Add boot42-otel module: Spring Boot 4.2.0-RC1 OpenTelemetry conventions, shared OTLP settings and MDC keys vs 4.1.2

2026-10-22 18:37:10 +00:00
parent 917d39fb65
commit 8252cba4c5
29 changed files with 958 additions and 0 deletions
@@ -0,0 +1,57 @@
+package com.ankurm.otel;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.TreeSet;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.web.client.RestClient;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * What a dashboard query sees. Scrapes /actuator/prometheus after one request and lists the
+ * http_server* families and one labelled sample, for the default conventions and for the
+ * open-telemetry conventions (spelled the way RC1 accepts it).
+ */
+class PrometheusNamesTest {
+
+	@Test
+	void promNames() throws Exception {
+		Transcript t = new Transcript("06-prometheus-names");
+		List<String> modes = List.of("micrometer", "opentelemetry");
+		java.util.Map<String, List<String>> families = new java.util.LinkedHashMap<>();
+		for (String mode : modes) {
+			ConfigurableApplicationContext ctx = Apps.start("management.observations.conventions=" + mode,
+					"management.otlp.metrics.export.enabled=false");
+			Apps.call(ctx, "/hello/ankur");
+			io.micrometer.core.instrument.MeterRegistry registry = ctx.getBean(io.micrometer.core.instrument.MeterRegistry.class);
+			Apps.awaitHttpMeter(registry);
+			String port = ctx.getEnvironment().getProperty("local.server.port");
+			String body = RestClient.create().get().uri("http://localhost:" + port + "/actuator/prometheus")
+				.retrieve().body(String.class);
+			TreeSet<String> names = new TreeSet<>();
+			String sample = "";
+			for (String line : body.split("\n")) {
+				if (line.startsWith("http_server")) {
+					names.add(line.substring(0, line.indexOf('{') > 0 ? line.indexOf('{') : line.indexOf(' ')));
+					if (line.contains("_count{") && sample.isEmpty()) {
+						sample = line.substring(0, line.lastIndexOf(' '));
+					}
+				}
+			}
+			t.line("");
+			t.line("== management.observations.conventions=" + mode);
+			names.forEach(n -> t.line("   " + n));
+			t.line("   sample: " + sample);
+			families.put(mode, new ArrayList<>(names));
+			ctx.close();
+		}
+		t.write();
+		if (Transcript.is42()) {
+			assertThat(families.get("micrometer")).contains("http_server_requests_seconds_count");
+			assertThat(families.get("opentelemetry")).contains("http_server_request_duration_seconds_count");
+		}
+	}
+}