OTLP metrics

# Stream loadr's live metrics into an OpenTelemetry collector, driven by the
# `loadr-plugin-otlp-metrics` native OUTPUT plugin.
#
# An output plugin follows the same start / on_snapshot / finish lifecycle as
# the built-in exporters: loadr calls `start(config)` once, hands the plugin a
# metric snapshot roughly once a second during the run, then `finish(summary)`
# at the end. This plugin converts each snapshot's series into an OTLP
# `ExportMetricsServiceRequest` and POSTs it to the collector's `/v1/metrics`
# endpoint over OTLP/HTTP. The body is protobuf by default (or JSON via
# `encoding: json`); the transport is pure hyper + hyper-rustls, so nothing
# beyond outbound HTTP(S) to the collector is required.
#
# Counters (e.g. `http_reqs`) become monotonic OTLP Sums; gauges (e.g. `vus`)
# and rates (e.g. `checks`) become Gauges; trends (e.g. `http_req_duration`)
# emit one gauge per published quantile — `http_req_duration.p95`, `.p99`,
# `.avg`, `.max`. Every data point carries the run's `run_id` plus the series'
# tags as attributes so concurrent runs stay separable in a shared backend.
#
# Build + install the plugin, then run:
#   cargo build -p loadr-plugin-otlp-metrics --release
#   mkdir -p dist && cp plugins/loadr-plugin-otlp-metrics/plugin.toml dist/ \
#     && cp target/release/libloadr_plugin_otlp_metrics.so dist/
#   loadr plugin install dist
#   OTLP_ENDPOINT=http://localhost:4318 loadr run examples/plugins/otlp-metrics.yaml
name: otlp-export
description: Export live loadr metrics to an OpenTelemetry collector over OTLP/HTTP

defaults:
  http:
    base_url: https://api.example.com

scenarios:
  browse:
    executor: ramping-vus
    stages:
      - { target: 20, duration: 30s }
      - { target: 20, duration: 2m }
      - { target: 0, duration: 30s }
    flow:
      - request: { name: list, url: /api/v1/items }
      - request:
          name: detail
          url: /api/v1/items/1
          checks: [ { type: status, equals: 200 } ]

outputs:
  # Resolve `otlp-metrics` by name from the plugins dir (after `loadr plugin install`).
  - type: plugin
    name: otlp-metrics
    config:
      # Required. Base URL of the OTLP/HTTP collector — point at the 4318 port,
      # NOT the 4317 gRPC port. The plugin appends `/v1/metrics`. Supplied per
      # run from the environment so it stays out of the plan file.
      endpoint: ${env.OTLP_ENDPOINT}
      # Wire encoding: `protobuf` (default, application/x-protobuf) or `json`.
      encoding: protobuf
      # `service.name` resource attribute on every exported metric.
      service_name: checkout
      # Extra OTLP resource attributes attached to every metric.
      resource_attributes:
        deployment.environment: staging
      # Extra HTTP headers — typically an auth header for a hosted collector.
      # Set from the environment, never hard-coded.
      headers:
        Authorization: Bearer ${env.OTLP_TOKEN}
      # Per-request timeout and 5xx retry budget (exponential backoff).
      timeout_ms: 10000
      max_retries: 3

thresholds:
  http_req_failed: [ "rate<0.02" ]
  http_req_duration: [ "p(95)<600" ]