Support watch for azure functions and fix a bug with active replicas (#595)

src/Microsoft.Tye.Core/ApplicationFactory.cs

@@ -225,15 +225,27 @@ namespace Microsoft.Tye
                     }
                     else if (!string.IsNullOrEmpty(configService.AzureFunction))
                     {
+                        var azureFunctionDirectory = Path.Combine(config.Source.DirectoryName!, configService.AzureFunction);
+
                         var functionBuilder = new AzureFunctionServiceBuilder(
                             configService.Name,
-                            Path.Combine(config.Source.DirectoryName!, configService.AzureFunction))
+                            azureFunctionDirectory)
                         {
                             Args = configService.Args,
                             Replicas = configService.Replicas ?? 1,
-                            FuncExecutablePath = configService.FuncExecutable
+                            FuncExecutablePath = configService.FuncExecutable,
                         };
 
+                        foreach (var proj in Directory.EnumerateFiles(azureFunctionDirectory))
+                        {
+                            var fileInfo = new FileInfo(proj);
+                            if (fileInfo.Extension == ".csproj" || fileInfo.Extension == ".fsproj")
+                            {
+                                functionBuilder.ProjectFile = fileInfo.FullName;
+                                break;
+                            }
+                        }
+
                         // TODO liveness?
                         service = functionBuilder;
                     }

src/Microsoft.Tye.Core/AzureFunctionServiceBuilder.cs

@@ -16,5 +16,6 @@ namespace Microsoft.Tye
         public string? Args { get; set; }
         public string FunctionPath { get; }
         public string? FuncExecutablePath { get; set; }
+        public string? ProjectFile { get; set; }
     }
 }

src/Microsoft.Tye.Hosting/Model/AzureFunctionRunInfo.cs

@@ -13,10 +13,12 @@ namespace Microsoft.Tye.Hosting.Model
             Args = function.Args;
             FunctionPath = function.FunctionPath;
             FuncExecutablePath = function.FuncExecutablePath;
+            ProjectFile = function.ProjectFile;
         }
 
         public string? Args { get; }
         public string FunctionPath { get; }
         public string? FuncExecutablePath { get; set; }
+        public string? ProjectFile { get; set; }
     }
 }

src/Microsoft.Tye.Hosting/ProcessRunner.cs

@@ -322,7 +322,7 @@ namespace Microsoft.Tye.Hosting
 
                                 WriteReplicaToStore(pid.ToString());
 
-                                if (_options.Watch && service.Description.RunInfo is ProjectRunInfo runInfo)
+                                if (_options.Watch)
                                 {
                                     // OnStart/OnStop will be called multiple times for watch.
                                     // Watch will constantly be adding and removing from the list, so only add here for watch.
@@ -359,16 +359,21 @@ namespace Microsoft.Tye.Hosting
                             },
                             Build = async () =>
                             {
-                                var buildResult = await ProcessUtil.RunAsync("dotnet", $"build \"{service.Status.ProjectFilePath}\" /nologo", throwOnError: false, workingDirectory: application.ContextDirectory);
-                                if (buildResult.ExitCode != 0)
+                                if (service.Description.RunInfo is ProjectRunInfo)
                                 {
-                                    _logger.LogInformation("Building projects failed with exit code {ExitCode}: \r\n" + buildResult.StandardOutput, buildResult.ExitCode);
+                                    var buildResult = await ProcessUtil.RunAsync("dotnet", $"build \"{service.Status.ProjectFilePath}\" /nologo", throwOnError: false, workingDirectory: application.ContextDirectory);
+                                    if (buildResult.ExitCode != 0)
+                                    {
+                                        _logger.LogInformation("Building projects failed with exit code {ExitCode}: \r\n" + buildResult.StandardOutput, buildResult.ExitCode);
+                                    }
+                                    return buildResult.ExitCode;
                                 }
-                                return buildResult.ExitCode;
+
+                                return 0;
                             }
                         };
 
-                        if (_options.Watch && service.Description.RunInfo is ProjectRunInfo runInfo)
+                        if (_options.Watch && (service.Description.RunInfo is ProjectRunInfo runInfo))
                         {
                             var projectFile = runInfo.ProjectFile.FullName;
                             var fileSetFactory = new MsBuildFileSetFactory(_logger,
@@ -380,6 +385,18 @@ namespace Microsoft.Tye.Hosting
                             await new DotNetWatcher(_logger)
                                 .WatchAsync(processInfo, fileSetFactory, replica, status.StoppingTokenSource.Token);
                         }
+                        else if (_options.Watch && (service.Description.RunInfo is AzureFunctionRunInfo azureFunctionRunInfo) && !string.IsNullOrEmpty(azureFunctionRunInfo.ProjectFile))
+                        {
+                            var projectFile = azureFunctionRunInfo.ProjectFile;
+                            var fileSetFactory = new MsBuildFileSetFactory(_logger,
+                                projectFile,
+                                waitOnError: true,
+                                trace: false);
+                            environment["DOTNET_WATCH"] = "1";
+
+                            await new DotNetWatcher(_logger)
+                                .WatchAsync(processInfo, fileSetFactory, replica, status.StoppingTokenSource.Token);
+                        }
                         else
                         {
                             await ProcessUtil.RunAsync(processInfo, status.StoppingTokenSource.Token, throwOnError: false);

src/Microsoft.Tye.Hosting/Watch/DotNetWatcher.cs

@@ -100,6 +100,11 @@ namespace Microsoft.DotNet.Watcher
                     {
                         while (true)
                         {
+                            if (cancellationToken.IsCancellationRequested)
+                            {
+                                break;
+                            }
+
                             var exitCode = await processSpec.Build();
                             if (exitCode == 0)
                             {