LogEmitter System.Diagnostics.Tracing extension project

examples/AspNetCore/Controllers/WeatherForecastController.cs

@@ -17,23 +17,28 @@
 namespace Examples.AspNetCore.Controllers;
 
 using Microsoft.AspNetCore.Mvc;
+using OpenTelemetry.Logs;
 
 [ApiController]
 [Route("[controller]")]
 public class WeatherForecastController : ControllerBase
 {
     private static readonly string[] Summaries = new[]
     {
-            "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching",
+        "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching",
     };
 
     private static readonly HttpClient HttpClient = new();
 
     private readonly ILogger<WeatherForecastController> logger;
+    private readonly LogEmitter logEmitter;
 
-    public WeatherForecastController(ILogger<WeatherForecastController> logger)
+    public WeatherForecastController(
+        ILogger<WeatherForecastController> logger,
+        LogEmitter logEmitter)
     {
         this.logger = logger ?? throw new ArgumentNullException(nameof(logger));
+        this.logEmitter = logEmitter ?? throw new ArgumentNullException(nameof(logEmitter));
     }
 
     [HttpGet]
@@ -54,11 +59,20 @@ public IEnumerable<WeatherForecast> Get()
         })
         .ToArray();
 
+        // Log using ILogger API.
         this.logger.LogInformation(
             "WeatherForecasts generated {count}: {forecasts}",
             forecast.Length,
             forecast);
 
+        // Log using LogEmitter API.
+        this.logEmitter.Log(new(
+            categoryName: "WeatherForecasts",
+            timestamp: DateTime.UtcNow,
+            logLevel: LogLevel.Information,
+            message: "WeatherForecasts generated.",
+            stateValues: new List<KeyValuePair<string, object?>>() { new KeyValuePair<string, object?>("count", forecast.Length) }));
+
         return forecast;
     }
 }

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

@@ -1,4 +1,9 @@
 #nullable enable
+OpenTelemetry.Logs.LogEmitter
+OpenTelemetry.Logs.LogEmitter.Log(OpenTelemetry.Logs.LogRecord! logRecord) -> void
+OpenTelemetry.Logs.LogEmitter.LogEmitter(OpenTelemetry.Logs.OpenTelemetryLoggerProvider! loggerProvider) -> void
 OpenTelemetry.Logs.LogRecord.FormattedMessage.set -> void
+OpenTelemetry.Logs.LogRecord.LogRecord(string! categoryName, System.DateTime timestamp, Microsoft.Extensions.Logging.LogLevel logLevel, string! message, Microsoft.Extensions.Logging.EventId eventId = default(Microsoft.Extensions.Logging.EventId), System.Exception? exception = null, System.Collections.Generic.IReadOnlyList<System.Collections.Generic.KeyValuePair<string!, object?>>? stateValues = null) -> void
 OpenTelemetry.Logs.LogRecord.State.set -> void
 OpenTelemetry.Logs.LogRecord.StateValues.set -> void
+OpenTelemetry.Logs.OpenTelemetryLoggerProvider.CreateEmitter() -> OpenTelemetry.Logs.LogEmitter!

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

@@ -1,4 +1,9 @@
 #nullable enable
+OpenTelemetry.Logs.LogEmitter
+OpenTelemetry.Logs.LogEmitter.Log(OpenTelemetry.Logs.LogRecord! logRecord) -> void
+OpenTelemetry.Logs.LogEmitter.LogEmitter(OpenTelemetry.Logs.OpenTelemetryLoggerProvider! loggerProvider) -> void
 OpenTelemetry.Logs.LogRecord.FormattedMessage.set -> void
+OpenTelemetry.Logs.LogRecord.LogRecord(string! categoryName, System.DateTime timestamp, Microsoft.Extensions.Logging.LogLevel logLevel, string! message, Microsoft.Extensions.Logging.EventId eventId = default(Microsoft.Extensions.Logging.EventId), System.Exception? exception = null, System.Collections.Generic.IReadOnlyList<System.Collections.Generic.KeyValuePair<string!, object?>>? stateValues = null) -> void
 OpenTelemetry.Logs.LogRecord.State.set -> void
 OpenTelemetry.Logs.LogRecord.StateValues.set -> void
+OpenTelemetry.Logs.OpenTelemetryLoggerProvider.CreateEmitter() -> OpenTelemetry.Logs.LogEmitter!

src/OpenTelemetry/Logs/LogEmitter.cs

@@ -0,0 +1,67 @@
+// <copyright file="LogEmitter.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>
+
+#nullable enable
+
+using OpenTelemetry.Internal;
+
+namespace OpenTelemetry.Logs
+{
+    /// <summary>
+    /// LogEmitter implementation.
+    /// </summary>
+    /// <remarks>
+    /// Spec reference: <a href="https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/logs/logging-library-sdk.md#logemitter">LogEmitter</a>.
+    /// </remarks>
+    public sealed class LogEmitter
+    {
+        private readonly OpenTelemetryLoggerProvider loggerProvider;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="LogEmitter"/> class.
+        /// </summary>
+        /// <param name="loggerProvider"><see cref="OpenTelemetryLoggerProvider"/>.</param>
+        public LogEmitter(OpenTelemetryLoggerProvider loggerProvider)
+        {
+            Guard.ThrowIfNull(loggerProvider);
+
+            this.loggerProvider = loggerProvider;
+        }
+
+        /// <summary>
+        /// Emit a <see cref="LogRecord"/>.
+        /// </summary>
+        /// <param name="logRecord"><see cref="LogRecord"/>.</param>
+        public void Log(LogRecord logRecord)
+        {
+            Guard.ThrowIfNull(logRecord);
+
+            var provider = this.loggerProvider;
+            var processor = provider.Processor;
+            if (processor != null)
+            {
+                if (provider.IncludeScopes)
+                {
+                    logRecord.ScopeProvider = provider.ScopeProvider;
+                }
+
+                processor.OnEnd(logRecord);
+
+                logRecord.ScopeProvider = null;
+            }
+        }
+    }
+}

src/OpenTelemetry/Logs/LogRecord.cs

@@ -36,6 +36,29 @@ public sealed class LogRecord
 
         private List<object?>? bufferedScopes;
 
+        public LogRecord(
+            string categoryName,
+            DateTime timestamp,
+            LogLevel logLevel,
+            string message,
+            EventId eventId = default,
+            Exception? exception = null,
+            IReadOnlyList<KeyValuePair<string, object?>>? stateValues = null)
+            : this(
+                  scopeProvider: null,
+                  timestamp.Kind == DateTimeKind.Local ? timestamp.ToUniversalTime() : timestamp,
+                  categoryName,
+                  logLevel,
+                  eventId,
+                  message,
+                  state: null,
+                  exception,
+                  stateValues)
+        {
+            Guard.ThrowIfNullOrEmpty(categoryName);
+            Guard.ThrowIfNullOrEmpty(message);
+        }
+
         internal LogRecord(
             IExternalScopeProvider? scopeProvider,
             DateTime timestamp,

src/OpenTelemetry/Logs/OpenTelemetryLoggerProvider.cs

@@ -112,6 +112,12 @@ public ILogger CreateLogger(string categoryName)
             return logger;
         }
 
+        /// <summary>
+        /// Create a <see cref="LogEmitter"/>.
+        /// </summary>
+        /// <returns><see cref="LogEmitter"/>.</returns>
+        public LogEmitter CreateEmitter() => new(this);
+
         internal OpenTelemetryLoggerProvider AddProcessor(BaseProcessor<LogRecord> processor)
         {
             Guard.ThrowIfNull(processor);

src/OpenTelemetry/Logs/OpenTelemetryLoggingExtensions.cs

@@ -42,7 +42,11 @@ public static ILoggingBuilder AddOpenTelemetry(this ILoggingBuilder builder, Act
             Guard.ThrowIfNull(builder);
 
             builder.AddConfiguration();
-            builder.Services.TryAddEnumerable(ServiceDescriptor.Singleton<ILoggerProvider, OpenTelemetryLoggerProvider>());
+            builder.Services.TryAddSingleton<OpenTelemetryLoggerProvider>();
+            builder.Services.TryAddSingleton<LogEmitter>();
+            builder.Services.TryAddEnumerable(
+                ServiceDescriptor.Singleton<ILoggerProvider, OpenTelemetryLoggerProvider>(
+                    sp => sp.GetRequiredService<OpenTelemetryLoggerProvider>()));
 
             if (configure != null)
             {