Resolving PostgreSQL Authentication Errors in Docker Compose for Redash

Introduction

When setting up Redash with Docker Compose, one of the common errors users might encounter is related to PostgreSQL authentication. Specifically, the psycopg2.OperationalError: fe_sendauth: no password supplied error can be frustrating, especially when you believe everything is configured correctly. This post will guide you through understanding and resolving this error.

Understanding the Error

The fe_sendauth: no password supplied error indicates that PostgreSQL is expecting a password for the connection, but none was provided. This can happen due to misconfigurations in your environment variables, Docker Compose file, or the way the create_db command is executed.

Common Setup

Typically, the Docker Compose setup for Redash might look something like this:

version: "2"
x-redash-service: &redash-service
  image: redash/redash:8.0.0.b32245
  depends_on:
    - postgres
    - redis
  env_file: /opt/redash/env
  restart: always

services:
  server:
    <<: *redash-service
    command: server
    ports:
      - "5000:5000"
    environment:
      REDASH_WEB_WORKERS: 4
  scheduler:
    <<: *redash-service
    command: scheduler
    environment:
      QUEUES: "celery"
      WORKERS_COUNT: 1
  scheduled_worker:
    <<: *redash-service
    command: worker
    environment:
      QUEUES: "scheduled_queries,schemas"
      WORKERS_COUNT: 1
  adhoc_worker:
    <<: *redash-service
    command: worker
    environment:
      QUEUES: "queries"
      WORKERS_COUNT: 2
  redis:
    image: redis:7-alpine
    restart: unless-stopped
  postgres:
    image: pgautoupgrade/pgautoupgrade:15-alpine3.8
    env_file: /opt/redash/env
    volumes:
      - /opt/redash/postgres-data:/var/lib/postgresql/data
    restart: unless-stopped
  nginx:
    image: redash/nginx:latest
    ports:
      - "80:80"
    depends_on:
      - server
    links:
      - server:redash
    restart: always

And the env file might look like this:

REDASH_HOST=http://localhost/redash
PYTHONUNBUFFERED=0
REDASH_LOG_LEVEL=INFO
REDASH_REDIS_URL=redis://redis:6379/0
POSTGRES_PASSWORD=postgres
REDASH_COOKIE_SECRET=redash-selfhosted
REDASH_SECRET_KEY=redash-selfhosted
REDASH_DATABASE_URL=postgresql://postgres@postgres/postgres

Encountering the Error

When you try to initialize the Redash database with the following command:

docker-compose run --rm server create_db

You might encounter the fe_sendauth: no password supplied error. This indicates that the POSTGRES_PASSWORD environment variable isn’t being correctly used by the create_db command.

Solution

To resolve this issue, you can pass the POSTGRES_PASSWORD directly when running the create_db command. Here’s how:

1. Remove the env_file Reference: Ensure that the env_file reference in your docker-compose.yml file for the server service is removed or overridden, so it doesn’t interfere.
2. Run the Command with Password: Use the -e option to explicitly pass the POSTGRES_PASSWORD as an environment variable:

docker-compose run --rm -e POSTGRES_PASSWORD=postgres server create_db

1. Replace postgres with the actual password if it’s different.

Conclusion

By passing the POSTGRES_PASSWORD directly in the docker-compose run command, you ensure that the correct password is used for PostgreSQL authentication. This method is effective in resolving the fe_sendauth: no password supplied error and allows you to proceed with setting up Redash successfully.