grafana-agent: honor prometheus.io/port and prometheus.io/path#42
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The flow-mode relabel kept scrape=true pods but ignored the port/path annotations, so an annotated pod was scraped only on its discovered container port at /metrics. Adds the two canonical relabel rules: prometheus.io/path overrides __metrics_path__, and prometheus.io/port rewrites __address__ to the pod IP plus the annotated port. Both are no-ops for pods without the annotations (the port rule's regex requires a port digit), so existing scrape targets are unaffected. Lets a workload publish metrics on a non-default port — e.g. the portal worker on its 8081 health port.
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The
discovery.relabel "pods"block keeps pods annotatedprometheus.io/scrape=trueand stamps namespace/pod/container labels, but never readprometheus.io/portorprometheus.io/path. So an annotated workload was scraped on whatever container port discovery found, at the default/metrics— a pod publishing metrics on a non-default port (e.g. portal's worker on:8081) was scraped on the wrong port or missed.Adds two River rules in the same relabel block:
prometheus.io/path→__metrics_path__(regex(.+), default replace).[__address__, prometheus.io/port]→__address__rewrite (([^:]+)(?::\d+)?;(\d+)→$1:$2), host:discovered-port → host:annotated-port.Both are no-ops when the annotation is absent (the port regex requires a trailing digit; the path regex requires a value), so existing scrape targets are unaffected. Wire-compatible with Grafana Alloy's
discovery.relabelif/when this addon migrates off Flow mode.Validation: statically verified — correct River/Flow dialect (chart grafana-agent 0.44.2,
agent.mode: flow), regex semantics and no-op safety confirmed, and the rules match portal's server (:8080) and worker (:8081) pod annotations. yamllint clean. Not yet exercised against a live scrape; that confirms on the next cluster run.