# Sub2API 单机版轻量告警规则
# 针对 2核4G 环境优化，避免告警风暴

groups:
  # ==================== 系统资源告警 ====================
  - name: system-alerts
    interval: 60s
    rules:
      - alert: HighCPUUsage
        expr: 100 - (avg by(instance) (irate(node_cpu_seconds_total{mode="idle"}[5m])) * 100) > 80
        for: 5m
        labels:
          severity: warning
          category: infrastructure
        annotations:
          summary: "CPU 使用率过高"
          description: "实例 {{ $labels.instance }} CPU 使用率超过 80%，当前值: {{ $value }}%"

      - alert: HighMemoryUsage
        expr: (node_memory_MemTotal_bytes - node_memory_MemAvailable_bytes) / node_memory_MemTotal_bytes * 100 > 85
        for: 5m
        labels:
          severity: warning
          category: infrastructure
        annotations:
          summary: "内存使用率过高"
          description: "实例 {{ $labels.instance }} 内存使用率超过 85%，当前值: {{ $value }}%"

      - alert: DiskSpaceLow
        expr: (node_filesystem_avail_bytes{mountpoint="/"} / node_filesystem_size_bytes{mountpoint="/"}) * 100 < 10
        for: 5m
        labels:
          severity: critical
          category: infrastructure
        annotations:
          summary: "磁盘空间不足"
          description: "实例 {{ $labels.instance }} 磁盘剩余空间不足 10%，当前值: {{ $value }}%"

      - alert: DiskWillFillIn24Hours
        expr: predict_linear(node_filesystem_avail_bytes{mountpoint="/"}[6h], 24*3600) < 0
        for: 1h
        labels:
          severity: warning
          category: infrastructure
        annotations:
          summary: "磁盘预计24小时内写满"
          description: "实例 {{ $labels.instance }} 按当前趋势，磁盘将在24小时内写满"

  # ==================== 应用健康告警 ====================
  - name: application-alerts
    interval: 30s
    rules:
      - alert: Sub2APIDown
        expr: up{job="sub2api-app"} == 0
        for: 1m
        labels:
          severity: critical
          category: availability
        annotations:
          summary: "Sub2API 服务不可用"
          description: "Sub2API 应用实例 {{ $labels.instance }} 已宕机超过 1 分钟"

      - alert: HighErrorRate
        expr: |
          (
            sum(rate(sub2api_http_requests_total{job="sub2api-app",status=~"5.."}[5m]))
            /
            sum(rate(sub2api_http_requests_total{job="sub2api-app"}[5m]))
          ) > 0.05
        for: 2m
        labels:
          severity: warning
          category: availability
        annotations:
          summary: "错误率过高"
          description: "API 错误率超过 5%，当前值: {{ $value | humanizePercentage }}"

      - alert: HighLatencyP99
        expr: histogram_quantile(0.99, sum(rate(sub2api_http_request_duration_seconds_bucket{job="sub2api-app"}[5m])) by (le)) > 5
        for: 3m
        labels:
          severity: warning
          category: performance
        annotations:
          summary: "P99 延迟过高"
          description: "API P99 延迟超过 5 秒，当前值: {{ $value }}s"

      - alert: HighLatencyP95
        expr: histogram_quantile(0.95, sum(rate(sub2api_http_request_duration_seconds_bucket{job="sub2api-app"}[5m])) by (le)) > 2
        for: 5m
        labels:
          severity: info
          category: performance
        annotations:
          summary: "P95 延迟升高"
          description: "API P95 延迟超过 2 秒，当前值: {{ $value }}s"

  # ==================== 数据库告警 ====================
  - name: database-alerts
    interval: 60s
    rules:
      - alert: DatabaseConnectionsHigh
        expr: |
          (
            sub2api_db_connections{state="active"} / sub2api_db_connections{state="max"}
          ) > 0.8
        for: 5m
        labels:
          severity: warning
          category: database
        annotations:
          summary: "数据库连接池使用率过高"
          description: "数据库连接池使用率超过 80%，当前值: {{ $value | humanizePercentage }}"

  # ==================== 业务指标告警 ====================
  - name: business-alerts
    interval: 60s
    rules:
      - alert: LowUpstreamSuccessRate
        expr: |
          (
            sum(rate(sub2api_upstream_requests_total{status="success"}[10m]))
            /
            sum(rate(sub2api_upstream_requests_total[10m]))
          ) < 0.95
        for: 5m
        labels:
          severity: warning
          category: business
        annotations:
          summary: "上游服务成功率下降"
          description: "上游服务成功率低于 95%，当前值: {{ $value | humanizePercentage }}"

      - alert: HighRateLimitHits
        expr: rate(sub2api_rate_limit_hits_total[5m]) > 10
        for: 5m
        labels:
          severity: info
          category: business
        annotations:
          summary: "限流触发频繁"
          description: "限流触发频率过高，当前: {{ $value }}/s"

  # ==================== Prometheus 自身监控告警 ====================
  - name: prometheus-alerts
    interval: 60s
    rules:
      - alert: PrometheusTargetMissing
        expr: up == 0
        for: 5m
        labels:
          severity: warning
          category: monitoring
        annotations:
          summary: "Prometheus 抓取目标丢失"
          description: "{{ $labels.job }} 实例 {{ $labels.instance }} 无法访问"

      - alert: PrometheusHighMemoryUsage
        expr: |
          (
            process_resident_memory_bytes{job="prometheus"} / 1024 / 1024
          ) > 100
        for: 5m
        labels:
          severity: warning
          category: monitoring
        annotations:
          summary: "Prometheus 内存使用过高"
          description: "Prometheus 内存使用超过 100MB，当前: {{ $value }}MB"

      - alert: PrometheusTSDBReloadsFailing
        expr: rate(prometheus_tsdb_reloads_failures_total[5m]) > 0
        for: 5m
        labels:
          severity: critical
          category: monitoring
        annotations:
          summary: "Prometheus TSDB 重载失败"
          description: "Prometheus 时序数据库重载失败，可能需要人工介入"

      - alert: PrometheusRuleEvaluationFailures
        expr: rate(prometheus_rule_evaluation_failures_total[5m]) > 0
        for: 5m
        labels:
          severity: warning
          category: monitoring
        annotations:
          summary: "Prometheus 规则评估失败"
          description: "告警规则评估失败，请检查规则配置"

      - alert: PrometheusDiskSpaceLow
        expr: |
          (
            prometheus_tsdb_storage_blocks_bytes / 1024 / 1024 / 1024
          ) > 1.8
        for: 5m
        labels:
          severity: critical
          category: monitoring
        annotations:
          summary: "Prometheus 磁盘空间不足"
          description: "Prometheus 数据占用超过 1.8GB，接近 2GB 限制"

  # ==================== 证书过期告警 ====================
  - name: certificate-alerts
    interval: 3600s  # 每小时检查一次
    rules:
      - alert: TLSCertificateExpiringSoon7Days
        expr: |
          (
            sub2api_tls_certificate_expiry_timestamp - time()
          ) / 86400 < 7
        for: 1h
        labels:
          severity: warning
          category: security
        annotations:
          summary: "TLS 证书即将过期 (7天内)"
          description: "{{ $labels.domain }} 证书将在 {{ $value | humanizeDuration }} 后过期"

      - alert: TLSCertificateExpiringSoon3Days
        expr: |
          (
            sub2api_tls_certificate_expiry_timestamp - time()
          ) / 86400 < 3
        for: 1h
        labels:
          severity: critical
          category: security
        annotations:
          summary: "TLS 证书即将过期 (3天内)"
          description: "{{ $labels.domain }} 证书将在 {{ $value | humanizeDuration }} 后过期，请立即续期"

      - alert: TLSCertificateExpired
        expr: sub2api_tls_certificate_expiry_timestamp - time() < 0
        for: 1m
        labels:
          severity: critical
          category: security
        annotations:
          summary: "TLS 证书已过期"
          description: "{{ $labels.domain }} 证书已过期，服务可能无法正常访问"

  # ==================== 备份任务告警 ====================
  - name: backup-alerts
    interval: 3600s  # 每小时检查一次
    rules:
      - alert: DatabaseBackupFailed
        expr: |
          time() - sub2api_job_heartbeat_last_success_timestamp{job_name="database_backup"} > 90000
        for: 1h
        labels:
          severity: warning
          category: backup
        annotations:
          summary: "数据库备份失败"
          description: "数据库备份已超过 25 小时未成功执行"

      - alert: DatabaseBackupMissing
        expr: absent(sub2api_job_heartbeat_last_success_timestamp{job_name="database_backup"})
        for: 1h
        labels:
          severity: info
          category: backup
        annotations:
          summary: "数据库备份监控未配置"
          description: "未检测到数据库备份心跳指标，请检查备份脚本是否上报"

      - alert: GrafanaConfigBackupFailed
        expr: |
          time() - sub2api_job_heartbeat_last_success_timestamp{job_name="grafana_backup"} > 172800
        for: 1h
        labels:
          severity: info
          category: backup
        annotations:
          summary: "Grafana 配置备份失败"
          description: "Grafana 配置备份已超过 48 小时未成功执行"

  # ==================== SLO 基础告警 (简化版) ====================
  - name: slo-alerts
    interval: 60s
    rules:
      # 可用性 SLO: 99.9% (30天窗口)
      # 快速燃烧率: 2% 错误预算在1小时内消耗完
      - alert: SLOErrorBudgetBurnRateFast
        expr: |
          (
            sum(rate(sub2api_http_requests_total{job="sub2api-app",status=~"5.."}[1h]))
            /
            sum(rate(sub2api_http_requests_total{job="sub2api-app"}[1h]))
          ) > 0.0144 * 14.4
        for: 5m
        labels:
          severity: critical
          category: slo
          slo: availability
        annotations:
          summary: "SLO 错误预算快速燃烧"
          description: "可用性错误预算正在快速消耗，可能在1小时内耗尽"

      # 慢速燃烧率: 5% 错误预算在6小时内消耗完
      - alert: SLOErrorBudgetBurnRateSlow
        expr: |
          (
            sum(rate(sub2api_http_requests_total{job="sub2api-app",status=~"5.."}[6h]))
            /
            sum(rate(sub2api_http_requests_total{job="sub2api-app"}[6h]))
          ) > 0.0144 * 6
        for: 30m
        labels:
          severity: warning
          category: slo
          slo: availability
        annotations:
          summary: "SLO 错误预算慢速燃烧"
          description: "可用性错误预算正在持续消耗，可能在6小时内耗尽"

  # ==================== Prometheus 自身监控 ====================
  - name: prometheus-self-monitoring
    interval: 60s
    rules:
      # 采集目标下线
      - alert: PrometheusTargetMissing
        expr: up == 0
        for: 3m
        labels:
          severity: critical
          category: monitoring
        annotations:
          summary: "监控采集目标下线"
          description: "目标 {{ $labels.job }}/{{ $labels.instance }} 已无法采集超过 3 分钟"

      # 采集耗时过长 (可能影响数据精度)
      - alert: PrometheusScrapeDurationHigh
        expr: scrape_duration_seconds > 10
        for: 5m
        labels:
          severity: warning
          category: monitoring
        annotations:
          summary: "Prometheus 采集耗时过长"
          description: "目标 {{ $labels.job }} 采集耗时 {{ $value }}s，超过 10s"

      # TSDB 重载失败
      - alert: PrometheusTSDBReloadFailing
        expr: increase(prometheus_tsdb_reloads_failures_total[1h]) > 0
        for: 0m
        labels:
          severity: critical
          category: monitoring
        annotations:
          summary: "Prometheus TSDB 重载失败"
          description: "过去 1 小时内 TSDB 重载出现失败，可能影响数据持久化"

      # WAL 截断失败
      - alert: PrometheusWALCorruption
        expr: increase(prometheus_tsdb_wal_corruptions_total[5m]) > 0
        for: 0m
        labels:
          severity: critical
          category: monitoring
        annotations:
          summary: "Prometheus WAL 损坏"
          description: "Prometheus WAL 出现损坏，请立即检查数据完整性"

      # 告警规则评估失败
      - alert: PrometheusRuleEvaluationFailing
        expr: increase(prometheus_rule_evaluation_failures_total[5m]) > 0
        for: 5m
        labels:
          severity: warning
          category: monitoring
        annotations:
          summary: "告警规则评估失败"
          description: "Prometheus 有告警规则评估失败，可能导致漏报"

      # Prometheus 存储接近容量上限
      - alert: PrometheusStorageFull
        expr: |
          (prometheus_tsdb_storage_blocks_bytes / 1024 / 1024 / 1024) > 1.8
        for: 10m
        labels:
          severity: warning
          category: monitoring
        annotations:
          summary: "Prometheus 存储接近上限"
          description: "Prometheus 存储已用 {{ $value | humanize }}GB，接近 2GB 上限，请及时清理"

  # ==================== 证书过期告警 ====================
  - name: certificate-alerts
    interval: 300s   # 5分钟检查一次，不需要高频
    rules:
      # 证书 7 天内过期
      - alert: TLSCertificateExpiringSoon
        expr: (probe_ssl_earliest_cert_expiry - time()) / 86400 < 7
        for: 1h
        labels:
          severity: warning
          category: security
        annotations:
          summary: "TLS 证书即将过期"
          description: "{{ $labels.instance }} 的证书将在 {{ $value | humanizeDuration }} 后过期，请及时续期"

      # 证书 3 天内过期 - 提升为 critical
      - alert: TLSCertificateExpiringCritical
        expr: (probe_ssl_earliest_cert_expiry - time()) / 86400 < 3
        for: 0m
        labels:
          severity: critical
          category: security
        annotations:
          summary: "TLS 证书紧急过期警告"
          description: "{{ $labels.instance }} 的证书将在 {{ $value | humanizeDuration }} 后过期！"

      # 证书已过期
      - alert: TLSCertificateExpired
        expr: probe_ssl_earliest_cert_expiry - time() <= 0
        for: 0m
        labels:
          severity: critical
          category: security
        annotations:
          summary: "TLS 证书已过期！"
          description: "{{ $labels.instance }} 的 TLS 证书已过期，请立即续期"

  # ==================== 备份与定时任务监控 ====================
  - name: backup-and-job-alerts
    interval: 300s
    rules:
      # 数据库备份超过 25 小时未成功 (允许 1 小时误差)
      - alert: DatabaseBackupMissing
        expr: time() - sub2api_job_heartbeat_last_success_timestamp{job_name="db-backup"} > 90000
        for: 0m
        labels:
          severity: warning
          category: backup
        annotations:
          summary: "数据库备份超时未完成"
          description: "距上次成功备份已超过 25 小时，请检查备份任务"

      # 数据库备份超过 49 小时 - 严重
      - alert: DatabaseBackupCriticallyMissing
        expr: time() - sub2api_job_heartbeat_last_success_timestamp{job_name="db-backup"} > 176400
        for: 0m
        labels:
          severity: critical
          category: backup
        annotations:
          summary: "数据库备份连续 2 天未完成！"
          description: "距上次成功备份已超过 49 小时，存在数据丢失风险"

      # OpsMetricsCollector 定时任务停止心跳
      - alert: OpsCollectorJobStale
        expr: time() - sub2api_job_heartbeat_last_success_timestamp{job_name="ops-collector"} > 180
        for: 5m
        labels:
          severity: warning
          category: monitoring
        annotations:
          summary: "OpsMetricsCollector 心跳超时"
          description: "OpsMetricsCollector 定时任务已超过 3 分钟未上报心跳，可能已停止"