Why is CamelExchangesFailed_total metrics not increased? - apache-camel

Question

I have a Apache Camel application which is monitored by Prometheus. Therefore, I added Micrometer to my POM (see Spring Boot Auto-Configuration) and MicrometerRoutePolicyFactory to my application (see Using Micrometer Route Policy Factory). But the metric CamelExchangesFailed_total doesn't change, althought a route failed.
Source
#SpringBootApplication
public class TestApplication {
public static void main(String[] args) {
SpringApplication.run(TestApplication.class, args);
}
#Bean
public MicrometerRoutePolicyFactory micrometerRoutePolicyFactory() {
return new MicrometerRoutePolicyFactory();
}
#Bean
public EndpointRouteBuilder route() {
return new EndpointRouteBuilder() {
#Override
public void configure() throws Exception {
errorHandler(deadLetterChannel("log:dead"));
from(timer("testTimer").repeatCount(1)).throwException(new RuntimeException());
}
};
}
}
Logs
INFO 5060 --- [ restartedMain] o.a.c.i.e.InternalRouteStartupManager : Route: route1 started and consuming from: timer://testTimer
INFO 5060 --- [ restartedMain] o.a.c.impl.engine.AbstractCamelContext : Total 1 routes, of which 1 are started
INFO 5060 --- [ restartedMain] o.a.c.impl.engine.AbstractCamelContext : Apache Camel 3.5.0 (camel-1) started in 0.007 seconds
INFO 5060 --- [ restartedMain] test.TestApplication : Started TestApplication in 6.626 seconds (JVM running for 7.503)
INFO 5060 --- [on(3)-127.0.0.1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'
INFO 5060 --- [on(3)-127.0.0.1] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
INFO 5060 --- [on(3)-127.0.0.1] o.s.web.servlet.DispatcherServlet : Completed initialization in 5 ms
INFO 5060 --- [mer://testTimer] dead : Exchange[ExchangePattern: InOnly, BodyType: null, Body: [Body is null]]
Metrics
# HELP CamelExchangesFailed_total
# TYPE CamelExchangesFailed_total counter
CamelExchangesFailed_total{application="test",camelContext="camel-1",routeId="route1",serviceName="MicrometerRoutePolicyService",} 0.0
# HELP CamelExchangesSucceeded_total
# TYPE CamelExchangesSucceeded_total counter
CamelExchangesSucceeded_total{application="test",camelContext="camel-1",routeId="route1",serviceName="MicrometerRoutePolicyService",} 1.0
Resaerch
If I remove the custom error handler, the metric CamelExchangesFailed_total is increased, but then the default error handler is used, which is not desired for some reasons.
Question
Why is CamelExchangesFailed_total metrics not increased? Is there any way to count all failed routes with a custom error handler?

Answer 1

Apache Camel LTS version 3.7.0 added a new metric CamelExchangesFailuresHandled_total, which is a counter of handled errors, see CAMEL-15908:
Similar to CAMEL-15255, there are some additional counter metrics we could add to the MicrometerRoutePolicy for:
Total exchanges processed
Number of failures handled
Number of external redeliveries
Metrics
# HELP CamelExchangesFailed_total
# TYPE CamelExchangesFailed_total counter
CamelExchangesFailed_total{application="test",camelContext="camel-1",routeId="route1",serviceName="MicrometerRoutePolicyService",} 0.0
# HELP CamelExchangesSucceeded_total
# TYPE CamelExchangesSucceeded_total counter
CamelExchangesSucceeded_total{application="test",camelContext="camel-1",routeId="route1",serviceName="MicrometerRoutePolicyService",} 1.0
# HELP CamelExchangesFailuresHandled_total
# TYPE CamelExchangesFailuresHandled_total counter
CamelExchangesFailuresHandled_total{application="test",camelContext="camel-1",routeId="route1",serviceName="MicrometerRoutePolicyService",} 1.0