Claude
03bdf7ee87
Companion module for the rewritten ankurm.com Prometheus/Grafana monitoring post. Verified against a real running grafana/otel-lgtm container (not mocked): 8 real requests produce a real orders_placed_total metric queried back from the bundled Prometheus-compatible API with zero management.otlp.* properties, auto-wired entirely by Boot's Docker Compose service-connection detection. Two real findings surfaced along the way and documented rather than smoothed over: @Observed silently produces no span without an explicit ObservedAspect bean (AspectJ weaving alone is not sufficient, despite Micrometer Tracing being active), and OTEL_EXPORTER_OTLP_ENDPOINT already worked on Boot 4.0 via Micrometer's own OtlpConfig fallback -- what's actually new in 4.1 is the rest of the standard OTEL_* surface (verified with OTEL_METRIC_EXPORT_INTERVAL against identical source compiled on both Boot 4.0.8 and 4.1.1). Also fixes the root README's module table, which was missing a row for resilience4j-circuit-breaker (added in a previous commit but never indexed here).
33 lines
1.7 KiB
Plaintext
33 lines
1.7 KiB
Plaintext
OrderController#placeOrder is annotated @Observed(name = "place-order", contextualName =
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"order-controller#placeOrder"). Before ObservationConfig (an explicit ObservedAspect @Bean)
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existed in this repo, spring-boot-starter-opentelemetry, spring-boot-starter-aspectj (AspectJ
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weaver on the classpath) and micrometer-tracing were ALL already present and active -- and the
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annotation still did nothing. Real trace, fetched straight from Tempo's query API, before the fix:
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$ curl -s "http://localhost:3200/api/traces/<trace-id>"
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span: http post /orders/{id} | kind: SPAN_KIND_SERVER | parent: (root)
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# one span. @Observed's child span never appears.
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After adding:
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@Configuration(proxyBeanMethods = false)
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class ObservationConfig {
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@Bean
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ObservedAspect observedAspect(ObservationRegistry registry) {
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return new ObservedAspect(registry);
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}
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}
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Same annotation, same request, new trace:
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$ curl -s "http://localhost:3200/api/traces/<trace-id>"
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span: order-controller#placeOrder | kind: SPAN_KIND_INTERNAL | parent: <server-span-id>
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span: http post /orders/{id} | kind: SPAN_KIND_SERVER | parent: (root)
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# two spans. The @Observed child span now nests correctly under the HTTP server span.
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Spring Boot's autoconfiguration wires an ObservationRegistry bean for you the moment Micrometer
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Tracing is on the classpath -- it does NOT also register an ObservedAspect. AspectJ weaving
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being present is necessary but not sufficient; without the aspect bean there is nothing for the
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weaver to apply. This is easy to miss because the app starts cleanly, the HTTP server span still
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shows up, and nothing logs a warning -- the method-level span is just silently absent.
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