Making function level initialization error handling more robust

Author: mathewc

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

@@ -2,6 +2,7 @@
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Linq;
 using System.Net;
 using System.Net.Http;
@@ -52,5 +53,31 @@ public HttpResponseMessage Invoke(string name, [FromBody] FunctionInvocation inv
 
             return new HttpResponseMessage(HttpStatusCode.Accepted);
         }
+
+        [HttpGet]
+        [Route("admin/functions/{name}")]
+        public FunctionStatus Get(string name)
+        {
+            FunctionStatus status = new FunctionStatus();
+            Collection<string> functionErrors = null;
+
+            FunctionDescriptor function = _scriptHostManager.Instance.Functions.FirstOrDefault(p => p.Name.ToLowerInvariant() == name.ToLowerInvariant());
+            if (function == null)
+            {
+                // if the function doesn't exist in the host, see if it the function
+                // has errors
+                if (_scriptHostManager.Instance.FunctionErrors.TryGetValue(name, out functionErrors))
+                {
+                    status.Errors = functionErrors;
+                }
+                else
+                {
+                    // we don't know anything about this function
+                    throw new HttpResponseException(HttpStatusCode.NotFound);
+                }
+            }
+
+            return status;
+        }
     }
 }

src/WebJobs.Script.WebHost/GlobalSuppressions.cs

@@ -0,0 +1,17 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using System.Collections.ObjectModel;
+using Newtonsoft.Json;
+
+namespace WebJobs.Script.WebHost.Models
+{
+    public class FunctionStatus
+    {
+        /// <summary>
+        /// Gets or sets the collection of initialization errors for the function.
+        /// </summary>
+        [JsonProperty(PropertyName = "errors", DefaultValueHandling = DefaultValueHandling.Ignore)]
+        public Collection<string> Errors { get; set; }
+    }
+}

src/WebJobs.Script.WebHost/Models/FunctionStatus.cs

@@ -245,6 +245,7 @@
     <Compile Include="Handlers\EnsureHostRunningHandler.cs" />
     <Compile Include="HostSecrets.cs" />
     <Compile Include="Models\FunctionInvocation.cs" />
+    <Compile Include="Models\FunctionStatus.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="SecretManager.cs" />
     <Compile Include="WebHooks\DynamicWebHookReceiverConfig.cs" />

src/WebJobs.Script.WebHost/WebJobs.Script.WebHost.csproj

@@ -16,6 +16,11 @@ public class BlobBinding : FunctionBinding
 
         public BlobBinding(ScriptHostConfiguration config, string name, string path, FileAccess access, bool isTrigger) : base(config, name, "blob", access, isTrigger)
         {
+            if (string.IsNullOrEmpty(path))
+            {
+                throw new ArgumentException("The blob path cannot be null or empty.");
+            }
+
             Path = path;
             _pathBindingTemplate = BindingTemplate.FromString(Path);
         }

src/WebJobs.Script/Binding/BlobBinding.cs

@@ -17,6 +17,11 @@ public class EventHubBinding : FunctionBinding
         public EventHubBinding(ScriptHostConfiguration config, string name, string eventHubName, FileAccess access, bool isTrigger) : 
             base(config, name, "eventhub", access, isTrigger)
         {
+            if (string.IsNullOrEmpty(eventHubName))
+            {
+                throw new ArgumentException("The event hub path cannot be null or empty.");
+            }
+
             EventHubName = eventHubName;
             _eventHubNameBindingTemplate = BindingTemplate.FromString(EventHubName);
         }

src/WebJobs.Script/Binding/EventHubBinding.cs

@@ -15,7 +15,12 @@ public class QueueBinding : FunctionBinding
         private readonly BindingTemplate _queueNameBindingTemplate;
 
         public QueueBinding(ScriptHostConfiguration config, string name, string queueName, FileAccess access, bool isTrigger) : base(config, name, "queue", access, isTrigger)
-        {   
+        {
+            if (string.IsNullOrEmpty(queueName))
+            {
+                throw new ArgumentException("The queue name cannot be null or empty.");
+            }
+
             QueueName = queueName;
             _queueNameBindingTemplate = BindingTemplate.FromString(QueueName);
         }

src/WebJobs.Script/Binding/QueueBinding.cs

@@ -16,6 +16,11 @@ public class ServiceBusBinding : FunctionBinding
 
         public ServiceBusBinding(ScriptHostConfiguration config, string name, string queueOrTopicName, FileAccess access, bool isTrigger) : base(config, name, "serviceBus", access, isTrigger)
         {
+            if (string.IsNullOrEmpty(queueOrTopicName))
+            {
+                throw new ArgumentException("A valid queue or topic name must be specified.");
+            }
+
             QueueOrTopicName = queueOrTopicName;
             _queueOrTopicNameBindingTemplate = BindingTemplate.FromString(QueueOrTopicName);
         }

src/WebJobs.Script/Binding/ServiceBusBinding.cs

@@ -23,6 +23,11 @@ public class TableBinding : FunctionBinding
 
         public TableBinding(ScriptHostConfiguration config, string name, string tableName, string partitionKey, string rowKey, FileAccess access, TableQuery tableQuery = null) : base(config, name, "queue", access, false)
         {
+            if (string.IsNullOrEmpty(tableName))
+            {
+                throw new ArgumentException("The table name cannot be null or empty.");
+            }
+
             TableName = tableName;
             PartitionKey = partitionKey;
             RowKey = rowKey;

src/WebJobs.Script/Binding/TableBinding.cs

@@ -30,11 +30,11 @@ internal ScriptFunctionInvokerBase(ScriptHost host, FunctionMetadata functionMet
 
         public TraceWriter TraceWriter { get; private set; }
 
-        private static TraceWriter CreateTraceWriter(ScriptHostConfiguration scriptContig, string functionName)
+        private static TraceWriter CreateTraceWriter(ScriptHostConfiguration scriptConfig, string functionName)
         {
-            if (scriptContig.FileLoggingEnabled)
+            if (scriptConfig.FileLoggingEnabled)
             {
-                string logFilePath = Path.Combine(scriptContig.RootLogPath, "Function", functionName);
+                string logFilePath = Path.Combine(scriptConfig.RootLogPath, "Function", functionName);
                 return new FileTraceWriter(logFilePath, TraceLevel.Verbose);
             }