[sdk-logs] Define LoggerSdk (#4455)

src/OpenTelemetry/Logs/LoggerProviderSdk.cs

@@ -202,8 +202,8 @@ public bool ContainsBatchProcessor(BaseProcessor<LogRecord> processor)
     /// <inheritdoc />
     protected override bool TryCreateLogger(string? name, out Logger? logger)
     {
-        // TODO: return new LoggerSdk(this, name);
-        throw new NotImplementedException();
+        logger = new LoggerSdk(this, name);
+        return true;
     }
 
     /// <inheritdoc/>

src/OpenTelemetry/Logs/LoggerSdk.cs

@@ -0,0 +1,65 @@
+// <copyright file="LoggerSdk.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>
+/// SDK <see cref="Logger"/> implementation.
+/// </summary>
+internal sealed class LoggerSdk : Logger
+{
+    private readonly LoggerProviderSdk loggerProvider;
+
+    public LoggerSdk(
+        LoggerProviderSdk loggerProvider,
+        string? name)
+        : base(name)
+    {
+        Guard.ThrowIfNull(loggerProvider);
+
+        this.loggerProvider = loggerProvider;
+    }
+
+    /// <inheritdoc />
+    public override void EmitLog(in LogRecordData data, in LogRecordAttributeList attributes = default)
+    {
+        var provider = this.loggerProvider;
+        var processor = provider.Processor;
+        if (processor != null)
+        {
+            var pool = provider.LogRecordPool;
+
+            var logRecord = pool.Rent();
+
+            logRecord.Data = data;
+            logRecord.ILoggerData = default;
+
+            // TODO: logRecord.Logger = this;
+
+            logRecord.Attributes = attributes.Export(ref logRecord.AttributeStorage);
+
+            processor.OnEnd(logRecord);
+
+            // Attempt to return the LogRecord to the pool. This will no-op
+            // if a batch exporter has added a reference.
+            pool.Return(logRecord);
+        }
+    }
+}