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 +1,88 @@
+package com.ankurm.otel;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.TreeSet;
+
+import io.micrometer.core.instrument.Meter;
+import io.micrometer.core.instrument.MeterRegistry;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.boot.test.system.CapturedOutput;
+import org.springframework.boot.test.system.OutputCaptureExtension;
+import org.springframework.context.ConfigurableApplicationContext;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Two smaller 4.2 changes that break dashboards and log queries rather than builds: the MDC keys
+ * that carry the trace and span ids, and the active-observation LongTaskTimer that is no longer
+ * created by default.
+ */
+@ExtendWith(OutputCaptureExtension.class)
+class MdcAndLongTaskTimerTest {
+
+	@Test
+	void mdcKeys(CapturedOutput output) {
+		Transcript t = new Transcript("04-mdc-keys");
+		// The pattern reads both the default key names and the custom ones, so one log line shows
+		// which key the tracing bridge really populated.
+		ConfigurableApplicationContext ctx = Apps.start("management.otlp.metrics.export.enabled=false",
+				"management.tracing.mdc.trace-id-key=trace_id", "management.tracing.mdc.span-id-key=span_id",
+				"logging.pattern.correlation=default[%X{traceId:-}] custom[%X{trace_id:-}] ");
+		Apps.call(ctx, "/hello/ankur");
+		ctx.close();
+		String line = output.getAll().lines().filter(l -> l.contains("handling hello for ankur")).findFirst().orElseThrow();
+		String correlation = line.substring(line.indexOf("default["), line.indexOf("] : ") > 0 ? line.indexOf("] :") : line.length());
+		t.line("management.tracing.mdc.trace-id-key = trace_id");
+		t.line("management.tracing.mdc.span-id-key  = span_id");
+		t.line("log pattern correlation part reads both MDC keys");
+		t.line("");
+		t.line("log line: " + line.replaceAll("^\\S+\\s+", "").replaceAll("(?<=\\[)[0-9a-f]{32}(?=\\])", "<32-hex-trace-id>"));
+		boolean defaultKeyFilled = line.matches(".*default\\[[0-9a-f]{32}\\].*");
+		boolean customKeyFilled = line.matches(".*custom\\[[0-9a-f]{32}\\].*");
+		t.line("default key traceId populated: " + defaultKeyFilled);
+		t.line("custom key trace_id populated: " + customKeyFilled);
+		if (Transcript.is42()) {
+			assertThat(customKeyFilled).isTrue();
+			assertThat(defaultKeyFilled).isFalse();
+		}
+		else {
+			assertThat(customKeyFilled).isFalse();
+			assertThat(defaultKeyFilled).isTrue();
+		}
+		t.write();
+	}
+
+	@Test
+	void activeLongTaskTimer() throws Exception {
+		Transcript t = new Transcript("05-active-long-task-timer");
+		for (String setting : List.of("(default)", "management.metrics.observations.include-active-long-task-timer=true")) {
+			ConfigurableApplicationContext ctx = setting.startsWith("(")
+					? Apps.start("management.otlp.metrics.export.enabled=false")
+					: Apps.start("management.otlp.metrics.export.enabled=false", setting);
+			Apps.call(ctx, "/hello/ankur");
+			MeterRegistry registry = ctx.getBean(MeterRegistry.class);
+			Apps.awaitHttpMeter(registry);
+			TreeSet<String> names = new TreeSet<>();
+			for (Meter m : registry.getMeters()) {
+				if (m.getId().getName().startsWith("http.server")) {
+					names.add(m.getId().getName() + "  (" + m.getId().getType() + ")");
+				}
+			}
+			t.line("");
+			t.line("== " + setting);
+			names.forEach(n -> t.line("   " + n));
+			boolean active = names.stream().anyMatch(n -> n.startsWith("http.server.requests.active"));
+			t.line("   http.server.requests.active present: " + active);
+			if (Transcript.is42()) {
+				assertThat(active).isEqualTo(!setting.startsWith("("));
+			}
+			else if (setting.startsWith("(")) {
+				assertThat(active).isTrue();
+			}
+			ctx.close();
+		}
+		t.write();
+	}
+}