How to fix ERROR: Cannot find service 'base' referenced in extends in Docker

# common-services.yml - the file you're extending FROM
services:
  base-app:           # <-- This name must match exactly
    image: node:18
    environment:
      - NODE_ENV=production
    working_dir: /app

# docker-compose.yml - your main compose file
services:
  webapp:
    extends:
      file: common-services.yml
      service: base-app  # Must match exactly, case-sensitive
    ports:
      - "3000:3000"

# Check if the file exists
ls -la common-services.yml

# If in a subdirectory
ls -la ./config/common-services.yml

services:
  webapp:
    extends:
      file: ./config/common-services.yml  # Path relative to this file
      service: base-app

services:
  base-app:
    image: node:18

  webapp:
    extends:
      service: base-app  # Extends from same file (no file key needed)
    ports:
      - "3000:3000"

# Validate and show merged configuration
docker-compose config

# If using a custom file
docker-compose -f docker-compose.yml config

# This will cause "can't be used with extends" error
services:
  base:
    image: node:18
    depends_on:        # <-- Remove this from base service
      - database

# Instead, add depends_on in the extending service
services:
  webapp:
    extends:
      service: base
    depends_on:        # <-- Add it here instead
      - database

# Check your Docker Compose version
docker compose version
# or
docker-compose --version

# Change version or remove it entirely (recommended for modern Docker)
# Old way (may not support extends):
version: "3.7"

# New way (supports extends):
# Just remove the version line entirely
services:
  ...

# Define a reusable configuration block
x-common: &common-config
  image: node:18
  environment:
    - NODE_ENV=production
  working_dir: /app

services:
  webapp:
    <<: *common-config  # Merge the common config
    ports:
      - "3000:3000"
    command: npm start

  worker:
    <<: *common-config
    command: npm run worker