entrypoint.sh

#!/bin/bash

# Declare an associative array
declare -A services

# Read key-value pairs from JSON and add to the associative array
while IFS="=" read -r key value; do
    # Validate and sanitize the key before using it as an array subscript
    if [ -z "$key" ]; then
        key="_empty_key"  # Assign a placeholder key for empty keys
    fi
    
    # Add the key-value pair to the services array
    services["$key"]="$value"
done < <(jq -r "to_entries | map(\"\(.key)=\(.value)\") | .[]" "${BALANCER_NGINX_SERVICES_FILE}")

# To demonstrate, print the array elements
for key in "${!services[@]}"; do
    # Display placeholder for empty keys during debugging
    if [ "$key" == "_empty_key" ]; then
        echo "(empty) -> ${services[$key]}"
    else
        echo "$key -> ${services[$key]}"
    fi
done

# Load or source additional script modules
update_config() {
    source /etc/nginx/modules/initialize_project_conf.sh
    source /etc/nginx/modules/generate_certificate.sh
    source /etc/nginx/modules/generate_dh_params.sh
    source /etc/nginx/modules/create_nginx_server_block.sh
    source /etc/nginx/modules/generate_certificates_and_nginx_blocks.sh
    nginx -s reload
}

# Function to check DNS availability and use fallbacks
initialize_dns_check_with_fallback() {
    for service in "${!services[@]}"; do
        local hostname=$(echo "${services[$service]}" | cut -d: -f1)
        # Only check DNS if hostname is non-empty
        if [ -n "$hostname" ] && ! host "$hostname" > /dev/null 2>&1; then
            echo "DNS resolution failed for $hostname, using fallback."
            services["$service"]="gitlab-runner:404"  # Set fallback host and port
        fi
    done
}

# Update services, configure NGINX, and start NGINX
initialize_dns_check_with_fallback
update_config
nginx -g "daemon off;" &

# Initialize original settings in a separate array to ensure they are preserved
declare -A original_services
for key in "${!services[@]}"; do
    original_services["$key"]="${services[$key]}"
done

update_services_and_reload_nginx() {
    local changed=false
    for service in "${!services[@]}"; do
        local original_setting="${original_services[$service]}"
        local hostname=$(echo "$original_setting" | cut -d: -f1)

        # Only check DNS if hostname is non-empty
        if [ -n "$hostname" ] && ! host "$hostname" > /dev/null 2>&1; then
            if [ "${services[$service]}" != "gitlab-runner:404" ]; then
                services["$service"]="gitlab-runner:404"
                changed=true
            fi
        else
            if [ "${services[$service]}" != "$original_setting" ]; then
                services["$service"]="$original_setting"
                changed=true
            fi
        fi
    done

    if [ "$changed" = true ]; then
        update_config
        nginx -s reload
        echo "*** Detected change in local DNS - config was updated ***"
    fi
}

# Periodically check service DNS and update NGINX config as needed
while true; do
    update_services_and_reload_nginx
    sleep "${BALANCER_SLEEP_BUFFER}"
done