Check DOTNET_HOST_* for host (COREHOST_*) tracing environment variables

src/installer/tests/HostActivation.Tests/HostVersionCompatibility.cs

@@ -80,7 +80,8 @@ private void OldHost_LatestRuntime_ForwardCompatible(TestApp previousVersionApp)
             //  2) App rolls forward to newer runtime
             File.Copy(previousVersionApp.AppExe, appExe, true);
             Command.Create(appExe)
-                .EnableTracingAndCaptureOutputs()
+                .CaptureStdOut().CaptureStdErr()
+                .EnvironmentVariable("COREHOST_TRACE", "1") // Old host, so we need to use the old variable name
                 .Execute()
                 .Should().Pass()
                 .And.HaveStdOutContaining("Hello World")
@@ -95,7 +96,8 @@ private void OldHost_LatestRuntime_ForwardCompatible(TestApp previousVersionApp)
             {
                 File.Copy(previousVersionApp.HostFxrDll, app.HostFxrDll, true);
                 Command.Create(appExe)
-                    .EnableTracingAndCaptureOutputs()
+                    .CaptureStdOut().CaptureStdErr()
+                    .EnvironmentVariable("COREHOST_TRACE", "1") // Old host, so we need to use the old variable name
                     .Execute()
                     .Should().Pass()
                     .And.HaveStdOutContaining("Hello World")

src/installer/tests/HostActivation.Tests/Tracing.cs

@@ -7,24 +7,18 @@
 
 namespace Microsoft.DotNet.CoreSetup.Test.HostActivation
 {
-    public class Tracing : IClassFixture<Tracing.SharedTestState>
+    public class Tracing
     {
-        private SharedTestState sharedTestState;
+        // Trace messages currently expected for running dotnet --list-runtimes
+        private const string ExpectedVerboseMessage = "--- Executing in muxer mode";
+        private const string ExpectedInfoMessage = "--- Invoked dotnet";
 
-        // Trace messages currently expected for a passing app (somewhat randomly selected)
-        private const string ExpectedVerboseMessage = "--- Begin breadcrumb write";
-        private const string ExpectedInfoMessage = "Deps file:";
-        private const string ExpectedBadPathMessage = "Unable to open COREHOST_TRACEFILE=";
-
-        public Tracing(Tracing.SharedTestState fixture)
-        {
-            sharedTestState = fixture;
-        }
+        private const string ExpectedBadPathMessage = "Unable to open specified trace file for writing:";
 
         [Fact]
         public void TracingOff()
         {
-            TestContext.BuiltDotNet.Exec(sharedTestState.App.AppDll)
+            TestContext.BuiltDotNet.Exec("--list-runtimes")
                 .CaptureStdOut()
                 .CaptureStdErr()
                 .Execute()
@@ -36,66 +30,60 @@ public void TracingOff()
         [Fact]
         public void TracingOnDefault()
         {
-            TestContext.BuiltDotNet.Exec(sharedTestState.App.AppDll)
+            TestContext.BuiltDotNet.Exec("--list-runtimes")
                 .EnableTracingAndCaptureOutputs()
                 .Execute()
                 .Should().Pass()
-                .And.HaveStdOutContaining("Hello World")
                 .And.HaveStdErrContaining(ExpectedInfoMessage)
                 .And.HaveStdErrContaining(ExpectedVerboseMessage);
         }
 
         [Fact]
         public void TracingOnVerbose()
         {
-            TestContext.BuiltDotNet.Exec(sharedTestState.App.AppDll)
+            TestContext.BuiltDotNet.Exec("--list-runtimes")
                 .EnableTracingAndCaptureOutputs()
                 .EnvironmentVariable(Constants.HostTracing.VerbosityEnvironmentVariable, "4")
                 .Execute()
                 .Should().Pass()
-                .And.HaveStdOutContaining("Hello World")
                 .And.HaveStdErrContaining(ExpectedInfoMessage)
                 .And.HaveStdErrContaining(ExpectedVerboseMessage);
         }
 
         [Fact]
         public void TracingOnInfo()
         {
-            TestContext.BuiltDotNet.Exec(sharedTestState.App.AppDll)
+            TestContext.BuiltDotNet.Exec("--list-runtimes")
                 .EnableTracingAndCaptureOutputs()
                 .EnvironmentVariable(Constants.HostTracing.VerbosityEnvironmentVariable, "3")
                 .Execute()
                 .Should().Pass()
-                .And.HaveStdOutContaining("Hello World")
                 .And.HaveStdErrContaining(ExpectedInfoMessage)
                 .And.NotHaveStdErrContaining(ExpectedVerboseMessage);
         }
 
         [Fact]
         public void TracingOnWarning()
         {
-            TestContext.BuiltDotNet.Exec(sharedTestState.App.AppDll)
+            TestContext.BuiltDotNet.Exec("--list-runtimes")
                 .EnableTracingAndCaptureOutputs()
                 .EnvironmentVariable(Constants.HostTracing.VerbosityEnvironmentVariable, "2")
                 .Execute()
                 .Should().Pass()
-                .And.HaveStdOutContaining("Hello World")
                 .And.NotHaveStdErrContaining(ExpectedInfoMessage)
                 .And.NotHaveStdErrContaining(ExpectedVerboseMessage);
         }
 
         [Fact]
         public void TracingOnToFileDefault()
         {
-
             string traceFilePath;
-            TestContext.BuiltDotNet.Exec(sharedTestState.App.AppDll)
+            TestContext.BuiltDotNet.Exec("--list-runtimes")
                 .EnableHostTracingToFile(out traceFilePath)
                 .CaptureStdOut()
                 .CaptureStdErr()
                 .Execute()
                 .Should().Pass()
-                .And.HaveStdOutContaining("Hello World")
                 .And.NotHaveStdErrContaining(ExpectedInfoMessage)
                 .And.NotHaveStdErrContaining(ExpectedVerboseMessage)
                 .And.FileExists(traceFilePath)
@@ -107,12 +95,11 @@ public void TracingOnToFileDefault()
         [Fact]
         public void TracingOnToFileBadPathDefault()
         {
-            TestContext.BuiltDotNet.Exec(sharedTestState.App.AppDll)
+            TestContext.BuiltDotNet.Exec("--list-runtimes")
                 .EnableTracingAndCaptureOutputs()
                 .EnvironmentVariable(Constants.HostTracing.TraceFileEnvironmentVariable, "badpath/TracingOnToFileBadPathDefault.log")
                 .Execute()
                 .Should().Pass()
-                .And.HaveStdOutContaining("Hello World")
                 .And.HaveStdErrContaining(ExpectedInfoMessage)
                 .And.HaveStdErrContaining(ExpectedVerboseMessage)
                 .And.HaveStdErrContaining(ExpectedBadPathMessage);
@@ -123,36 +110,31 @@ public void TracingOnToDirectory()
         {
             using (TestArtifact directory = TestArtifact.Create("trace"))
             {
-                var result = TestContext.BuiltDotNet.Exec(sharedTestState.App.AppDll)
+                var result = TestContext.BuiltDotNet.Exec("--list-runtimes")
                     .EnableHostTracingToPath(directory.Location)
                     .CaptureStdOut()
                     .CaptureStdErr()
                     .Execute();
 
                 string traceFilePath = Path.Combine(directory.Location, $"{Path.GetFileNameWithoutExtension(Binaries.DotNet.FileName)}.{result.ProcessId}.log");
                 result.Should().Pass()
-                    .And.HaveStdOutContaining("Hello World")
                     .And.NotHaveStdErrContaining(ExpectedInfoMessage)
                     .And.NotHaveStdErrContaining(ExpectedVerboseMessage)
                     .And.FileExists(traceFilePath)
                     .And.FileContains(traceFilePath, ExpectedVerboseMessage);
             }
         }
 
-        public class SharedTestState : IDisposable
+        [Fact]
+        public void LegacyVariableName()
         {
-            public TestApp App { get; }
-
-            public SharedTestState()
-            {
-                App = TestApp.CreateFromBuiltAssets("HelloWorld");
-                App.CreateAppHost();
-            }
-
-            public void Dispose()
-            {
-                App?.Dispose();
-            }
+            TestContext.BuiltDotNet.Exec("--list-runtimes")
+                .EnvironmentVariable("COREHOST_TRACE", "1")
+                .CaptureStdErr()
+                .Execute()
+                .Should().Pass()
+                .And.HaveStdErrContaining(ExpectedInfoMessage)
+                .And.HaveStdErrContaining(ExpectedVerboseMessage);
         }
     }
 }

src/installer/tests/TestUtils/Constants.cs

@@ -103,9 +103,9 @@ public static class MultilevelLookup
 
         public static class HostTracing
         {
-            public const string TraceLevelEnvironmentVariable = "COREHOST_TRACE";
-            public const string TraceFileEnvironmentVariable = "COREHOST_TRACEFILE";
-            public const string VerbosityEnvironmentVariable = "COREHOST_TRACE_VERBOSITY";
+            public const string TraceLevelEnvironmentVariable = "DOTNET_HOST_TRACE";
+            public const string TraceFileEnvironmentVariable = "DOTNET_HOST_TRACEFILE";
+            public const string VerbosityEnvironmentVariable = "DOTNET_HOST_TRACE_VERBOSITY";
         }
 
         public static class DotnetRoot

src/native/corehost/hostmisc/trace.cpp

@@ -12,13 +12,13 @@
 #define TRACE_VERBOSITY_INFO 3
 #define TRACE_VERBOSITY_VERBOSE 4
 
-// g_trace_verbosity is used to encode COREHOST_TRACE and COREHOST_TRACE_VERBOSITY to selectively control output of
+// g_trace_verbosity is used to encode DOTNET_HOST_TRACE and DOTNET_HOST_TRACE_VERBOSITY to selectively control output of
 //    trace::warn(), trace::info(), and trace::verbose()
-//  COREHOST_TRACE=0 COREHOST_TRACE_VERBOSITY=N/A        implies g_trace_verbosity = 0.  // Trace "disabled". error() messages will be produced.
-//  COREHOST_TRACE=1 COREHOST_TRACE_VERBOSITY=4 or unset implies g_trace_verbosity = 4.  // Trace "enabled".  verbose(), info(), warn() and error() messages will be produced
-//  COREHOST_TRACE=1 COREHOST_TRACE_VERBOSITY=3          implies g_trace_verbosity = 3.  // Trace "enabled".  info(), warn() and error() messages will be produced
-//  COREHOST_TRACE=1 COREHOST_TRACE_VERBOSITY=2          implies g_trace_verbosity = 2.  // Trace "enabled".  warn() and error() messages will be produced
-//  COREHOST_TRACE=1 COREHOST_TRACE_VERBOSITY=1          implies g_trace_verbosity = 1.  // Trace "enabled".  error() messages will be produced
+//  DOTNET_HOST_TRACE=0 DOTNET_HOST_TRACE_VERBOSITY=N/A        implies g_trace_verbosity = 0.  // Trace "disabled". error() messages will be produced.
+//  DOTNET_HOST_TRACE=1 DOTNET_HOST_TRACE_VERBOSITY=4 or unset implies g_trace_verbosity = 4.  // Trace "enabled".  verbose(), info(), warn() and error() messages will be produced
+//  DOTNET_HOST_TRACE=1 DOTNET_HOST_TRACE_VERBOSITY=3          implies g_trace_verbosity = 3.  // Trace "enabled".  info(), warn() and error() messages will be produced
+//  DOTNET_HOST_TRACE=1 DOTNET_HOST_TRACE_VERBOSITY=2          implies g_trace_verbosity = 2.  // Trace "enabled".  warn() and error() messages will be produced
+//  DOTNET_HOST_TRACE=1 DOTNET_HOST_TRACE_VERBOSITY=1          implies g_trace_verbosity = 1.  // Trace "enabled".  error() messages will be produced
 static int g_trace_verbosity = 0;
 static FILE * g_trace_file = nullptr;
 thread_local static trace::error_writer_fn g_error_writer = nullptr;
@@ -52,16 +52,35 @@ namespace
     };
 
     spin_lock g_trace_lock;
+
+    template<size_t NameLen>
+    bool get_host_env_var(const pal::char_t (&name)[NameLen], pal::string_t* value)
+    {
+        assert(name[NameLen - 1] == _X('\0')); // name is expected to be null-terminated
+
+        // DOTNET_HOST_* takes precedence
+        constexpr size_t dotnet_host_prefix_len = STRING_LENGTH("DOTNET_HOST_");
+        pal::char_t dotnet_host_name[dotnet_host_prefix_len + NameLen];
+        pal::snwprintf(dotnet_host_name, ARRAY_SIZE(dotnet_host_name), _X("DOTNET_HOST_%s"), name);
+        if (pal::getenv(dotnet_host_name, value))
+            return true;
+
+        // COREHOST_* for backwards compatibility
+        constexpr size_t corehost_prefix_len = STRING_LENGTH("COREHOST_");
+        pal::char_t corehost_name[corehost_prefix_len + NameLen];
+        pal::snwprintf(corehost_name, ARRAY_SIZE(corehost_name), _X("COREHOST_%s"), name);
+        return pal::getenv(corehost_name, value);
+    }
 }
 
 //
-// Turn on tracing for the corehost based on "COREHOST_TRACE" & "COREHOST_TRACEFILE" env.
+// Turn on tracing for the corehost based on "DOTNET_HOST_TRACE" & "DOTNET_HOST_TRACEFILE" env.
 //
 void trace::setup()
 {
     // Read trace environment variable
     pal::string_t trace_str;
-    if (!pal::getenv(_X("COREHOST_TRACE"), &trace_str))
+    if (!get_host_env_var(_X("TRACE"), &trace_str))
     {
         return;
     }
@@ -91,7 +110,7 @@ bool trace::enable()
         std::lock_guard<spin_lock> lock(g_trace_lock);
 
         g_trace_file = stderr;  // Trace to stderr by default
-        if (pal::getenv(_X("COREHOST_TRACEFILE"), &tracefile_str))
+        if (get_host_env_var(_X("TRACEFILE"), &tracefile_str))
         {
             if (pal::is_directory(tracefile_str))
             {
@@ -122,7 +141,7 @@ bool trace::enable()
         }
 
         pal::string_t trace_str;
-        if (!pal::getenv(_X("COREHOST_TRACE_VERBOSITY"), &trace_str))
+        if (!get_host_env_var(_X("TRACE_VERBOSITY"), &trace_str))
         {
             g_trace_verbosity = TRACE_VERBOSITY_VERBOSE;  // Verbose trace by default
         }
@@ -134,7 +153,7 @@ bool trace::enable()
 
     if (file_open_error)
     {
-        trace::error(_X("Unable to open COREHOST_TRACEFILE=%s for writing"), tracefile_str.c_str());
+        trace::error(_X("Unable to open specified trace file for writing: %s"), tracefile_str.c_str());
     }
     return true;
 }

src/native/corehost/hostpolicy/hostpolicy_context.cpp

@@ -224,7 +224,7 @@ int hostpolicy_context_t::initialize(const hostpolicy_init_t &hostpolicy_init, c
         // otherwise fail early.
         if (!bundle::info_t::is_single_file_bundle())
         {
-            trace::error(_X("Could not resolve CoreCLR path. For more details, enable tracing by setting COREHOST_TRACE environment variable to 1"));
+            trace::error(_X("Could not resolve CoreCLR path. For more details, enable tracing by setting DOTNET_HOST_TRACE environment variable to 1"));
             return StatusCode::CoreClrResolveFailure;
         }