#!/usr/bin/env bash
# 不自动运行：单机 Docker Compose 部署脚本示例——拉取指定版本、健康检查、失败自动回滚
# 用法：IMAGE_TAG=<提交哈希> ./deploy.sh
# 约定：compose.yaml 里 api 服务的镜像写成 image: registry.example.com/app/api:${IMAGE_TAG}
set -euo pipefail

: "${IMAGE_TAG:?需要指定 IMAGE_TAG}"
HEALTH_URL="${HEALTH_URL:-http://127.0.0.1:8080/healthz}"
STATE_FILE="${STATE_FILE:-.deployed_tag}"
previous="$(cat "$STATE_FILE" 2>/dev/null || true)"

deploy() {
  local tag="$1"
  echo "部署版本 $tag"
  IMAGE_TAG="$tag" docker compose pull api
  IMAGE_TAG="$tag" docker compose up -d --no-deps api
}

healthy() {
  for _ in $(seq 1 30); do
    if curl -fsS --max-time 2 "$HEALTH_URL" >/dev/null; then
      return 0
    fi
    sleep 2
  done
  return 1
}

deploy "$IMAGE_TAG"
if healthy; then
  echo "$IMAGE_TAG" > "$STATE_FILE"
  echo "部署成功：$IMAGE_TAG"
else
  echo "健康检查失败" >&2
  if [[ -n "$previous" ]]; then
    echo "回滚到 $previous" >&2
    deploy "$previous"
    healthy && echo "已回滚到 $previous" >&2
  fi
  exit 1
fi