Run Redis on a specific port and dedicated config file

run-redis.sh

#!/bin/bash

# Check if a port number was provided
if [ -z "$1" ]; then
    echo "Usage: $0 <port_number>"
    echo "Example: $0 6380"
    exit 1
fi

PORT=$1
# Define file paths based on the port number
CONFIG_FILE="/etc/redis/redis_$PORT.conf"
DATA_DIR="/var/lib/redis_$PORT"
LOG_FILE="/var/log/redis/redis_$PORT.log"
PID_FILE="/var/run/redis/redis_$PORT.pid"
DEFAULT_CONFIG="/etc/redis/redis.conf"

# Check if the default config exists
if [ ! -f "$DEFAULT_CONFIG" ]; then
    echo "❌ Error: Default Redis configuration file not found at $DEFAULT_CONFIG."
    echo "Please ensure Redis is installed or update the DEFAULT_CONFIG path."
    exit 1
fi

echo "--- Setting up Redis instance on port $PORT ---"

# 1. Create the dedicated data and log directories
if [ ! -d "$DATA_DIR" ]; then
    sudo mkdir -p "$DATA_DIR"
    echo "Created data directory: $DATA_DIR"
fi
sudo mkdir -p /var/log/redis

# 2. Create the new configuration file ONLY IF IT DOES NOT EXIST (Configuration Guard)
if [ -f "$CONFIG_FILE" ]; then
    echo "Configuration file **ALREADY EXISTS**: $CONFIG_FILE"
    echo "Skipping configuration creation to prevent override."
else
    echo "Creating new configuration file: $CONFIG_FILE"
    
    # Copy the default configuration file
    sudo cp "$DEFAULT_CONFIG" "$CONFIG_FILE"

    # Use | (pipe) as the delimiter in sed commands
    
    # Update Port
    sudo sed -i "s|port 6379|port $PORT|" "$CONFIG_FILE"
    
    # Update PID file path
    sudo sed -i "s|pidfile /var/run/redis/redis-server.pid|pidfile $PID_FILE|" "$CONFIG_FILE"
    
    # Update Log file path
    sudo sed -i "s|^logfile \"\"|logfile $LOG_FILE|" "$CONFIG_FILE"
    
    # Update Data Directory path
    sudo sed -i "s|^dir .*$|dir $DATA_DIR|" "$CONFIG_FILE"
    
    # Ensure a unique RDB file name
    sudo sed -i "s|dbfilename dump.rdb|dbfilename dump_$PORT.rdb|" "$CONFIG_FILE"

    # ⭐ PERSISTENCE FIX: UNCOMMENT/ENABLE default RDB save points
    # This uses a pattern (^[[:space:]]*#) to match the start of a line containing optional spaces and a #
    sudo sed -i "/^[[:space:]]*# save 900 1/s/^#//" "$CONFIG_FILE"
    sudo sed -i "/^[[:space:]]*# save 300 10/s/^#//" "$CONFIG_FILE"
    sudo sed -i "/^[[:space:]]*# save 60 10000/s/^#//" "$CONFIG_FILE"

    # Final cleanup to remove any leading whitespace left after removing '#'
    sudo sed -i 's/^[[:space:]]*//' "$CONFIG_FILE"

    echo "Configuration written successfully."
fi

# 3. Check if a server is already running on this port before attempting to start
if sudo ss -tuln | grep ":$PORT " > /dev/null; then
    echo "⚠️ A process is already listening on port $PORT. Check PID file: $PID_FILE"
    echo "   Stopping the script."
    exit 1
fi

# 4. Start the Redis server
echo "Starting Redis server on port $PORT using config $CONFIG_FILE..."
sudo redis-server "$CONFIG_FILE"

if [ $? -eq 0 ]; then
    echo "✅ Redis server on port $PORT started successfully."
    echo "Connect with: redis-cli -p $PORT"
else
    echo "❌ Failed to start Redis server on port $PORT."
fi