feat(observability): default logging metrics on shutdown

Author: squakez

components/camel-observability-services/src/main/docs/observability-services.adoc

@@ -13,7 +13,7 @@ The Camel Observability Services provide services for observing the state of Cam
 
 == What is observability?
 
-Modern systems (especially distributed ones like Camel) are complex. When something breaks or slows down, you need visibility into what's happening inside without manually digging into every part. Observability gives you that visibility. 
+Modern systems (especially distributed ones like Camel) are complex. When something breaks or slows down, you need visibility into what's happening inside without manually digging into every part. Observability gives you that visibility.
 
 There are 4 different types of observability:
 
@@ -22,7 +22,7 @@ There are 4 different types of observability:
 3. Tracing (Follows the path of a message as it moves through routes.)
 4. Logging (Records of events happening in Camel.)
 
-Camel Observability services unifies all the different types of observability, and provides standardized endpoints for each. 
+Camel Observability services unifies all the different types of observability, and provides standardized endpoints for each.
 
 == Usage
 
@@ -76,6 +76,14 @@ If you need to customize each of the different components provided within this s
 
 WARNING: The customization of the configuration for this component is not available for Spring Boot runtime due to a https://github.com/spring-projects/spring-boot/issues/24688[known limitation]. You can use this component in Spring Boot runtime with the default settings only. If you need to provide any customization, you'll need to configure each component separately.
 
+== Default logging metrics on shutdown
+
+NOTE: feature available since version 4.19.0
+
+The presence of this component will make sure that when the application is shutting down, certain metrics are stored on log of the application in order to be preserved for any future analysis or shared with your log aggregator. This could be a solution to investigate how many exchanges were processed, how many have failed, etc, on an application that has a sudden or even a controlled shutdown. You can think on a cronjob running and being able at any moment to learn certain stats without the need to have your application running to scrape the `/metrics` endpoint.
+
+You can even change `camel.metrics.logMetricsOnShutdown` and `camel.metrics.logMetricsOnShutdownFilters` in order to qualify better this behavior, which defaults to `true` and `app.info,camel.exchanges.*` by default.
+
 === OpenTelemetry configuration
 
 The presence of this component will provide the required instrumentation to easily enable the collection of OpenTelemetry metrics.

components/camel-observability-services/src/main/resources/observability-services.properties

@@ -24,5 +24,7 @@ camel.management.healthPath=/observe/health
 camel.health.exposure-level=full
 camel.metrics.enabled=true
 camel.metrics.path=/observe/metrics
+camel.metrics.logMetricsOnShutdown=true
+camel.metrics.logMetricsOnShutdownFilters=app.info,camel.exchanges.*
 # Opentelemetry
 camel.opentelemetry2.enabled=true