Package org.apache.juneau.rest.server.metrics.micrometer

Class MetricsManager

java.lang.Object

org.apache.juneau.rest.server.metrics.micrometer.MetricsManager

public class MetricsManager
extends Object

Shared worker for the /metrics management endpoint: resolves a consumer-provided Micrometer MeterRegistry from the host bean store and renders a scrape payload.

Consistent with micrometer-core being a provided dependency and Juneau's explicit-over-magic stance, this adapter strictly consumes a consumer-provided registry — it never auto-registers a default. When no MeterRegistry bean is present it degrades cleanly (returns null, which the endpoints surface as HTTP 501).

A Prometheus text scrape is produced when the resolved registry is a PrometheusMeterRegistry. That type lives in the separate micrometer-registry-prometheus artifact which this module does not depend on, so its scrape() method is invoked reflectively — keeping the registry choice entirely the consumer's, with no extra dependency leaked here.

See Also:

• MicrometerMetricsRecorder
• Management Surface (Actuator-style endpoints)

Since:

10.0.0

Constructor Summary

Constructors

Constructor	Description
MetricsManager()

Method Summary

Modifier and Type	Method	Description
io.micrometer.core.instrument.MeterRegistry	resolveRegistry(RestContext context)	Resolves the consumer-provided MeterRegistry from the host context's bean store.
String	scrape(io.micrometer.core.instrument.MeterRegistry registry)	Renders a Prometheus text scrape from the registry, if it is a PrometheusMeterRegistry.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

MetricsManager

public MetricsManager()

Method Details

resolveRegistry

public io.micrometer.core.instrument.MeterRegistry resolveRegistry(RestContext context)

Resolves the consumer-provided MeterRegistry from the host context's bean store.

Parameters:

context - The REST context whose bean store is searched. May be null.

Returns:

The registry, or null if none is registered (or the context is null).

scrape

public String scrape(io.micrometer.core.instrument.MeterRegistry registry)

Renders a Prometheus text scrape from the registry, if it is a PrometheusMeterRegistry.

Invoked reflectively to avoid a hard dependency on micrometer-registry-prometheus. Returns null when the registry is null, is not a Prometheus registry, or does not expose a no-arg scrape() method — the endpoints surface that as HTTP 501.

Parameters:

registry - The resolved registry, or null.

Returns:

The Prometheus exposition text, or null if no scrape is available.