how to setup multiple fastapi instances -micro services

[sivajik34]

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Example Code

services:
  # --------------------
  # Databases
  # --------------------
  user-db:
    image: postgres:17
    restart: always
    env_file: .env
    environment:
      POSTGRES_USER: ${USER_DB_USER}
      POSTGRES_PASSWORD: ${USER_DB_PASSWORD}
      POSTGRES_DB: ${USER_DB}
    volumes:
      - user-db-data:/var/lib/postgresql/data
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U ${USER_DB_USER} -d ${USER_DB}"]
      interval: 10s
      timeout: 5s
      retries: 5

  product-db:
    image: postgres:17
    restart: always
    env_file: .env
    environment:
      POSTGRES_USER: ${PRODUCT_DB_USER}
      POSTGRES_PASSWORD: ${PRODUCT_DB_PASSWORD}
      POSTGRES_DB: ${PRODUCT_DB}
    volumes:
      - product-db-data:/var/lib/postgresql/data
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U ${PRODUCT_DB_USER} -d ${PRODUCT_DB}"]
      interval: 10s
      timeout: 5s
      retries: 5

  order-db:
    image: postgres:17
    restart: always
    env_file: .env
    environment:
      POSTGRES_USER: ${ORDER_DB_USER}
      POSTGRES_PASSWORD: ${ORDER_DB_PASSWORD}
      POSTGRES_DB: ${ORDER_DB}
    volumes:
      - order-db-data:/var/lib/postgresql/data
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U ${ORDER_DB_USER} -d ${ORDER_DB}"]
      interval: 10s
      timeout: 5s
      retries: 5

  # --------------------
  # Prestart Jobs
  # --------------------
  prestart-user:
    image: '${DOCKER_IMAGE_USER_SERVICE?Variable not set}:${TAG-latest}'
    build:
      context: ./services/user-service
    networks:
      - traefik-public
      - default
    depends_on:
      user-db:
        condition: service_healthy
    command: bash scripts/prestart.sh
    env_file:
      - .env
    environment:
      - DOMAIN=${DOMAIN}
      - FRONTEND_HOST=${FRONTEND_HOST?Variable not set}
      - ENVIRONMENT=${ENVIRONMENT}
      - BACKEND_CORS_ORIGINS=${BACKEND_CORS_ORIGINS}
      - SECRET_KEY=${SECRET_KEY?Variable not set}
      - FIRST_SUPERUSER=${FIRST_SUPERUSER?Variable not set}
      - FIRST_SUPERUSER_PASSWORD=${FIRST_SUPERUSER_PASSWORD?Variable not set}
      - SMTP_HOST=${SMTP_HOST}
      - SMTP_USER=${SMTP_USER}
      - SMTP_PASSWORD=${SMTP_PASSWORD}
      - EMAILS_FROM_EMAIL=${EMAILS_FROM_EMAIL}
      - POSTGRES_SERVER=${USER_DB_SERVER}
      - POSTGRES_USER=${USER_DB_USER}
      - POSTGRES_PASSWORD=${USER_DB_PASSWORD}
      - POSTGRES_DB=${USER_DB}
      - DATABASE_URL=postgresql://${USER_DB_USER}:${USER_DB_PASSWORD}@${USER_DB_SERVER}:5432/${USER_DB}
      - SENTRY_DSN=${SENTRY_DSN}

  prestart-product:
    image: '${DOCKER_IMAGE_PRODUCT_SERVICE?Variable not set}:${TAG-latest}'
    build:
      context: ./services/product-service
    
    networks:
      - traefik-public
      - default
    depends_on:
      product-db:
        condition: service_healthy
    command: bash scripts/prestart.sh
    env_file:
      - .env
    environment:
      - DOMAIN=${DOMAIN}
      - FRONTEND_HOST=${FRONTEND_HOST?Variable not set}
      - ENVIRONMENT=${ENVIRONMENT}
      - BACKEND_CORS_ORIGINS=${BACKEND_CORS_ORIGINS}
      - SECRET_KEY=${SECRET_KEY?Variable not set}
      - FIRST_SUPERUSER=${FIRST_SUPERUSER?Variable not set}
      - FIRST_SUPERUSER_PASSWORD=${FIRST_SUPERUSER_PASSWORD?Variable not set}
      - SMTP_HOST=${SMTP_HOST}
      - SMTP_USER=${SMTP_USER}
      - SMTP_PASSWORD=${SMTP_PASSWORD}
      - EMAILS_FROM_EMAIL=${EMAILS_FROM_EMAIL}
      - POSTGRES_SERVER=${PRODUCT_DB_SERVER}
      - POSTGRES_USER=${PRODUCT_DB_USER}
      - POSTGRES_PASSWORD=${PRODUCT_DB_PASSWORD}
      - POSTGRES_DB=${PRODUCT_DB}
      - DATABASE_URL=postgresql://${PRODUCT_DB_USER}:${PRODUCT_DB_PASSWORD}@${PRODUCT_DB_SERVER}:5432/${PRODUCT_DB}
      - SENTRY_DSN=${SENTRY_DSN}

  prestart-order:
    image: '${DOCKER_IMAGE_ORDER_SERVICE?Variable not set}:${TAG-latest}'
    build:
      context: ./services/order-service
    networks:
      - traefik-public
      - default
    depends_on:
      order-db:
        condition: service_healthy
    command: bash scripts/prestart.sh
    env_file:
      - .env
    environment:
      - DOMAIN=${DOMAIN}
      - FRONTEND_HOST=${FRONTEND_HOST?Variable not set}
      - ENVIRONMENT=${ENVIRONMENT}
      - BACKEND_CORS_ORIGINS=${BACKEND_CORS_ORIGINS}
      - SECRET_KEY=${SECRET_KEY?Variable not set}
      - FIRST_SUPERUSER=${FIRST_SUPERUSER?Variable not set}
      - FIRST_SUPERUSER_PASSWORD=${FIRST_SUPERUSER_PASSWORD?Variable not set}
      - SMTP_HOST=${SMTP_HOST}
      - SMTP_USER=${SMTP_USER}
      - SMTP_PASSWORD=${SMTP_PASSWORD}
      - EMAILS_FROM_EMAIL=${EMAILS_FROM_EMAIL}
      - POSTGRES_SERVER=${ORDER_DB_SERVER}
      - POSTGRES_USER=${ORDER_DB_USER}
      - POSTGRES_PASSWORD=${ORDER_DB_PASSWORD}
      - POSTGRES_DB=${ORDER_DB}
      - DATABASE_URL=postgresql://${ORDER_DB_USER}:${ORDER_DB_PASSWORD}@${ORDER_DB_SERVER}:5432/${ORDER_DB}
      - SENTRY_DSN=${SENTRY_DSN}    

  # --------------------
  # Microservices
  # --------------------
  user-service:
    build: ./services/user-service
    restart: always
    networks:
      - traefik-public
      - default
    depends_on:
      user-db:
        condition: service_healthy
        restart: true
      prestart-user:
        condition: service_completed_successfully
    env_file:
      - .env
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:8001/users/utils/health-check/"]
      interval: 10s
      timeout: 5s
      retries: 5  
    environment:
      - DOMAIN=${DOMAIN}
      - FRONTEND_HOST=${FRONTEND_HOST?Variable not set}
      - ENVIRONMENT=${ENVIRONMENT}
      - BACKEND_CORS_ORIGINS=${BACKEND_CORS_ORIGINS}
      - SECRET_KEY=${SECRET_KEY?Variable not set}
      - FIRST_SUPERUSER=${FIRST_SUPERUSER?Variable not set}
      - FIRST_SUPERUSER_PASSWORD=${FIRST_SUPERUSER_PASSWORD?Variable not set}
      - SMTP_HOST=${SMTP_HOST}
      - SMTP_USER=${SMTP_USER}
      - SMTP_PASSWORD=${SMTP_PASSWORD}
      - EMAILS_FROM_EMAIL=${EMAILS_FROM_EMAIL}
      - POSTGRES_SERVER=${USER_DB_SERVER}
      - POSTGRES_USER=${USER_DB_USER}
      - POSTGRES_PASSWORD=${USER_DB_PASSWORD}
      - POSTGRES_DB=${USER_DB}
      - DATABASE_URL=postgresql://${USER_DB_USER}:${USER_DB_PASSWORD}@${USER_DB_SERVER}:5432/${USER_DB}
      - SENTRY_DSN=${SENTRY_DSN}
      - DATABASE_URL=postgresql://user_admin:user_pass@user-db:5432/user_db
    labels:
      - traefik.enable=true
      - traefik.docker.network=traefik-public
      - traefik.constraint-label=traefik-public

      # Service port
      - traefik.http.services.user-service.loadbalancer.server.port=8000

      # HTTP Router
      - traefik.http.routers.user-service-http.rule= PathPrefix('/users')
      - traefik.http.routers.user-service-http.entrypoints=http
      

      # HTTPS Router
      - traefik.http.routers.user-service-https.rule= PathPrefix('/users')
      - traefik.http.routers.user-service-https.entrypoints=https
      - traefik.http.routers.user-service-https.tls=true
      - traefik.http.routers.user-service-https.tls.certresolver=le

      - traefik.http.routers.user-service-http.middlewares=https-redirect

  product-service:
    build: ./services/product-service
    restart: always
    networks:
      - traefik-public
      - default
    depends_on:
      product-db:
        condition: service_healthy
        restart: true
      prestart-product:
        condition: service_completed_successfully
    env_file:
      - .env
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:8002/products/utils/health-check/"]
      interval: 10s
      timeout: 5s
      retries: 5
    environment:
      - DOMAIN=${DOMAIN}
      - FRONTEND_HOST=${FRONTEND_HOST?Variable not set}
      - ENVIRONMENT=${ENVIRONMENT}
      - BACKEND_CORS_ORIGINS=${BACKEND_CORS_ORIGINS}
      - SECRET_KEY=${SECRET_KEY?Variable not set}
      - FIRST_SUPERUSER=${FIRST_SUPERUSER?Variable not set}
      - FIRST_SUPERUSER_PASSWORD=${FIRST_SUPERUSER_PASSWORD?Variable not set}
      - SMTP_HOST=${SMTP_HOST}
      - SMTP_USER=${SMTP_USER}
      - SMTP_PASSWORD=${SMTP_PASSWORD}
      - EMAILS_FROM_EMAIL=${EMAILS_FROM_EMAIL}
      - POSTGRES_SERVER=${PRODUCT_DB_SERVER}
      - POSTGRES_USER=${PRODUCT_DB_USER}
      - POSTGRES_PASSWORD=${PRODUCT_DB_PASSWORD}
      - POSTGRES_DB=${PRODUCT_DB}
      - DATABASE_URL=postgresql://${PRODUCT_DB_USER}:${PRODUCT_DB_PASSWORD}@${PRODUCT_DB_SERVER}:5432/${PRODUCT_DB}
      - SENTRY_DSN=${SENTRY_DSN}
      - DATABASE_URL=postgresql://product_admin:product_pass@product-db:5432/product_db
    labels:
      - traefik.enable=true
      - traefik.docker.network=traefik-public
      - traefik.constraint-label=traefik-public

      # Service port
      - traefik.http.services.product-service.loadbalancer.server.port=8000

      # HTTP Router
      - traefik.http.routers.product-service-http.rule=  PathPrefix(`/products`)
      - traefik.http.routers.product-service-http.entrypoints=http
      - traefik.http.routers.product-service-http.middlewares=https-redirect

      # HTTPS Router
      - traefik.http.routers.product-service-https.rule=PathPrefix(`/products`)
      - traefik.http.routers.product-service-https.entrypoints=https
      - traefik.http.routers.product-service-https.tls=true
      - traefik.http.routers.product-service-https.tls.certresolver=le

  order-service:
    build: ./services/order-service
    restart: always
    networks:
      - traefik-public
      - default
    depends_on:
      order-db:
        condition: service_healthy
        restart: true
      prestart-order:
        condition: service_completed_successfully
    env_file:
      - .env
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:8003/orders/utils/health-check/"]
      interval: 10s
      timeout: 5s
      retries: 5
    environment:
      - DOMAIN=${DOMAIN}
      - FRONTEND_HOST=${FRONTEND_HOST?Variable not set}
      - ENVIRONMENT=${ENVIRONMENT}
      - BACKEND_CORS_ORIGINS=${BACKEND_CORS_ORIGINS}
      - SECRET_KEY=${SECRET_KEY?Variable not set}
      - FIRST_SUPERUSER=${FIRST_SUPERUSER?Variable not set}
      - FIRST_SUPERUSER_PASSWORD=${FIRST_SUPERUSER_PASSWORD?Variable not set}
      - SMTP_HOST=${SMTP_HOST}
      - SMTP_USER=${SMTP_USER}
      - SMTP_PASSWORD=${SMTP_PASSWORD}
      - EMAILS_FROM_EMAIL=${EMAILS_FROM_EMAIL}
      - POSTGRES_SERVER=${ORDER_DB_SERVER}
      - POSTGRES_USER=${ORDER_DB_USER}
      - POSTGRES_PASSWORD=${ORDER_DB_PASSWORD}
      - POSTGRES_DB=${ORDER_DB}
      - DATABASE_URL=postgresql://${ORDER_DB_USER}:${ORDER_DB_PASSWORD}@${ORDER_DB_SERVER}:5432/${ORDER_DB}
      - SENTRY_DSN=${SENTRY_DSN}
      - DATABASE_URL=postgresql://order_admin:order_pass@order-db:5432/order_db
    labels:
      - traefik.enable=true
      - traefik.docker.network=traefik-public
      - traefik.constraint-label=traefik-public

      # Service port
      - traefik.http.services.order-service.loadbalancer.server.port=8000

      # HTTP Router
      - traefik.http.routers.order-service-http.rule=PathPrefix(`/orders`)
      - traefik.http.routers.order-service-http.entrypoints=http
      - traefik.http.routers.order-service-http.middlewares=https-redirect

      # HTTPS Router
      - traefik.http.routers.order-service-https.rule= PathPrefix(`/orders`)
      - traefik.http.routers.order-service-https.entrypoints=https
      - traefik.http.routers.order-service-https.tls=true
      - traefik.http.routers.order-service-https.tls.certresolver=le
      
  adminer:
    image: adminer
    restart: always
    networks:
      - traefik-public
      - default
    depends_on:
      - user-db
    environment:
      - ADMINER_DESIGN=pepa-linha-dark
    labels:
      - traefik.enable=true
      - traefik.docker.network=traefik-public
      - traefik.constraint-label=traefik-public
      - traefik.http.routers.${STACK_NAME?Variable not set}-adminer-http.rule=Host(`adminer.${DOMAIN?Variable not set}`)
      - traefik.http.routers.${STACK_NAME?Variable not set}-adminer-http.entrypoints=http
      - traefik.http.routers.${STACK_NAME?Variable not set}-adminer-http.middlewares=https-redirect
      - traefik.http.routers.${STACK_NAME?Variable not set}-adminer-https.rule=Host(`adminer.${DOMAIN?Variable not set}`)
      - traefik.http.routers.${STACK_NAME?Variable not set}-adminer-https.entrypoints=https
      - traefik.http.routers.${STACK_NAME?Variable not set}-adminer-https.tls=true
      - traefik.http.routers.${STACK_NAME?Variable not set}-adminer-https.tls.certresolver=le
      - traefik.http.services.${STACK_NAME?Variable not set}-adminer.loadbalancer.server.port=8080    

  # --------------------
  # Frontend
  # --------------------
  frontend:
    build:
      context: ./frontend
      args:
        - VITE_API_URL=https://api.${DOMAIN}
        - NODE_ENV=production
    restart: always
    networks:
      - traefik-public
      - default
    labels:
      - traefik.enable=true
      - traefik.docker.network=traefik-public
      - traefik.constraint-label=traefik-public

      # Service port
      - traefik.http.services.frontend.loadbalancer.server.port=80

      # HTTP Router
      - traefik.http.routers.frontend-http.rule=Host(`dashboard.${DOMAIN}`)
      - traefik.http.routers.frontend-http.entrypoints=http
      - traefik.http.routers.frontend-http.middlewares=https-redirect

      # HTTPS Router
      - traefik.http.routers.frontend-https.rule=Host(`dashboard.${DOMAIN}`)
      - traefik.http.routers.frontend-https.entrypoints=https
      - traefik.http.routers.frontend-https.tls=true
      - traefik.http.routers.frontend-https.tls.certresolver=le
  

# --------------------
# Volumes & Networks
# --------------------
volumes:
  user-db-data:
  product-db-data:
  order-db-data:
  

networks:
  traefik-public:
    external: true

Description

https://github.com/sivajik34/FastCart
I'm trying to add micro services user_service order_service product_service and getting port issues.
below 3 are working
http://localhost:8001/users/docs#/
http://localhost:8002/products/docs#/
http://localhost:8003/orders/docs#/
but from frontend it is not working http://localhost:8000/users/users/me net::ERR_CONNECTION_REFUSED
it seems I'm not able to configure api gateway.
can you help me on this

Operating System

Windows

Operating System Details

windows

Python Version

python 3.12

Additional Context

No response

[Flpvoigt]

There are two different address spaces being mixed here.

Inside each service container, Uvicorn/Traefik targets port 8000. Host mappings such as 8001/8002/8003 (if defined in an override file) exist only on the Docker host. Therefore these health checks are wrong inside the containers:

user-service:
  healthcheck:
    test: ["CMD", "curl", "-f", "http://localhost:8000/users/utils/health-check/"]
product-service:
  healthcheck:
    test: ["CMD", "curl", "-f", "http://localhost:8000/products/utils/health-check/"]
order-service:
  healthcheck:
    test: ["CMD", "curl", "-f", "http://localhost:8000/orders/utils/health-check/"]

For container-to-container calls use service DNS names and the container port, e.g. http://user-service:8000/.... For browser calls, do not use localhost:8000 unless you explicitly publish a gateway there. Your production frontend already builds with VITE_API_URL=https://api.${DOMAIN}, so requests should go through Traefik, for example:

https://api.example.com/users/me

The observed /users/users/me also shows that the prefix is being added twice. Choose one owner for it:

• gateway base URL = https://api.example.com, endpoint = /users/me; or
• service base URL = https://api.example.com/users, endpoint = /me.

Your Traefik service target loadbalancer.server.port=8000 is correct. If the FastAPI app itself does not define routes with the external /users prefix, add a Traefik StripPrefix middleware; otherwise leave the prefix intact. Publish 8001/8002/8003 only for direct host debugging—they are not the ports other containers should use.