Make the baggage API fully functional in the API

api/src/main/java/io/opentelemetry/OpenTelemetry.java

@@ -6,7 +6,6 @@
 package io.opentelemetry;
 
 import io.opentelemetry.baggage.BaggageManager;
-import io.opentelemetry.baggage.DefaultBaggageManager;
 import io.opentelemetry.baggage.spi.BaggageManagerFactory;
 import io.opentelemetry.context.propagation.ContextPropagators;
 import io.opentelemetry.context.propagation.DefaultContextPropagators;
@@ -37,13 +36,13 @@
  */
 @ThreadSafe
 public final class OpenTelemetry {
+
   private static final Object mutex = new Object();
 
   @Nullable private static volatile OpenTelemetry instance;
 
   private final TracerProvider tracerProvider;
   private final MeterProvider meterProvider;
-  private final BaggageManager contextManager;
 
   private volatile ContextPropagators propagators = DefaultContextPropagators.builder().build();
 
@@ -126,17 +125,6 @@ public static Meter getMeter(String instrumentationName, String instrumentationV
     return getMeterProvider().get(instrumentationName, instrumentationVersion);
   }
 
-  /**
-   * Returns a singleton {@link BaggageManager}.
-   *
-   * @return registered manager or default via {@link DefaultBaggageManager#getInstance()}.
-   * @throws IllegalStateException if a specified manager (via system properties) could not be
-   *     found.
-   */
-  public static BaggageManager getBaggageManager() {
-    return getInstance().contextManager;
-  }
-
   /**
    * Returns a {@link ContextPropagators} object, which can be used to access the set of registered
    * propagators for each supported format.
@@ -188,11 +176,6 @@ private OpenTelemetry() {
         meterProviderFactory != null
             ? meterProviderFactory.create()
             : DefaultMeterProvider.getInstance();
-    BaggageManagerFactory contextManagerProvider = loadSpi(BaggageManagerFactory.class);
-    contextManager =
-        contextManagerProvider != null
-            ? contextManagerProvider.create()
-            : DefaultBaggageManager.getInstance();
   }
 
   /**

api/src/main/java/io/opentelemetry/baggage/Baggage.java

@@ -19,6 +19,17 @@
  */
 @Immutable
 public interface Baggage {
+
+  /** Baggage with no entries. */
+  static Baggage empty() {
+    return ImmutableBaggage.EMPTY;
+  }
+
+  /** Creates a new {@link Builder} for creating Baggage. */
+  static Builder builder() {
+    return ImmutableBaggage.builder();
+  }
+
   /**
    * Returns an immutable collection of the entries in this {@code Baggage}. Order of entries is not
    * guaranteed.
@@ -39,10 +50,11 @@ public interface Baggage {
 
   /** Builder for the {@link Baggage} class. */
   interface Builder {
+
     /**
      * Sets the parent {@link Baggage} to use from the specified {@code Context}. If no parent
-     * {@link Baggage} is provided, the value of {@link BaggageManager#getCurrentBaggage()} at
-     * {@link #build()} time will be used as parent, unless {@link #setNoParent()} was called.
+     * {@link Baggage} is provided, the value of {@link BaggageUtils#getCurrentBaggage()} at {@link
+     * #build()} time will be used as parent, unless {@link #setNoParent()} was called.
      *
      * <p>If no parent {@link Baggage} is available in the specified {@code Context}, the resulting
      * {@link Baggage} will become a root instance, as if {@link #setNoParent()} had been called.
@@ -62,7 +74,7 @@ interface Builder {
     /**
      * Sets the option to become a root {@link Baggage} with no parent. If <b>not</b> called, the
      * value provided using {@link #setParent(Context)} or otherwise {@link
-     * BaggageManager#getCurrentBaggage()} at {@link #build()} time will be used as parent.
+     * BaggageUtils#getCurrentBaggage()} at {@link #build()} time will be used as parent.
      *
      * @return this.
      */
@@ -78,6 +90,15 @@ interface Builder {
      */
     Builder put(String key, String value, EntryMetadata entryMetadata);
 
+    /**
+     * Adds the key/value pair with empty metadata regardless of whether the key is present.
+     *
+     * @param key the {@code String} key which will be set.
+     * @param value the {@code String} value to set for the given key.
+     * @return this
+     */
+    Builder put(String key, String value);
+
     /**
      * Removes the key if it exists.
      *

api/src/main/java/io/opentelemetry/baggage/BaggageUtils.java

@@ -47,7 +47,7 @@ public static Baggage getCurrentBaggage() {
    */
   public static Baggage getBaggage(Context context) {
     Baggage baggage = context.getValue(CORR_CONTEXT_KEY);
-    return baggage == null ? EmptyBaggage.getInstance() : baggage;
+    return baggage == null ? Baggage.empty() : baggage;
   }
 
   /**

sdk/baggage/src/main/java/io/opentelemetry/sdk/baggage/BaggageSdk.java → api/src/main/java/io/opentelemetry/baggage/ImmutableBaggage.java

@@ -3,13 +3,8 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-package io.opentelemetry.sdk.baggage;
+package io.opentelemetry.baggage;
 
-import io.opentelemetry.OpenTelemetry;
-import io.opentelemetry.baggage.Baggage;
-import io.opentelemetry.baggage.BaggageUtils;
-import io.opentelemetry.baggage.Entry;
-import io.opentelemetry.baggage.EntryMetadata;
 import io.opentelemetry.context.Context;
 import java.util.Collection;
 import java.util.Collections;
@@ -22,24 +17,29 @@
 @Immutable
 // TODO: Migrate to AutoValue
 // @AutoValue
-class BaggageSdk implements Baggage {
+class ImmutableBaggage implements Baggage {
+  static final Baggage EMPTY = new ImmutableBaggage.Builder().build();
 
   // The types of the EntryKey and Entry must match for each entry.
   private final Map<String, Entry> entries;
   @Nullable private final Baggage parent;
 
   /**
-   * Creates a new {@link BaggageSdk} with the given entries.
+   * Creates a new {@link ImmutableBaggage} with the given entries.
    *
    * @param entries the initial entries for this {@code BaggageSdk}.
    * @param parent providing a default set of entries
    */
-  private BaggageSdk(Map<String, ? extends Entry> entries, Baggage parent) {
+  private ImmutableBaggage(Map<String, ? extends Entry> entries, Baggage parent) {
     this.entries =
         Collections.unmodifiableMap(new HashMap<>(Objects.requireNonNull(entries, "entries")));
     this.parent = parent;
   }
 
+  public static Baggage.Builder builder() {
+    return new Builder();
+  }
+
   @Override
   public Collection<Entry> getEntries() {
     Map<String, Entry> combined = new HashMap<>(entries);
@@ -72,16 +72,16 @@ public boolean equals(Object o) {
     if (this == o) {
       return true;
     }
-    if (!(o instanceof BaggageSdk)) {
+    if (!(o instanceof ImmutableBaggage)) {
       return false;
     }
 
-    BaggageSdk baggageSdk = (BaggageSdk) o;
+    ImmutableBaggage baggage = (ImmutableBaggage) o;
 
-    if (!entries.equals(baggageSdk.entries)) {
+    if (!entries.equals(baggage.entries)) {
       return false;
     }
-    return Objects.equals(parent, baggageSdk.parent);
+    return Objects.equals(parent, baggage.parent);
   }
 
   @Override
@@ -91,6 +91,11 @@ public int hashCode() {
     return result;
   }
 
+  @Override
+  public String toString() {
+    return "ImmutableBaggage{" + "entries=" + entries + ", parent=" + parent + '}';
+  }
+
   // TODO: Migrate to AutoValue.Builder
   // @AutoValue.Builder
   static class Builder implements Baggage.Builder {
@@ -128,6 +133,14 @@ public Baggage.Builder put(String key, String value, EntryMetadata entryMetadata
       return this;
     }
 
+    @Override
+    public Baggage.Builder put(String key, String value) {
+      entries.put(
+          Objects.requireNonNull(key, "key"),
+          Entry.create(key, Objects.requireNonNull(value, "value"), EntryMetadata.EMPTY));
+      return this;
+    }
+
     @Override
     public Baggage.Builder remove(String key) {
       entries.remove(Objects.requireNonNull(key, "key"));
@@ -138,11 +151,11 @@ public Baggage.Builder remove(String key) {
     }
 
     @Override
-    public BaggageSdk build() {
+    public ImmutableBaggage build() {
       if (parent == null && !noImplicitParent) {
-        parent = OpenTelemetry.getBaggageManager().getCurrentBaggage();
+        parent = BaggageUtils.getCurrentBaggage();
       }
-      return new BaggageSdk(entries, parent);
+      return new ImmutableBaggage(entries, parent);
     }
   }
 }

api/src/main/java/io/opentelemetry/baggage/propagation/W3CBaggagePropagator.java

@@ -11,7 +11,6 @@
 import io.opentelemetry.baggage.Baggage;
 import io.opentelemetry.baggage.BaggageManager;
 import io.opentelemetry.baggage.BaggageUtils;
-import io.opentelemetry.baggage.EmptyBaggage;
 import io.opentelemetry.baggage.Entry;
 import io.opentelemetry.baggage.EntryMetadata;
 import io.opentelemetry.context.Context;
@@ -26,15 +25,7 @@ public class W3CBaggagePropagator implements TextMapPropagator {
 
   private static final String FIELD = "baggage";
   private static final List<String> FIELDS = singletonList(FIELD);
-  private static final W3CBaggagePropagator INSTANCE =
-      new W3CBaggagePropagator(OpenTelemetry.getBaggageManager());
-
-  private final BaggageManager baggageManager;
-
-  // visible for testing
-  W3CBaggagePropagator(BaggageManager baggageManager) {
-    this.baggageManager = baggageManager;
-  }
+  private static final W3CBaggagePropagator INSTANCE = new W3CBaggagePropagator();
 
   /**
    * Singleton instance of the W3C Baggage Propagator. Uses the {@link BaggageManager} from the
@@ -77,14 +68,14 @@ public <C> Context extract(Context context, @Nullable C carrier, Getter<C> gette
       return context;
     }
     if (baggageHeader.isEmpty()) {
-      return BaggageUtils.withBaggage(EmptyBaggage.getInstance(), context);
+      return BaggageUtils.withBaggage(Baggage.empty(), context);
     }
 
-    Baggage.Builder baggageBuilder = baggageManager.baggageBuilder();
+    Baggage.Builder baggageBuilder = Baggage.builder();
     try {
       extractEntries(baggageHeader, baggageBuilder);
     } catch (Exception e) {
-      return BaggageUtils.withBaggage(EmptyBaggage.getInstance(), context);
+      return BaggageUtils.withBaggage(Baggage.empty(), context);
     }
     return BaggageUtils.withBaggage(baggageBuilder.build(), context);
   }