Hi everyone ! I discovered prefect and I really like to give it a shot ! I am using coolify on a GCP VM, I used the template of prefect which was not working when launching with the error :

Can't connect to Server API at <http://127.0.0.1:4200/api>. Check that it's accessible from your machine.

I did some research, and from what I understand, it comes from network issue. But I can't see which one... Here's my docker-compose:

services:
  prefect:
    image: 'prefecthq/prefect:3-latest'
    depends_on:
      postgresql:
        condition: service_healthy
    environment:
      - SERVICE_FQDN_PREFECT_4200
      - 'PREFECT_API_DATABASE_CONNECTION_URL=postgresql+asyncpg://${SERVICE_USER_POSTGRES}:${SERVICE_PASSWORD_POSTGRES}@postgresql:5432/${POSTGRES_DB:-prefect}'
      - 'PREFECT_API_KEY=${SERVICE_PASSWORD_APIKEY}'
      - 'PREFECT_EXPERIMENTAL_WARN=${PREFECT_EXPERIMENTAL_WARN:-false}'
      - 'PREFECT_EXPERIMENTAL_ENABLE_SCHEDULE_CONCURRENCY=${PREFECT_EXPERIMENTAL_ENABLE_SCHEDULE_CONCURRENCY:-false}'
      - 'PREFECT_RUNNER_SERVER_ENABLE=${PREFECT_RUNNER_SERVER_ENABLE:-false}'
      - 'PREFECT_DEFAULT_WORK_POOL_NAME=${DEFAULT_POOL_NAME:-default}'
      - 'PREFECT_API_URL=<http://0.0.0.0:4200/api>'
      - 'PREFECT_SERVER_API_HOST=127.0.0.1'
      #- 'PREFECT_UI_API_URL=<http://localhost:4200/api>'
      #- 'PREFECT_UI_API_URL=<http://127.0.0.1:4200/api>'
    command:
      - prefect
      - server
      - start
      - '--host'
      - 0.0.0.0
      - '--port'
      - '4200'
    healthcheck:
      test:
        - CMD
        - python
        - '-c'
        - "import requests as r;r.get('<http://127.0.0.1:4200/api/health').raise_for_status(>)"
      interval: 5s
      timeout: 5s
      retries: 3
  postgresql:
    image: 'postgres:16-alpine'
    volumes:
      - 'pg-data:/var/lib/postgresql/data'
    environment:
      - POSTGRES_USER=$SERVICE_USER_POSTGRES
      - POSTGRES_PASSWORD=$SERVICE_PASSWORD_POSTGRES
      - 'POSTGRES_DB=${POSTGRES_DB:-prefect}'
    healthcheck:
      test:
        - CMD-SHELL
        - 'pg_isready -U $${POSTGRES_USER} -d $${POSTGRES_DB}'
      interval: 5s
      timeout: 5s
      retries: 3
  agent:
    image: 'prefecthq/prefect:3-python3.12'
    depends_on:
      prefect:
        condition: service_healthy
    entrypoint:
      - /opt/prefect/entrypoint.sh
      - prefect
      - worker
      - start
      - '--pool=${DEFAULT_POOL_NAME}'
      - '--with-healthcheck'
      - '--name=${DEFAULT_WORKER_NAME}'
      - '--limit=${DEFAULT_POOL_LIMIT}'
    environment:
      - 'PREFECT_API_URL=<http://prefect:4200/api>'
      - 'PREFECT_API_KEY=${SERVICE_PASSWORD_APIKEY}'
      - 'DEFAULT_POOL_NAME=${DEFAULT_POOL_NAME:-default}'
      - 'DEFAULT_POOL_LIMIT=${DEFAULT_POOL_LIMIT:-1}'
      - 'DEFAULT_WORKER_NAME=${DEFAULT_WORKER_NAME:-worker1}'
    healthcheck:
      test:
        - CMD-SHELL
        - pwd
      interval: 5s
      timeout: 5s
      retries: 3

Also I tried to relate with this issue, but couldn't see the bottom of it https://linen.prefect.io/t/9562601/hi-guys-hope-someone-can-help-me-with-my-current-problem-i-h Under the hood coolify use docker-compose, but it shouldn't interfer since it's in the local network of dockers... I'm a bit confused with this setup, any help is welcome ! Thanks in advance 🙂