabase instance. Depending on your setup, consider the following:

• If Supabase is running on your host machine:
  Inside the n8n container, use the host’s IP alias. For Docker Desktop, using the hostname host.docker.internal lets your container connect to services running on your host. For example, set your Supabase host to:

  host.docker.internal
  

• If Supabase is running in a separate Docker container:
  Ensure both containers are on the same Docker network. You can then reference the Supabase container by its container name. For example, if your Supabase container is named supabase-db, use that as the host in your n8n credentials:

  supabase-db
  

Verify Port Configuration

Supabase’s default PostgreSQL port is typically 5432. Verify that the port mapping is correctly set when starting the Supabase container. For example, the command below maps port 5432 on your host to the container:

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docker run -d --name supabase-db -p 5432:5432 -e POSTGRES_PASSWORD=your_password supabase/postgres

Docker Networking Check

If you’re using Docker Compose for ease, define both services in the same docker-compose.yml so they share a common network. For instance:

YAMLCopied
version: '3.7'
services:
  n8n:
    image: docker.n8n.io/n8nio/n8n
    ports:
      - "5678:5678"
    environment:
      # Set Supabase host to the service name below
      SUPABASE_HOST: supabase-db
      SUPABASE_PORT: 5432
  supabase-db:
    image: supabase/postgres
    environment:
      POSTGRES_PASSWORD: your_password
    ports:
      - "5432:5432"

Steps to Troubleshoot Further

1. Double-check connection credentials:
   Ensure that the database name, user, and password in n8n’s Supabase configuration match what you set in the Supabase container.

2. Ping the database from within the n8n container:
   You can run a shell in the n8n container to test connectivity. For example:

   SHCopied
   docker exec -it <n8n_container_id> sh
   # Once inside, see if you can reach the Supabase host:
   ping supabase-db
   # Or if using host.docker.internal:
   ping host.docker.internal

3. Examine logs:
   Check logs of both containers for any error messages or connectivity issues:

   SHCopied
   docker logs n8n
   docker logs supabase-db

By ensuring that your environment variables and network settings correctly point to your Supabase instance, you should be able to overcome the connectivity issue. Let us know if you need further assistance with the configuration or logs for a deeper analysis!