apiVersion: monitoring.coreos.com/v1
kind: PrometheusRule
metadata:
  name: api-company-slo-alerts
  namespace: monitoring
  labels:
    # Must match kube-prometheus-stack's ruleSelector (release label is standard)
    app: kube-prometheus-stack
    release: kube-prometheus-stack
spec:
  groups:
    - name: api-company.slo
      interval: 1m
      rules:
        # -------------------------------------------------------------------
        # APIHighErrorRate — warning: >5% 5xx over 5 min
        # -------------------------------------------------------------------
        - alert: APIHighErrorRate
          expr: |
            (
              sum by (job) (rate(api_requests_total{status=~"5..", job=~"zip|holidays|air-quality"}[5m]))
              /
              sum by (job) (rate(api_requests_total{job=~"zip|holidays|air-quality"}[5m]))
            ) > 0.05
          for: 5m
          labels:
            severity: warning
            team: api-company
          annotations:
            summary: "High 5xx error rate on {{ $labels.job }}"
            description: "{{ $labels.job }} 5xx error rate is {{ $value | humanizePercentage }} over the last 5 minutes (threshold: 5%)."

        # -------------------------------------------------------------------
        # APIHighErrorRate — critical: >20% 5xx over 5 min
        # -------------------------------------------------------------------
        - alert: APIHighErrorRate
          expr: |
            (
              sum by (job) (rate(api_requests_total{status=~"5..", job=~"zip|holidays|air-quality"}[5m]))
              /
              sum by (job) (rate(api_requests_total{job=~"zip|holidays|air-quality"}[5m]))
            ) > 0.20
          for: 5m
          labels:
            severity: critical
            team: api-company
          annotations:
            summary: "Critical 5xx error rate on {{ $labels.job }}"
            description: "{{ $labels.job }} 5xx error rate is {{ $value | humanizePercentage }} over the last 5 minutes (threshold: 20%)."

        # -------------------------------------------------------------------
        # APIHighLatency — P95 > 2 s over 5 min
        # -------------------------------------------------------------------
        - alert: APIHighLatency
          expr: |
            histogram_quantile(
              0.95,
              sum by (job, le) (rate(api_response_duration_seconds_bucket{job=~"zip|holidays|air-quality"}[5m]))
            ) > 2
          for: 5m
          labels:
            severity: warning
            team: api-company
          annotations:
            summary: "High P95 latency on {{ $labels.job }}"
            description: "{{ $labels.job }} P95 response time is {{ $value | humanizeDuration }} (threshold: 2s)."

        # -------------------------------------------------------------------
        # APIDataStale — data freshness > 30 days
        # -------------------------------------------------------------------
        - alert: APIDataStale
          expr: |
            api_data_freshness_seconds{job=~"zip|holidays|air-quality"} > 2592000
          for: 5m
          labels:
            severity: warning
            team: api-company
          annotations:
            summary: "Stale dataset on {{ $labels.job }} ({{ $labels.dataset }})"
            description: "{{ $labels.job }} dataset '{{ $labels.dataset }}' has not been re-seeded in {{ $value | humanizeDuration }} (threshold: 30 days). Re-seed required."

        # -------------------------------------------------------------------
        # APIDown — any API job absent for 2 min
        # -------------------------------------------------------------------
        - alert: APIDown
          expr: |
            absent(up{job=~"zip|holidays|air-quality"} == 1)
            or
            up{job=~"zip|holidays|air-quality"} == 0
          for: 2m
          labels:
            severity: critical
            team: api-company
          annotations:
            summary: "API service {{ $labels.job }} is down"
            description: "Prometheus target {{ $labels.job }} has been unreachable for more than 2 minutes."