Prejit support on FunctionsNetHost

eng/ci/host/official-build.yml

@@ -41,6 +41,7 @@ extends:
 
       jobs:
       - template: /eng/ci/templates/official/jobs/build-host-prelaunch-artifacts.yml@self
+      - template: /eng/ci/templates/official/jobs/build-host-prejit-artifacts.yml@self
       - template: /eng/ci/templates/official/jobs/build-host-artifacts-linux.yml@self
         parameters:
           PoolName: 1es-pool-azfunc

eng/ci/host/public-build.yml

@@ -44,6 +44,7 @@ extends:
 
       jobs:
       - template: /eng/ci/templates/official/jobs/build-host-prelaunch-artifacts.yml@self
+      - template: /eng/ci/templates/official/jobs/build-host-prejit-artifacts.yml@self  
       - template: /eng/ci/templates/official/jobs/build-host-artifacts-linux.yml@self
         parameters:
           PoolName: 1es-pool-azfunc-public

eng/ci/templates/official/jobs/build-host-prejit-artifacts.yml

@@ -0,0 +1,29 @@
+jobs:
+
+- job: BuildPreJitApp
+  displayName: Build Pre-jit placeholder app artifacts
+
+  templateContext:
+    outputParentDirectory: $(Build.ArtifactStagingDirectory)
+    outputs:
+    - output: pipelineArtifact
+      displayName: Publish Pre-jit placeholder app artifacts
+      path: $(Build.ArtifactStagingDirectory)/_preJitAppPackages
+      artifact: _preJitAppPackages
+
+  variables:
+    targetFrameworks: 'net8.0,net9.0'
+
+  steps:
+  - template: /eng/ci/templates/steps/install-dotnet.yml@self
+
+  - ${{ each tfm in split(variables.targetFrameworks, ',') }}:
+    - task: DotNetCoreCLI@2
+      displayName: ${{ tfm }} publish of pre-jit app
+      inputs:
+        command: publish
+        publishWebProjects: false
+        zipAfterPublish: false
+        modifyOutputPath: false
+        arguments: -c Release -o $(Build.ArtifactStagingDirectory)/_preJitAppPackages/${{ replace(tfm, 'net', '') }} -f ${{ tfm }} -p:UseAppHost=false
+        projects: host/src/FunctionsNetHost.PlaceholderApp/FunctionsNetHost.PlaceholderApp.csproj

eng/ci/templates/official/jobs/build-host-prelaunch-artifacts.yml

@@ -17,13 +17,13 @@ jobs:
   steps:
   - template: /eng/ci/templates/steps/install-dotnet.yml@self
 
-  - ${{ each version in split(variables.dotnetVersions, ',') }}:
+  - ${{ each tfm in split(variables.dotnetVersions, ',') }}:
     - task: DotNetCoreCLI@2
-      displayName: Publish prelaunch App.csproj
+      displayName: ${{ tfm }} publish of prelaunch app
       inputs:
         command: publish
         publishWebProjects: false
         zipAfterPublish: false
         modifyOutputPath: false
-        arguments: -c Release -o $(Build.ArtifactStagingDirectory)/_preLaunchAppPackages/${{ version }} -f ${{ version }} -p:UseAppHost=false
+        arguments: -c Release -o $(Build.ArtifactStagingDirectory)/_preLaunchAppPackages/${{ replace(tfm, 'net', '') }} -f ${{ tfm }} -p:UseAppHost=false
         projects: host/src/PrelaunchApp/App.csproj

eng/ci/templates/official/jobs/pack-host-artifacts.yml

@@ -21,7 +21,13 @@ jobs:
     displayName: Download prelaunch artifacts
     inputs:
       artifactName: _preLaunchAppPackages
-      path: $(Build.SourcesDirectory)/host/dist/portable
+      path: $(Build.SourcesDirectory)/host/dist/portable/prelaunchapps
+
+  - task: DownloadPipelineArtifact@2
+    displayName: Download pre-jit artifacts
+    inputs:
+      artifactName: _preJitAppPackages
+      path: $(Build.SourcesDirectory)/host/dist/portable/prejit-placeholder-app
 
   - task: DownloadPipelineArtifact@2
     displayName: Download host artifacts - linux

eng/ci/templates/steps/install-dotnet.yml

@@ -12,6 +12,12 @@ steps:
     packageType: sdk
     version: 7.x
 
+- task: UseDotNet@2 # Needed by our test projects
+  displayName: Install .NET 8
+  inputs:
+    packageType: sdk
+    version: 8.x
+
 - task: UseDotNet@2 # The pinned SDK we use to build
   displayName: Install .NET SDK from global.json
   inputs:

host/src/FunctionsNetHost.PlaceholderApp/FunctionsNetHost.PlaceholderApp.csproj

@@ -0,0 +1,26 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFrameworks>net8.0;net9.0</TargetFrameworks>
+    <AssemblyName>Microsoft.Azure.Functions.NetHost.Placeholder</AssemblyName>
+    <Version>1.0.0</Version>
+    <SignAssembly>true</SignAssembly>
+    <AssemblyOriginatorKeyFile>$(MSBuildThisFileDirectory)/../../../key.snk</AssemblyOriginatorKeyFile>
+    <DebugSymbols>False</DebugSymbols>
+    <DebugType>None</DebugType>
+    <TieredCompilation>false</TieredCompilation>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+  </PropertyGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\FunctionsNetHost.Shared\FunctionsNetHost.Shared.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <None Update="JitTrace\linux.coldstart.jittrace">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+    <None Update="JitTrace\coldstart.jittrace">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+</Project>

host/src/FunctionsNetHost.PlaceholderApp/FunctionsNetHost.PlaceholderApp.sln

@@ -0,0 +1,31 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.12.35209.166
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "FunctionsNetHost.PlaceholderApp", "FunctionsNetHost.PlaceholderApp.csproj", "{A102AA50-8331-4E2E-B926-F37BA4CA4F83}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "FunctionsNetHost.Shared", "..\FunctionsNetHost.Shared\FunctionsNetHost.Shared.csproj", "{298B4E58-F398-4943-9F68-9B9F0DCE0B84}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{A102AA50-8331-4E2E-B926-F37BA4CA4F83}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{A102AA50-8331-4E2E-B926-F37BA4CA4F83}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{A102AA50-8331-4E2E-B926-F37BA4CA4F83}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{A102AA50-8331-4E2E-B926-F37BA4CA4F83}.Release|Any CPU.Build.0 = Release|Any CPU
+		{298B4E58-F398-4943-9F68-9B9F0DCE0B84}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{298B4E58-F398-4943-9F68-9B9F0DCE0B84}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{298B4E58-F398-4943-9F68-9B9F0DCE0B84}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{298B4E58-F398-4943-9F68-9B9F0DCE0B84}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {93CA0BCF-0402-4BDF-86B8-2600B81AFFEB}
+	EndGlobalSection
+EndGlobal

host/src/FunctionsNetHost.PlaceholderApp/Interop/NativeMethods.cs

@@ -0,0 +1,74 @@
+// 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.InteropServices;
+using System.Threading;
+using FunctionsNetHost.Shared.Interop;
+
+namespace FunctionsNetHost.PlaceholderApp.Interop
+{
+    internal static unsafe class NativeMethods
+    {
+        private const string NativeWorkerDll = "FunctionsNetHost.exe";
+        private static readonly ManualResetEventSlim SpecializationWaitHandle = new(false);
+        private static SpecializeMessage _specializationMessage;
+
+        static NativeMethods()
+        {
+            NativeLibrary.SetDllImportResolver(typeof(NativeMethods).Assembly, ImportResolver);
+        }
+
+        internal static unsafe void RegisterForStartupHookCallback()
+        {
+            RegisterStartupHookMessageHandlingCallback(&StartupHookCallbackHandler, nint.Zero);
+        }
+
+        /// <summary>
+        /// Waits for the specialization message from the native code. 
+        /// This method blocks until the specialization event occurs and the message is received.
+        /// Once the message is received, it returns the content of the specialization message.
+        /// </summary>
+        internal static SpecializeMessage WaitForSpecializationMessage()
+        {
+            SpecializationWaitHandle.Wait();
+
+            // Don't need _specializationWaitHandle anymore. Dispose it.
+            SpecializationWaitHandle.Dispose();
+
+            return _specializationMessage;
+        }
+
+        private static void RegisterStartupHookMessageHandlingCallback(delegate* unmanaged<byte**, int, nint, nint> requestCallback, nint grpcHandler)
+        {
+            _ = register_startuphook_callback(nint.Zero, requestCallback, grpcHandler);
+        }
+
+        [DllImport(NativeWorkerDll)]
+        private static extern unsafe int register_startuphook_callback(nint pInProcessApplication, delegate* unmanaged<byte**, int, nint, nint> requestCallback, nint grpcHandler);
+
+        [UnmanagedCallersOnly]
+        private static unsafe nint StartupHookCallbackHandler(byte** nativeMessage, int nativeMessageSize, nint grpcHandler)
+        {
+            _specializationMessage = SpecializeMessage.FromByteArray(new Span<byte>(*nativeMessage, nativeMessageSize).ToArray());
+            SpecializationWaitHandle.Set();
+
+            return nint.Zero;
+        }
+
+        /// <summary>
+        /// Custom import resolve callback.
+        /// When trying to resolve "FunctionsNetHost", we return the handle using GetMainProgramHandle API in this callback.
+        /// </summary>
+        private static nint ImportResolver(string libraryName, System.Reflection.Assembly assembly, DllImportSearchPath? searchPath)
+        {
+            if (libraryName == NativeWorkerDll)
+            {
+                return NativeLibrary.GetMainProgramHandle();
+            }
+
+            // Return 0 so that built-in resolving code will be executed.
+            return nint.Zero;
+        }
+    }
+}