CorrelationContext -> Baggage

examples/MicroserviceExample/Utils/Messaging/MessageSender.cs

@@ -19,6 +19,7 @@
 using System.Diagnostics;
 using System.Text;
 using Microsoft.Extensions.Logging;
+using OpenTelemetry;
 using OpenTelemetry.Context.Propagation;
 using RabbitMQ.Client;
 
@@ -61,7 +62,7 @@ public string SendMessage()
                     if (activity != null)
                     {
                         // Inject the ActivityContext into the message headers to propagate trace context to the receiving service.
-                        TextFormat.Inject(new PropagationContext(activity.Context, activity.Baggage), props, this.InjectTraceContextIntoBasicProperties);
+                        TextFormat.Inject(new PropagationContext(activity.Context, Baggage.Current), props, this.InjectTraceContextIntoBasicProperties);
 
                         // The OpenTelemetry messaging specification defines a number of attributes. These attributes are added here.
                         RabbitMqHelper.AddMessagingTags(activity);

src/OpenTelemetry.Api/Baggage.cs

@@ -0,0 +1,305 @@
+// <copyright file="Baggage.cs" company="OpenTelemetry Authors">
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// </copyright>
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using OpenTelemetry.Context;
+
+namespace OpenTelemetry
+{
+    /// <summary>
+    /// Baggage implementation.
+    /// </summary>
+    /// <remarks>
+    /// Spec reference: <a href="https://github.com/open-telemetry/opentelemetry-specification/blob/master/specification/baggage/api.md">Baggage API</a>.
+    /// </remarks>
+    public readonly struct Baggage : IEquatable<Baggage>
+    {
+        private static readonly RuntimeContextSlot<Baggage> RuntimeContextSlot = RuntimeContext.RegisterSlot<Baggage>("otel.baggage");
+        private static readonly Dictionary<string, string> EmptyBaggage = new Dictionary<string, string>();
+
+        private readonly Dictionary<string, string> baggage;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Baggage"/> struct.
+        /// </summary>
+        /// <param name="baggage">Baggage key/value pairs.</param>
+        internal Baggage(Dictionary<string, string> baggage)
+        {
+            this.baggage = baggage;
+        }
+
+        /// <summary>
+        /// Gets or sets the current <see cref="Baggage"/>.
+        /// </summary>
+        public static Baggage Current
+        {
+            get => RuntimeContextSlot.Get();
+            set => RuntimeContextSlot.Set(value);
+        }
+
+        /// <summary>
+        /// Gets the number of key/value pairs in the baggage.
+        /// </summary>
+        public int Count => this.baggage?.Count ?? 0;
+
+        /// <summary>
+        /// Compare two entries of <see cref="Baggage"/> for equality.
+        /// </summary>
+        /// <param name="left">First Entry to compare.</param>
+        /// <param name="right">Second Entry to compare.</param>
+        public static bool operator ==(Baggage left, Baggage right) => left.Equals(right);
+
+        /// <summary>
+        /// Compare two entries of <see cref="Baggage"/> for not equality.
+        /// </summary>
+        /// <param name="left">First Entry to compare.</param>
+        /// <param name="right">Second Entry to compare.</param>
+        public static bool operator !=(Baggage left, Baggage right) => !(left == right);
+
+        /// <summary>
+        /// Create a <see cref="Baggage"/> instance from dictionary of baggage key/value pairs.
+        /// </summary>
+        /// <param name="baggageItems">Baggage key/value pairs.</param>
+        /// <returns><see cref="Baggage"/>.</returns>
+        public static Baggage Create(Dictionary<string, string> baggageItems = null)
+        {
+            if (baggageItems == null)
+            {
+                return default;
+            }
+
+            Dictionary<string, string> baggageCopy = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
+            foreach (KeyValuePair<string, string> baggageItem in baggageItems)
+            {
+                if (string.IsNullOrEmpty(baggageItem.Value))
+                {
+                    baggageCopy.Remove(baggageItem.Key);
+                    continue;
+                }
+
+                baggageCopy[baggageItem.Key] = baggageItem.Value;
+            }
+
+            return new Baggage(baggageCopy);
+        }
+
+        /// <summary>
+        /// Returns the name/value pairs in the <see cref="Baggage"/>.
+        /// </summary>
+        /// <param name="baggage">Optional <see cref="Baggage"/>. <see cref="Current"/> is used if not specified.</param>
+        /// <returns>Baggage key/value pairs.</returns>
+        public static IReadOnlyDictionary<string, string> GetBaggage(Baggage baggage = default)
+            => baggage == default ? Current.GetBaggage() : baggage.GetBaggage();
+
+        /// <summary>
+        /// Returns an enumerator that iterates through the <see cref="Baggage"/>.
+        /// </summary>
+        /// <param name="baggage">Optional <see cref="Baggage"/>. <see cref="Current"/> is used if not specified.</param>
+        /// <returns><see cref="Dictionary{TKey, TValue}.Enumerator"/>.</returns>
+        public static Dictionary<string, string>.Enumerator GetEnumerator(Baggage baggage = default)
+            => baggage == default ? Current.GetEnumerator() : baggage.GetEnumerator();
+
+        /// <summary>
+        /// Returns the value associated with the given name, or <see langword="null"/> if the given name is not present.
+        /// </summary>
+        /// <param name="name">Baggage item name.</param>
+        /// <param name="baggage">Optional <see cref="Baggage"/>. <see cref="Current"/> is used if not specified.</param>
+        /// <returns>Baggage item or <see langword="null"/> if nothing was found.</returns>
+        public static string GetBaggage(string name, Baggage baggage = default)
+            => baggage == default ? Current.GetBaggage(name) : baggage.GetBaggage(name);
+
+        /// <summary>
+        /// Returns a new <see cref="Baggage"/> which contains the new key/value pair.
+        /// </summary>
+        /// <param name="name">Baggage item name.</param>
+        /// <param name="value">Baggage item value.</param>
+        /// <param name="baggage">Optional <see cref="Baggage"/>. <see cref="Current"/> is used if not specified.</param>
+        /// <returns>New <see cref="Baggage"/> containing the key/value pair.</returns>
+        public static Baggage SetBaggage(string name, string value, Baggage baggage = default)
+            => baggage == default ? Current.SetBaggage(name, value) : baggage.SetBaggage(name, value);
+
+        /// <summary>
+        /// Returns a new <see cref="Baggage"/> which contains the new key/value pair.
+        /// </summary>
+        /// <param name="baggageItems">Baggage key/value pairs.</param>
+        /// <param name="baggage">Optional <see cref="Baggage"/>. <see cref="Current"/> is used if not specified.</param>
+        /// <returns>New <see cref="Baggage"/> containing the key/value pair.</returns>
+        public static Baggage SetBaggage(IEnumerable<KeyValuePair<string, string>> baggageItems, Baggage baggage = default)
+           => baggage == default ? Current.SetBaggage(baggageItems) : baggage.SetBaggage(baggageItems);
+
+        /// <summary>
+        /// Returns a new <see cref="Baggage"/> with the key/value pair removed.
+        /// </summary>
+        /// <param name="name">Baggage item name.</param>
+        /// <param name="baggage">Optional <see cref="Baggage"/>. <see cref="Current"/> is used if not specified.</param>
+        /// <returns>New <see cref="Baggage"/> containing the key/value pair.</returns>
+        public static Baggage RemoveBaggage(string name, Baggage baggage = default)
+            => baggage == default ? Current.RemoveBaggage(name) : baggage.RemoveBaggage(name);
+
+        /// <summary>
+        /// Returns a new <see cref="Baggage"/> with all the key/value pairs removed.
+        /// </summary>
+        /// <param name="baggage">Optional <see cref="Baggage"/>. <see cref="Current"/> is used if not specified.</param>
+        /// <returns>New <see cref="Baggage"/> containing the key/value pair.</returns>
+        public static Baggage ClearBaggage(Baggage baggage = default)
+            => baggage == default ? Current.ClearBaggage() : baggage.ClearBaggage();
+
+        /// <summary>
+        /// Returns the name/value pairs in the <see cref="Baggage"/>.
+        /// </summary>
+        /// <returns>Baggage key/value pairs.</returns>
+        public IReadOnlyDictionary<string, string> GetBaggage()
+            => this.baggage ?? EmptyBaggage;
+
+        /// <summary>
+        /// Returns the value associated with the given name, or <see langword="null"/> if the given name is not present.
+        /// </summary>
+        /// <param name="name">Baggage item name.</param>
+        /// <returns>Baggage item or <see langword="null"/> if nothing was found.</returns>
+        public string GetBaggage(string name)
+        {
+            if (string.IsNullOrEmpty(name))
+            {
+                throw new ArgumentNullException(nameof(name));
+            }
+
+            return this.baggage != null && this.baggage.TryGetValue(name, out string value)
+                ? value
+                : null;
+        }
+
+        /// <summary>
+        /// Returns a new <see cref="Baggage"/> which contains the new key/value pair.
+        /// </summary>
+        /// <param name="name">Baggage item name.</param>
+        /// <param name="value">Baggage item value.</param>
+        /// <returns>New <see cref="Baggage"/> containing the key/value pair.</returns>
+        public Baggage SetBaggage(string name, string value)
+        {
+            if (string.IsNullOrEmpty(value))
+            {
+                return this.RemoveBaggage(name);
+            }
+
+            return Current = new Baggage(
+                new Dictionary<string, string>(this.baggage ?? EmptyBaggage, StringComparer.OrdinalIgnoreCase)
+                {
+                    [name] = value,
+                });
+        }
+
+        /// <summary>
+        /// Returns a new <see cref="Baggage"/> which contains the new key/value pair.
+        /// </summary>
+        /// <param name="baggageItems">Baggage key/value pairs.</param>
+        /// <returns>New <see cref="Baggage"/> containing the key/value pair.</returns>
+        public Baggage SetBaggage(params KeyValuePair<string, string>[] baggageItems)
+            => this.SetBaggage((IEnumerable<KeyValuePair<string, string>>)baggageItems);
+
+        /// <summary>
+        /// Returns a new <see cref="Baggage"/> which contains the new key/value pair.
+        /// </summary>
+        /// <param name="baggageItems">Baggage key/value pairs.</param>
+        /// <returns>New <see cref="Baggage"/> containing the key/value pair.</returns>
+        public Baggage SetBaggage(IEnumerable<KeyValuePair<string, string>> baggageItems)
+        {
+            if ((baggageItems?.Count() ?? 0) <= 0)
+            {
+                return this;
+            }
+
+            var newBaggage = new Dictionary<string, string>(this.baggage ?? EmptyBaggage, StringComparer.OrdinalIgnoreCase);
+
+            foreach (var item in baggageItems)
+            {
+                if (string.IsNullOrEmpty(item.Value))
+                {
+                    newBaggage.Remove(item.Key);
+                }
+                else
+                {
+                    newBaggage[item.Key] = item.Value;
+                }
+            }
+
+            return Current = new Baggage(newBaggage);
+        }
+
+        /// <summary>
+        /// Returns a new <see cref="Baggage"/> with the key/value pair removed.
+        /// </summary>
+        /// <param name="name">Baggage item name.</param>
+        /// <returns>New <see cref="Baggage"/> containing the key/value pair.</returns>
+        public Baggage RemoveBaggage(string name)
+        {
+            var baggage = new Dictionary<string, string>(this.baggage ?? EmptyBaggage, StringComparer.OrdinalIgnoreCase);
+            baggage.Remove(name);
+
+            return Current = new Baggage(baggage);
+        }
+
+        /// <summary>
+        /// Returns a new <see cref="Baggage"/> with all the key/value pairs removed.
+        /// </summary>
+        /// <returns>New <see cref="Baggage"/> containing the key/value pair.</returns>
+        public Baggage ClearBaggage()
+            => Current = default;
+
+        /// <summary>
+        /// Returns an enumerator that iterates through the <see cref="Baggage"/>.
+        /// </summary>
+        /// <returns><see cref="Dictionary{TKey, TValue}.Enumerator"/>.</returns>
+        public Dictionary<string, string>.Enumerator GetEnumerator()
+            => (this.baggage ?? EmptyBaggage).GetEnumerator();
+
+        /// <inheritdoc/>
+        public bool Equals(Baggage other)
+        {
+            bool baggageIsNullOrEmpty = this.baggage == null || this.baggage.Count <= 0;
+
+            if (baggageIsNullOrEmpty != (other.baggage == null || other.baggage.Count <= 0))
+            {
+                return false;
+            }
+
+            return baggageIsNullOrEmpty || this.baggage.SequenceEqual(other.baggage);
+        }
+
+        /// <inheritdoc/>
+        public override bool Equals(object obj)
+            => (obj is Baggage baggage) && this.Equals(baggage);
+
+        /// <inheritdoc/>
+        public override int GetHashCode()
+        {
+            var baggage = this.baggage ?? EmptyBaggage;
+
+            unchecked
+            {
+                int res = 17;
+                foreach (var item in baggage)
+                {
+                    res = (res * 23) + baggage.Comparer.GetHashCode(item.Key);
+                    res = (res * 23) + item.Value.GetHashCode();
+                }
+
+                return res;
+            }
+        }
+    }
+}

src/OpenTelemetry.Api/CHANGELOG.md

@@ -44,6 +44,11 @@
 * Changed `StartSpan` to not set the created span as Active to match the spec
   ([#994](https://github.com/open-telemetry/opentelemetry-dotnet/pull/994))
 * Updated System.Diagnostics.DiagnosticSource to version 5.0.0-preview.8.20407.11.
+* Removed `CorrelationContext` and added `Baggage`, an implementation of the
+  [`Baggage
+  API`](https://github.com/open-telemetry/opentelemetry-specification/blob/master/specification/baggage/api.md)
+  spec
+  ([#1106](https://github.com/open-telemetry/opentelemetry-dotnet/pull/1106))
 
 ## 0.4.0-beta.2