Class ActuatorClient

java.lang.Object

com.nmontytskyi.monitoring.server.polling.ActuatorClient

@Component
public class ActuatorClient
extends Object

HTTP client for retrieving monitoring data from Spring Boot Actuator endpoints.

Sends GET requests to /actuator/health (service availability and status) and /actuator/metrics (JVM CPU, heap, thread, and GC metrics) on behalf of MetricsPollingScheduler. Connection and read timeouts are configurable via PollingProperties.

Author:

Nazar Montytskyi

See Also:

• MetricsPollingScheduler
• PollingProperties

Constructor Summary

Constructors

Constructor	Description
ActuatorClient(PollingProperties properties)

Method Summary

Modifier and Type	Method	Description
Optional<HealthStatus>	fetchHealth(String actuatorUrl)
Optional<Double>	fetchMetricValue(String actuatorUrl, String metricName)
Optional<Double>	fetchMetricValue(String actuatorUrl, String metricName, String tag)	Fetches a metric filtered by a URL tag dimension (e.g.
Optional<Double>	fetchTimerStatistic(String actuatorUrl, String metricName, String statistic)	Fetches a Timer metric and returns the value of a specific statistic (COUNT, TOTAL_TIME, MAX).

Methods inherited from class java.lang.Object

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

Constructor Details

ActuatorClient

public ActuatorClient(PollingProperties properties)

Method Details

fetchHealth

public Optional<HealthStatus> fetchHealth(String actuatorUrl)

fetchMetricValue

public Optional<Double> fetchMetricValue(String actuatorUrl,
 String metricName)

fetchMetricValue

public Optional<Double> fetchMetricValue(String actuatorUrl,
 String metricName,
 String tag)

Fetches a metric filtered by a URL tag dimension (e.g. area:nonheap). Use this only for metrics where the tag is a real Micrometer tag key, not for timer statistics such as TOTAL_TIME / COUNT / MAX — use fetchTimerStatistic(java.lang.String, java.lang.String, java.lang.String) for those.

fetchTimerStatistic

public Optional<Double> fetchTimerStatistic(String actuatorUrl,
 String metricName,
 String statistic)

Fetches a Timer metric and returns the value of a specific statistic (COUNT, TOTAL_TIME, MAX). The statistic is a field inside the measurements array of the Actuator response — it is NOT a URL tag filter.

Returns Optional.empty() when the metric does not exist yet (e.g. no GC pauses have occurred) or when the requested statistic is absent.