Improving MSBuild error reporting (#269)

Author: fabiocav

sdk/Sdk/FunctionMetadataGenerator.cs

@@ -22,12 +22,12 @@ internal class FunctionMetadataGenerator
         private readonly IDictionary<string, string> _extensions;
 
         public FunctionMetadataGenerator()
-            : this((l, m) => { })
+            : this((l, m, p) => { })
         {
             _extensions = new Dictionary<string, string>();
         }
 
-        public FunctionMetadataGenerator(Action<TraceLevel, string> log)
+        public FunctionMetadataGenerator(Action<TraceLevel, string, string> log)
         {
             _logger = new IndentableLogger(log);
             _extensions = new Dictionary<string, string>();
@@ -81,12 +81,12 @@ public IEnumerable<SdkFunctionMetadata> GenerateFunctionMetadata(string assembly
                         }
                         catch (FunctionsMetadataGenerationException ex)
                         {
-                            _logger.LogError($"Failed to generate function metadata from {Path.GetFileName(path)}.");
+                            _logger.LogError($"Failed to generate function metadata from {Path.GetFileName(path)}: {ex.Message}", path);
                             throw ex;
                         }
                         catch (Exception ex)
                         {
-                            _logger.LogWarning($"Could not evaluate '{Path.GetFileName(path)}' for functions metadata. Exception message: {ex.ToString()}");
+                            _logger.LogWarning($"Could not evaluate '{Path.GetFileName(path)}' for functions metadata. Exception message: {ex}");
                         }
                     }
                 }
@@ -130,14 +130,23 @@ private void AddFunctionMetadataIfFunction(IList<SdkFunctionMetadata> functions,
             if (TryCreateFunctionMetadata(method, out SdkFunctionMetadata? metadata)
                 && metadata != null)
             {
-                var allBindings = CreateBindingMetadataAndAddExtensions(method);
+                try
+                {
+
+                    var allBindings = CreateBindingMetadataAndAddExtensions(method);
+
+
+                    foreach (var binding in allBindings)
+                    {
+                        metadata.Bindings.Add(binding);
+                    }
 
-                foreach(var binding in allBindings)
+                    functions.Add(metadata);
+                }
+                catch (FunctionsMetadataGenerationException ex)
                 {
-                    metadata.Bindings.Add(binding);
+                    throw new FunctionsMetadataGenerationException($"Failed to generate medata for function '{metadata.Name}' (method '{method.FullName}'): {ex.Message}");
                 }
-
-                functions.Add(metadata);
             }
         }
 
@@ -217,7 +226,7 @@ private void AddOutputBindingsFromReturnType(IList<ExpandoObject> bindingMetadat
                 else
                 {                    
                     TypeDefinition returnDefinition = returnType.Resolve()
-                        ?? throw new FunctionsMetadataGenerationException($"Couldn't find the type definition {returnType}");
+                        ?? throw new FunctionsMetadataGenerationException($"Couldn't find the type definition '{returnType}' for method '{method.FullName}'");
 
                     bool hasOutputModel = TryAddOutputBindingsFromProperties(bindingMetadata, returnDefinition);
 

sdk/Sdk/FunctionsMetadataGenerationException.cs

@@ -1,12 +1,21 @@
-using System;
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using System;
+using System.Runtime.Serialization;
 
 namespace Microsoft.Azure.Functions.Worker.Sdk
 {
+    [Serializable]
     internal class FunctionsMetadataGenerationException: Exception
     {
+        public FunctionsMetadataGenerationException() { }
+
         internal FunctionsMetadataGenerationException(string message): base(message) { }
 
         internal FunctionsMetadataGenerationException(string message, Exception innerException) : base(message, innerException) { }
-
+        
+        protected FunctionsMetadataGenerationException(SerializationInfo info, StreamingContext context)
+            : base(info, context) { }
     }
 }

sdk/Sdk/IndentableLogger.cs

@@ -1,4 +1,4 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
 using System;
@@ -9,10 +9,10 @@ namespace Microsoft.Azure.Functions.Worker.Sdk
     internal class IndentableLogger
     {
         private const int SpacesPerIndent = 2;
-        private readonly Action<TraceLevel, string> _log;
+        private readonly Action<TraceLevel, string, string> _log;
         private int _indent = 0;
 
-        public IndentableLogger(Action<TraceLevel, string> log)
+        public IndentableLogger(Action<TraceLevel, string, string> log)
         {
             _log = log ?? throw new ArgumentNullException(nameof(log));
         }
@@ -37,17 +37,17 @@ private void PopIndent()
 
         public void LogMessage(string message)
         {
-            _log(TraceLevel.Info, Indent(message));
+            _log(TraceLevel.Info, Indent(message), string.Empty);
         }
 
-        public void LogError(string message)
+        public void LogError(string message, string? filePath = null)
         {
-            _log(TraceLevel.Error, Indent(message));
+            _log(TraceLevel.Error, Indent(message), filePath ?? string.Empty);
         }
 
         public void LogWarning(string message)
         {
-            _log(TraceLevel.Warning, Indent(message));
+            _log(TraceLevel.Warning, Indent(message), string.Empty);
         }
 
         private string Indent(string message)

sdk/Sdk/Tasks/GenerateFunctionMetadata.cs

@@ -32,25 +32,34 @@ public class GenerateFunctionMetadata : Task
 
         public override bool Execute()
         {
-            var functionGenerator = new FunctionMetadataGenerator(MSBuildLogger);
-            var functions = functionGenerator.GenerateFunctionMetadata(AssemblyPath!, ReferencePaths.Select(p => p.ItemSpec));
+            try
+            {
+                var functionGenerator = new FunctionMetadataGenerator(MSBuildLogger);
+
+                var functions = functionGenerator.GenerateFunctionMetadata(AssemblyPath!, ReferencePaths.Select(p => p.ItemSpec));
 
-            var extensions = functionGenerator.Extensions;
-            var extensionsCsProjGenerator = new ExtensionsCsprojGenerator(extensions, ExtensionsCsProjFilePath!, ExtensionsTargetFramework!);
+                var extensions = functionGenerator.Extensions;
+                var extensionsCsProjGenerator = new ExtensionsCsprojGenerator(extensions, ExtensionsCsProjFilePath!, ExtensionsTargetFramework!);
 
-            extensionsCsProjGenerator.Generate();
+                extensionsCsProjGenerator.Generate();
 
-            FunctionMetadataJsonWriter.WriteMetadata(functions, OutputPath!);
+                FunctionMetadataJsonWriter.WriteMetadata(functions, OutputPath!);
+            }
+            catch (FunctionsMetadataGenerationException)
+            {
+                Log.LogError($"Unable to build Azure Functios metadata for {AssemblyPath}");
+                return false;
+            }
 
             return true;
         }
 
-        private void MSBuildLogger(TraceLevel level, string message)
+        private void MSBuildLogger(TraceLevel level, string message, string path)
         {
             switch (level)
             {
                 case TraceLevel.Error:
-                    Log.LogError(message);
+                    Log.LogError(null, null, null, file: path, 0, 0, 0, 0, message: message);
                     break;
                 case TraceLevel.Info:
                     Log.LogMessage(message);