# =============================================================================
# Sub2API 告警规则
# =============================================================================

groups:
  # ===========================================================================
  # SLO 相关告警 - 基于错误预算燃烧率
  # ===========================================================================
  - name: slo_alerts
    interval: 30s
    rules:
      # 错误预算快速燃烧 (Critical) - 2% 预算在1小时内耗尽
      - alert: ErrorBudgetBurnRateCritical
        expr: |
          (
            sum(rate(sub2api_http_requests_total{status=~"5.."}[5m]))
            /
            sum(rate(sub2api_http_requests_total[5m]))
          ) > 0.0005 * 14.4
        for: 2m
        labels:
          severity: critical
          slo: api-availability
          team: sre
        annotations:
          summary: "错误预算快速燃烧 (Critical)"
          description: "过去5分钟错误率是30天预算的 {{ $value | humanizePercentage }}，预计1小时内耗尽2%错误预算"
          runbook_url: "https://wiki.internal/runbooks/error-budget-burn"
          dashboard: "http://localhost:3000/d/slo-dashboard"

      # 错误预算燃烧加速 (Warning) - 5% 预算在6小时内耗尽
      - alert: ErrorBudgetBurnRateWarning
        expr: |
          (
            sum(rate(sub2api_http_requests_total{status=~"5.."}[30m]))
            /
            sum(rate(sub2api_http_requests_total[30m]))
          ) > 0.0005 * 6
        for: 5m
        labels:
          severity: high
          slo: api-availability
          team: sre
        annotations:
          summary: "错误预算燃烧加速 (Warning)"
          description: "过去30分钟错误率是30天预算的 {{ $value | humanizePercentage }}"
          runbook_url: "https://wiki.internal/runbooks/error-budget-burn"

      # SLO 即将违约告警
      - alert: SLOViolationImminent
        expr: |
          (
            1 - (
              sum(rate(sub2api_http_requests_total{status=~"5.."}[24h]))
              /
              sum(rate(sub2api_http_requests_total[24h]))
            )
          ) < 0.9995
        for: 5m
        labels:
          severity: high
          slo: api-availability
        annotations:
          summary: "SLO 即将违约"
          description: "过去24小时可用性为 {{ $value | humanizePercentage }}，低于目标 99.95%"

  # ===========================================================================
  # 延迟告警
  # ===========================================================================
  - name: latency_alerts
    rules:
      - alert: HighLatencyP99
        expr: |
          histogram_quantile(0.99, 
            sum(rate(sub2api_http_request_duration_seconds_bucket[5m])) by (le)
          ) > 5
        for: 5m
        labels:
          severity: high
        annotations:
          summary: "P99 延迟过高"
          description: "P99 延迟: {{ $value }}s，超过阈值 5s"

      - alert: HighLatencyP95
        expr: |
          histogram_quantile(0.95, 
            sum(rate(sub2api_http_request_duration_seconds_bucket[5m])) by (le)
          ) > 2
        for: 10m
        labels:
          severity: medium
        annotations:
          summary: "P95 延迟过高"
          description: "P95 延迟: {{ $value }}s，超过阈值 2s"

      - alert: HighTTFT
        expr: |
          histogram_quantile(0.99,
            sum(rate(sub2api_gateway_ttft_seconds_bucket[5m])) by (le)
          ) > 3
        for: 5m
        labels:
          severity: high
        annotations:
          summary: "首 Token 延迟过高"
          description: "TTFT P99: {{ $value }}s，超过阈值 3s"

  # ===========================================================================
  # 错误率告警
  # ===========================================================================
  - name: error_alerts
    rules:
      - alert: HighErrorRate
        expr: |
          sum(rate(sub2api_http_requests_total{status=~"5.."}[5m]))
          /
          sum(rate(sub2api_http_requests_total[5m])) > 0.05
        for: 2m
        labels:
          severity: critical
        annotations:
          summary: "错误率过高 (Critical)"
          description: "错误率: {{ $value | humanizePercentage }}，超过 5%"

      - alert: ElevatedErrorRate
        expr: |
          sum(rate(sub2api_http_requests_total{status=~"5.."}[5m]))
          /
          sum(rate(sub2api_http_requests_total[5m])) > 0.01
        for: 5m
        labels:
          severity: medium
        annotations:
          summary: "错误率升高"
          description: "错误率: {{ $value | humanizePercentage }}，超过 1%"

      - alert: UpstreamErrorRateHigh
        expr: |
          sum(rate(sub2api_gateway_upstream_errors_total[5m]))
          /
          sum(rate(sub2api_gateway_requests_total[5m])) > 0.1
        for: 5m
        labels:
          severity: high
        annotations:
          summary: "上游错误率过高"
          description: "上游错误率: {{ $value | humanizePercentage }}"

  # ===========================================================================
  # 基础设施告警
  # ===========================================================================
  - name: infrastructure_alerts
    rules:
      - alert: DatabaseConnectionsHigh
        expr: |
          sub2api_db_connections{state="active"} / sub2api_db_connections{state="max"} > 0.8
        for: 5m
        labels:
          severity: high
        annotations:
          summary: "数据库连接池使用率过高"
          description: "数据库连接池使用率: {{ $value | humanizePercentage }}"

      - alert: RedisMemoryHigh
        expr: |
          redis_memory_used_bytes / redis_memory_max_bytes > 0.9
        for: 5m
        labels:
          severity: critical
        annotations:
          summary: "Redis 内存使用率过高"
          description: "Redis 内存使用率: {{ $value | humanizePercentage }}"

      - alert: HighCPUUsage
        expr: |
          100 - (avg by (instance) (irate(node_cpu_seconds_total{mode="idle"}[5m])) * 100) > 80
        for: 10m
        labels:
          severity: medium
        annotations:
          summary: "CPU 使用率过高"
          description: "实例 {{ $labels.instance }} CPU 使用率: {{ $value }}%"

      - alert: HighMemoryUsage
        expr: |
          (node_memory_MemTotal_bytes - node_memory_MemAvailable_bytes) / node_memory_MemTotal_bytes > 0.85
        for: 5m
        labels:
          severity: high
        annotations:
          summary: "内存使用率过高"
          description: "实例 {{ $labels.instance }} 内存使用率: {{ $value | humanizePercentage }}"

      - alert: DiskSpaceLow
        expr: |
          (node_filesystem_avail_bytes{mountpoint="/"} / node_filesystem_size_bytes{mountpoint="/"}) < 0.15
        for: 5m
        labels:
          severity: high
        annotations:
          summary: "磁盘空间不足"
          description: "实例 {{ $labels.instance }} 磁盘剩余空间: {{ $value | humanizePercentage }}"

  # ===========================================================================
  # 业务告警
  # ===========================================================================
  - name: business_alerts
    rules:
      - alert: LowQPS
        expr: |
          sum(rate(sub2api_http_requests_total[5m])) < 1
        for: 10m
        labels:
          severity: medium
        annotations:
          summary: "请求量异常低"
          description: "当前 QPS: {{ $value }}，可能存在流量异常"

      - alert: AccountSwitchRateHigh
        expr: |
          sum(rate(sub2api_account_switches_total[5m])) > 10
        for: 5m
        labels:
          severity: warning
        annotations:
          summary: "账号切换频率过高"
          description: "账号切换率: {{ $value }}/s，可能存在上游不稳定"

      - alert: JobHeartbeatStale
        expr: |
          time() - sub2api_job_heartbeat_last_success_timestamp > 300
        for: 2m
        labels:
          severity: high
        annotations:
          summary: "后台任务心跳超时"
          description: "任务 {{ $labels.job_name }} 超过5分钟未报告成功"