Merge pull request #12128 from jtattermusch/csharp_easierlogging

Make C# logging & tracing more intuitive

src/csharp/Grpc.Core.Tests/NUnitMain.cs

@@ -33,7 +33,7 @@ namespace Grpc.Core.Tests
         public static int Main(string[] args)
         {
             // Make logger immune to NUnit capturing stdout and stderr to workaround https://github.com/nunit/nunit/issues/1406.
-            GrpcEnvironment.SetLogger(new TextWriterLogger(Console.Error));
+            GrpcEnvironment.SetLogger(new ConsoleLogger());
 #if NETCOREAPP1_0
             return new AutoRun(typeof(NUnitMain).GetTypeInfo().Assembly).Execute(args, new ExtendedTextWrapper(Console.Out), Console.In);
 #else

src/csharp/Grpc.Core/GrpcEnvironment.cs

@@ -43,7 +43,7 @@ namespace Grpc.Core
         static readonly HashSet<Channel> registeredChannels = new HashSet<Channel>();
         static readonly HashSet<Server> registeredServers = new HashSet<Server>();
 
-        static ILogger logger = new NullLogger();
+        static ILogger logger = new LogLevelFilterLogger(new ConsoleLogger(), LogLevel.Off, true);
 
         readonly GrpcThreadPool threadPool;
         readonly DebugStats debugStats = new DebugStats();

src/csharp/Grpc.Core/Logging/LogLevel.cs

@@ -39,6 +39,10 @@ namespace Grpc.Core.Logging
         /// <summary>
         /// Error severity.
         /// </summary>
-        Error
+        Error,
+        /// <summary>
+        /// Logging is off.
+        /// </summary>
+        Off = int.MaxValue
     }
 }

src/csharp/Grpc.Core/Logging/LogLevelFilterLogger.cs

@@ -27,6 +27,8 @@ namespace Grpc.Core.Logging
     /// <summary>Logger that filters out messages below certain log level.</summary>
     public class LogLevelFilterLogger : ILogger
     {
+        // Verbosity environment variable used by C core.
+        private const string CoreVerbosityEnvVarName = "GRPC_VERBOSITY";
         readonly ILogger innerLogger;
         readonly LogLevel logLevel;
 
@@ -39,6 +41,19 @@ namespace Grpc.Core.Logging
             this.logLevel = logLevel;
         }
 
+        /// <summary>
+        /// Creates and instance of <c>LogLevelFilter.</c>
+        /// The <c>fromEnvironmentVariable</c> parameter allows looking up "GRPC_VERBOSITY" setting provided by C-core
+        /// and uses the same log level for C# logs. Using this setting is recommended as it can prevent unintentionally hiding
+        /// C core logs requested by "GRPC_VERBOSITY" environment variable (which could happen if C# logger's log level was set to a more restrictive value).
+        /// </summary>
+        /// <param name="logger">the logger to forward filtered logs to.</param>
+        /// <param name="defaultLogLevel">the default log level, unless overriden by env variable.</param>
+        /// <param name="fromEnvironmentVariable">if <c>true</c>, override log level with setting from environment variable.</param>
+        public LogLevelFilterLogger(ILogger logger, LogLevel defaultLogLevel, bool fromEnvironmentVariable) : this(logger, GetLogLevelFromEnvironment(defaultLogLevel, fromEnvironmentVariable))
+        {
+        }
+
         /// <summary>
         /// Returns a logger associated with the specified type.
         /// </summary>
@@ -141,5 +156,33 @@ namespace Grpc.Core.Logging
                 innerLogger.Error(exception, message);
             }
         }
+
+        /// <summary>Get log level based on a default and lookup of <c>GRPC_VERBOSITY</c> environment variable.</summary>
+        private static LogLevel GetLogLevelFromEnvironment(LogLevel defaultLogLevel, bool fromEnvironmentVariable)
+        {
+            if (!fromEnvironmentVariable)
+            {
+                return defaultLogLevel;
+            }
+
+            var verbosityString = System.Environment.GetEnvironmentVariable(CoreVerbosityEnvVarName);
+            if (verbosityString == null)
+            {
+                return defaultLogLevel;
+            }
+
+            // NOTE: C core doesn't have "WARNING" log level
+            switch (verbosityString.ToUpperInvariant())
+            {
+                case "DEBUG":
+                    return LogLevel.Debug;
+                case "INFO":
+                    return LogLevel.Info;
+                case "ERROR":
+                    return LogLevel.Error;
+                default:
+                    return defaultLogLevel;
+            }
+        }
     }
 }

src/csharp/Grpc.Examples.Tests/NUnitMain.cs

@@ -33,7 +33,7 @@ namespace Grpc.Examples.Tests
         public static int Main(string[] args)
         {
             // Make logger immune to NUnit capturing stdout and stderr to workaround https://github.com/nunit/nunit/issues/1406.
-            GrpcEnvironment.SetLogger(new TextWriterLogger(Console.Error));
+            GrpcEnvironment.SetLogger(new ConsoleLogger());
 #if NETCOREAPP1_0
             return new AutoRun(typeof(NUnitMain).GetTypeInfo().Assembly).Execute(args, new ExtendedTextWrapper(Console.Out), Console.In);
 #else

src/csharp/Grpc.HealthCheck.Tests/NUnitMain.cs

@@ -33,7 +33,7 @@ namespace Grpc.HealthCheck.Tests
         public static int Main(string[] args)
         {
             // Make logger immune to NUnit capturing stdout and stderr to workaround https://github.com/nunit/nunit/issues/1406.
-            GrpcEnvironment.SetLogger(new TextWriterLogger(Console.Error));
+            GrpcEnvironment.SetLogger(new ConsoleLogger());
 #if NETCOREAPP1_0
             return new AutoRun(typeof(NUnitMain).GetTypeInfo().Assembly).Execute(args, new ExtendedTextWrapper(Console.Out), Console.In);
 #else

src/csharp/Grpc.IntegrationTesting/NUnitMain.cs

@@ -33,7 +33,7 @@ namespace Grpc.IntegrationTesting
         public static int Main(string[] args)
         {
             // Make logger immune to NUnit capturing stdout and stderr to workaround https://github.com/nunit/nunit/issues/1406.
-            GrpcEnvironment.SetLogger(new TextWriterLogger(Console.Error));
+            GrpcEnvironment.SetLogger(new ConsoleLogger());
 #if NETCOREAPP1_0
             return new AutoRun(typeof(NUnitMain).GetTypeInfo().Assembly).Execute(args, new ExtendedTextWrapper(Console.Out), Console.In);
 #else

src/csharp/Grpc.Microbenchmarks/Program.cs

@@ -27,7 +27,7 @@ namespace Grpc.Microbenchmarks
     {
         public static void Main(string[] args)
         {
-            GrpcEnvironment.SetLogger(new TextWriterLogger(Console.Error));
+            GrpcEnvironment.SetLogger(new ConsoleLogger());
             var benchmark = new SendMessageBenchmark();
             benchmark.Init();
             foreach (int threadCount in new int[] {1, 1, 2, 4, 8, 12})

src/csharp/Grpc.Reflection.Tests/NUnitMain.cs

@@ -33,7 +33,7 @@ namespace Grpc.Reflection.Tests
         public static int Main(string[] args)
         {
             // Make logger immune to NUnit capturing stdout and stderr to workaround https://github.com/nunit/nunit/issues/1406.
-            GrpcEnvironment.SetLogger(new TextWriterLogger(Console.Error));
+            GrpcEnvironment.SetLogger(new ConsoleLogger());
 #if NETCOREAPP1_0
             return new AutoRun(typeof(NUnitMain).GetTypeInfo().Assembly).Execute(args, new ExtendedTextWrapper(Console.Out), Console.In);
 #else