OTLP push (optional)

The exporter's primary mode is on-demand: Prometheus scrapes /metrics?target=<bmc>. Optionally, an off-by-default background loop polls the configured hosts: on a fixed interval and pushes their metrics via OTLP.

collection:
  interval: 60s            # snapshot-loop cadence (default 60s when otlp.enabled)
otlp:
  enabled: false           # master switch — the loop runs only when true
  endpoint: "localhost:4317"
  protocol: grpc           # grpc | http
  insecure: false          # set true for a plaintext local collector
  interval: 0s             # OTLP push cadence; 0 = use collection.interval
  identity_label: system   # per-series target label (system | instance | ...)
  headers: {}              # optional static exporter headers

Every pushed series carries <identity_label>=<target> (the OTLP path has no Prometheus relabel to supply instance). A per-target idrac_up gauge reports 1 when the last cycle collected metrics and 0 when the target was unreachable or produced nothing. Host/credential changes hot-reload via SIGHUP; changing OTLP transport settings (endpoint/protocol/interval/enabled) requires a restart. Environment overrides: CONFIG_OTLP_ENABLED, CONFIG_OTLP_ENDPOINT, CONFIG_OTLP_PROTOCOL, CONFIG_OTLP_INSECURE, CONFIG_OTLP_INTERVAL, CONFIG_OTLP_IDENTITY_LABEL, CONFIG_COLLECTION_INTERVAL.