Both Metrics and Observations in Spring

[tushar-sharma]

I followed the Spring's documentation to see traces in Mongodb by adding the bean

@Bean
MongoClientSettingsBuilderCustomizer mongoMetricsSynchronousContextProvider(ObservationRegistry registry) {
    return (clientSettingsBuilder) -> {
        clientSettingsBuilder.contextProvider(ContextProviderFactory.create(registry))
                             .addCommandListener(new MongoObservationCommandListener(registry));
    };
}

and adding the following properties to :

# Disable Spring Boot's autoconfigured tracing
management.metrics.mongo.command.enabled=false
# Enable it manually
management.tracing.enabled=true

I can see the traces in the zipkins. However my question was since, Spring Already provides an autoconfiguration class metrics MongoAutoConfiguration.

@AutoConfiguration(before = MongoAutoConfiguration.class,
        after = { MetricsAutoConfiguration.class, CompositeMeterRegistryAutoConfiguration.class })
@ConditionalOnClass(MongoClientSettings.class)
@ConditionalOnBean(MeterRegistry.class)
public class MongoMetricsAutoConfiguration {

    @ConditionalOnClass(MongoMetricsCommandListener.class)
    @ConditionalOnProperty(name = "management.metrics.mongo.command.enabled", havingValue = "true",
            matchIfMissing = true)
    static class MongoCommandMetricsConfiguration {

    

        @Bean
        MongoClientSettingsBuilderCustomizer mongoMetricsCommandListenerClientSettingsBuilderCustomizer(
                MongoMetricsCommandListener mongoMetricsCommandListener) {
            return (clientSettingsBuilder) -> clientSettingsBuilder.addCommandListener(mongoMetricsCommandListener);
        }

Why do we need to disable bean from MongoAutoConfiguration? Can’t we got both metrics and traces?

[mp911de]

MongoMetricsCommandListener is a component that registers timers to capture runtime durations of commands. MongoObservationCommandListener captures not only timing, but also spans by using Micrometer's Observation API.

If you enable both, then you will have two places for timers.

[michaldo]

Configuration is overcomplicated.

If MongoObservationCommandListener exceeds MongoMetricsCommandListener, why is not default Spring Boot choice?
If not exceeds but is considerable replacement, why is not simply configurable by Spring Boot property?

[mp911de]

This is because Spring Data ships the observation listener and not the driver.

[christophstrobl]

@michaldo you may want to give the MongoDB Team a heads up on eventually adding tracing support to their drivers.
https://jira.mongodb.org/browse/JAVA-5732

[michaldo]

My goal is limited to configuration.

I understand that disabling Spring Boot autoconfiguation for .MongoMetricsCommandListener and adding MongoObservationCommandListener in application works.

I simply think that
a) Spring Boot should prefer MOCL over MMCL
b) or at least the preference should easy to setup by property

Actually it looks that Spring Boot team enabled by default listener from micrometer, Spring Data Mongo team implemented listener with observability and missing part is connecting the dots