Addjaeger (#7)

* added jaeger progagator with tests

* updated changelog

* moved comment to unreleased

src/OpenTelemetry.Extensions.Propagators/.publicApi/net462/PublicAPI.Unshipped.txt

@@ -0,0 +1,5 @@
+OpenTelemetry.Extensions.Propagators.JaegerPropagator
+OpenTelemetry.Extensions.Propagators.JaegerPropagator.JaegerPropagator() -> void
+override OpenTelemetry.Extensions.Propagators.JaegerPropagator.Extract<T>(OpenTelemetry.Context.Propagation.PropagationContext context, T carrier, System.Func<T, string, System.Collections.Generic.IEnumerable<string>> getter) -> OpenTelemetry.Context.Propagation.PropagationContext
+override OpenTelemetry.Extensions.Propagators.JaegerPropagator.Fields.get -> System.Collections.Generic.ISet<string>
+override OpenTelemetry.Extensions.Propagators.JaegerPropagator.Inject<T>(OpenTelemetry.Context.Propagation.PropagationContext context, T carrier, System.Action<T, string, string> setter) -> void

src/OpenTelemetry.Extensions.Propagators/.publicApi/netstandard2.0/PublicAPI.Unshipped.txt

@@ -0,0 +1,5 @@
+OpenTelemetry.Extensions.Propagators.JaegerPropagator
+OpenTelemetry.Extensions.Propagators.JaegerPropagator.JaegerPropagator() -> void
+override OpenTelemetry.Extensions.Propagators.JaegerPropagator.Extract<T>(OpenTelemetry.Context.Propagation.PropagationContext context, T carrier, System.Func<T, string, System.Collections.Generic.IEnumerable<string>> getter) -> OpenTelemetry.Context.Propagation.PropagationContext
+override OpenTelemetry.Extensions.Propagators.JaegerPropagator.Fields.get -> System.Collections.Generic.ISet<string>
+override OpenTelemetry.Extensions.Propagators.JaegerPropagator.Inject<T>(OpenTelemetry.Context.Propagation.PropagationContext context, T carrier, System.Action<T, string, string> setter) -> void

src/OpenTelemetry.Extensions.Propagators/CHANGELOG.md

@@ -4,3 +4,5 @@
 
 * Initial release. This has been ported as is from
 [OpenTelemetry.Api](../OpenTelemetry.Api/README.md) package.
+
+* added jaegerpropagator for issue [1881](https://github.com/open-telemetry/opentelemetry-dotnet/issues/1881)

src/OpenTelemetry.Extensions.Propagators/JaegerPropagator.cs

@@ -0,0 +1,180 @@
+// <copyright file="JaegerPropagator.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.Diagnostics;
+using System.Linq;
+using OpenTelemetry.Context.Propagation;
+using OpenTelemetry.Internal;
+
+namespace OpenTelemetry.Extensions.Propagators;
+
+/// <summary>
+/// A text map propagator for Jaeger trace context. See https://www.jaegertracing.io/docs/next-release/client-libraries/#propagation-format.
+/// </summary>
+public class JaegerPropagator : TextMapPropagator
+{
+    internal const string JaegerHeader = "uber-trace-id";
+    internal const string JaegerDelimiter = ":";
+    internal const string JaegerDelimiterEncoded = "%3A"; // while the spec defines the delimiter as a ':', some clients will url encode headers.
+    internal const string SampledValue = "1";
+
+    internal static readonly string[] JaegerDelimiters = { JaegerDelimiter, JaegerDelimiterEncoded };
+
+    private static readonly int TraceId128BitLength = "0af7651916cd43dd8448eb211c80319c".Length;
+    private static readonly int SpanIdLength = "00f067aa0ba902b7".Length;
+
+    /// <inheritdoc/>
+    public override ISet<string> Fields => new HashSet<string> { JaegerHeader };
+
+    /// <inheritdoc/>
+    public override PropagationContext Extract<T>(PropagationContext context, T carrier, Func<T, string, IEnumerable<string>> getter)
+    {
+        if (context.ActivityContext.IsValid())
+        {
+            // If a valid context has already been extracted, perform a noop.
+            return context;
+        }
+
+        if (carrier == null)
+        {
+            OpenTelemetryApiEventSource.Log.FailedToExtractActivityContext(nameof(JaegerPropagator), "null carrier");
+            return context;
+        }
+
+        if (getter == null)
+        {
+            OpenTelemetryApiEventSource.Log.FailedToExtractActivityContext(nameof(JaegerPropagator), "null getter");
+            return context;
+        }
+
+        try
+        {
+            var jaegerHeaderCollection = getter(carrier, JaegerHeader);
+            var jaegerHeader = jaegerHeaderCollection?.First();
+
+            if (string.IsNullOrWhiteSpace(jaegerHeader))
+            {
+                return context;
+            }
+
+            var jaegerHeaderParsed = TryExtractTraceContext(jaegerHeader, out var traceId, out var spanId, out var traceOptions);
+
+            if (!jaegerHeaderParsed)
+            {
+                return context;
+            }
+
+            return new PropagationContext(
+                new ActivityContext(traceId, spanId, traceOptions, isRemote: true),
+                context.Baggage);
+        }
+        catch (Exception ex)
+        {
+            OpenTelemetryApiEventSource.Log.ActivityContextExtractException(nameof(JaegerPropagator), ex);
+        }
+
+        return context;
+    }
+
+    /// <inheritdoc/>
+    public override void Inject<T>(PropagationContext context, T carrier, Action<T, string, string> setter)
+    {
+        // from https://www.jaegertracing.io/docs/next-release/client-libraries/#propagation-format
+        // parent id is optional and deprecated, will not attempt to set it.
+        // 128 bit uber-trace-id=e0ad975be108cd107990683f59cda9e6:e422f3fe664f6342:0:1
+        const string defaultParentSpanId = "0";
+
+        if (context.ActivityContext.TraceId == default || context.ActivityContext.SpanId == default)
+        {
+            OpenTelemetryApiEventSource.Log.FailedToInjectActivityContext(nameof(JaegerPropagator), "Invalid context");
+            return;
+        }
+
+        if (carrier == null)
+        {
+            OpenTelemetryApiEventSource.Log.FailedToInjectActivityContext(nameof(JaegerPropagator), "null carrier");
+            return;
+        }
+
+        if (setter == null)
+        {
+            OpenTelemetryApiEventSource.Log.FailedToInjectActivityContext(nameof(JaegerPropagator), "null setter");
+            return;
+        }
+
+        var flags = (context.ActivityContext.TraceFlags & ActivityTraceFlags.Recorded) != 0 ? "1" : "0";
+
+        var jaegerTrace = string.Join(
+            JaegerDelimiter,
+            context.ActivityContext.TraceId.ToHexString(),
+            context.ActivityContext.SpanId.ToHexString(),
+            defaultParentSpanId,
+            flags);
+
+        setter(carrier, JaegerHeader, jaegerTrace);
+    }
+
+    internal static bool TryExtractTraceContext(string jaegerHeader, out ActivityTraceId traceId, out ActivitySpanId spanId, out ActivityTraceFlags traceOptions)
+    {
+        // from https://www.jaegertracing.io/docs/next-release/client-libraries/#propagation-format
+        // parent id is optional and deprecated. will not attempt to store it.
+        // 128 bit uber-trace-id=e0ad975be108cd107990683f59cda9e6:e422f3fe664f6342:0:1
+        // 128 bit with encoded delimiter uber-trace-id=e0ad975be108cd107990683f59cda9e6%3Ae422f3fe664f6342%3A0%3A1
+        //  64 bit uber-trace-id=7990683f59cda9e6:e422f3fe664f6342:0:1
+        //  64 bit with encoded delimiter uber-trace-id=7990683f59cda9e6%3Ae422f3fe664f6342%3A0%3A1
+
+        traceId = default;
+        spanId = default;
+        traceOptions = ActivityTraceFlags.None;
+
+        if (string.IsNullOrWhiteSpace(jaegerHeader))
+        {
+            return false;
+        }
+
+        var traceComponents = jaegerHeader.Split(JaegerDelimiters, StringSplitOptions.RemoveEmptyEntries);
+        if (traceComponents.Length != 4)
+        {
+            return false;
+        }
+
+        var traceIdStr = traceComponents[0];
+        if (traceIdStr.Length < TraceId128BitLength)
+        {
+            traceIdStr = traceIdStr.PadLeft(TraceId128BitLength, '0');
+        }
+
+        traceId = ActivityTraceId.CreateFromString(traceIdStr.AsSpan());
+
+        var spanIdStr = traceComponents[1];
+        if (spanIdStr.Length < SpanIdLength)
+        {
+            spanIdStr = spanIdStr.PadLeft(SpanIdLength, '0');
+        }
+
+        spanId = ActivitySpanId.CreateFromString(spanIdStr.AsSpan());
+
+        var traceFlagsStr = traceComponents[3];
+        if (SampledValue.Equals(traceFlagsStr))
+        {
+            traceOptions |= ActivityTraceFlags.Recorded;
+        }
+
+        return true;
+    }
+}