I have a Spring boot application with Prometheus Pushgateway using Micrometer, mainly based on this tutorial: https://luramarchanjo.tech/2020/01/05/spring-boot-2.2-and-prometheus-pushgateway-with-micrometer.html

pom.xml has following related dependencies:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
    <groupId>io.micrometer</groupId>
    <artifactId>micrometer-core</artifactId>
</dependency>
<dependency>
    <groupId>io.micrometer</groupId>
    <artifactId>micrometer-registry-prometheus</artifactId>
</dependency>
<dependency>
    <groupId>io.prometheus</groupId>
    <artifactId>simpleclient_pushgateway</artifactId>
    <version>0.16.0</version>
</dependency>

And application.properties file has:

management.metrics.export.prometheus.pushgateway.enabled=true
management.metrics.export.prometheus.pushgateway.shutdown-operation=PUSH
management.metrics.export.prometheus.pushgateway.baseUrl=localhost:9091

This works fine if I leave the application running however with my particular Spring boot application, sometimes it looses the metrics sent just before the shutdown.

I can view the following logs which indicates the PrometheusPushGatewayManager is successfully calling the shutdown() method before the application shuts down which has configured with PUSH operation in the application.properties file as above:

level":"INFO","message":"Shutting down ExecutorService","file":"ExecutorConfigurationSupport.java","line_number":"208","thread_name":"Thread-1","@version":1,"logger_name":"org.springframework.boot.actuate.metrics.export.prometheus.PrometheusPushGatewayManager$PushGatewayTaskScheduler","class":"org.springframework.scheduling.concurrent.ExecutorConfigurationSupport"

I have tried to invoke the shutdown() method on PrometheusPushGatewayManager from my application code but still having the same issue where metrics are not appearing consistently in the Pushgateway/Prometheus (randomly).