Fixed OTel baggage tagging

- currently we're having a wrong equality check, we're converting baggage keys to lowercase but we're comparing it to non lowercase tags. We should do ignore case equality check instead
- Added tests for baggage tagging for both OTel and Brave

fixes gh-375

Author: marcingrzejszczak

micrometer-tracing-bridges/micrometer-tracing-bridge-brave/src/test/java/io/micrometer/tracing/brave/bridge/BaggageTests.java

@@ -15,10 +15,12 @@
  */
 package io.micrometer.tracing.brave.bridge;
 
+import brave.Tags;
 import brave.Tracing;
 import brave.baggage.BaggageField;
 import brave.baggage.BaggagePropagation;
 import brave.baggage.BaggagePropagationConfig;
+import brave.handler.MutableSpan;
 import brave.handler.SpanHandler;
 import brave.propagation.B3Propagation;
 import brave.propagation.StrictCurrentTraceContext;
@@ -46,7 +48,11 @@ class BaggageTests {
 
     public static final String VALUE_1 = "value1";
 
-    SpanHandler spanHandler = new TestSpanHandler();
+    public static final String TAG_KEY = "tagKey";
+
+    public static final String TAG_VALUE = "tagValue";
+
+    TestSpanHandler spanHandler = new TestSpanHandler();
 
     StrictCurrentTraceContext braveCurrentTraceContext = StrictCurrentTraceContext.create();
 
@@ -58,9 +64,11 @@ class BaggageTests {
         .traceId128Bit(true)
         .propagationFactory(BaggagePropagation.newFactoryBuilder(B3Propagation.FACTORY)
             .add(BaggagePropagationConfig.SingleBaggageField.remote(BaggageField.create(KEY_1)))
+            .add(BaggagePropagationConfig.SingleBaggageField.local(BaggageField.create(TAG_KEY)))
             .build())
         .sampler(Sampler.ALWAYS_SAMPLE)
         .addSpanHandler(this.spanHandler)
+        .addSpanHandler(new BaggageTagSpanHandler(new BaggageField[] { BaggageField.create(TAG_KEY) }))
         .build();
 
     brave.Tracer braveTracer = this.tracing.tracer();
@@ -138,4 +146,43 @@ void baggageWithContextPropagation() {
         }
     }
 
+    @Test
+    void baggageTagKey() {
+        ScopedSpan span = this.tracer.startScopedSpan("call1");
+        try {
+            try (BaggageInScope scope7 = this.tracer.createBaggage(TAG_KEY, TAG_VALUE).makeCurrent()) {
+                // span should get tagged with baggage
+            }
+        }
+        catch (RuntimeException | Error ex) {
+            span.error(ex);
+            throw ex;
+        }
+        finally {
+            span.end();
+        }
+
+        then(spanHandler.spans()).hasSize(1);
+        MutableSpan mutableSpan = spanHandler.spans().get(0);
+        then(mutableSpan.tags().get(TAG_KEY)).isEqualTo(TAG_VALUE);
+    }
+
+    static final class BaggageTagSpanHandler extends SpanHandler {
+
+        final BaggageField[] fieldsToTag;
+
+        BaggageTagSpanHandler(BaggageField[] fieldsToTag) {
+            this.fieldsToTag = fieldsToTag;
+        }
+
+        @Override
+        public boolean end(brave.propagation.TraceContext context, MutableSpan span, Cause cause) {
+            for (BaggageField field : fieldsToTag) {
+                Tags.BAGGAGE_FIELD.tag(field, context, span);
+            }
+            return true;
+        }
+
+    }
+
 }

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

@@ -101,7 +101,7 @@ private io.micrometer.tracing.Baggage doSet(TraceContext context, String value)
         Context withBaggage = current.with(baggage);
         ctx.updateContext(withBaggage);
         contextWithBaggage.set(withBaggage);
-        if (this.tagFields.stream().map(String::toLowerCase).anyMatch(s -> s.equals(entry().getKey()))) {
+        if (this.tagFields.stream().anyMatch(s -> s.equalsIgnoreCase(entry().getKey()))) {
             currentSpan.setAttribute(entry().getKey(), value);
         }
         Entry previous = entry();

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

@@ -17,18 +17,18 @@
 
 import io.micrometer.common.util.internal.logging.InternalLogger;
 import io.micrometer.common.util.internal.logging.InternalLoggerFactory;
-import io.micrometer.tracing.Baggage;
-import io.micrometer.tracing.BaggageInScope;
-import io.micrometer.tracing.Span;
-import io.micrometer.tracing.Tracer;
+import io.micrometer.tracing.*;
 import io.micrometer.tracing.otel.propagation.BaggageTextMapPropagator;
 import io.opentelemetry.api.baggage.propagation.W3CBaggagePropagator;
+import io.opentelemetry.api.common.AttributeKey;
 import io.opentelemetry.api.trace.propagation.W3CTraceContextPropagator;
 import io.opentelemetry.context.propagation.ContextPropagators;
 import io.opentelemetry.context.propagation.TextMapPropagator;
 import io.opentelemetry.extension.trace.propagation.B3Propagator;
 import io.opentelemetry.sdk.OpenTelemetrySdk;
 import io.opentelemetry.sdk.trace.SdkTracerProvider;
+import io.opentelemetry.sdk.trace.data.SpanData;
+import io.opentelemetry.sdk.trace.export.SimpleSpanProcessor;
 import org.junit.jupiter.api.Test;
 import reactor.core.publisher.Hooks;
 import reactor.core.publisher.Mono;
@@ -52,8 +52,15 @@ class BaggageTests {
 
     public static final String VALUE_2 = "value2";
 
+    public static final String TAG_KEY = "tagKey";
+
+    public static final String TAG_VALUE = "tagValue";
+
+    ArrayListSpanProcessor spanExporter = new ArrayListSpanProcessor();
+
     SdkTracerProvider sdkTracerProvider = SdkTracerProvider.builder()
         .setSampler(io.opentelemetry.sdk.trace.samplers.Sampler.alwaysOn())
+        .addSpanProcessor(SimpleSpanProcessor.create(spanExporter))
         .build();
 
     OpenTelemetrySdk openTelemetrySdk = OpenTelemetrySdk.builder()
@@ -66,7 +73,7 @@ class BaggageTests {
     OtelCurrentTraceContext otelCurrentTraceContext = new OtelCurrentTraceContext();
 
     OtelBaggageManager otelBaggageManager = new OtelBaggageManager(otelCurrentTraceContext,
-            Collections.singletonList(KEY_1), Collections.emptyList());
+            Collections.singletonList(KEY_1), Collections.singletonList(TAG_KEY));
 
     ContextPropagators contextPropagators = ContextPropagators
         .create(TextMapPropagator.composite(W3CBaggagePropagator.getInstance(), W3CTraceContextPropagator.getInstance(),
@@ -144,4 +151,25 @@ void baggageWithContextPropagation() {
         }
     }
 
+    @Test
+    void baggageTagKey() {
+        ScopedSpan span = this.tracer.startScopedSpan("call1");
+        try {
+            try (BaggageInScope scope7 = this.tracer.createBaggage(TAG_KEY, TAG_VALUE).makeCurrent()) {
+                // span should get tagged with baggage
+            }
+        }
+        catch (RuntimeException | Error ex) {
+            span.error(ex);
+            throw ex;
+        }
+        finally {
+            span.end();
+        }
+
+        then(spanExporter.spans()).hasSize(1);
+        SpanData spanData = spanExporter.spans().poll();
+        then(spanData.getAttributes().get(AttributeKey.stringKey(TAG_KEY))).isEqualTo(TAG_VALUE);
+    }
+
 }