metrics test

.http/actuator.http

@@ -0,0 +1,9 @@
+### Thing
+GET http://localhost:8080/actuator
+
+### info
+GET http://localhost:8080/actuator/info
+
+### Prometheus
+GET http://localhost:8080/actuator/prometheus
+

build.gradle.kts

@@ -14,6 +14,12 @@ dependencies {
     implementation(aa.springboot.starter.actuator)
     implementation(aa.springboot.starter.webflux)
 
+    implementation("io.micrometer:micrometer-registry-otlp")
+    implementation("io.micrometer:micrometer-registry-prometheus")
+    implementation("io.micrometer:micrometer-tracing")
+    implementation("io.micrometer:micrometer-tracing-bridge-otel")
+    implementation("io.opentelemetry:opentelemetry-exporter-otlp")
+
     testImplementation(aa.kotlin.junit5)
     testImplementation(aa.kotlinx.coroutines.test)
     testImplementation(aa.springboot.starter.test)

src/main/kotlin/ltd/lulz/controller/HomeController.kt

@@ -0,0 +1,14 @@
+package ltd.lulz.controller
+
+import org.springframework.web.bind.annotation.GetMapping
+import org.springframework.web.bind.annotation.RequestMapping
+import org.springframework.web.bind.annotation.RestController
+import reactor.core.publisher.Mono
+
+@RestController
+@RequestMapping("/")
+class HomeController {
+
+    @GetMapping
+    fun home(): Mono<String> = Mono.just("Hello World")
+}

src/main/resources/application.yml

@@ -17,12 +17,17 @@ management:
       show-details: always
     info:
       access: read_only
+    prometheus:
+      access: read_only
   endpoints:
     access:
       default: none
     web:
       exposure:
-        include: "health,info"
+        include: "health,info,prometheus"
+  tracing:
+    sampling:
+      probability: '1.0'
 
 ---
 ###########################
@@ -50,3 +55,15 @@ spring:
   config:
     activate:
       on-profile: kubernetes
+
+management:
+  otlp:
+    tracing:
+      endpoint: http://opentelemetry-collector.observability.svc.cluster.local:4318/v1/traces
+    metrics:
+      export:
+        url: http://opentelemetry-collector.observability.svc.cluster.local:4318/v1/metrics  # Or gRPC: http://... but stick to HTTP for consistency
+  metrics:
+    export:
+      otlp:
+        step: 30s  # Optional: Push every 30s for demo; default 60s