Allow for recording an error in spans without throwables

micrometer-tracing-bridges/micrometer-tracing-bridge-brave/src/main/java/io/micrometer/tracing/brave/bridge/BraveSpan.java

@@ -114,6 +114,12 @@ public Span error(Throwable throwable) {
         return this;
     }
 
+    @Override
+    public Span error(String message) {
+        this.delegate.tag("error", message);
+        return this;
+    }
+
     @Override
     public void end() {
         this.delegate.finish();

micrometer-tracing-bridges/micrometer-tracing-bridge-otel/src/main/java/io/micrometer/tracing/otel/bridge/OtelSpan.java

@@ -17,11 +17,13 @@
 
 import io.micrometer.tracing.Span;
 import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.api.common.Attributes;
 import io.opentelemetry.api.trace.StatusCode;
 import io.opentelemetry.context.Context;
 import io.opentelemetry.sdk.trace.ReadableSpan;
 import io.opentelemetry.semconv.SemanticAttributes;
 
+import java.time.Instant;
 import java.util.List;
 import java.util.Objects;
 import java.util.concurrent.TimeUnit;
@@ -34,6 +36,8 @@
  */
 public class OtelSpan implements Span {
 
+    private static final AttributeKey<String> ERROR_MESSAGE = AttributeKey.stringKey("error.message");
+
     final io.opentelemetry.api.trace.Span delegate;
 
     final OtelTraceContext otelTraceContext;
@@ -172,6 +176,14 @@ public Span error(Throwable throwable) {
         return this;
     }
 
+    @Override
+    public Span error(String message) {
+        Attributes attributes = Attributes.of(ERROR_MESSAGE, message);
+        this.delegate.setStatus(StatusCode.ERROR, message);
+        this.delegate.addEvent(message, attributes, Instant.now());
+        return this;
+    }
+
     @Override
     public void end() {
         if (this.isStatusUnset()) {

micrometer-tracing-bridges/micrometer-tracing-bridge-otel/src/test/java/io/micrometer/tracing/otel/bridge/OtelSpanTests.java

@@ -59,6 +59,18 @@ void should_set_status_to_error_when_recording_exception() {
         then(poll.getEvents().get(0).getAttributes().asMap().values()).containsAnyOf("boom!");
     }
 
+    @Test
+    void should_set_status_to_error_when_recording_error() {
+        OtelSpan otelSpan = new OtelSpan(otelTracer.spanBuilder("foo").startSpan());
+
+        otelSpan.error("boom!").end();
+
+        SpanData poll = arrayListSpanProcessor.spans().poll();
+        then(poll.getStatus()).isEqualTo(StatusData.create(StatusCode.ERROR, "boom!"));
+        then(poll.getEvents()).hasSize(1);
+        then(poll.getEvents().get(0).getAttributes().asMap().values()).containsAnyOf("boom!");
+    }
+
     @Test
     void should_be_equal_when_two_span_delegates_are_equal() {
         Span span = otelTracer.spanBuilder("foo").startSpan();

micrometer-tracing-tests/micrometer-tracing-test/src/main/java/io/micrometer/tracing/test/simple/SimpleSpan.java

@@ -121,6 +121,11 @@ public SimpleSpan error(Throwable throwable) {
         return this;
     }
 
+    @Override
+    public Span error(String message) {
+        return this;
+    }
+
     @Override
     public SimpleSpan remoteIpAndPort(String ip, int port) {
         this.ip = ip;

micrometer-tracing/src/main/java/io/micrometer/tracing/Span.java

@@ -77,6 +77,11 @@ public Span error(Throwable throwable) {
             return this;
         }
 
+        @Override
+        public Span error(String message) {
+            return this;
+        }
+
         @Override
         public void end() {
 
@@ -229,6 +234,13 @@ default Span tagOfBooleans(String key, List<Boolean> values) {
      */
     Span error(Throwable throwable);
 
+    /**
+     * Records an error in this span.
+     * @param message to record
+     * @return this span
+     */
+    Span error(String message);
+
     /**
      * Ends the span. The span gets stopped and recorded if not noop.
      */