CODEWITHSUNDEEP
dockerdocker-composeredisfastapiredis-om
Luigi Loria
Luigi Loria

Reputation: 60

Redis Error 111: Connection Refused in Docker Compose with FastAPI

I'm working on a FastAPI project using Docker Compose and Redis (specifically redis-om-python), but I keep encountering a ConnectionError: Error 111 connecting to localhost:6379. Connection refused error when both the API and Redis are running in Docker containers.

My docker-compose looks like this:

services:
  api:
    build: .
    container_name: api
    command: uv run fastapi dev --host 0.0.0.0
    ports:
      - "8000:8000"
    env_file:
      - .env.dev
    depends_on:
      redis:
        condition: service_healthy

  redis:
    image: redis/redis-stack:latest
    container_name: redis
    ports:
      - "6379:6379"
      - "8001:8001"
    healthcheck:
      test: ["CMD", "redis-cli", "ping"]
      interval: 5s
      retries: 5
      start_period: 5s

And in the .env.dev file I have:

REDIS_HOST=redis
REDIS_PORT=6379

I'm using redis-om to store data in Redis as a NoSQL database. Here's how I'm initializing the connection:

from redis_om import get_redis_connection, JsonModel
from pydantic import BaseSettings, Field
import os

class Settings(BaseSettings):
    REDIS_HOST: str = "localhost"
    REDIS_PORT: int = 6379

    class Config:
        env_file = (".env.dev", ".env")

ENV = Settings()

redis_client = get_redis_connection(host=ENV.REDIS_HOST, port=ENV.REDIS_PORT)

class CustomerModel(JsonModel):
    first_name: str = Field(index=True)
    last_name: str = Field(index=True)
    email: str = Field(index=True)
    age: int = Field(index=True)
    bio: str | None = Field(index=True, full_text_search=True)

    class Meta:
        database = redis_client

NOTE: Settings and CustomerModel are in two separate files, I wrote them together just to simplify the explanation.

If I run Redis in a container and the FastAPI app locally, it works as expected. But if I run both API and Redis in containers, I get the error mentioned above. Even when I hardcode redis instead of localhost (host="redis"), the error still points to localhost:6379 in the logs.

What I've Tried:

  1. Confirmed .env.dev is properly loaded inside the container.
  2. Verified connectivity between the containers (ping redis and redis-cli -h redis -p 6379 ping → PONG).
  3. Hardcoded "redis" instead of using the environment variable.
  4. Checked the Redis health status (docker ps, docker logs redis).
  5. Pruned the docker system and rebuilt containers completely.

Therefore, I don't get...

  1. Why does redis-om still default to localhost:6379 despite explicitly passing the correct host (redis) and port (6379) to get_redis_connection?
  2. Is there something I'm missing in my Docker Compose setup or the way redis-om initializes the connection?

Upvotes: 0

Views: 96

Answers (2)

Luigi Loria
Luigi Loria

Reputation: 60

Since for some reason get_redis_connection does not use the arguments I gave it, I saw that in its implementation it also looks for an environment variable REDIS_OM_URL and if it finds it, it is used to create the connection. I then updated my .env.dev file with:

REDIS_OM_URL=redis://redis:6379

And I changed the connection setting to:

redis_client = get_redis_connection()

And now it works like a charm.

Upvotes: 1

Yuvraj
Yuvraj

Reputation: 267

When you run FastAPI and redis in separate containers the host of the redis is not localhost anymore for other containers instead you should get the host by running docker inspect <redis_container_name> there you will find IPAdress which is "IPAddress": "172.17.0.2" in my case. You need to configure you fast api to connect to this host by replacing the localhost with IPAddress.

Upvotes: -1

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