Make 'HttpResponseContext' not needed in PS function script (#113)

To properly convert a value for a specific output binding name implicitly, we need to know the metadata of the binding referred by that name, such as the type of the output binding.
The changes in this PR register the output binding metadata to a concurrent dictionary with the Runspace's InstanceId as the key before start running a function script, and then unregister after the function script finishes running. When a function script that calls `Push-OutputBinding` is running, we can figure out the current Runspace by `Runspace.DefaultRunspace`, and then we can query for the output binding metadata by using the InstanceId.

This approach take into the concurrency support that we will have in future. `Push-OutputBinding` is able to get the metadata about the function script that is running even with multiple Runspaces/PowerShellManagers processing requests at the same time.

Author: daxian-dbw

src/Http/HttpResponseContext.cs

@@ -1,3 +1,8 @@
+#
+# Copyright (c) Microsoft. All rights reserved.
+# Licensed under the MIT license. See LICENSE file in the project root for full license information.
+#
+
 @{
 
 # Script module or binary module file associated with this manifest.

src/Modules/Microsoft.Azure.Functions.PowerShellWorker/Microsoft.Azure.Functions.PowerShellWorker.psd1

@@ -3,8 +3,14 @@
 # Licensed under the MIT license. See LICENSE file in the project root for full license information.
 #
 
-# This holds the current state of the output bindings
+using namespace System.Management.Automation
+using namespace System.Management.Automation.Runspaces
+using namespace Microsoft.Azure.Functions.PowerShellWorker
+
+# This holds the current state of the output bindings.
 $script:_OutputBindings = @{}
+# This loads the resource strings.
+Import-LocalizedData LocalizedData -FileName PowerShellWorker.Resource.psd1
 
 <#
 .SYNOPSIS
@@ -49,6 +55,50 @@ function Get-OutputBinding {
     }
 }
 
+# Helper private function that validates the output value and does necessary conversion.
+function Convert-OutputBindingValue {
+    param(
+        [Parameter(Mandatory=$true)]
+        [string]
+        $Name,
+
+        [Parameter(Mandatory=$true)]
+        [object]
+        $Value
+    )
+
+    # Check if we can get the binding metadata of the current running function.
+    $funcMetadataType = "FunctionMetadata" -as [type]
+    if ($null -eq $funcMetadataType) {
+        return $Value
+    }
+
+    # Get the runspace where we are currently running in and then get all output bindings.
+    $bindingMap = $funcMetadataType::GetOutputBindingInfo([Runspace]::DefaultRunspace.InstanceId)
+    if ($null -eq $bindingMap) {
+        return $Value
+    }
+
+    # Get the binding information of given output binding name.
+    $bindingInfo = $bindingMap[$Name]
+    if ($bindingInfo.Type -ne "http") {
+        return $Value
+    }
+
+    # Nothing to do if the value is already a HttpResponseContext object.
+    if ($Value -as [HttpResponseContext]) {
+        return $Value
+    }
+
+    try {
+        return [LanguagePrimitives]::ConvertTo($Value, [HttpResponseContext])
+    } catch [PSInvalidCastException] {
+        $conversionMsg = $_.Exception.Message
+        $errorMsg = $LocalizedData.InvalidHttpOutputValue -f $Name, $conversionMsg
+        throw $errorMsg
+    }
+}
+
 # Helper private function that sets an OutputBinding.
 function Push-KeyValueOutputBinding {
     param (
@@ -63,10 +113,13 @@ function Push-KeyValueOutputBinding {
         [switch]
         $Force
     )
-    if(!$script:_OutputBindings.ContainsKey($Name) -or $Force.IsPresent) {
+
+    if (!$script:_OutputBindings.ContainsKey($Name) -or $Force.IsPresent) {
+        $Value = Convert-OutputBindingValue -Name $Name -Value $Value
         $script:_OutputBindings[$Name] = $Value
     } else {
-        throw "Output binding '$Name' is already set. To override the value, use -Force."
+        $errorMsg = $LocalizedData.OutputBindingAlreadySet -f $Name
+        throw $errorMsg
     }
 }
 

src/Modules/Microsoft.Azure.Functions.PowerShellWorker/Microsoft.Azure.Functions.PowerShellWorker.psm1

@@ -0,0 +1,11 @@
+#
+# Copyright (c) Microsoft. All rights reserved.
+# Licensed under the MIT license. See LICENSE file in the project root for full license information.
+#
+
+ConvertFrom-StringData @'
+###PSLOC
+    OutputBindingAlreadySet=Output binding '{0}' is already set. To override the value, use -Force.
+    InvalidHttpOutputValue=The given value for the 'http' output binding '{0}' cannot be converted to the type 'HttpResponseContext'. The conversion failed with the following error: {1}
+###PSLOC
+'@

src/Modules/Microsoft.Azure.Functions.PowerShellWorker/PowerShellWorker.Resource.psd1

@@ -206,9 +206,36 @@ internal string ConvertToJson(object fromObj)
                         .InvokeAndClearCommands<string>()[0];
         }
 
-        private Dictionary<string, ParameterMetadata> RetriveParameterMetadata(
-            AzFunctionInfo functionInfo,
-            out string moduleName)
+        /// <summary>
+        /// Helper method to prepend the FunctionApp module folder to the module path.
+        /// </summary>
+        internal void PrependToPSModulePath(string directory)
+        {
+            // Adds the passed in directory to the front of the PSModulePath using the path separator of the OS.
+            string psModulePath = Environment.GetEnvironmentVariable("PSModulePath");
+            Environment.SetEnvironmentVariable("PSModulePath", $"{directory}{Path.PathSeparator}{psModulePath}");
+        }
+
+        /// <summary>
+        /// Helper method to set the output binding metadata for the function that is about to run.
+        /// </summary>
+        internal void RegisterFunctionMetadata(AzFunctionInfo functionInfo)
+        {
+            var outputBindings = new ReadOnlyDictionary<string, BindingInfo>(functionInfo.OutputBindings);
+            FunctionMetadata.OutputBindingCache.AddOrUpdate(_pwsh.Runspace.InstanceId,
+                                                            outputBindings,
+                                                            (key, value) => outputBindings);
+        }
+
+        /// <summary>
+        /// Helper method to clear the output binding metadata for the function that has done running.
+        /// </summary>
+        internal void UnregisterFunctionMetadata()
+        {
+            FunctionMetadata.OutputBindingCache.TryRemove(_pwsh.Runspace.InstanceId, out _);
+        }
+
+        private Dictionary<string, ParameterMetadata> RetriveParameterMetadata(AzFunctionInfo functionInfo, out string moduleName)
         {
             moduleName = null;
             string scriptPath = functionInfo.ScriptPath;
@@ -232,13 +259,6 @@ private Dictionary<string, ParameterMetadata> RetriveParameterMetadata(
             }
         }
 
-        internal void PrependToPSModulePath(string directory)
-        {
-            // Adds the passed in directory to the front of the PSModulePath using the path separator of the OS.
-            string psModulePath = Environment.GetEnvironmentVariable("PSModulePath");
-            Environment.SetEnvironmentVariable("PSModulePath", $"{directory}{Path.PathSeparator}{psModulePath}");
-        }
-
         private void ResetRunspace(string moduleName)
         {
             // Reset the runspace to the Initial Session State

src/PowerShell/PowerShellManager.cs

@@ -0,0 +1,32 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+using System.Collections.Concurrent;
+using System.Collections.ObjectModel;
+using Microsoft.Azure.WebJobs.Script.Grpc.Messages;
+using Google.Protobuf.Collections;
+
+namespace Microsoft.Azure.Functions.PowerShellWorker
+{
+    /// <summary>
+    /// Function metadata for the PowerShellWorker module to query.
+    /// </summary>
+    public static class FunctionMetadata
+    {
+        internal static ConcurrentDictionary<Guid, ReadOnlyDictionary<string, BindingInfo>> OutputBindingCache
+            = new ConcurrentDictionary<Guid, ReadOnlyDictionary<string, BindingInfo>>();
+
+        /// <summary>
+        /// Get the binding metadata for the given Runspace instance id.
+        /// </summary>
+        public static ReadOnlyDictionary<string, BindingInfo> GetOutputBindingInfo(Guid runspaceInstanceId)
+        {
+            ReadOnlyDictionary<string, BindingInfo> outputBindings = null;
+            OutputBindingCache.TryGetValue(runspaceInstanceId, out outputBindings);
+            return outputBindings;
+        }
+    }
+}

src/Public/FunctionMetadata.cs

@@ -4,7 +4,9 @@
 //
 
 using System;
+using System.Collections;
 using System.Collections.Generic;
+using System.Net;
 
 namespace Microsoft.Azure.Functions.PowerShellWorker
 {
@@ -58,4 +60,35 @@ public HttpRequestContext()
         /// </summary>
         public object RawBody { get; internal set; }
     }
+
+    /// <summary>
+    /// Custom type represent the context of the Http response.
+    /// </summary>
+    public class HttpResponseContext
+    {
+        /// <summary>
+        /// Gets or sets the Body of the Http response.
+        /// </summary>
+        public object Body { get; set; }
+
+        /// <summary>
+        /// Gets or sets the ContentType of the Http response.
+        /// </summary>
+        public string ContentType { get; set; } = "text/plain";
+
+        /// <summary>
+        /// Gets or sets the EnableContentNegotiation of the Http response.
+        /// </summary>
+        public bool EnableContentNegotiation { get; set; }
+
+        /// <summary>
+        /// Gets or sets the Headers of the Http response.
+        /// </summary>
+        public IDictionary Headers { get; set; }
+
+        /// <summary>
+        /// Gets or sets the StatusCode of the Http response.
+        /// </summary>
+        public HttpStatusCode StatusCode { get; set; } = HttpStatusCode.OK;
+    }
 }

src/Http/HttpRequestContext.cs renamed to src/Public/HttpContext.cs

@@ -143,6 +143,7 @@ internal StreamingMessage ProcessInvocationRequest(StreamingMessage request)
             {
                 // Load information about the function
                 var functionInfo = _functionLoader.GetFunctionInfo(invocationRequest.FunctionId);
+                _powerShellManager.RegisterFunctionMetadata(functionInfo);
 
                 Hashtable results = functionInfo.Type == AzFunctionType.OrchestrationFunction
                     ? InvokeOrchestrationFunction(functionInfo, invocationRequest)
@@ -155,6 +156,10 @@ internal StreamingMessage ProcessInvocationRequest(StreamingMessage request)
                 status.Status = StatusResult.Types.Status.Failure;
                 status.Exception = e.ToRpcException();
             }
+            finally
+            {
+                _powerShellManager.UnregisterFunctionMetadata();
+            }
 
             return response;
         }

src/RequestProcessor.cs

@@ -143,10 +143,15 @@ private static RpcHttp ToRpcHttp(this HttpResponseContext httpResponseContext, P
                 rpcHttp.Body = httpResponseContext.Body.ToTypedData(psHelper);
             }
 
+            rpcHttp.EnableContentNegotiation = httpResponseContext.EnableContentNegotiation;
+
             // Add all the headers. ContentType is separated for convenience
-            foreach (var item in httpResponseContext.Headers)
+            if (httpResponseContext.Headers != null)
             {
-                rpcHttp.Headers.Add(item.Key, item.Value);
+                foreach (DictionaryEntry item in httpResponseContext.Headers)
+                {
+                    rpcHttp.Headers.Add(item.Key.ToString(), item.Value.ToString());
+                }
             }
 
             // Allow the user to set content-type in the Headers

src/Utility/TypeExtensions.cs

@@ -14,16 +14,16 @@ $name = $req.Query.Name
 if (-not $name) { $name = $req.Body.Name }
 
 if($name) {
-    $status = 202
-    $body = "Hello " + $name
+    # Cast the value to HttpResponseContext explicitly.
+    Push-OutputBinding -Name res -Value ([HttpResponseContext]@{
+        StatusCode = 202
+        Body = "Hello " + $name
+    })
 }
 else {
-    $status = "400"
-    $body = "Please pass a name on the query string or in the request body."
+    # Convert value to HttpResponseContext implicitly for 'http' output.
+    Push-OutputBinding -Name res -Value @{
+        StatusCode = "400"
+        Body = "Please pass a name on the query string or in the request body."
+    }
 }
-
-# You associate values to output bindings by calling 'Push-OutputBinding'.
-Push-OutputBinding -Name res -Value ([HttpResponseContext]@{
-    StatusCode = $status
-    Body = $body
-})

test/E2E/TestFunctionApp/TestBasicHttpTrigger/run.ps1

@@ -14,16 +14,16 @@ $name = $TriggerMetadata.req.Query.Name
 if (-not $name) { $name = $TriggerMetadata.req.Body.Name }
 
 if($name) {
-    $status = [System.Net.HttpStatusCode]::Accepted
-    $body = "Hello " + $name
+    # Cast the value to HttpResponseContext explicitly.
+    Push-OutputBinding -Name res -Value ([HttpResponseContext]@{
+        StatusCode = [System.Net.HttpStatusCode]::Accepted
+        Body = "Hello " + $name
+    })
 }
 else {
-    $status = 400
-    $body = "Please pass a name on the query string or in the request body."
+    # Convert value to HttpResponseContext implicitly for 'http' output.
+    Push-OutputBinding -Name res -Value @{
+        StatusCode = 400
+        Body = "Please pass a name on the query string or in the request body."
+    }
 }
-
-# You associate values to output bindings by calling 'Push-OutputBinding'.
-Push-OutputBinding -Name res -Value ([HttpResponseContext]@{
-    StatusCode = $status
-    Body = $body
-})

test/E2E/TestFunctionApp/TestBasicHttpTriggerWithTriggerMetadata/run.ps1

@@ -145,5 +145,19 @@ public void PrependingToPSModulePathShouldWork()
                 Environment.SetEnvironmentVariable("PSModulePath", modulePathBefore);
             }
         }
+
+        [Fact]
+        public void RegisterAndUnregisterFunctionMetadataShouldWork()
+        {
+            var logger = new ConsoleLogger();
+            var manager = new PowerShellManager(logger);
+            var functionInfo = GetAzFunctionInfo("dummy-path", string.Empty);
+
+            Assert.Empty(FunctionMetadata.OutputBindingCache);
+            manager.RegisterFunctionMetadata(functionInfo);
+            Assert.Single(FunctionMetadata.OutputBindingCache);
+            manager.UnregisterFunctionMetadata();
+            Assert.Empty(FunctionMetadata.OutputBindingCache);
+        }
     }
 }

test/Unit/PowerShell/PowerShellManagerTests.cs

@@ -368,7 +368,7 @@ public void TestObjectToTypedDataRpcHttpContentTypeInHeader()
             var input = new HttpResponseContext
             {
                 Body = data,
-                Headers =  { { "content-type", "text/html" } }
+                Headers = new Hashtable { { "content-type", "text/html" } }
             };
             var expected = new TypedData
             {