Limen.Telemetry (limen v0.2.1)

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Telemetry events emitted by Limen.

Handlers run synchronously in the request process, so they must be cheap and must not block. Every event's metadata includes the :instance name. Attach heavier consumers to a sampled source instead, such as a Limen.DecisionLog.Sink.

Events

  • [:limen, :decision] - every evaluated request, in every mode.

    • Measurements: :duration (native time units), :score.
    • Metadata: :decision (a Limen.Decision), :conn.

  • [:limen, :challenge, :issued] - a challenge page was served.

    • Measurements: :difficulty.
    • Metadata: :identity.

  • [:limen, :challenge, :verified] - a challenge solution was checked.

    • Measurements: :count (always 1).
    • Metadata: :result (:ok or {:error, reason}), :method (:pow or :wait), :identity.

  • [:limen, :ban, :added] - a prefix was banned, or flagged for the maze.

    • Measurements: :ttl (seconds).
    • Metadata: :prefix, :reason, :origin (:policy, :admin, :trap or :remote), :action (:deny or :maze), :expires_at.

  • [:limen, :maze, :served] - a maze response ended.

    • Measurements: :duration (native time units), :bytes, :chunks.
    • Metadata: :result (:complete, :deadline when the rest was sent at once, or :closed when the client went away), :path, :identity.

  • [:limen, :maze, :refused] - a client sent to the maze got an immediate 429 instead.

    • Measurements: :count (always 1).
    • Metadata: :reason (:full beyond :max_concurrent, :admission when the :admit function turned it away), :path, :identity.

  • [:limen, :state, :saturated] - a capped table refused a new key; requests for it fall back to approximate state.

    • Measurements: :count (always 1).
    • Metadata: :table.

  • [:limen, :state, :rotated] - a time window moved to a new epoch.

    • Measurements: :cleared (entries dropped).
    • Metadata: :window, :epoch.

  • [:limen, :asn, :loaded] - IP-to-ASN data was loaded, see Limen.Signal.Asn.Loader.

    • Measurements: :duration (native time units, building included), :ranges, :bytes.
    • Metadata: :source ({:file, path}, {:url, url} or :rows).

  • [:limen, :asn, :checked] - the :url was checked for new data.

    • Measurements: :duration (native time units).
    • Metadata: :url, :result (:updated, :unchanged, :postponed or :error) and :reason (why it was postponed or failed, else nil).

  • [:limen, :fcrdns, :resolved] - a crawler verification finished, see Limen.Signal.Fcrdns.

    • Measurements: :duration (native time units).
    • Metadata: :ip, :crawler (the name it claimed), :result (:verified, :failed or :error for a transient DNS error), :host (the verified host, else nil) and :reason (why it failed, else nil).