Add workflow sample task chaining

Signed-off-by: MregXN <mregxn@gmail.com>

all.sln

@@ -104,6 +104,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "BulkPublishEventExample", "
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "WorkflowUnitTest", "examples\Workflow\WorkflowUnitTest\WorkflowUnitTest.csproj", "{8CA09061-2BEF-4506-A763-07062D2BD6AC}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "WorkflowFanOutFanIn", "examples\Workflow\WorkflowTaskChaining\WorkflowFanOutFanIn.csproj", "{96C8AD2A-D0BF-4E41-B681-A4DFA2A3BFC1}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -248,6 +250,10 @@ Global
 		{DDC41278-FB60-403A-B969-2AEBD7C2D83C}.Release|Any CPU.Build.0 = Release|Any CPU
 		{8CA09061-2BEF-4506-A763-07062D2BD6AC}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{8CA09061-2BEF-4506-A763-07062D2BD6AC}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{96C8AD2A-D0BF-4E41-B681-A4DFA2A3BFC1}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{96C8AD2A-D0BF-4E41-B681-A4DFA2A3BFC1}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{96C8AD2A-D0BF-4E41-B681-A4DFA2A3BFC1}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{96C8AD2A-D0BF-4E41-B681-A4DFA2A3BFC1}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -293,6 +299,7 @@ Global
 		{4A175C27-EAFE-47E7-90F6-873B37863656} = {0EF6EA64-D7C3-420D-9890-EAE8D54A57E6}
 		{DDC41278-FB60-403A-B969-2AEBD7C2D83C} = {0EF6EA64-D7C3-420D-9890-EAE8D54A57E6}
 		{8CA09061-2BEF-4506-A763-07062D2BD6AC} = {BF3ED6BF-ADF3-4D25-8E89-02FB8D945CA9}
+		{96C8AD2A-D0BF-4E41-B681-A4DFA2A3BFC1} = {BF3ED6BF-ADF3-4D25-8E89-02FB8D945CA9}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {65220BF2-EAE1-4CB2-AA58-EBE80768CB40}

examples/Workflow/WorkflowTaskChaining/Activities/Step1.cs

@@ -0,0 +1,13 @@
+using Dapr.Workflow;
+
+namespace WorkflowTaskChianing.Activities
+{
+    public class Step1 : WorkflowActivity<int, int>
+    {
+        public override Task<int> RunAsync(WorkflowActivityContext context, int input)
+        {
+            Console.WriteLine($"Step 1: Received input: {input}.");
+            return Task.FromResult<int>(input + 1);
+        }
+    }
+}

examples/Workflow/WorkflowTaskChaining/Activities/Step2.cs

@@ -0,0 +1,13 @@
+using Dapr.Workflow;
+
+namespace WorkflowTaskChianing.Activities
+{
+    public class Step2 : WorkflowActivity<int, int>
+    {
+        public override Task<int> RunAsync(WorkflowActivityContext context, int input)
+        {
+            Console.WriteLine($"Step 2: Received input: {input}.");
+            return Task.FromResult<int>(input * 2);
+        }
+    }
+}

examples/Workflow/WorkflowTaskChaining/Activities/Step3.cs

@@ -0,0 +1,13 @@
+using Dapr.Workflow;
+
+namespace WorkflowTaskChianing.Activities
+{
+    public class Step3 : WorkflowActivity<int, int>
+    {
+        public override Task<int> RunAsync(WorkflowActivityContext context, int input)
+        {
+            Console.WriteLine($"Step 3: Received input: {input}.");
+            return Task.FromResult<int>(input ^ 2);
+        }
+    }
+}

examples/Workflow/WorkflowTaskChaining/Program.cs

@@ -0,0 +1,67 @@
+using Dapr.Client;
+using Dapr.Workflow;
+using WorkflowTaskChianing.Activities;
+using WorkflowTaskChianing.Workflows;
+using Microsoft.Extensions.Hosting;
+
+const string DaprWorkflowComponent = "dapr";
+
+// The workflow host is a background service that connects to the sidecar over gRPC
+var builder = Host.CreateDefaultBuilder(args).ConfigureServices(services =>
+{
+    services.AddDaprWorkflow(options =>
+    {
+        options.RegisterWorkflow<DemoWorkflow>();
+        options.RegisterActivity<Step1>();
+        options.RegisterActivity<Step2>();
+        options.RegisterActivity<Step3>();
+    });
+});
+
+// Dapr uses a random port for gRPC by default. If we don't know what that port
+// is (because this app was started separate from dapr), then assume 4001.
+if (string.IsNullOrEmpty(Environment.GetEnvironmentVariable("DAPR_GRPC_PORT")))
+{
+    Environment.SetEnvironmentVariable("DAPR_GRPC_PORT", "4001");
+}
+
+// Start the app - this is the point where we connect to the Dapr sidecar to
+// listen for workflow work-items to execute.
+using var host = builder.Build();
+host.Start();
+
+
+DaprClient daprClient = new DaprClientBuilder().Build();
+
+while (!await daprClient.CheckHealthAsync())
+{
+    Thread.Sleep(TimeSpan.FromSeconds(5));
+}
+
+int wfInput = 42;
+using (daprClient)
+{
+    Console.WriteLine($"Workflow Started.");
+    await daprClient.WaitForSidecarAsync();
+
+    string instanceId = $"demo-workflow-{Guid.NewGuid().ToString()[..8]}";
+
+    await daprClient.StartWorkflowAsync(
+    workflowComponent: DaprWorkflowComponent,
+    workflowName: nameof(DemoWorkflow),
+    instanceId: instanceId,
+    input: wfInput);
+
+
+    await daprClient.WaitForWorkflowCompletionAsync(
+        workflowComponent: DaprWorkflowComponent,
+        instanceId: instanceId);
+
+    GetWorkflowResponse state = await daprClient.GetWorkflowAsync(
+    instanceId: instanceId,
+    workflowComponent: DaprWorkflowComponent);
+    Console.WriteLine($"Workflow state: {state.RuntimeStatus}");
+
+    string result = string.Join(" ", state.ReadOutputAs<int[]>());  
+    Console.WriteLine($"Workflow result: {result}");
+}

examples/Workflow/WorkflowTaskChaining/WorkflowFanOutFanIn.csproj

@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\src\Dapr.Workflow\Dapr.Workflow.csproj" />
+  </ItemGroup>
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <NoWarn>612,618</NoWarn>
+  </PropertyGroup>
+
+</Project>

examples/Workflow/WorkflowTaskChaining/Workflows/DemoWorkflow.cs

@@ -0,0 +1,18 @@
+using Dapr.Workflow;
+using WorkflowTaskChianing.Activities;
+
+namespace WorkflowTaskChianing.Workflows
+{
+    public class DemoWorkflow : Workflow<int, int[]>
+    {
+        public override async Task<int[]> RunAsync(WorkflowContext context, int input)
+        {
+            int result1 = await context.CallActivityAsync<int>(nameof(Step1), input);
+            int result2 = await context.CallActivityAsync<int>(nameof(Step2), result1);
+            int result3 = await context.CallActivityAsync<int>(nameof(Step3), result2);
+            int[] ret = new int[] { result1, result2, result3 };
+
+            return ret;
+        }
+    }
+}