fix(ops): restore bundled Zipkin tracing transport

docker-compose.yml

@@ -87,7 +87,8 @@ services:
   zipkin:
     image: openzipkin/zipkin:2
     ports:
-      - "9412:9412"
+      # Keep the historical host port while routing to Zipkin's standard HTTP collector port.
+      - "9412:9411"
 
   eureka-server:
     build:
@@ -121,6 +122,7 @@ services:
       FLYWAY_BASELINE_ON_MIGRATE: "true"
       EUREKA_HOST: eureka-server
       ZIPKIN_HOST: zipkin
+      MANAGEMENT_ZIPKIN_TRACING_ENDPOINT: http://zipkin:9411/api/v2/spans
     ports:
       - "8000:8000"
 
@@ -155,6 +157,7 @@ services:
       REPLICA_PGPASSWORD: ${REPLICA_POSTGRES_PASSWORD:-xtrmetl}
       EUREKA_HOST: eureka-server
       ZIPKIN_HOST: zipkin
+      MANAGEMENT_ZIPKIN_TRACING_ENDPOINT: http://zipkin:9411/api/v2/spans
       KAFKA_BOOTSTRAP_SERVERS: kafka:9092
     ports:
       - "8001:8001"
@@ -173,6 +176,7 @@ services:
     environment:
       EUREKA_HOST: eureka-server
       ZIPKIN_HOST: zipkin
+      MANAGEMENT_ZIPKIN_TRACING_ENDPOINT: http://zipkin:9411/api/v2/spans
     ports:
       - "8080:8080"
 

etl-service/src/test/java/com/xtrmetl/etl/documentation/DockerComposeZipkinTransportTest.java

@@ -0,0 +1,74 @@
+package com.xtrmetl.etl.documentation;
+
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/**
+ * Verifies that the bundled Docker Compose tracing path targets Zipkin's documented HTTP port.
+ */
+class DockerComposeZipkinTransportTest {
+
+    private static final Path PROJECT_ROOT = findProjectRoot();
+    private static final String INTERNAL_ZIPKIN_ENDPOINT =
+            "MANAGEMENT_ZIPKIN_TRACING_ENDPOINT: http://zipkin:9411/api/v2/spans";
+
+    @Test
+    void bundledServicesTargetTheStandardZipkinCollectorPort() throws IOException {
+        String compose = Files.readString(
+                PROJECT_ROOT.resolve("docker-compose.yml"),
+                StandardCharsets.UTF_8
+        );
+
+        assertTrue(compose.contains("image: openzipkin/zipkin:2"));
+        assertTrue(
+                compose.contains("- \"9412:9411\""),
+                "The compatibility host port must forward to Zipkin's documented container port 9411"
+        );
+        assertFalse(
+                compose.contains("- \"9412:9412\""),
+                "The bundled image must not be treated as listening on undocumented container port 9412"
+        );
+        assertEquals(
+                3,
+                countOccurrences(compose, INTERNAL_ZIPKIN_ENDPOINT),
+                "ETL, CDC, and gateway must all export traces to Zipkin port 9411 inside Compose"
+        );
+    }
+
+    private static int countOccurrences(String text, String needle) {
+        int count = 0;
+        int cursor = 0;
+        while ((cursor = text.indexOf(needle, cursor)) >= 0) {
+            count++;
+            cursor += needle.length();
+        }
+        return count;
+    }
+
+    private static Path findProjectRoot() {
+        Path current = Paths.get(System.getProperty("user.dir")).toAbsolutePath();
+        Path lastPomParent = null;
+        while (current != null) {
+            if (Files.exists(current.resolve(".git"))) {
+                return current;
+            }
+            if (Files.exists(current.resolve("pom.xml"))) {
+                lastPomParent = current;
+            }
+            current = current.getParent();
+        }
+        if (lastPomParent != null) {
+            return lastPomParent;
+        }
+        throw new IllegalStateException("Could not find project root (no .git or pom.xml found)");
+    }
+}