enable distribution otlp tracing

.env.example

@@ -7,4 +7,6 @@ DB_SCHEMA=public
 DB_USERNAME=postgres
 DB_PASSWORD=postgres
 
-KAFKA_SERVERS=localhost:9095
+KAFKA_SERVERS=localhost:9095
+
+OTLP_TRACING_HTTP_URL=http://localhost:4318/v1/traces

build.gradle.kts

@@ -27,12 +27,15 @@ dependencies {
 	implementation("com.fasterxml.jackson.module:jackson-module-kotlin:2.15.4")
 	implementation("com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.15.4")
 	implementation("io.github.optimumcode:json-schema-validator:0.2.3")
+	implementation("io.micrometer:micrometer-tracing-bridge-otel")
+	implementation("io.opentelemetry:opentelemetry-exporter-otlp")
 	implementation("net.logstash.logback:logstash-logback-encoder:8.0")
 	implementation("org.flywaydb:flyway-core:9.22.3")
 	implementation("org.jetbrains.kotlin:kotlin-reflect:2.0.20")
 	implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.6.3")
 	implementation("org.postgresql:postgresql:42.6.2")
 	implementation("org.springdoc:springdoc-openapi-starter-webmvc-ui:2.6.0")
+	implementation("org.springframework:spring-aspects")
 	implementation("org.springframework.boot:spring-boot-starter-actuator:3.2.10")
 	implementation("org.springframework.boot:spring-boot-starter-mustache:3.2.10")
 	implementation("org.springframework.boot:spring-boot-starter-validation:3.2.10")

checklist.md

@@ -8,4 +8,4 @@ Some simple checklist for this demo repo:
 - [x] make kafka consumer
 - [x] register prometheus metrics
 - [x] expose prometheus metrics
-- [ ] add otel collector
+- [x] add otel collector

docker-compose.yml

@@ -14,6 +14,7 @@ services:
       DB_USERNAME: $DB_USERNAME
       DB_PASSWORD: $DB_PASSWORD
       KAFKA_SERVERS: $KAFKA_SERVERS
+      OTLP_TRACING_HTTP_URL: $OTLP_TRACING_HTTP_URL
     expose:
       - 8080
       - 8081

src/main/kotlin/com/example/demo/config/AppConfig.kt

@@ -13,7 +13,11 @@ import com.example.demo.services.validation.SchemaValidator
 import com.fasterxml.jackson.databind.ObjectMapper
 import com.fasterxml.jackson.databind.SerializationFeature
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule
+import io.micrometer.observation.ObservationRegistry
+import io.micrometer.observation.aop.ObservedAspect
+import io.opentelemetry.exporter.otlp.http.trace.OtlpHttpSpanExporter
 import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.beans.factory.annotation.Value
 import org.springframework.boot.context.properties.EnableConfigurationProperties
 import org.springframework.context.annotation.Bean
 import org.springframework.context.annotation.Configuration
@@ -50,5 +54,17 @@ class AppConfig(
 
     @Bean
     fun schemaValidator(): SchemaValidator = SchemaValidator(kafkaProperties.validation.schema)
+
+    @Bean
+    fun otlpHttpSpanExporter(@Value("\${tracing.url}") url: String): OtlpHttpSpanExporter {
+        return OtlpHttpSpanExporter.builder()
+            .setEndpoint(url)
+            .build()
+    }
+
+    @Bean
+    fun observedAspect(@Autowired observationRegistry: ObservationRegistry): ObservedAspect {
+        return ObservedAspect(observationRegistry)
+    }
 }
 

src/main/resources/application.yml

@@ -59,4 +59,10 @@ management:
   metrics:
     distribution:
       percentiles-histogram:
-        "[http.server.requests]": true
+        "[http.server.requests]": true
+  tracing:
+    sampling:
+      probability: 1.0
+
+tracing:
+  url: ${OTLP_TRACING_HTTP_URL:http://localhost:4318/v1/traces}