# Topology-driven metrics example
# Demonstrates all four OTel instrument types at both service and operation level.
# Run with:
#   motel run --signals traces,metrics --duration 30s docs/examples/topology-driven-metrics.yaml

version: 1

services:
  gateway:
    metrics:
      # Span-derived histogram: records each request's duration in seconds
      - name: http.server.request.duration
        type: histogram
        unit: s
      # Span-derived updowncounter: tracks in-flight requests (requires --realtime for meaningful values)
      - name: http.server.active_requests
        type: updowncounter
        unit: "{request}"
      # Topology-defined gauge: sampled on each collection cycle, independent of spans
      - name: gateway.cpu.utilisation
        type: gauge
        value: 0.40 +/- 0.08
    operations:
      GET /api:
        duration: 40ms +/- 10ms
        error_rate: 0.5%
        metrics:
          # Operation-level metric: only fires for this operation
          - name: gateway.cache.hit_ratio
            type: gauge
            value: 0.75 +/- 0.05
        calls:
          - backend.process

  backend:
    metrics:
      # Span-derived counter: +1 per completed span
      - name: backend.requests.total
        type: counter
      # Topology-defined counter: sampled bytes-per-request added on each span
      - name: backend.response.bytes
        type: counter
        unit: "By"
        value: 4096 +/- 512
    operations:
      process:
        duration: 20ms +/- 5ms
        error_rate: 0.2%

traffic:
  rate: 50/s