Add Getter.Keys() with Jaeger Baggage support.

api/src/jmh/java/io/opentelemetry/trace/propagation/HttpTraceContextExtractBenchmark.java

@@ -9,6 +9,7 @@
 import io.opentelemetry.context.propagation.TextMapPropagator.Getter;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -40,6 +41,11 @@ public class HttpTraceContextExtractBenchmark {
   private final HttpTraceContext httpTraceContext = HttpTraceContext.getInstance();
   private final Getter<Map<String, String>> getter =
       new Getter<Map<String, String>>() {
+        @Override
+        public Collection<String> keys(Map<String, String> carrier) {
+          return carrier.keySet();
+        }
+
         @Override
         public String get(Map<String, String> carrier, String key) {
           return carrier.get(key);

api/src/test/java/io/opentelemetry/baggage/propagation/W3CBaggagePropagatorTest.java

@@ -13,12 +13,29 @@
 import io.opentelemetry.baggage.BaggageUtils;
 import io.opentelemetry.baggage.EntryMetadata;
 import io.opentelemetry.context.Context;
+import io.opentelemetry.context.propagation.TextMapPropagator.Getter;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
+import javax.annotation.Nullable;
 import org.junit.jupiter.api.Test;
 
 class W3CBaggagePropagatorTest {
 
+  private static final Getter<Map<String, String>> getter =
+      new Getter<Map<String, String>>() {
+        @Override
+        public Collection<String> keys(Map<String, String> carrier) {
+          return carrier.keySet();
+        }
+
+        @Nullable
+        @Override
+        public String get(Map<String, String> carrier, String key) {
+          return carrier.get(key);
+        }
+      };
+
   @Test
   void fields() {
     assertThat(W3CBaggagePropagator.getInstance().fields()).containsExactly("baggage");
@@ -28,8 +45,7 @@ void fields() {
   void extract_noBaggageHeader() {
     W3CBaggagePropagator propagator = new W3CBaggagePropagator();
 
-    Context result =
-        propagator.extract(Context.root(), ImmutableMap.<String, String>of(), Map::get);
+    Context result = propagator.extract(Context.root(), ImmutableMap.<String, String>of(), getter);
 
     assertThat(result).isEqualTo(Context.root());
   }
@@ -38,8 +54,7 @@ void extract_noBaggageHeader() {
   void extract_emptyBaggageHeader() {
     W3CBaggagePropagator propagator = new W3CBaggagePropagator();
 
-    Context result =
-        propagator.extract(Context.root(), ImmutableMap.of("baggage", ""), ImmutableMap::get);
+    Context result = propagator.extract(Context.root(), ImmutableMap.of("baggage", ""), getter);
 
     assertThat(BaggageUtils.getBaggage(result)).isEqualTo(Baggage.empty());
   }
@@ -49,8 +64,7 @@ void extract_singleEntry() {
     W3CBaggagePropagator propagator = new W3CBaggagePropagator();
 
     Context result =
-        propagator.extract(
-            Context.root(), ImmutableMap.of("baggage", "key=value"), ImmutableMap::get);
+        propagator.extract(Context.root(), ImmutableMap.of("baggage", "key=value"), getter);
 
     Baggage expectedBaggage = Baggage.builder().put("key", "value").build();
     assertThat(BaggageUtils.getBaggage(result)).isEqualTo(expectedBaggage);
@@ -62,9 +76,7 @@ void extract_multiEntry() {
 
     Context result =
         propagator.extract(
-            Context.root(),
-            ImmutableMap.of("baggage", "key1=value1,key2=value2"),
-            ImmutableMap::get);
+            Context.root(), ImmutableMap.of("baggage", "key1=value1,key2=value2"), getter);
 
     Baggage expectedBaggage = Baggage.builder().put("key1", "value1").put("key2", "value2").build();
     assertThat(BaggageUtils.getBaggage(result)).isEqualTo(expectedBaggage);
@@ -76,7 +88,7 @@ void extract_duplicateKeys() {
 
     Context result =
         propagator.extract(
-            Context.root(), ImmutableMap.of("baggage", "key=value1,key=value2"), ImmutableMap::get);
+            Context.root(), ImmutableMap.of("baggage", "key=value1,key=value2"), getter);
 
     Baggage expectedBaggage = Baggage.builder().put("key", "value2").build();
     assertThat(BaggageUtils.getBaggage(result)).isEqualTo(expectedBaggage);
@@ -90,7 +102,7 @@ void extract_withMetadata() {
         propagator.extract(
             Context.root(),
             ImmutableMap.of("baggage", "key=value;metadata-key=value;othermetadata"),
-            ImmutableMap::get);
+            getter);
 
     Baggage expectedBaggage =
         Baggage.builder()
@@ -110,7 +122,7 @@ void extract_fullComplexities() {
                 "baggage",
                 "key1= value1; metadata-key = value; othermetadata, "
                     + "key2 =value2 , key3 =\tvalue3 ; "),
-            ImmutableMap::get);
+            getter);
 
     Baggage expectedBaggage =
         Baggage.builder()
@@ -136,7 +148,7 @@ void extract_invalidHeader() {
                 "baggage",
                 "key1= v;alsdf;-asdflkjasdf===asdlfkjadsf ,,a sdf9asdf-alue1; metadata-key = "
                     + "value; othermetadata, key2 =value2 , key3 =\tvalue3 ; "),
-            ImmutableMap::get);
+            getter);
 
     assertThat(BaggageUtils.getBaggage(result)).isEqualTo(Baggage.empty());
   }

api/src/test/java/io/opentelemetry/trace/propagation/HttpTraceContextTest.java

@@ -19,10 +19,12 @@
 import io.opentelemetry.trace.TraceFlags;
 import io.opentelemetry.trace.TraceId;
 import io.opentelemetry.trace.TraceState;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.Map;
+import javax.annotation.Nullable;
 import org.junit.jupiter.api.Test;
 
 /** Unit tests for {@link HttpTraceContext}. */
@@ -39,7 +41,19 @@ class HttpTraceContextTest {
   private static final String TRACEPARENT_HEADER_NOT_SAMPLED =
       "00-" + TRACE_ID_BASE16 + "-" + SPAN_ID_BASE16 + "-00";
   private static final Setter<Map<String, String>> setter = Map::put;
-  private static final Getter<Map<String, String>> getter = Map::get;
+  private static final Getter<Map<String, String>> getter =
+      new Getter<Map<String, String>>() {
+        @Override
+        public Collection<String> keys(Map<String, String> carrier) {
+          return carrier.keySet();
+        }
+
+        @Nullable
+        @Override
+        public String get(Map<String, String> carrier, String key) {
+          return carrier.get(key);
+        }
+      };
   // Encoding preserves the order which is the reverse order of adding.
   private static final String TRACESTATE_NOT_DEFAULT_ENCODING = "bar=baz,foo=bar";
   private static final String TRACESTATE_NOT_DEFAULT_ENCODING_WITH_SPACES =
@@ -151,7 +165,7 @@ void extract_Nothing() {
     // Context remains untouched.
     assertThat(
             httpTraceContext.extract(
-                Context.current(), Collections.<String, String>emptyMap(), Map::get))
+                Context.current(), Collections.<String, String>emptyMap(), getter))
         .isSameAs(Context.current());
   }
 
@@ -169,9 +183,7 @@ void extract_SampledContext() {
   void extract_NullCarrier() {
     Map<String, String> carrier = new LinkedHashMap<>();
     carrier.put(TRACE_PARENT, TRACEPARENT_HEADER_SAMPLED);
-    assertThat(
-            getSpanContext(
-                httpTraceContext.extract(Context.current(), null, (c, k) -> carrier.get(k))))
+    assertThat(getSpanContext(httpTraceContext.extract(Context.current(), carrier, getter)))
         .isEqualTo(
             SpanContext.createFromRemoteParent(
                 TRACE_ID_BASE16, SPAN_ID_BASE16, SAMPLED_TRACE_OPTIONS, TRACE_STATE_DEFAULT));

context_prop/src/main/java/io/opentelemetry/context/propagation/TextMapPropagator.java

@@ -6,6 +6,7 @@
 package io.opentelemetry.context.propagation;
 
 import io.opentelemetry.context.Context;
+import java.util.Collection;
 import java.util.List;
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
@@ -115,6 +116,14 @@ interface Setter<C> {
    */
   interface Getter<C> {
 
+    /**
+     * Returns all the keys in the given carrier.
+     *
+     * @param carrier carrier of propagation fields, such as an http request.
+     * @since 0.10.0
+     */
+    Collection<String> keys(C carrier);
+
     /**
      * Returns the first value of the given propagation {@code key} or returns {@code null}.
      *

context_prop/src/test/java/io/opentelemetry/context/propagation/DefaultPropagatorsTest.java

@@ -10,6 +10,7 @@
 
 import io.opentelemetry.context.Context;
 import io.opentelemetry.context.ContextKey;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
@@ -155,6 +156,11 @@ private MapSetter() {}
   private static final class MapGetter implements TextMapPropagator.Getter<Map<String, String>> {
     private static final MapGetter INSTANCE = new MapGetter();
 
+    @Override
+    public Collection<String> keys(Map<String, String> map) {
+      return map.keySet();
+    }
+
     @Override
     public String get(Map<String, String> map, String key) {
       return map.get(key);

extensions/trace_propagators/src/jmh/java/io/opentelemetry/extensions/trace/propagation/PropagatorContextExtractBenchmark.java

@@ -9,6 +9,7 @@
 import io.opentelemetry.context.propagation.TextMapPropagator;
 import io.opentelemetry.trace.Span;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
@@ -94,6 +95,11 @@ public static class JaegerContextExtractBenchmark extends AbstractContextExtract
 
     private final TextMapPropagator.Getter<Map<String, String>> getter =
         new TextMapPropagator.Getter<Map<String, String>>() {
+          @Override
+          public Collection<String> keys(Map<String, String> carrier) {
+            return carrier.keySet();
+          }
+
           @Override
           public String get(Map<String, String> carrier, String key) {
             return carrier.get(key);
@@ -137,6 +143,11 @@ public static class JaegerUrlEncodedContextExtractBenchmark
 
     private final TextMapPropagator.Getter<Map<String, String>> getter =
         new TextMapPropagator.Getter<Map<String, String>>() {
+          @Override
+          public Collection<String> keys(Map<String, String> carrier) {
+            return carrier.keySet();
+          }
+
           @Override
           public String get(Map<String, String> carrier, String key) {
             return carrier.get(key);
@@ -180,6 +191,11 @@ public static class B3SingleHeaderContextExtractBenchmark
 
     private final TextMapPropagator.Getter<Map<String, String>> getter =
         new TextMapPropagator.Getter<Map<String, String>>() {
+          @Override
+          public Collection<String> keys(Map<String, String> carrier) {
+            return carrier.keySet();
+          }
+
           @Override
           public String get(Map<String, String> carrier, String key) {
             return carrier.get(key);
@@ -226,6 +242,11 @@ private static Map<String, String> createHeaders(
 
     private final TextMapPropagator.Getter<Map<String, String>> getter =
         new TextMapPropagator.Getter<Map<String, String>>() {
+          @Override
+          public Collection<String> keys(Map<String, String> carrier) {
+            return carrier.keySet();
+          }
+
           @Override
           public String get(Map<String, String> carrier, String key) {
             return carrier.get(key);

extensions/trace_propagators/src/main/java/io/opentelemetry/extensions/trace/propagation/JaegerPropagator.java

@@ -5,6 +5,9 @@
 
 package io.opentelemetry.extensions.trace.propagation;
 
+import io.opentelemetry.baggage.Baggage;
+import io.opentelemetry.baggage.BaggageUtils;
+import io.opentelemetry.baggage.Entry;
 import io.opentelemetry.context.Context;
 import io.opentelemetry.context.propagation.TextMapPropagator;
 import io.opentelemetry.trace.Span;
@@ -34,6 +37,8 @@ public class JaegerPropagator implements TextMapPropagator {
   private static final Logger logger = Logger.getLogger(JaegerPropagator.class.getName());
 
   static final String PROPAGATION_HEADER = "uber-trace-id";
+  static final String BAGGAGE_HEADER = "jaeger-baggage";
+  static final String BAGGAGE_PREFIX = "uberctx-";
   // Parent span has been deprecated but Jaeger propagation protocol requires it
   static final char DEPRECATED_PARENT_SPAN = '0';
   static final char PROPAGATION_HEADER_DELIMITER = ':';
@@ -84,10 +89,15 @@ public <C> void inject(Context context, C carrier, Setter<C> setter) {
     Objects.requireNonNull(setter, "setter");
 
     SpanContext spanContext = Span.fromContext(context).getSpanContext();
-    if (!spanContext.isValid()) {
-      return;
+    if (spanContext.isValid()) {
+      injectSpan(spanContext, carrier, setter);
     }
 
+    injectBaggage(BaggageUtils.getBaggage(context), carrier, setter);
+  }
+
+  private static <C> void injectSpan(SpanContext spanContext, C carrier, Setter<C> setter) {
+
     char[] chars = new char[PROPAGATION_HEADER_SIZE];
 
     String traceId = spanContext.getTraceIdAsHexString();
@@ -108,16 +118,27 @@ public <C> void inject(Context context, C carrier, Setter<C> setter) {
     setter.set(carrier, PROPAGATION_HEADER, new String(chars));
   }
 
+  private static <C> void injectBaggage(Baggage baggage, C carrier, Setter<C> setter) {
+    for (Entry entry : baggage.getEntries()) {
+      setter.set(carrier, BAGGAGE_PREFIX + entry.getKey(), entry.getValue());
+    }
+  }
+
   @Override
   public <C> Context extract(Context context, @Nullable C carrier, Getter<C> getter) {
     Objects.requireNonNull(getter, "getter");
 
     SpanContext spanContext = getSpanContextFromHeader(carrier, getter);
-    if (!spanContext.isValid()) {
-      return context;
+    if (spanContext.isValid()) {
+      context = context.with(Span.wrap(spanContext));
+    }
+
+    Baggage baggage = getBaggageFromHeader(carrier, getter);
+    if (baggage != null) {
+      context = context.with(baggage);
     }
 
-    return context.with(Span.wrap(spanContext));
+    return context;
   }
 
   @SuppressWarnings("StringSplitter")
@@ -187,6 +208,42 @@ private static <C> SpanContext getSpanContextFromHeader(C carrier, Getter<C> get
     return buildSpanContext(traceId, spanId, flags);
   }
 
+  private static <C> Baggage getBaggageFromHeader(C carrier, Getter<C> getter) {
+    Baggage.Builder builder = null;
+
+    for (String key : getter.keys(carrier)) {
+      if (key.startsWith(BAGGAGE_PREFIX)) {
+        if (key.length() <= BAGGAGE_PREFIX.length()) {
+          continue;
+        }
+
+        if (builder == null) {
+          builder = Baggage.builder();
+        }
+        builder.put(key.substring(BAGGAGE_PREFIX.length()), getter.get(carrier, key));
+      } else if (key.equals(BAGGAGE_HEADER)) {
+        builder = parseBaggageHeader(getter.get(carrier, key), builder);
+      }
+    }
+    return builder == null ? null : builder.build();
+  }
+
+  @SuppressWarnings("StringSplitter")
+  private static Baggage.Builder parseBaggageHeader(String header, Baggage.Builder builder) {
+    for (String part : header.split("\\s*,\\s*")) {
+      String[] kv = part.split("\\s*=\\s*");
+      if (kv.length == 2) {
+        if (builder == null) {
+          builder = Baggage.builder();
+        }
+        builder.put(kv[0], kv[1]);
+      } else {
+        logger.fine("malformed token in " + BAGGAGE_HEADER + " header: " + part);
+      }
+    }
+    return builder;
+  }
+
   private static SpanContext buildSpanContext(String traceId, String spanId, String flags) {
     try {
       int flagsInt = Integer.parseInt(flags);