Add trace validation to testcontainer example (#451)

replaces #424

---------

Co-authored-by: Jay DeLuca <jaydeluca4@gmail.com>

Author: zeitlinger

examples/java/testcontainer/README.md

@@ -1,33 +1,41 @@
 # Using Testcontainers
 
-The provided code demonstrates how to use **Testcontainers** with **Grafana's LGTM stack** to test OpenTelemetry metrics in a Java application. Here's a step-by-step explanation:
+The provided code demonstrates how to use **Testcontainers** with **Grafana's LGTM stack** to test OpenTelemetry metrics
+in a Java application. Here's a step-by-step explanation:
 
 1. **Set Up the Testcontainers Environment**:
 
-   - The `@Testcontainers` annotation enables the Testcontainers extension for JUnit 5.
-   - The `@Container` annotation is used to define a `LgtmStackContainer` that runs the Grafana LGTM stack in a Docker container.
+- The `@Testcontainers` annotation enables the Testcontainers extension for JUnit 5.
+- The `@Container` annotation is used to define a `LgtmStackContainer` that runs the Grafana LGTM stack in a Docker
+  container.
 
 2. **Configure OpenTelemetry**:
 
-   - In the `@BeforeEach` method, system properties are set to configure the OpenTelemetry exporter to send metrics to the LGTM stack running in the container.
+- In the `@BeforeEach` method, system properties are set to configure the OpenTelemetry exporter to send metrics to
+  the LGTM stack running in the container.
 
 3. **Run the Application**:
 
-   - The `OtelApp` class initializes OpenTelemetry and generates a custom metric (`sold_items`) with attributes (e.g., `tenant`).
+- The `OtelApp` class initializes OpenTelemetry and generates a custom metric (`sold_items`) with attributes (e.g.,
+  `tenant`) as well as a span representing the block the code.
 
-4. **Test the Metrics Export**:
+4. **Test Exporting Metrics and Traces**:
 
-   - The test method `testExportMetric` runs the application and queries the Prometheus endpoint in the LGTM stack to verify that the metric (`sold_items`) has been exported successfully.
-   - The `Awaitility` library is used to poll the Prometheus endpoint until the metric is found or a timeout occurs.
+- The test method `testExportMetricsAndTraces` runs the application and queries the Prometheus and Tempo endpoints
+  in the LGTM stack to verify that the metric (`sold_items`) and span have been exported successfully.
+- The `Awaitility` library is used to poll the endpoints until the telemetry is found or a timeout occurs.
 
 5. **Debugging with Grafana**:
-   - The test outputs the Grafana URL (`lgtm.getGrafanaHttpUrl()`) to the console, allowing you to manually inspect the metrics in the Grafana UI.
+
+- The test outputs the Grafana URL (`lgtm.getGrafanaHttpUrl()`) to the console, allowing you to manually inspect the
+  telemetry in the Grafana UI if needed.
 
 ## Example Usage
 
 1. Start the test using `mvn test`.
 2. Check the console output for the Grafana URL.
-3. Open the Grafana UI, navigate to the Explore tab, and query the metrics.
-4. The test will pass if the metric is successfully exported and found in Prometheus.
+3. Open the Grafana UI, navigate to the Explore tab, and query the metrics or traces.
+4. The test will pass if the metric and span are successfully exported and found in Prometheus and Tempo.
 
-This setup is useful for validating OpenTelemetry instrumentation and ensuring metrics are correctly exported to a monitoring system.
+This setup is useful for validating OpenTelemetry instrumentation and ensuring metrics are correctly exported to a
+monitoring system.

examples/java/testcontainer/pom.xml

@@ -4,7 +4,7 @@
     <modelVersion>4.0.0</modelVersion>
 
     <groupId>com.grafana.example</groupId>
-    <artifactId>testcontaier</artifactId>
+    <artifactId>testcontainer</artifactId>
     <version>1.0.0-SNAPSHOT</version>
 
     <name>Java Testcontainer Demo</name>

examples/java/testcontainer/src/test/java/com/grafana/example/TestcontainerTest.java

@@ -26,34 +26,32 @@ void setUp() {
     System.setProperty("otel.exporter.otlp.protocol", "http/protobuf");
     System.setProperty("otel.resource.attributes", "service.name=otel-java-test");
     System.setProperty("otel.metric.export.interval", "1s");
+    System.setProperty("otel.bsp.schedule.delay", "500ms");
   }
 
   @Test
-  void testExportMetric() {
-    // Howto:
-    // 1. The test with a really long timeout
+  void testExportMetricsAndTraces() throws InterruptedException {
+    // How to debug:
+    // 1. Run the test with a really long timeout (update the awaitility argument)
     // 2. Go to the Grafana UI
     // 3. Open the Explore tab
     // 4. Select the Prometheus data source
     // 5. Find your metric by name or attribute (e.g. "tenant1")
     // 6. Click on the metric to see the details
     // 7. Copy the query and paste it into the test
     System.out.println("Grafana URL to debug telemetry: " + lgtm.getGrafanaHttpUrl());
-
     var app = new OtelApp();
     app.run();
 
+    HttpClient client = HttpClient.newHttpClient();
     String query =
         URLEncoder.encode(
             "sold_items_total{job=\"otel-java-test\",service_name=\"otel-java-test\",tenant=\"tenant1\"}",
             StandardCharsets.UTF_8);
-    String prometheusHttpUrl = lgtm.getPromehteusHttpUrl() + "/api/v1/query?query=" + query;
+    String prometheusHttpUrl = lgtm.getPrometheusHttpUrl() + "/api/v1/query?query=" + query;
 
-    HttpClient client = HttpClient.newHttpClient();
     HttpRequest request = HttpRequest.newBuilder().uri(URI.create(prometheusHttpUrl)).build();
 
-    // Total time: 18.448 s (for the whole test, will take longer when the image needs to be
-    // downloaded)
     await()
         .atMost(Duration.ofSeconds(10))
         .until(
@@ -63,5 +61,20 @@ void testExportMetric() {
               String body = response.body();
               return response.statusCode() == 200 && body.contains("sold_items");
             });
+
+    HttpRequest traceRequest =
+        HttpRequest.newBuilder()
+            .uri(URI.create(String.format("%s/api/search", lgtm.getTempoUrl())))
+            .build();
+
+    await()
+        .atMost(Duration.ofSeconds(10))
+        .until(
+            () -> {
+              HttpResponse<String> response =
+                  client.send(traceRequest, HttpResponse.BodyHandlers.ofString());
+              String body = response.body();
+              return response.statusCode() == 200 && body.contains("otel-java-test");
+            });
   }
 }