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Observability

Observability

Failover emits structured logs and Micrometer counters on every operation. Add failover-observable-micrometer to enable metrics and the Actuator health indicator.

Enable Micrometer Metrics

pom.xml
<dependency>
    <groupId>com.societegenerale.failover</groupId>
    <artifactId>failover-observable-micrometer</artifactId>
    <version>3.0.0</version>
</dependency>

Requires micrometer-core and spring-boot-starter-actuator on the classpath (typically already present).

Micrometer Counters

Every store and recover operation increments the failover.store counter:

Tag Values Description
name <failover name> The @Failover(name=...) value
action store, recover, nonRecover, cleanByExpiry The operation performed
  • store — upstream succeeded, entry stored.
  • recover — upstream failed, stored entry served.
  • nonRecover — upstream failed, no valid entry found.
  • cleanByExpiry — expiry cleanup deleted entries.

Prometheus Scrape Example

prometheus.yml
scrape_configs:
  - job_name: myapp
    static_configs:
      - targets: ['localhost:8080']
    metrics_path: /actuator/prometheus

Query to track recovery rate:

rate(failover_store_total{action="recover"}[5m])
/
(rate(failover_store_total{action="recover"}[5m]) + rate(failover_store_total{action="nonRecover"}[5m]))

Actuator Health Indicator

The FailoverHealthIndicator is registered at /actuator/health:

{
  "status": "UP",
  "components": {
    "failover": {
      "status": "UP",
      "details": {
        "enabled": "true",
        "type": "BASIC",
        "store.type": "JDBC"
      }
    }
  }
}

Structured Logs

Level Event Logger
INFO Entry stored successfully DefaultFailoverHandler
INFO Entry recovered successfully DefaultFailoverHandler
WARN No stored entry found DefaultFailoverHandler
INFO Expiry cleanup executed DefaultFailoverHandler
ERROR Recovery threw unexpected exception AdvancedFailoverHandler

Adjust Log Level

application.yml
logging:
  level:
    com.societegenerale.failover: INFO    # DEBUG for full payload detail

Custom ObservablePublisher

AdvancedFailoverHandler calls ObservablePublisher.publish(Metrics) on every operation. Implement ObservablePublisher to send metrics to a custom sink:

KafkaObservablePublisher.java
@Component
public class KafkaObservablePublisher implements ObservablePublisher {

    @Override
    public void publish(Metrics metrics) {
        kafkaTemplate.send("failover-events", metrics.getName(), metrics.toMap());
    }
}

Next Steps