Error handling improvements

Author: mathewc

src/WebJobs.Script.WebHost/Controllers/AdminController.cs

@@ -90,7 +90,7 @@ public HostStatus GetHostStatus()
             if (lastError != null)
             {
                 status.Errors = new Collection<string>();
-                status.Errors.Add(lastError.Message);
+                status.Errors.Add(Utility.FlattenException(lastError));
             }
 
             return status;

src/WebJobs.Script/Host/ScriptHost.cs

@@ -465,6 +465,7 @@ private static ScriptType ParseScriptType(string scriptFilePath)
             switch (extension)
             {
                 case "csx":
+                case "cs":
                     return ScriptType.CSharp;
                 case "js":
                     return ScriptType.Javascript;

src/WebJobs.Script/Utility.cs

@@ -3,10 +3,11 @@
 
 using System;
 using System.Configuration;
+using System.Text;
 
 namespace Microsoft.Azure.WebJobs.Script
 {
-    internal static class Utility
+    public static class Utility
     {
         public static string GetFunctionShortName(string functionName)
         {
@@ -21,14 +22,47 @@ public static string GetFunctionShortName(string functionName)
 
         public static string FlattenException(Exception ex)
         {
-            string formattedError = ex.Message;
+            StringBuilder flattenedErrorsBuilder = new StringBuilder();
+            string lastError = null;
 
-            while ((ex = ex.InnerException) != null)
+            if (ex is AggregateException)
             {
-                formattedError += ". " + ex.Message;
+                ex = ex.InnerException;
             }
 
-            return formattedError;
+            do
+            {
+                StringBuilder currentErrorBuilder = new StringBuilder();
+                if (!string.IsNullOrEmpty(ex.Source))
+                {
+                    currentErrorBuilder.AppendFormat("{0}: ", ex.Source);
+                }
+
+                currentErrorBuilder.Append(ex.Message);
+
+                if (!ex.Message.EndsWith("."))
+                {
+                    currentErrorBuilder.Append(".");
+                }
+
+                // sometimes inner exceptions are exactly the same
+                // so first check before duplicating
+                string currentError = currentErrorBuilder.ToString();
+                if (lastError == null ||
+                    string.Compare(lastError.Trim(), currentError.Trim()) != 0)
+                {
+                    if (flattenedErrorsBuilder.Length > 0)
+                    {
+                        flattenedErrorsBuilder.Append(" ");
+                    }
+                    flattenedErrorsBuilder.Append(currentError);
+                }
+
+                lastError = currentError;
+            }
+            while ((ex = ex.InnerException) != null);
+
+            return flattenedErrorsBuilder.ToString();
         }
 
         public static string GetAppSettingOrEnvironmentValue(string name)

src/src.ruleset

@@ -19,5 +19,7 @@
     <Rule Id="CA1062" Action="None" />
     <Rule Id="CA1303" Action="None" /> <!-- Enable when we move literals to resx -->
     <Rule Id="CA1800" Action="None" />
+    <Rule Id="CA1307" Action="None" />
+    <Rule Id="CA1305" Action="None" />
   </Rules>
 </RuleSet>

test/WebJobs.Script.Tests/UtilityTests.cs

@@ -0,0 +1,53 @@
+// 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 Microsoft.Azure.WebJobs.Script;
+using Xunit;
+
+namespace WebJobs.Script.Tests
+{
+    public class UtilityTests
+    {
+        [Fact]
+        public void FlattenException_AggregateException_ReturnsExpectedResult()
+        {
+            ApplicationException ex1 = new ApplicationException("Incorrectly configured setting 'Foo'");
+            ex1.Source = "Acme.CloudSystem";
+
+            // a dupe of the first
+            ApplicationException ex2 = new ApplicationException("Incorrectly configured setting 'Foo'");
+            ex1.Source = "Acme.CloudSystem";
+
+            AggregateException aex = new AggregateException("One or more errors occurred.", ex1, ex2);
+
+            string formattedResult = Utility.FlattenException(aex);
+            Assert.Equal("Acme.CloudSystem: Incorrectly configured setting 'Foo'.", formattedResult);
+        }
+
+        [Fact]
+        public void FlattenException_SingleException_ReturnsExpectedResult()
+        {
+            ApplicationException ex = new ApplicationException("Incorrectly configured setting 'Foo'");
+            ex.Source = "Acme.CloudSystem";
+
+            string formattedResult = Utility.FlattenException(ex);
+            Assert.Equal("Acme.CloudSystem: Incorrectly configured setting 'Foo'.", formattedResult);
+        }
+
+        [Fact]
+        public void FlattenException_MultipleInnerExceptions_ReturnsExpectedResult()
+        {
+            ApplicationException ex1 = new ApplicationException("Exception message 1");
+            ex1.Source = "Source1";
+
+            ApplicationException ex2 = new ApplicationException("Exception message 2.", ex1);
+            ex2.Source = "Source2";
+
+            ApplicationException ex3 = new ApplicationException("Exception message 3", ex2);
+
+            string formattedResult = Utility.FlattenException(ex3);
+            Assert.Equal("Exception message 3. Source2: Exception message 2. Source1: Exception message 1.", formattedResult);
+        }
+    }
+}

test/WebJobs.Script.Tests/WebJobs.Script.Tests.csproj

@@ -13,6 +13,7 @@
     <AssemblyName>WebJobs.Script.Tests</AssemblyName>
     <TargetFrameworkVersion>v4.6</TargetFrameworkVersion>
     <FileAlignment>512</FileAlignment>
+    <StyleCopTreatErrorsAsWarnings>false</StyleCopTreatErrorsAsWarnings>
     <NuGetPackageImportStamp>
     </NuGetPackageImportStamp>
     <TargetFrameworkProfile />
@@ -232,6 +233,7 @@
     <Compile Include="TestHelpers.cs" />
     <Compile Include="TestInvoker.cs" />
     <Compile Include="TestTraceWriter.cs" />
+    <Compile Include="UtilityTests.cs" />
     <Compile Include="WindowsBatchEndToEndTests.cs" />
   </ItemGroup>
   <ItemGroup>