# OpenTelemetry Collector. Mounted read-only by the root docker-compose.yml.
# Development defaults: no auth, no TLS.
#
# The gateway exports OTLP/HTTP spans here when OTEL_EXPORTER_OTLP_ENDPOINT is
# set. The traces pipeline fans out three ways, each independent - Tempo being
# down cannot stop metrics:
#
#   gateway --OTLP--> otlp receiver --+--> otlp/tempo   --> Tempo (storage)
#                                     +--> spanmetrics  --> :8889 --> Prometheus
#                                     \--> debug        --> stdout

receivers:
  otlp:
    protocols:
      http:
        endpoint: 0.0.0.0:4318
      grpc:
        endpoint: 0.0.0.0:4317

connectors:
  # Spans in, RED metrics out: traces_span_metrics_calls_total (rate + errors
  # via status_code) and _duration_milliseconds (latency).
  spanmetrics:
    namespace: traces.span.metrics
    histogram:
      explicit:
        buckets: [5ms, 25ms, 100ms, 250ms, 500ms, 1s, 2s, 5s, 10s, 30s, 60s, 120s]
    # Every dimension multiplies the series count, so only bounded attributes
    # are listed. gen_ai.request.model / gen_ai.response.model are deliberately
    # ABSENT - they stay on the span for Tempo but are unbounded. The gateway
    # supplies frosty.metrics.model as their bounded twin, capped at
    # FROSTY_OTEL_MODEL_CARDINALITY_CAP distinct values (see decision-log 53).
    dimensions:
      - name: gen_ai.provider.name
      - name: frosty.metrics.model
      - name: gen_ai.response.finish_reason
      - name: gen_ai.stream
    exemplars:
      enabled: false
    # Divides the 15s scrape interval, so a scrape never reads a half-updated
    # series. Expiration stops a dead series being exported forever.
    metrics_flush_interval: 15s
    metrics_expiration: 30m

processors:
  batch: {}

exporters:
  otlp/tempo:
    endpoint: tempo-distributor:4317
    tls:
      insecure: true

  # Scraped as job `otel-spanmetrics`. Resource attributes are not converted to
  # labels wholesale, to keep cardinality bounded.
  prometheus:
    endpoint: 0.0.0.0:8889
    send_timestamps: true
    metric_expiration: 30m
    resource_to_telemetry_conversion:
      enabled: false

  # `docker compose logs -f otel-collector`. Raise to `detailed` to see attributes.
  debug:
    verbosity: normal

service:
  telemetry:
    metrics:
      # `address` defaults to :8888 and applies IN ADDITION to `readers`, which
      # double-binds the port and crash-loops the collector. Blanking it makes
      # `readers` authoritative and silences the deprecation warning.
      address: ""
      readers:
        - pull:
            exporter:
              prometheus:
                host: 0.0.0.0
                port: 8888
  pipelines:
    traces:
      receivers: [otlp]
      processors: [batch]
      exporters: [otlp/tempo, spanmetrics, debug]
    metrics/spanmetrics:
      receivers: [spanmetrics]
      processors: [batch]
      exporters: [prometheus]