ActivityTraceLayoutRenderer - Renders System.Diagnostics.Activity.Cur…

…rent properties

src/NLog.Extensions.Logging/LayoutRenderers/ActivityTraceLayoutRenderer.cs

@@ -0,0 +1,143 @@
+#if NETCOREAPP3_0
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+using NLog.Config;
+using NLog.LayoutRenderers;
+
+namespace NLog.Extensions.Logging
+{
+    /// <summary>
+    /// Layout renderer that can render properties from <see cref="System.Diagnostics.Activity.Current"/>
+    /// </summary>
+    [LayoutRenderer("activity")]
+    [ThreadSafe]
+    public sealed class ActivityTraceLayoutRenderer : LayoutRenderer
+    {
+        private static readonly string EmptySpanId = default(System.Diagnostics.ActivitySpanId).ToString();
+        private static readonly string EmptyTraceId = default(System.Diagnostics.ActivityTraceId).ToString();
+
+        /// <summary>
+        /// Gets or sets the property to retrieve.
+        /// </summary>
+        public ActivityTraceProperty Property { get; set; } = ActivityTraceProperty.Id;
+
+        /// <summary>
+        /// Single item to extract from <see cref="System.Diagnostics.Activity.Baggage"/> or <see cref="System.Diagnostics.Activity.Tags"/>
+        /// </summary>
+        public string Item { get; set; }
+
+        /// <summary>
+        /// Control output formating of selected property (if supported)
+        /// </summary>
+        public string Format { get; set; }
+
+        /// <inheritdoc />
+        protected override void Append(StringBuilder builder, LogEventInfo logEvent)
+        {
+            var activity = System.Diagnostics.Activity.Current;
+            if (activity == null)
+                return;
+
+            if ((Property == ActivityTraceProperty.Baggage || Property == ActivityTraceProperty.Tags) && string.IsNullOrEmpty(Item))
+            {
+                var collection = Property == ActivityTraceProperty.Baggage ? activity.Baggage : activity.Tags;
+                if (Format == "@")
+                {
+                    RenderStringDictionaryJson(collection, builder);
+                }
+                else
+                {
+                    RenderStringDictionaryFlat(collection, builder);
+                }
+            }
+            else
+            {
+                var value = GetValue(activity);
+                builder.Append(value);
+            }
+        }
+
+        private string GetValue(System.Diagnostics.Activity activity)
+        {
+            switch (Property)
+            {
+                case ActivityTraceProperty.Id: return activity.Id;
+                case ActivityTraceProperty.TraceId: return CoalesceTraceId(activity.TraceId.ToString());
+                case ActivityTraceProperty.SpanId: return CoalesceSpanId(activity.SpanId.ToString());
+                case ActivityTraceProperty.OperationName: return activity.OperationName;
+                case ActivityTraceProperty.StartTimeUtc:return activity.StartTimeUtc > DateTime.MinValue ? activity.StartTimeUtc.ToString(Format) : string.Empty;
+                case ActivityTraceProperty.Duration: return activity.StartTimeUtc > DateTime.MinValue ? activity.Duration.ToString(Format) : string.Empty;
+                case ActivityTraceProperty.ParentId: return activity.ParentId;
+                case ActivityTraceProperty.ParentSpanId: return CoalesceSpanId(activity.ParentSpanId.ToString());
+                case ActivityTraceProperty.RootId: return activity.RootId;
+                case ActivityTraceProperty.TraceState: return activity.TraceStateString;
+                case ActivityTraceProperty.ActivityTraceFlags: return activity.ActivityTraceFlags == System.Diagnostics.ActivityTraceFlags.None && string.IsNullOrEmpty(Format) ? string.Empty : activity.ActivityTraceFlags.ToString(Format);
+                case ActivityTraceProperty.Baggage: return GetCollectionItem(Item, activity.Baggage);
+                case ActivityTraceProperty.Tags: return GetCollectionItem(Item, activity.Tags);
+                default: return string.Empty;
+            }
+        }
+
+        private static void RenderStringDictionaryFlat(IEnumerable<KeyValuePair<string, string>> collection, StringBuilder builder)
+        {
+            var firstItem = true;
+            foreach (var keyValue in collection)
+            {
+                if (!firstItem)
+                    builder.Append(",");
+                firstItem = false;
+                builder.Append(keyValue.Key);
+                builder.Append("=");
+                builder.Append(keyValue.Value);
+            }
+        }
+
+        private static void RenderStringDictionaryJson(IEnumerable<KeyValuePair<string, string>> collection, StringBuilder builder)
+        {
+            var firstItem = true;
+            foreach (var keyValue in collection)
+            {
+                if (firstItem)
+                    builder.Append("{ ");
+                else
+                    builder.Append(", ");
+                firstItem = false;
+                builder.Append("\"");
+                builder.Append(keyValue.Key);
+                builder.Append("\": \"");
+                builder.Append(keyValue.Value);
+                builder.Append("\"");
+            }
+            if (!firstItem)
+                builder.Append(" }");
+        }
+
+        private static string GetCollectionItem(string item, IEnumerable<KeyValuePair<string,string>> collection)
+        {
+            foreach (var keyValue in collection)
+                if (item.Equals(keyValue.Key, StringComparison.OrdinalIgnoreCase))
+                    return keyValue.Value;
+            return string.Empty;
+        }
+
+        private string CoalesceTraceId(string traceId)
+        {
+            if (EmptyTraceId == traceId)
+                return string.Empty;
+            else
+                return traceId;
+        }
+
+        private string CoalesceSpanId(string spanId)
+        {
+            if (EmptySpanId == spanId)
+                return string.Empty;
+            else
+                return spanId;
+        }
+    }
+}
+
+#endif

src/NLog.Extensions.Logging/LayoutRenderers/ActivityTraceProperty.cs

@@ -0,0 +1,65 @@
+#if NETCOREAPP3_0
+
+namespace NLog.Extensions.Logging
+{
+    /// <summary>
+    /// Properties from <see cref="System.Diagnostics.Activity"/> available for <see cref="ActivityTraceLayoutRenderer"/> 
+    /// </summary>
+    public enum ActivityTraceProperty
+    {
+        /// <summary>
+        /// Identifier that is specific to a particular request.
+        /// </summary>
+        Id,
+        /// <summary>
+        /// TraceId part of the <see cref="Id"/>
+        /// </summary>
+        TraceId,
+        /// <summary>
+        /// SPAN part of the <see cref="Id"/>
+        /// </summary>
+        SpanId,
+        /// <summary>
+        /// Operation name.
+        /// </summary>
+        OperationName,
+        /// <summary>
+        /// Time when the operation started.
+        /// </summary>
+        StartTimeUtc,
+        /// <summary>
+        /// Duration of the operation.
+        /// </summary>
+        Duration,
+        /// <summary>
+        /// Collection of key/value pairs that are passed to children of this Activity.
+        /// </summary>
+        Baggage,
+        /// <summary>
+        /// Collection of key/value pairs that are NOT passed to children of this Activity
+        /// </summary>
+        Tags,
+        /// <summary>
+        /// Activity's Parent ID.
+        /// </summary>
+        ParentId,
+        /// <summary>
+        /// Activity's Parent SpanID.
+        /// </summary>
+        ParentSpanId,
+        /// <summary>
+        /// Root ID of this Activity.
+        /// </summary>
+        RootId,
+        /// <summary>
+        /// W3C tracestate header.
+        /// </summary>
+        TraceState,
+        /// <summary>
+        /// <see cref="System.Diagnostics.ActivityTraceFlags"/> for activity (defined by the W3C ID specification) 
+        /// </summary>
+        ActivityTraceFlags,
+    }
+}
+
+#endif