honey-be/DOCKER_LOGGING_SETUP.md

Docker Logging Setup - Automatic Configuration

Overview

The Docker setup is automatically configured to use external logback-spring.xml for runtime log level changes. No manual configuration needed!

How It Works

1. Dockerfile Configuration

Both Dockerfile and Dockerfile.inferno automatically:

• Copy logback-spring.xml to /app/config/logback-spring.xml in the container
• Create /app/logs directory for log files
• Set default environment variables:
  • LOGGING_CONFIG=/app/config/logback-spring.xml
  • LOG_DIR=/app/logs
• Configure Java to use external config via -Dlogging.config and -DLOG_DIR

2. Docker Compose Configuration

Both docker-compose.inferno.yml and docker-compose.prod.yml automatically:

• Mount external config: /opt/app/backend/config/logback-spring.xml → /app/config/logback-spring.xml (read-write, editable on VPS)
• Mount logs directory: /opt/app/logs → /app/logs (persistent storage)
• Set environment variables: LOGGING_CONFIG and LOG_DIR

Initial Setup (One-Time)

Option 1: Use Setup Script (Recommended)

cd /opt/app/backend
# Make script executable (if not already)
chmod +x scripts/setup-logging.sh
# Run the script
./scripts/setup-logging.sh

This script will:

1. Create /opt/app/backend/config directory
2. Create /opt/app/logs directory
3. Extract logback-spring.xml from JAR (if available)
4. Set proper permissions

Option 2: Manual Setup

# Create directories
mkdir -p /opt/app/backend/config
mkdir -p /opt/app/logs

# Extract logback-spring.xml from JAR
cd /opt/app/backend
unzip -p target/lottery-be-*.jar BOOT-INF/classes/logback-spring.xml > /opt/app/backend/config/logback-spring.xml

# Or copy from source (if building from source on VPS)
cp src/main/resources/logback-spring.xml /opt/app/backend/config/logback-spring.xml

# Set permissions
chmod 644 /opt/app/backend/config/logback-spring.xml
chmod 755 /opt/app/logs

Usage

Start Application

Just start Docker Compose as usual:

cd /opt/app/backend
docker compose -f docker-compose.inferno.yml up -d

The external logging configuration is automatically active - no additional steps needed!

Change Log Level at Runtime

1. Edit the mounted config file:

   nano /opt/app/backend/config/logback-spring.xml
   

2. Change log level (example: enable DEBUG):

   <logger name="com.lottery" level="DEBUG"/>
   

3. Save the file. Logback will automatically reload within 30 seconds.

4. Verify:

   # View logs from VPS
   tail -f /opt/app/logs/lottery-be.log
   
   # Or from inside container
   docker exec lottery-backend tail -f /app/logs/lottery-be.log
   

View Logs

# Real-time monitoring
tail -f /opt/app/logs/lottery-be.log

# Search for errors
grep -i "error" /opt/app/logs/lottery-be.log

# View last 100 lines
tail -n 100 /opt/app/logs/lottery-be.log

# From inside container
docker exec lottery-backend tail -f /app/logs/lottery-be.log

File Locations

On VPS (Host)

• Config file: /opt/app/backend/config/logback-spring.xml (editable)
• Log files: /opt/app/logs/lottery-be.log and rolled files

Inside Container

• Config file: /app/config/logback-spring.xml (mounted from host)
• Log files: /app/logs/lottery-be.log (mounted to host)

Verification

Check Configuration is Active

# Check container logs for logback initialization
docker logs lottery-backend | grep -i "logback\|logging"

# Check mounted file exists
ls -la /opt/app/backend/config/logback-spring.xml

# Check log directory
ls -la /opt/app/logs/

# Check environment variables in container
docker exec lottery-backend env | grep LOG

Expected Output

You should see:

• LOGGING_CONFIG=/app/config/logback-spring.xml
• LOG_DIR=/app/logs
• Log files appearing in /opt/app/logs/

Benefits

✅ No manual configuration needed - Works automatically with Docker
✅ Runtime log level changes - Edit file, changes take effect in 30 seconds
✅ No container restart required - Changes apply without restarting
✅ Persistent logs - Logs survive container restarts
✅ Editable config - Edit logback-spring.xml directly on VPS

Troubleshooting

Config file not found

# Check if file exists
ls -la /opt/app/backend/config/logback-spring.xml

# If missing, extract from JAR or copy from source
./scripts/setup-logging.sh

Logs not appearing

# Check log directory permissions
ls -ld /opt/app/logs

# Check container can write
docker exec lottery-backend ls -la /app/logs

# Check disk space
df -h /opt/app/logs

Log level changes not working

1. Verify scan="true" scanPeriod="30 seconds" in logback-spring.xml
2. Check for XML syntax errors
3. Wait 30 seconds after saving
4. Check container logs for Logback errors:

   docker logs lottery-backend | grep -i "logback\|error"
   

Summary

You don't need to do anything manually! The Docker setup automatically:

• Uses external logback-spring.xml
• Mounts it as a volume (editable on VPS)
• Sets all required environment variables
• Configures log directory

Just run docker compose up and you're ready to go! 🚀