dotnet/src/webdriver/Internal/Logging/LogContextManager.cs

// <copyright file="LogContextManager.cs" company="Selenium Committers">
// Licensed to the Software Freedom Conservancy (SFC) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The SFC licenses this file
// to you 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.Diagnostics.CodeAnalysis;
using System.Threading;

namespace OpenQA.Selenium.Internal.Logging;

internal class LogContextManager
{
    internal const int DefaultTruncationLength = 1000;
    private static bool _seDebugWarned;
    private readonly AsyncLocal<ILogContext?> _currentAmbientLogContext = new();

    public LogContextManager()
    {
        var defaultLogHandler = new TextWriterHandler(Console.Error);

        // Enable debug logging if SE_DEBUG environment variable is set
        if (Environment.GetEnvironmentVariable("SE_DEBUG") is not null && !_seDebugWarned)
        {
            _seDebugWarned = true;
            Console.Error.WriteLine("WARNING: Environment Variable `SE_DEBUG` is set; Selenium is forcing verbose logging which may override user-specified settings.");
        }
        var level = Environment.GetEnvironmentVariable("SE_DEBUG") is not null
            ? LogEventLevel.Debug
            : LogEventLevel.Warn;

        GlobalContext = new LogContext(level, null, null, DefaultTruncationLength, [defaultLogHandler]);
    }

    public ILogContext GlobalContext { get; }

    [AllowNull]
    public ILogContext CurrentContext
    {
        get => _currentAmbientLogContext.Value ?? GlobalContext;
        set => _currentAmbientLogContext.Value = value;
    }
}