Module: Rubino::Metrics

Defined in:
lib/rubino/metrics.rb

Overview

In-process Prometheus-style metrics registry.

Counters and histograms only — no gauges (process state is queried lazily by the /v1/health operation). The registry is a process-wide singleton; tests can call Metrics.reset! between examples to start clean.

Metrics.counter(:http_requests_total, method: "GET", status: 200).increment
Metrics.histogram(:http_request_duration_seconds, path: "/v1/runs").observe(0.034)

Output is the Prometheus text exposition format (see Renderer), served by API::Operations::MetricsOperation.

Defined Under Namespace

Modules: Renderer Classes: Counter, Histogram, Proxy

Constant Summary collapse

DEFAULT_BUCKETS =

Default histogram bucket boundaries (seconds). Tuned for sub-second HTTP request latencies — fine granularity below 100ms, coarser past 1s.

[0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5, 10].freeze

Class Method Summary collapse

Class Method Details

.counter(name, **labels) ⇒ Object

Fetch (or lazily create) the named Counter and bind ‘labels` for use via Proxy.



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# File 'lib/rubino/metrics.rb', line 78

def counter(name, **labels)
  registry[name] ||= Counter.new(name, descriptions.fetch(name, name.to_s))
  Proxy.new(registry[name], labels)
end

.describe(name, help) ⇒ Object

Set the HELP text for ‘name`; applied when the metric is first created.



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# File 'lib/rubino/metrics.rb', line 90

def describe(name, help)
  descriptions[name] = help
end

.each ⇒ Object

Yield each registered metric (Counter or Histogram).



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# File 'lib/rubino/metrics.rb', line 95

def each(&) = registry.each_value(&)

.histogram(name, **labels) ⇒ Object

Fetch (or lazily create) the named Histogram and bind ‘labels` for use via Proxy.



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# File 'lib/rubino/metrics.rb', line 84

def histogram(name, **labels)
  registry[name] ||= Histogram.new(name, descriptions.fetch(name, name.to_s))
  Proxy.new(registry[name], labels)
end

.render ⇒ Object

Serialize the full registry to Prometheus text exposition format.



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# File 'lib/rubino/metrics.rb', line 103

def render
  Renderer.call(registry.values)
end

.reset! ⇒ Object

Drop all registered metrics. Intended for tests.



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# File 'lib/rubino/metrics.rb', line 98

def reset!
  @registry = nil
end