Add option to write the specified log level to standard error

sandbox/ConsoleApp/Program.cs

@@ -157,7 +157,6 @@ static async Task Main(string[] args)
         {
             Environment.SetEnvironmentVariable("DOTNET_ENVIRONMENT", "Development");
 
-
             var host = Host.CreateDefaultBuilder()
                 .ConfigureServices(x =>
                 {
@@ -174,6 +173,7 @@ static async Task Main(string[] args)
                     {
                         //options.FlushRate = TimeSpan.FromSeconds(5);
 
+                        options.LogToErrorThreshold = LogLevel.Error;
 #if DEBUG
                         options.UsePlainTextFormatter(plainText =>
                         {

src/ZLogger/AsyncStreamLineMessageWriter.cs

@@ -1,11 +1,7 @@
-using System;
-using System.Diagnostics;
-using System.IO;
+using System.Diagnostics;
 using System.Runtime.CompilerServices;
 using System.Text;
-using System.Threading;
 using System.Threading.Channels;
-using System.Threading.Tasks;
 
 namespace ZLogger
 {
@@ -17,12 +13,13 @@ public class AsyncStreamLineMessageWriter : IAsyncLogProcessor, IAsyncDisposable
         readonly byte newLine2;
 
         readonly Stream stream;
+        readonly Stream? errorStream;
         readonly Channel<IZLoggerEntry> channel;
         readonly Task writeLoop;
         readonly ZLoggerOptions options;
         readonly CancellationTokenSource cancellationTokenSource;
 
-        public AsyncStreamLineMessageWriter(Stream stream, ZLoggerOptions options)
+        public AsyncStreamLineMessageWriter(Stream stream, Stream? errorStream, ZLoggerOptions options)
         {
             this.newLine = Encoding.UTF8.GetBytes(Environment.NewLine);
             this.cancellationTokenSource = new CancellationTokenSource();
@@ -43,6 +40,7 @@ public AsyncStreamLineMessageWriter(Stream stream, ZLoggerOptions options)
 
             this.options = options;
             this.stream = stream;
+            this.errorStream = errorStream;
             this.channel = Channel.CreateUnbounded<IZLoggerEntry>(new UnboundedChannelOptions
             {
                 AllowSynchronousContinuations = false, // always should be in async loop.
@@ -86,6 +84,7 @@ void AppendLine(StreamBufferWriter writer)
         async Task WriteLoop()
         {
             var writer = new StreamBufferWriter(stream);
+            var errorWriter = errorStream != null ? new StreamBufferWriter(errorStream) : null;
             var formatter = options.CreateFormatter();
             var reader = channel.Reader;
             var sw = Stopwatch.StartNew();
@@ -99,9 +98,11 @@ async Task WriteLoop()
                         while (reader.TryRead(out var value))
                         {
                             info = value.LogInfo;
-                            value.FormatUtf8(writer, formatter);
-                            (value as IReturnableZLoggerEntry)?.Return();
-                            AppendLine(writer);
+                            var currentWriter = errorWriter != null && info.LogLevel >= options.LogToErrorThreshold
+                                ? errorWriter
+                                : writer;
+                            value.FormatUtf8(currentWriter, formatter);
+                            AppendLine(currentWriter);
                         }
                         info = default;
 
@@ -166,6 +167,7 @@ public async ValueTask DisposeAsync()
             finally
             {
                 this.stream.Dispose();
+                this.errorStream?.Dispose();
             }
         }
     }

src/ZLogger/Formatters/SystemTextJsonZLoggerFormatter.cs

@@ -1,4 +1,3 @@
-using System;
 using System.Buffers;
 using System.Text.Encodings.Web;
 using System.Text.Json;

src/ZLogger/Providers/ZLoggerConsoleLoggerProvider.cs

@@ -20,20 +20,19 @@ public ZLoggerConsoleLoggerProvider(IOptionsMonitor<ZLoggerOptions> options)
         }
 
         public ZLoggerConsoleLoggerProvider(bool consoleOutputEncodingToUtf8, string? optionName, IOptionsMonitor<ZLoggerOptions> options)
-            : this(consoleOutputEncodingToUtf8, false, optionName, options)
+            : this(consoleOutputEncodingToUtf8, LogLevel.None, optionName, options)
         {
         }
 
-        public ZLoggerConsoleLoggerProvider(bool consoleOutputEncodingToUtf8, bool outputToErrorStream, string? optionName, IOptionsMonitor<ZLoggerOptions> options)
+        public ZLoggerConsoleLoggerProvider(bool consoleOutputEncodingToUtf8, LogLevel logToStandardErrorThreshold, string? optionName, IOptionsMonitor<ZLoggerOptions> options)
         {
             if (consoleOutputEncodingToUtf8)
             {
                 Console.OutputEncoding = new UTF8Encoding(false);
             }
 
             this.options = options.Get(optionName ?? DefaultOptionName);
-            var stream = outputToErrorStream ? Console.OpenStandardError() : Console.OpenStandardOutput();
-            this.streamWriter = new AsyncStreamLineMessageWriter(stream, this.options);
+            this.streamWriter = new AsyncStreamLineMessageWriter(Console.OpenStandardOutput(), Console.OpenStandardError(), this.options);
         }
 
         public ILogger CreateLogger(string categoryName)

src/ZLogger/Providers/ZLoggerFileLoggerProvider.cs

@@ -30,7 +30,7 @@ public ZLoggerFileLoggerProvider(string filePath, string? optionName, IOptionsMo
 
             // useAsync:false, use sync(in thread) processor, don't use FileStream buffer(use buffer size = 1).
             var stream = new FileStream(filePath, FileMode.Append, FileAccess.Write, FileShare.ReadWrite, 1, false);
-            this.streamWriter = new AsyncStreamLineMessageWriter(stream, this.options);
+            this.streamWriter = new AsyncStreamLineMessageWriter(stream, null, this.options);
         }
 
         public ILogger CreateLogger(string categoryName)

src/ZLogger/Providers/ZLoggerRollingFileLoggerProvider.cs

@@ -22,7 +22,7 @@ public ZLoggerRollingFileLoggerProvider(Func<DateTimeOffset, int, string> fileNa
         {
             this.options = options.Get(optionName ?? DefaultOptionName);
             var stream = new RollingFileStream(fileNameSelector, timestampPattern, rollSizeKB, this.options);
-            this.streamWriter = new AsyncStreamLineMessageWriter(stream, this.options);
+            this.streamWriter = new AsyncStreamLineMessageWriter(stream, null, this.options);
         }
 
         public ILogger CreateLogger(string categoryName)

src/ZLogger/Providers/ZLoggerStreamLoggerProvider.cs

@@ -1,6 +1,5 @@
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
-using System.IO;
 
 namespace ZLogger.Providers
 {
@@ -21,7 +20,7 @@ public ZLoggerStreamLoggerProvider(Stream stream, IOptionsMonitor<ZLoggerOptions
         public ZLoggerStreamLoggerProvider(Stream stream, string? optionName, IOptionsMonitor<ZLoggerOptions> options)
         {
             this.options = options.Get(optionName ?? DefaultOptionName);
-            this.streamWriter = new AsyncStreamLineMessageWriter(stream, this.options);
+            this.streamWriter = new AsyncStreamLineMessageWriter(stream, null, this.options);
         }
 
         public ILogger CreateLogger(string categoryName)

src/ZLogger/ZLoggerLoggingBuilderExtensions.cs

@@ -2,35 +2,33 @@
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Configuration;
 using Microsoft.Extensions.Options;
-using System;
-using System.IO;
 using System.Runtime.InteropServices;
 using ZLogger.Providers;
 
 namespace ZLogger
 {
     public static class ZLoggerLoggingBuilderExtensions
     {
-        public static ILoggingBuilder AddZLoggerConsole(this ILoggingBuilder builder, bool consoleOutputEncodingToUtf8 = true, bool configureEnableAnsiEscapeCode = false, bool outputToErrorStream = false)
+        public static ILoggingBuilder AddZLoggerConsole(this ILoggingBuilder builder, bool consoleOutputEncodingToUtf8 = true, bool configureEnableAnsiEscapeCode = false)
         {
             if (configureEnableAnsiEscapeCode)
             {
                 EnableAnsiEscapeCode();
             }
 
             builder.AddConfiguration();
-            builder.Services.Add(ServiceDescriptor.Singleton<ILoggerProvider, ZLoggerConsoleLoggerProvider>(x => new ZLoggerConsoleLoggerProvider(consoleOutputEncodingToUtf8, outputToErrorStream, null, x.GetRequiredService<IOptionsMonitor<ZLoggerOptions>>())));
+            builder.Services.Add(ServiceDescriptor.Singleton<ILoggerProvider, ZLoggerConsoleLoggerProvider>(x => new ZLoggerConsoleLoggerProvider(consoleOutputEncodingToUtf8, null, x.GetRequiredService<IOptionsMonitor<ZLoggerOptions>>())));
             LoggerProviderOptions.RegisterProviderOptions<ZLoggerOptions, ZLoggerConsoleLoggerProvider>(builder.Services);
 
             return builder;
         }
 
-        public static ILoggingBuilder AddZLoggerConsole(this ILoggingBuilder builder, Action<ZLoggerOptions> configure, bool consoleOutputEncodingToUtf8 = true, bool configureEnableAnsiEscapeCode = false, bool outputToErrorStream = false)
+        public static ILoggingBuilder AddZLoggerConsole(this ILoggingBuilder builder, Action<ZLoggerOptions> configure, bool consoleOutputEncodingToUtf8 = true, bool configureEnableAnsiEscapeCode = false)
         {
-            return AddZLoggerConsole(builder, ZLoggerConsoleLoggerProvider.DefaultOptionName, configure, consoleOutputEncodingToUtf8: consoleOutputEncodingToUtf8, configureEnableAnsiEscapeCode: configureEnableAnsiEscapeCode, outputToErrorStream: outputToErrorStream);
+            return AddZLoggerConsole(builder, ZLoggerConsoleLoggerProvider.DefaultOptionName, configure, consoleOutputEncodingToUtf8: consoleOutputEncodingToUtf8, configureEnableAnsiEscapeCode: configureEnableAnsiEscapeCode);
         }
 
-        public static ILoggingBuilder AddZLoggerConsole(this ILoggingBuilder builder, string optionName, Action<ZLoggerOptions> configure, bool consoleOutputEncodingToUtf8 = true, bool configureEnableAnsiEscapeCode = false, bool outputToErrorStream = false)
+        public static ILoggingBuilder AddZLoggerConsole(this ILoggingBuilder builder, string optionName, Action<ZLoggerOptions> configure, bool consoleOutputEncodingToUtf8 = true, bool configureEnableAnsiEscapeCode = false)
         {
             if (configureEnableAnsiEscapeCode)
             {
@@ -43,7 +41,7 @@ public static ILoggingBuilder AddZLoggerConsole(this ILoggingBuilder builder, st
             }
 
             builder.AddConfiguration();
-            builder.Services.Add(ServiceDescriptor.Singleton<ILoggerProvider, ZLoggerConsoleLoggerProvider>(x => new ZLoggerConsoleLoggerProvider(consoleOutputEncodingToUtf8, outputToErrorStream, optionName, x.GetRequiredService<IOptionsMonitor<ZLoggerOptions>>())));
+            builder.Services.Add(ServiceDescriptor.Singleton<ILoggerProvider, ZLoggerConsoleLoggerProvider>(x => new ZLoggerConsoleLoggerProvider(consoleOutputEncodingToUtf8, optionName, x.GetRequiredService<IOptionsMonitor<ZLoggerOptions>>())));
             LoggerProviderOptions.RegisterProviderOptions<ZLoggerOptions, ZLoggerConsoleLoggerProvider>(builder.Services);
 
             builder.Services.AddOptions<ZLoggerOptions>(optionName).Configure(configure);

src/ZLogger/ZLoggerOptions.cs

@@ -1,4 +1,4 @@
-using System;
+using Microsoft.Extensions.Logging;
 using ZLogger.Formatters;
 
 namespace ZLogger
@@ -8,6 +8,7 @@ public class ZLoggerOptions
         public Action<LogInfo, Exception>? InternalErrorLogger { get; set; }
         public TimeSpan? FlushRate { get; set; }
         public bool IncludeScopes { get; set; }
+        public LogLevel LogToErrorThreshold { get; set; } = LogLevel.None;
 
         Func<IZLoggerFormatter> formatterFactory = DefaultFormatterFactory;