eagle0/scripts/deploy-blue-green.sh

#!/bin/bash
#
# Blue-Green Deployment Script for Eagle Server
#
# This script performs a zero-downtime deployment by:
# 1. Starting the new version on a staging port (green)
# 2. Waiting for it to become healthy
# 3. Running warmup traffic to pre-heat the JIT
# 4. Stopping the old version (blue) - which flushes state to storage
# 5. Switching nginx to route traffic to green
# 6. Users reconnect, triggering lazy game loading from fresh storage
# 7. Cleaning up
#
# Usage: ./deploy-blue-green.sh [NEW_IMAGE_TAG]
#
# Example:
#   ./deploy-blue-green.sh latest
#   ./deploy-blue-green.sh sha-abc123
#

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
APP_DIR="${APP_DIR:-/opt/eagle0}"
NGINX_CONF="${APP_DIR}/nginx/nginx.conf"
COMPOSE_FILE="${APP_DIR}/docker-compose.prod.yml"
WARMUP_SCRIPT="${SCRIPT_DIR}/warmup-eagle.sh"

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

log_info() { echo -e "${GREEN}[INFO]${NC} $1"; }
log_warn() { echo -e "${YELLOW}[WARN]${NC} $1"; }
log_error() { echo -e "${RED}[ERROR]${NC} $1"; }

# Determine which instance is currently active
get_active_instance() {
    if grep -q "eagle-blue:40032" "${NGINX_CONF}"; then
        echo "blue"
    elif grep -q "eagle-green:40032" "${NGINX_CONF}"; then
        echo "green"
    else
        log_error "Cannot determine active instance from nginx config"
        exit 1
    fi
}

# Pull image with retry using crane (handles OCI/Docker digest mismatch)
pull_with_retry() {
    local image=$1
    local max_attempts=${2:-3}
    local attempt=1

    # Use crane if available (handles OCI format correctly)
    if [ -x "${APP_DIR}/crane" ]; then
        while [ $attempt -le $max_attempts ]; do
            log_info "Pulling image with crane (attempt ${attempt}/${max_attempts})..."
            if "${APP_DIR}/crane" pull "${image}" /tmp/image.tar && docker load -i /tmp/image.tar; then
                rm -f /tmp/image.tar
                log_info "Image pulled and loaded successfully"
                return 0
            fi
            rm -f /tmp/image.tar
            log_warn "Pull failed, retrying in 5 seconds..."
            sleep 5
            attempt=$((attempt + 1))
        done
    else
        # Fallback to docker pull if crane not available
        log_warn "crane not found at ${APP_DIR}/crane, falling back to docker pull"
        while [ $attempt -le $max_attempts ]; do
            log_info "Pulling image (attempt ${attempt}/${max_attempts})..."
            if docker pull "${image}"; then
                log_info "Image pulled successfully"
                return 0
            fi
            log_warn "Pull failed, retrying in 5 seconds..."
            sleep 5
            attempt=$((attempt + 1))
        done
    fi
    log_error "Failed to pull image after ${max_attempts} attempts"
    return 1
}

# Wait for a container to be healthy
wait_for_healthy() {
    local container=$1
    local max_attempts=${2:-60}
    local attempt=1

    log_info "Waiting for ${container} to become healthy..."
    while [ $attempt -le $max_attempts ]; do
        health=$(docker inspect --format='{{.State.Health.Status}}' "${container}" 2>/dev/null || echo "unknown")
        if [ "$health" = "healthy" ]; then
            log_info "${container} is healthy"
            return 0
        fi
        echo -n "."
        sleep 2
        attempt=$((attempt + 1))
    done
    echo ""
    log_error "${container} did not become healthy after $((max_attempts * 2)) seconds"
    return 1
}

# Main deployment logic
main() {
    local new_tag="${1:-latest}"
    local registry="registry.digitalocean.com/eagle0/eagle-server"
    local new_image="${registry}:${new_tag}"

    log_info "Starting blue-green deployment"
    log_info "New image: ${new_image}"

    cd "${APP_DIR}"

    # Determine current active instance
    local active=$(get_active_instance)
    local staging
    if [ "$active" = "blue" ]; then
        staging="green"
    else
        staging="blue"
    fi

    log_info "Active instance: eagle-${active}"
    log_info "Staging instance: eagle-${staging}"

    # Pull the new image (with retry for intermittent registry issues)
    if ! pull_with_retry "${new_image}" 3; then
        log_error "Failed to pull new image, aborting deployment"
        exit 1
    fi

    # Start staging instance with new image
    log_info "Starting eagle-${staging} with new image..."
    if [ "$staging" = "green" ]; then
        EAGLE_IMAGE_NEW="${new_image}" docker compose -f "${COMPOSE_FILE}" --profile blue-green up -d eagle-green
    else
        EAGLE_IMAGE="${new_image}" docker compose -f "${COMPOSE_FILE}" up -d eagle-blue
    fi

    # Wait for staging to be healthy
    if ! wait_for_healthy "eagle-${staging}" 90; then
        log_error "Staging instance failed health check, aborting deployment"
        docker compose -f "${COMPOSE_FILE}" stop "eagle-${staging}"
        docker compose -f "${COMPOSE_FILE}" rm -f "eagle-${staging}"
        exit 1
    fi

    # Run warmup/smoke test
    local staging_port
    if [ "$staging" = "green" ]; then
        staging_port=40034
    else
        staging_port=40032
    fi

    log_info "Running warmup against eagle-${staging}..."
    if [ -x "${WARMUP_SCRIPT}" ]; then
        if ! "${WARMUP_SCRIPT}" "localhost:${staging_port}"; then
            log_error "Warmup/smoke test failed, aborting deployment"
            docker compose -f "${COMPOSE_FILE}" stop "eagle-${staging}"
            docker compose -f "${COMPOSE_FILE}" rm -f "eagle-${staging}"
            exit 1
        fi
    else
        log_warn "Warmup script not found at ${WARMUP_SCRIPT}, skipping warmup"
        log_warn "JIT will be cold on first requests"
    fi

    # Stop the active instance (this flushes state to storage)
    log_info "Stopping eagle-${active} (flushing state to storage)..."
    docker compose -f "${COMPOSE_FILE}" stop "eagle-${active}"

    # Note: No need to explicitly reload games - Eagle uses lazy loading.
    # Games are loaded on-demand when users reconnect after nginx switches traffic.
    # This ensures games are always loaded from the freshest storage state.

    # Switch nginx upstream
    log_info "Switching nginx upstream to eagle-${staging}..."
    if [ "$staging" = "green" ]; then
        sed -i.bak 's/eagle-blue:40032/eagle-green:40032/g' "${NGINX_CONF}"
    else
        sed -i.bak 's/eagle-green:40032/eagle-blue:40032/g' "${NGINX_CONF}"
    fi

    # Reload nginx
    log_info "Reloading nginx..."
    docker compose -f "${COMPOSE_FILE}" exec nginx nginx -s reload

    # Clean up old instance
    log_info "Removing old eagle-${active} container..."
    docker compose -f "${COMPOSE_FILE}" rm -f "eagle-${active}"

    # Update the staging instance's restart policy and image var
    # For blue, we need to update EAGLE_IMAGE; for green, update EAGLE_IMAGE_NEW
    if [ "$staging" = "blue" ]; then
        log_info "Updating EAGLE_IMAGE to ${new_image} for future restarts"
        # User should update their .env file
    else
        log_info "Green is now active. Consider switching to blue on next deployment."
    fi

    log_info "Deployment complete!"
    log_info "Active instance: eagle-${staging}"
    log_info ""
    log_info "Note: Update your .env file with EAGLE_IMAGE=${new_image}"
    log_info "      if you want future 'docker compose up' to use this version."
}

# Check for required tools
check_requirements() {
    if ! command -v docker &> /dev/null; then
        log_error "docker is required but not installed"
        exit 1
    fi

    if ! command -v sed &> /dev/null; then
        log_error "sed is required but not installed"
        exit 1
    fi

    if [ ! -f "${NGINX_CONF}" ]; then
        log_error "nginx config not found at ${NGINX_CONF}"
        exit 1
    fi

    if [ ! -f "${COMPOSE_FILE}" ]; then
        log_error "docker-compose file not found at ${COMPOSE_FILE}"
        exit 1
    fi
}

# Run
check_requirements
main "$@"