Docker Compose configuration for setting up a Redis container with a health check

docker-compose.yml

# Docker Compose configuration for setting up a Redis container with a health check
#
# This configuration pulls the latest Redis image and sets up a health check
# to monitor if the Redis service is running properly. The health check uses
# the 'redis-cli ping' command, which returns 'PONG' if Redis is healthy.
#
# Optional configurations include volume mounting for persistence, logging setup,
# and security options.

services:
  redis:
    image: redis:latest                     # Pull the latest version of the Redis image
    container_name: redis_container         # Name of the Redis container
    hostname: redis                         # Hostname for the Redis container

    restart: unless-stopped                 # Restart the container unless manually stopped

    # Logging configuration for Redis container
    logging:
      driver: "json-file"                   # Use the default json-file logging driver
      options:
        max-size: "100m"                    # Maximum log file size before rotation (100 MB)
        max-file: "10"                      # Maximum number of log files to retain (10)

    # Security options for Redis container
    security_opt:
      - no-new-privileges:true              # Prevent container processes from gaining additional privileges
      
    # Uncomment and define networks if needed for the service
    # networks:
    #   - application-net

    # Environment variables for Redis configuration (if needed)
    environment:
      # REDIS_PASSWORD: ${REDIS_PW:?Redis password required!}   # Uncomment to set a Redis password (for secure deployment)

    # Volume configuration for data persistence
    volumes:
      - ./data/redis:/data                  # Mount the Redis data directory for persistent storage

    # Health check configuration to verify Redis readiness
    healthcheck:
      test: 
        [
          "CMD-SHELL",                      # Use the shell form to execute the health check command
          "redis-cli ping | grep PONG"      # Check if Redis responds with PONG
        ]
      interval: 5s                          # Time between health check attempts
      timeout: 5s                           # Time to wait for a response from the health check command
      retries: 5                            # Number of retries before marking the container as unhealthy

    # Container labels for additional metadata
    labels:
      - "com.centurylinklabs.watchtower.enable=true" # Enable automatic updates with Watchtower (optional)

# Uncomment and define networks if needed for the service
# networks:
#   application-net:
#     driver: bridge                            # Example of a network configuration

# This health check ensures that the Redis container is only marked as healthy when the
# 'redis-cli ping' command successfully returns "PONG" within the specified timeout.
# If it fails after 5 attempts, the container is marked as unhealthy.