.NET Samples - Create 03-workflows learning path step (#4102)

dotnet/samples/03-workflows/Declarative/ExecuteCode/Program.cs

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+// Copyright (c) Microsoft. All rights reserved.
+
+// Uncomment this to enable JSON checkpointing to the local file system.
+//#define CHECKPOINT_JSON
+
+using System.Reflection;
+using Azure.Identity;
+using Microsoft.Agents.AI.Workflows;
+using Microsoft.Agents.AI.Workflows.Declarative;
+using Microsoft.Extensions.Configuration;
+using Shared.Workflows;
+
+namespace Demo.DeclarativeCode;
+
+/// <summary>
+/// HOW TO: Execute a declarative workflow that has been converted to code.
+/// </summary>
+/// <remarks>
+/// <b>Configuration</b>
+/// Define FOUNDRY_PROJECT_ENDPOINT as a user-secret or environment variable that
+/// points to your Foundry project endpoint.
+/// </remarks>
+internal sealed class Program
+{
+    public static async Task Main(string[] args)
+    {
+        string? workflowInput = ParseWorkflowInput(args);
+
+        Program program = new(workflowInput);
+        await program.ExecuteAsync();
+    }
+
+    private async Task ExecuteAsync()
+    {
+        Notify("\nWORKFLOW: Starting...");
+
+        string input = this.GetWorkflowInput();
+
+        // Execute the workflow:  The WorkflowRunner demonstrates how to execute
+        // a workflow, handle the workflow events, and providing external input.
+        // This also includes the ability to checkpoint workflow state and how to
+        // resume execution.
+        await this.Runner.ExecuteAsync(this.CreateWorkflow, input);
+
+        Notify("\nWORKFLOW: Done!\n");
+    }
+
+    private Workflow CreateWorkflow()
+    {
+        // WARNING: DefaultAzureCredential is convenient for development but requires careful consideration in production.
+        // In production, consider using a specific credential (e.g., ManagedIdentityCredential) to avoid
+        // latency issues, unintended credential probing, and potential security risks from fallback mechanisms.
+        // Use DeclarativeWorkflowBuilder to build a workflow based on a YAML file.
+        DeclarativeWorkflowOptions options =
+            new(new AzureAgentProvider(new Uri(this.FoundryEndpoint), new DefaultAzureCredential()))
+            {
+                Configuration = this.Configuration
+            };
+
+        // Use the generated provider to create a workflow instance.
+        return SampleWorkflowProvider.CreateWorkflow<string>(options);
+    }
+
+    private string? WorkflowInput { get; }
+    private string FoundryEndpoint { get; }
+    private IConfiguration Configuration { get; }
+    private WorkflowRunner Runner { get; }
+
+    private Program(string? workflowInput)
+    {
+        this.WorkflowInput = workflowInput;
+
+        this.Configuration = InitializeConfig();
+
+        this.FoundryEndpoint = this.Configuration[Application.Settings.FoundryEndpoint] ?? throw new InvalidOperationException($"Undefined configuration setting: {Application.Settings.FoundryEndpoint}");
+
+        this.Runner =
+            new()
+            {
+#if CHECKPOINT_JSON
+                // Use an json file checkpoint store that will persist checkpoints to the local file system.
+                UseJsonCheckpoints = true
+#else
+                // Use an in-memory checkpoint store that will not persist checkpoints beyond the lifetime of the process.
+                UseJsonCheckpoints = false
+#endif
+            };
+    }
+
+    private string GetWorkflowInput()
+    {
+        string? input = this.WorkflowInput;
+
+        try
+        {
+            Console.ForegroundColor = ConsoleColor.DarkGreen;
+
+            Console.Write("\nINPUT: ");
+
+            Console.ForegroundColor = ConsoleColor.White;
+
+            if (!string.IsNullOrWhiteSpace(input))
+            {
+                Console.WriteLine(input);
+                return input;
+            }
+            while (string.IsNullOrWhiteSpace(input))
+            {
+                input = Console.ReadLine();
+            }
+
+            return input.Trim();
+        }
+        finally
+        {
+            Console.ResetColor();
+        }
+    }
+
+    private static string? ParseWorkflowInput(string[] args)
+    {
+        return args?.FirstOrDefault();
+    }
+
+    // Load configuration from user-secrets
+    private static IConfigurationRoot InitializeConfig() =>
+        new ConfigurationBuilder()
+            .AddUserSecrets(Assembly.GetExecutingAssembly())
+            .AddEnvironmentVariables()
+            .Build();
+
+    private static void Notify(string message)
+    {
+        Console.ForegroundColor = ConsoleColor.Cyan;
+        try
+        {
+            Console.WriteLine(message);
+        }
+        finally
+        {
+            Console.ResetColor();
+        }
+    }
+}