Quickstart: Workflow

The order-processor console app starts and manages the lifecycle of an order processing workflow that stores and retrieves data in a state store. The workflow consists of four workflow activities, or tasks:

• notifyActivity: Utilizes a logger to print out messages throughout the workflow. These messages notify the user when there is insufficient inventory, their payment couldn’t be processed, and more.
• reserveInventoryActivity: Checks the state store to ensure that there is enough inventory present for purchase.
• requestApprovalActivity: Requests approval for orders over a certain threshold
• processPaymentActivity: Processes and authorizes the payment.
• updateInventoryActivity: Updates the state store with the new remaining inventory value.

Step 1: Pre-requisites

For this example, you will need:

• Dapr CLI and initialized environment.
• Latest Node.js installed.

• Docker Desktop

Step 2: Set up the environment

Clone the sample provided in the Quickstarts repo.

git clone https://github.com/dapr/quickstarts.git

In a new terminal window, navigate to the order-processor directory:

cd workflows/javascript/sdk/order-processor

Install the dependencies:

cd ./javascript/sdk
npm install
npm run build
cd ..

Step 3: Run the order processor app

In the terminal, start the order processor app alongside a Dapr sidecar using Multi-App Run:

dapr run -f .

This starts the order-processor app with unique workflow ID and runs the workflow activities.

Expected output:

== APP - workflowApp == == APP == Orchestration scheduled with ID: 0c332155-1e02-453a-a333-28cfc7777642
== APP - workflowApp == == APP == Waiting 30 seconds for instance 0c332155-1e02-453a-a333-28cfc7777642 to complete...
== APP - workflowApp == == APP == Received "Orchestrator Request" work item with instance id '0c332155-1e02-453a-a333-28cfc7777642'
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Rebuilding local state with 0 history event...
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Processing 2 new history event(s): [ORCHESTRATORSTARTED=1, EXECUTIONSTARTED=1]
== APP - workflowApp == == APP == Processing order 0c332155-1e02-453a-a333-28cfc7777642...
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Waiting for 1 task(s) and 0 event(s) to complete...
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Returning 1 action(s)
== APP - workflowApp == == APP == Received "Activity Request" work item
== APP - workflowApp == == APP == Received order 0c332155-1e02-453a-a333-28cfc7777642 for 10 item1 at a total cost of 100
== APP - workflowApp == == APP == Activity notifyActivity completed with output undefined (0 chars)
== APP - workflowApp == == APP == Received "Orchestrator Request" work item with instance id '0c332155-1e02-453a-a333-28cfc7777642'
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Rebuilding local state with 3 history event...
== APP - workflowApp == == APP == Processing order 0c332155-1e02-453a-a333-28cfc7777642...
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Processing 2 new history event(s): [ORCHESTRATORSTARTED=1, TASKCOMPLETED=1]
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Waiting for 1 task(s) and 0 event(s) to complete...
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Returning 1 action(s)
== APP - workflowApp == == APP == Received "Activity Request" work item
== APP - workflowApp == == APP == Reserving inventory for 0c332155-1e02-453a-a333-28cfc7777642 of 10 item1
== APP - workflowApp == == APP == 2024-02-16T03:15:59.498Z INFO [HTTPClient, HTTPClient] Sidecar Started
== APP - workflowApp == == APP == There are 100 item1 in stock
== APP - workflowApp == == APP == Activity reserveInventoryActivity completed with output {"success":true,"inventoryItem":{"perItemCost":100,"quantity":100,"itemName":"item1"}} (86 chars)
== APP - workflowApp == == APP == Received "Orchestrator Request" work item with instance id '0c332155-1e02-453a-a333-28cfc7777642'
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Rebuilding local state with 6 history event...
== APP - workflowApp == == APP == Processing order 0c332155-1e02-453a-a333-28cfc7777642...
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Processing 2 new history event(s): [ORCHESTRATORSTARTED=1, TASKCOMPLETED=1]
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Waiting for 1 task(s) and 0 event(s) to complete...
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Returning 1 action(s)
== APP - workflowApp == == APP == Received "Activity Request" work item
== APP - workflowApp == == APP == Processing payment for order item1
== APP - workflowApp == == APP == Payment of 100 for 10 item1 processed successfully
== APP - workflowApp == == APP == Activity processPaymentActivity completed with output true (4 chars)
== APP - workflowApp == == APP == Received "Orchestrator Request" work item with instance id '0c332155-1e02-453a-a333-28cfc7777642'
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Rebuilding local state with 9 history event...
== APP - workflowApp == == APP == Processing order 0c332155-1e02-453a-a333-28cfc7777642...
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Processing 2 new history event(s): [ORCHESTRATORSTARTED=1, TASKCOMPLETED=1]
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Waiting for 1 task(s) and 0 event(s) to complete...
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Returning 1 action(s)
== APP - workflowApp == == APP == Received "Activity Request" work item
== APP - workflowApp == == APP == Updating inventory for 0c332155-1e02-453a-a333-28cfc7777642 of 10 item1
== APP - workflowApp == == APP == Inventory updated for 0c332155-1e02-453a-a333-28cfc7777642, there are now 90 item1 in stock
== APP - workflowApp == == APP == Activity updateInventoryActivity completed with output {"success":true,"inventoryItem":{"perItemCost":100,"quantity":90,"itemName":"item1"}} (85 chars)
== APP - workflowApp == == APP == Received "Orchestrator Request" work item with instance id '0c332155-1e02-453a-a333-28cfc7777642'
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Rebuilding local state with 12 history event...
== APP - workflowApp == == APP == Processing order 0c332155-1e02-453a-a333-28cfc7777642...
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Processing 2 new history event(s): [ORCHESTRATORSTARTED=1, TASKCOMPLETED=1]
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Waiting for 1 task(s) and 0 event(s) to complete...
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Returning 1 action(s)
== APP - workflowApp == == APP == Received "Activity Request" work item
== APP - workflowApp == == APP == order 0c332155-1e02-453a-a333-28cfc7777642 processed successfully!
== APP - workflowApp == == APP == Activity notifyActivity completed with output undefined (0 chars)
== APP - workflowApp == == APP == Received "Orchestrator Request" work item with instance id '0c332155-1e02-453a-a333-28cfc7777642'
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Rebuilding local state with 15 history event...
== APP - workflowApp == == APP == Processing order 0c332155-1e02-453a-a333-28cfc7777642...
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Processing 2 new history event(s): [ORCHESTRATORSTARTED=1, TASKCOMPLETED=1]
== APP - workflowApp == == APP == Order 0c332155-1e02-453a-a333-28cfc7777642 processed successfully!
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Orchestration completed with status COMPLETED
== APP - workflowApp == == APP == 0c332155-1e02-453a-a333-28cfc7777642: Returning 1 action(s)
== APP - workflowApp == time="2024-02-15T21:15:59.5589687-06:00" level=info msg="0c332155-1e02-453a-a333-28cfc7777642: 'orderProcessingWorkflow' completed with a COMPLETED status." app_id=activity-sequence-workflow instance=kaibocai-devbox scope=wfengine.backend type=log ver=1.12.4
== APP - workflowApp == == APP == Instance 0c332155-1e02-453a-a333-28cfc7777642 completed

(Optional) Step 4: View in Zipkin

Running dapr init launches the openzipkin/zipkin Docker container. If the container has stopped running, launch the Zipkin Docker container with the following command:

docker run -d -p 9411:9411 openzipkin/zipkin

View the workflow trace spans in the Zipkin web UI (typically at http://localhost:9411/zipkin/).

What happened?

When you ran dapr run -f .:

1. A unique order ID for the workflow is generated (in the above example, 0c332155-1e02-453a-a333-28cfc7777642) and the workflow is scheduled.
2. The notifyActivity workflow activity sends a notification saying an order for 10 cars has been received.
3. The reserveInventoryActivity workflow activity checks the inventory data, determines if you can supply the ordered item, and responds with the number of cars in stock.
4. Your workflow starts and notifies you of its status.
5. The processPaymentActivity workflow activity begins processing payment for order 0c332155-1e02-453a-a333-28cfc7777642 and confirms if successful.
6. The updateInventoryActivity workflow activity updates the inventory with the current available cars after the order has been processed.
7. The notifyActivity workflow activity sends a notification saying that order 0c332155-1e02-453a-a333-28cfc7777642 has completed.
8. The workflow terminates as completed.

order-processor/workflowApp.ts

In the application file:

• The unique workflow order ID is generated
• The workflow is scheduled
• The workflow status is retrieved
• The workflow and the workflow activities it invokes are registered

import { DaprWorkflowClient, WorkflowRuntime, DaprClient } from "@dapr/dapr-dev";
import { InventoryItem, OrderPayload } from "./model";
import { notifyActivity, orderProcessingWorkflow, processPaymentActivity, requestApprovalActivity, reserveInventoryActivity, updateInventoryActivity } from "./orderProcessingWorkflow";

async function start() {
  // Update the gRPC client and worker to use a local address and port
  const workflowClient = new DaprWorkflowClient();
  const workflowWorker = new WorkflowRuntime();

  const daprClient = new DaprClient();
  const storeName = "statestore";

  const inventory = new InventoryItem("item1", 100, 100);
  const key = inventory.itemName;

  await daprClient.state.save(storeName, [
    {
      key: key,
      value: inventory,
    }
  ]);

  const order = new OrderPayload("item1", 100, 10);

  workflowWorker
  .registerWorkflow(orderProcessingWorkflow)
  .registerActivity(notifyActivity)
  .registerActivity(reserveInventoryActivity)
  .registerActivity(requestApprovalActivity)
  .registerActivity(processPaymentActivity)
  .registerActivity(updateInventoryActivity);

  // Wrap the worker startup in a try-catch block to handle any errors during startup
  try {
    await workflowWorker.start();
    console.log("Workflow runtime started successfully");
  } catch (error) {
    console.error("Error starting workflow runtime:", error);
  }

  // Schedule a new orchestration
  try {
    const id = await workflowClient.scheduleNewWorkflow(orderProcessingWorkflow, order);
    console.log(`Orchestration scheduled with ID: ${id}`);

    // Wait for orchestration completion
    const state = await workflowClient.waitForWorkflowCompletion(id, undefined, 30);

    console.log(`Orchestration completed! Result: ${state?.serializedOutput}`);
  } catch (error) {
    console.error("Error scheduling or waiting for orchestration:", error);
    throw error;
  }

  await workflowWorker.stop();
  await workflowClient.stop();
}

start().catch((e) => {
  console.error(e);
  process.exit(1);
});

The order-processor console app starts and manages the lifecycle of an order processing workflow that stores and retrieves data in a state store. The workflow consists of four workflow activities, or tasks:

• NotifyActivity: Utilizes a logger to print out messages throughout the workflow
• ReserveInventoryActivity: Checks the state store to ensure that there is enough inventory for the purchase
• ProcessPaymentActivity: Processes and authorizes the payment
• UpdateInventoryActivity: Removes the requested items from the state store and updates the store with the new remaining inventory value

Step 1: Pre-requisites

For this example, you will need:

• Dapr CLI and initialized environment.
• .NET SDK or .NET 6 SDK installed.

• Docker Desktop

Step 2: Set up the environment

Clone the sample provided in the Quickstarts repo.

git clone https://github.com/dapr/quickstarts.git

In a new terminal window, navigate to the order-processor directory:

cd workflows/csharp/sdk/order-processor

Step 3: Run the order processor app

In the terminal, start the order processor app alongside a Dapr sidecar using Multi-App Run:

dapr run -f .

This starts the order-processor app with unique workflow ID and runs the workflow activities.

Expected output:

== APP == Starting workflow 6d2abcc9 purchasing 10 Cars

== APP == info: Microsoft.DurableTask.Client.Grpc.GrpcDurableTaskClient[40]
== APP ==       Scheduling new OrderProcessingWorkflow orchestration with instance ID '6d2abcc9' and 47 bytes of input data.
== APP == info: WorkflowConsoleApp.Activities.NotifyActivity[0]
== APP ==       Received order 6d2abcc9 for 10 Cars at $15000
== APP == info: WorkflowConsoleApp.Activities.ReserveInventoryActivity[0]
== APP ==       Reserving inventory for order 6d2abcc9 of 10 Cars
== APP == info: WorkflowConsoleApp.Activities.ReserveInventoryActivity[0]
== APP ==       There are: 100, Cars available for purchase

== APP == Your workflow has started. Here is the status of the workflow: Dapr.Workflow.WorkflowState

== APP == info: WorkflowConsoleApp.Activities.ProcessPaymentActivity[0]
== APP ==       Processing payment: 6d2abcc9 for 10 Cars at $15000
== APP == info: WorkflowConsoleApp.Activities.ProcessPaymentActivity[0]
== APP ==       Payment for request ID '6d2abcc9' processed successfully
== APP == info: WorkflowConsoleApp.Activities.UpdateInventoryActivity[0]
== APP ==       Checking Inventory for: Order# 6d2abcc9 for 10 Cars
== APP == info: WorkflowConsoleApp.Activities.UpdateInventoryActivity[0]
== APP ==       There are now: 90 Cars left in stock
== APP == info: WorkflowConsoleApp.Activities.NotifyActivity[0]
== APP ==       Order 6d2abcc9 has completed!

== APP == Workflow Status: Completed

(Optional) Step 4: View in Zipkin

Running dapr init launches the openzipkin/zipkin Docker container. If the container has stopped running, launch the Zipkin Docker container with the following command:

docker run -d -p 9411:9411 openzipkin/zipkin

View the workflow trace spans in the Zipkin web UI (typically at http://localhost:9411/zipkin/).

What happened?

When you ran dapr run -f .:

1. A unique order ID for the workflow is generated (in the above example, 6d2abcc9) and the workflow is scheduled.
2. The NotifyActivity workflow activity sends a notification saying an order for 10 cars has been received.
3. The ReserveInventoryActivity workflow activity checks the inventory data, determines if you can supply the ordered item, and responds with the number of cars in stock.
4. Your workflow starts and notifies you of its status.
5. The ProcessPaymentActivity workflow activity begins processing payment for order 6d2abcc9 and confirms if successful.
6. The UpdateInventoryActivity workflow activity updates the inventory with the current available cars after the order has been processed.
7. The NotifyActivity workflow activity sends a notification saying that order 6d2abcc9 has completed.
8. The workflow terminates as completed.

order-processor/Program.cs

In the application’s program file:

• The unique workflow order ID is generated
• The workflow is scheduled
• The workflow status is retrieved
• The workflow and the workflow activities it invokes are registered

using Dapr.Client;
using Dapr.Workflow;
//...

{
    services.AddDaprWorkflow(options =>
    {
        // Note that it's also possible to register a lambda function as the workflow
        // or activity implementation instead of a class.
        options.RegisterWorkflow<OrderProcessingWorkflow>();

        // These are the activities that get invoked by the workflow(s).
        options.RegisterActivity<NotifyActivity>();
        options.RegisterActivity<ReserveInventoryActivity>();
        options.RegisterActivity<ProcessPaymentActivity>();
        options.RegisterActivity<UpdateInventoryActivity>();
    });
};

//...

// Generate a unique ID for the workflow
string orderId = Guid.NewGuid().ToString()[..8];
string itemToPurchase = "Cars";
int ammountToPurchase = 10;

// Construct the order
OrderPayload orderInfo = new OrderPayload(itemToPurchase, 15000, ammountToPurchase);

// Start the workflow
Console.WriteLine("Starting workflow {0} purchasing {1} {2}", orderId, ammountToPurchase, itemToPurchase);

await daprClient.StartWorkflowAsync(
    workflowComponent: DaprWorkflowComponent,
    workflowName: nameof(OrderProcessingWorkflow),
    input: orderInfo,
    instanceId: orderId);

// Wait for the workflow to start and confirm the input
GetWorkflowResponse state = await daprClient.WaitForWorkflowStartAsync(
    instanceId: orderId,
    workflowComponent: DaprWorkflowComponent);

Console.WriteLine("Your workflow has started. Here is the status of the workflow: {0}", state.RuntimeStatus);

// Wait for the workflow to complete
state = await daprClient.WaitForWorkflowCompletionAsync(
    instanceId: orderId,
    workflowComponent: DaprWorkflowComponent);

Console.WriteLine("Workflow Status: {0}", state.RuntimeStatus);

order-processor/Workflows/OrderProcessingWorkflow.cs

In OrderProcessingWorkflow.cs, the workflow is defined as a class with all of its associated tasks (determined by workflow activities).

using Dapr.Workflow;
//...

class OrderProcessingWorkflow : Workflow<OrderPayload, OrderResult>
    {
        public override async Task<OrderResult> RunAsync(WorkflowContext context, OrderPayload order)
        {
            string orderId = context.InstanceId;

            // Notify the user that an order has come through
            await context.CallActivityAsync(
                nameof(NotifyActivity),
                new Notification($"Received order {orderId} for {order.Quantity} {order.Name} at ${order.TotalCost}"));

            string requestId = context.InstanceId;

            // Determine if there is enough of the item available for purchase by checking the inventory
            InventoryResult result = await context.CallActivityAsync<InventoryResult>(
                nameof(ReserveInventoryActivity),
                new InventoryRequest(RequestId: orderId, order.Name, order.Quantity));

            // If there is insufficient inventory, fail and let the user know 
            if (!result.Success)
            {
                // End the workflow here since we don't have sufficient inventory
                await context.CallActivityAsync(
                    nameof(NotifyActivity),
                    new Notification($"Insufficient inventory for {order.Name}"));
                return new OrderResult(Processed: false);
            }

            // There is enough inventory available so the user can purchase the item(s). Process their payment
            await context.CallActivityAsync(
                nameof(ProcessPaymentActivity),
                new PaymentRequest(RequestId: orderId, order.Name, order.Quantity, order.TotalCost));

            try
            {
                // There is enough inventory available so the user can purchase the item(s). Process their payment
                await context.CallActivityAsync(
                    nameof(UpdateInventoryActivity),
                    new PaymentRequest(RequestId: orderId, order.Name, order.Quantity, order.TotalCost));                
            }
            catch (TaskFailedException)
            {
                // Let them know their payment was processed
                await context.CallActivityAsync(
                    nameof(NotifyActivity),
                    new Notification($"Order {orderId} Failed! You are now getting a refund"));
                return new OrderResult(Processed: false);
            }

            // Let them know their payment was processed
            await context.CallActivityAsync(
                nameof(NotifyActivity),
                new Notification($"Order {orderId} has completed!"));

            // End the workflow with a success result
            return new OrderResult(Processed: true);
        }
    }

order-processor/Activities directory

The Activities directory holds the four workflow activities used by the workflow, defined in the following files:

• NotifyActivity.cs
• ReserveInventoryActivity.cs
• ProcessPaymentActivity.cs
• UpdateInventoryActivity.cs

Watch the demo

Watch this video to walk through the Dapr Workflow .NET demo:

The order-processor console app starts and manages the lifecycle of an order processing workflow that stores and retrieves data in a state store. The workflow consists of four workflow activities, or tasks:

• NotifyActivity: Utilizes a logger to print out messages throughout the workflow
• RequestApprovalActivity: Requests approval for processing payment
• ReserveInventoryActivity: Checks the state store to ensure that there is enough inventory for the purchase
• ProcessPaymentActivity: Processes and authorizes the payment
• UpdateInventoryActivity: Removes the requested items from the state store and updates the store with the new remaining inventory value

Step 1: Pre-requisites

For this example, you will need:

• Dapr CLI and initialized environment.
• Java JDK 11 (or greater):
  • Microsoft JDK 11
  • Oracle JDK 11
  • OpenJDK 11
• Apache Maven version 3.x.

• Docker Desktop

Step 2: Set up the environment

Clone the sample provided in the Quickstarts repo.

git clone https://github.com/dapr/quickstarts.git

Navigate to the order-processor directory:

cd workflows/java/sdk/order-processor

Install the dependencies:

mvn clean install

Step 3: Run the order processor app

In the terminal, start the order processor app alongside a Dapr sidecar using Multi-App Run:

dapr run -f .

This starts the order-processor app with unique workflow ID and runs the workflow activities.

Expected output:

== APP == *** Welcome to the Dapr Workflow console app sample!
== APP == *** Using this app, you can place orders that start workflows.
== APP == Start workflow runtime
== APP == Sep 20, 2023 3:23:05 PM com.microsoft.durabletask.DurableTaskGrpcWorker startAndBlock
== APP == INFO: Durable Task worker is connecting to sidecar at 127.0.0.1:50001.

== APP == ==========Begin the purchase of item:==========
== APP == Starting order workflow, purchasing 10 of cars

== APP == scheduled new workflow instance of OrderProcessingWorkflow with instance ID: edceba90-9c45-4be8-ad40-60d16e060797
== APP == [Thread-0] INFO io.dapr.workflows.WorkflowContext - Starting Workflow: io.dapr.quickstarts.workflows.OrderProcessingWorkflow
== APP == [Thread-0] INFO io.dapr.workflows.WorkflowContext - Instance ID(order ID): edceba90-9c45-4be8-ad40-60d16e060797
== APP == [Thread-0] INFO io.dapr.workflows.WorkflowContext - Current Orchestration Time: 2023-09-20T19:23:09.755Z
== APP == [Thread-0] INFO io.dapr.workflows.WorkflowContext - Received Order: OrderPayload [itemName=cars, totalCost=150000, quantity=10]
== APP == [Thread-0] INFO io.dapr.quickstarts.workflows.activities.NotifyActivity - Received Order: OrderPayload [itemName=cars, totalCost=150000, quantity=10]
== APP == workflow instance edceba90-9c45-4be8-ad40-60d16e060797 started
== APP == [Thread-0] INFO io.dapr.quickstarts.workflows.activities.ReserveInventoryActivity - Reserving inventory for order 'edceba90-9c45-4be8-ad40-60d16e060797' of 10 cars
== APP == [Thread-0] INFO io.dapr.quickstarts.workflows.activities.ReserveInventoryActivity - There are 100 cars available for purchase
== APP == [Thread-0] INFO io.dapr.quickstarts.workflows.activities.ReserveInventoryActivity - Reserved inventory for order 'edceba90-9c45-4be8-ad40-60d16e060797' of 10 cars
== APP == [Thread-0] INFO io.dapr.quickstarts.workflows.activities.RequestApprovalActivity - Requesting approval for order: OrderPayload [itemName=cars, totalCost=150000, quantity=10]
== APP == [Thread-0] INFO io.dapr.quickstarts.workflows.activities.RequestApprovalActivity - Approved requesting approval for order: OrderPayload [itemName=cars, totalCost=150000, quantity=10]
== APP == [Thread-0] INFO io.dapr.quickstarts.workflows.activities.ProcessPaymentActivity - Processing payment: edceba90-9c45-4be8-ad40-60d16e060797 for 10 cars at $150000
== APP == [Thread-0] INFO io.dapr.quickstarts.workflows.activities.ProcessPaymentActivity - Payment for request ID 'edceba90-9c45-4be8-ad40-60d16e060797' processed successfully
== APP == [Thread-0] INFO io.dapr.quickstarts.workflows.activities.UpdateInventoryActivity - Updating inventory for order 'edceba90-9c45-4be8-ad40-60d16e060797' of 10 cars
== APP == [Thread-0] INFO io.dapr.quickstarts.workflows.activities.UpdateInventoryActivity - Updated inventory for order 'edceba90-9c45-4be8-ad40-60d16e060797': there are now 90 cars left in stock
== APP == [Thread-0] INFO io.dapr.quickstarts.workflows.activities.NotifyActivity - Order completed! : edceba90-9c45-4be8-ad40-60d16e060797

== APP == workflow instance edceba90-9c45-4be8-ad40-60d16e060797 completed, out is: {"processed":true}

(Optional) Step 4: View in Zipkin

Running dapr init launches the openzipkin/zipkin Docker container. If the container has stopped running, launch the Zipkin Docker container with the following command:

docker run -d -p 9411:9411 openzipkin/zipkin

View the workflow trace spans in the Zipkin web UI (typically at http://localhost:9411/zipkin/).

What happened?

When you ran dapr run -f .:

1. A unique order ID for the workflow is generated (in the above example, edceba90-9c45-4be8-ad40-60d16e060797) and the workflow is scheduled.
2. The NotifyActivity workflow activity sends a notification saying an order for 10 cars has been received.
3. The ReserveInventoryActivity workflow activity checks the inventory data, determines if you can supply the ordered item, and responds with the number of cars in stock.
4. Once approved, your workflow starts and notifies you of its status.
5. The ProcessPaymentActivity workflow activity begins processing payment for order edceba90-9c45-4be8-ad40-60d16e060797 and confirms if successful.
6. The UpdateInventoryActivity workflow activity updates the inventory with the current available cars after the order has been processed.
7. The NotifyActivity workflow activity sends a notification saying that order edceba90-9c45-4be8-ad40-60d16e060797 has completed.
8. The workflow terminates as completed.

order-processor/WorkflowConsoleApp.java

In the application’s program file:

• The unique workflow order ID is generated
• The workflow is scheduled
• The workflow status is retrieved
• The workflow and the workflow activities it invokes are registered

package io.dapr.quickstarts.workflows;
import io.dapr.client.DaprClient;
import io.dapr.client.DaprClientBuilder;
import io.dapr.workflows.client.DaprWorkflowClient;

public class WorkflowConsoleApp {

  private static final String STATE_STORE_NAME = "statestore-actors";

  // ...
  public static void main(String[] args) throws Exception {
    System.out.println("*** Welcome to the Dapr Workflow console app sample!");
    System.out.println("*** Using this app, you can place orders that start workflows.");
    // Wait for the sidecar to become available
    Thread.sleep(5 * 1000);

    // Register the OrderProcessingWorkflow and its activities with the builder.
    WorkflowRuntimeBuilder builder = new WorkflowRuntimeBuilder().registerWorkflow(OrderProcessingWorkflow.class);
    builder.registerActivity(NotifyActivity.class);
    builder.registerActivity(ProcessPaymentActivity.class);
    builder.registerActivity(RequestApprovalActivity.class);
    builder.registerActivity(ReserveInventoryActivity.class);
    builder.registerActivity(UpdateInventoryActivity.class);

    // Build the workflow runtime
    try (WorkflowRuntime runtime = builder.build()) {
      System.out.println("Start workflow runtime");
      runtime.start(false);
    }

    InventoryItem inventory = prepareInventoryAndOrder();

    DaprWorkflowClient workflowClient = new DaprWorkflowClient();
    try (workflowClient) {
      executeWorkflow(workflowClient, inventory);
    }

  }

  // Start the workflow runtime, pulling and executing tasks
  private static void executeWorkflow(DaprWorkflowClient workflowClient, InventoryItem inventory) {
    System.out.println("==========Begin the purchase of item:==========");
    String itemName = inventory.getName();
    int orderQuantity = inventory.getQuantity();
    int totalcost = orderQuantity * inventory.getPerItemCost();
    OrderPayload order = new OrderPayload();
    order.setItemName(itemName);
    order.setQuantity(orderQuantity);
    order.setTotalCost(totalcost);
    System.out.println("Starting order workflow, purchasing " + orderQuantity + " of " + itemName);

    String instanceId = workflowClient.scheduleNewWorkflow(OrderProcessingWorkflow.class, order);
    System.out.printf("scheduled new workflow instance of OrderProcessingWorkflow with instance ID: %s%n",
        instanceId);

    // Check workflow instance start status
    try {
      workflowClient.waitForInstanceStart(instanceId, Duration.ofSeconds(10), false);
      System.out.printf("workflow instance %s started%n", instanceId);
    } catch (TimeoutException e) {
      System.out.printf("workflow instance %s did not start within 10 seconds%n", instanceId);
      return;
    }

    // Check workflow instance complete status
    try {
      WorkflowInstanceStatus workflowStatus = workflowClient.waitForInstanceCompletion(instanceId,
          Duration.ofSeconds(30),
          true);
      if (workflowStatus != null) {
        System.out.printf("workflow instance %s completed, out is: %s %n", instanceId,
            workflowStatus.getSerializedOutput());
      } else {
        System.out.printf("workflow instance %s not found%n", instanceId);
      }
    } catch (TimeoutException e) {
      System.out.printf("workflow instance %s did not complete within 30 seconds%n", instanceId);
    }

  }

  private static InventoryItem prepareInventoryAndOrder() {
    // prepare 100 cars in inventory
    InventoryItem inventory = new InventoryItem();
    inventory.setName("cars");
    inventory.setPerItemCost(15000);
    inventory.setQuantity(100);
    DaprClient daprClient = new DaprClientBuilder().build();
    restockInventory(daprClient, inventory);

    // prepare order for 10 cars
    InventoryItem order = new InventoryItem();
    order.setName("cars");
    order.setPerItemCost(15000);
    order.setQuantity(10);
    return order;
  }

  private static void restockInventory(DaprClient daprClient, InventoryItem inventory) {
    String key = inventory.getName();
    daprClient.saveState(STATE_STORE_NAME, key, inventory).block();
  }
}

OrderProcessingWorkflow.java

In OrderProcessingWorkflow.java, the workflow is defined as a class with all of its associated tasks (determined by workflow activities).

package io.dapr.quickstarts.workflows;
import io.dapr.workflows.Workflow;

public class OrderProcessingWorkflow extends Workflow {

  @Override
  public WorkflowStub create() {
    return ctx -> {
      Logger logger = ctx.getLogger();
      String orderId = ctx.getInstanceId();
      logger.info("Starting Workflow: " + ctx.getName());
      logger.info("Instance ID(order ID): " + orderId);
      logger.info("Current Orchestration Time: " + ctx.getCurrentInstant());

      OrderPayload order = ctx.getInput(OrderPayload.class);
      logger.info("Received Order: " + order.toString());
      OrderResult orderResult = new OrderResult();
      orderResult.setProcessed(false);

      // Notify the user that an order has come through
      Notification notification = new Notification();
      notification.setMessage("Received Order: " + order.toString());
      ctx.callActivity(NotifyActivity.class.getName(), notification).await();

      // Determine if there is enough of the item available for purchase by checking
      // the inventory
      InventoryRequest inventoryRequest = new InventoryRequest();
      inventoryRequest.setRequestId(orderId);
      inventoryRequest.setItemName(order.getItemName());
      inventoryRequest.setQuantity(order.getQuantity());
      InventoryResult inventoryResult = ctx.callActivity(ReserveInventoryActivity.class.getName(),
          inventoryRequest, InventoryResult.class).await();

      // If there is insufficient inventory, fail and let the user know
      if (!inventoryResult.isSuccess()) {
        notification.setMessage("Insufficient inventory for order : " + order.getItemName());
        ctx.callActivity(NotifyActivity.class.getName(), notification).await();
        ctx.complete(orderResult);
        return;
      }

      // Require orders over a certain threshold to be approved
      if (order.getTotalCost() > 5000) {
        ApprovalResult approvalResult = ctx.callActivity(RequestApprovalActivity.class.getName(),
            order, ApprovalResult.class).await();
        if (approvalResult != ApprovalResult.Approved) {
          notification.setMessage("Order " + order.getItemName() + " was not approved.");
          ctx.callActivity(NotifyActivity.class.getName(), notification).await();
          ctx.complete(orderResult);
          return;
        }
      }

      // There is enough inventory available so the user can purchase the item(s).
      // Process their payment
      PaymentRequest paymentRequest = new PaymentRequest();
      paymentRequest.setRequestId(orderId);
      paymentRequest.setItemBeingPurchased(order.getItemName());
      paymentRequest.setQuantity(order.getQuantity());
      paymentRequest.setAmount(order.getTotalCost());
      boolean isOK = ctx.callActivity(ProcessPaymentActivity.class.getName(),
          paymentRequest, boolean.class).await();
      if (!isOK) {
        notification.setMessage("Payment failed for order : " + orderId);
        ctx.callActivity(NotifyActivity.class.getName(), notification).await();
        ctx.complete(orderResult);
        return;
      }

      inventoryResult = ctx.callActivity(UpdateInventoryActivity.class.getName(),
          inventoryRequest, InventoryResult.class).await();
      if (!inventoryResult.isSuccess()) {
        // If there is an error updating the inventory, refund the user
        // paymentRequest.setAmount(-1 * paymentRequest.getAmount());
        // ctx.callActivity(ProcessPaymentActivity.class.getName(),
        // paymentRequest).await();

        // Let users know their payment processing failed
        notification.setMessage("Order failed to update inventory! : " + orderId);
        ctx.callActivity(NotifyActivity.class.getName(), notification).await();
        ctx.complete(orderResult);
        return;
      }

      // Let user know their order was processed
      notification.setMessage("Order completed! : " + orderId);
      ctx.callActivity(NotifyActivity.class.getName(), notification).await();

      // Complete the workflow with order result is processed
      orderResult.setProcessed(true);
      ctx.complete(orderResult);
    };
  }

}

activities directory

The Activities directory holds the four workflow activities used by the workflow, defined in the following files:

• NotifyActivity.java
• RequestApprovalActivity
• ReserveInventoryActivity
• ProcessPaymentActivity
• UpdateInventoryActivity

The order-processor console app starts and manages the OrderProcessingWorkflow workflow, which simulates purchasing items from a store. The workflow consists of five unique workflow activities, or tasks:

• NotifyActivity: Utilizes a logger to print out messages throughout the workflow. These messages notify you when:
  • You have insufficient inventory
  • Your payment couldn’t be processed, etc.
• ProcessPaymentActivity: Processes and authorizes the payment.
• VerifyInventoryActivity: Checks the state store to ensure there is enough inventory present for purchase.
• UpdateInventoryActivity: Removes the requested items from the state store and updates the store with the new remaining inventory value.
• RequestApprovalActivity: Seeks approval from the manager if payment is greater than 50,000 USD.

Step 1: Pre-requisites

For this example, you will need:

• Dapr CLI and initialized environment.
• Latest version of Go.

• Docker Desktop

Step 2: Set up the environment

Clone the sample provided in the Quickstarts repo.

git clone https://github.com/dapr/quickstarts.git

In a new terminal window, navigate to the order-processor directory:

cd workflows/go/sdk/order-processor

Step 3: Run the order processor app

In the terminal, start the order processor app alongside a Dapr sidecar using Multi-App Run:

dapr run -f .

This starts the order-processor app with unique workflow ID and runs the workflow activities.

Expected output:

== APP - order-processor == *** Welcome to the Dapr Workflow console app sample!
== APP - order-processor == *** Using this app, you can place orders that start workflows.
== APP - order-processor == dapr client initializing for: 127.0.0.1:50056
== APP - order-processor == adding base stock item: paperclip
== APP - order-processor == 2024/02/01 12:59:52 work item listener started
== APP - order-processor == INFO: 2024/02/01 12:59:52 starting background processor
== APP - order-processor == adding base stock item: cars
== APP - order-processor == adding base stock item: computers
== APP - order-processor == ==========Begin the purchase of item:==========
== APP - order-processor == NotifyActivity: Received order 48ee83b7-5d80-48d5-97f9-6b372f5480a5 for 10 cars - $150000
== APP - order-processor == VerifyInventoryActivity: Verifying inventory for order 48ee83b7-5d80-48d5-97f9-6b372f5480a5 of 10 cars
== APP - order-processor == VerifyInventoryActivity: There are 100 cars available for purchase
== APP - order-processor == RequestApprovalActivity: Requesting approval for payment of 150000USD for 10 cars
== APP - order-processor == NotifyActivity: Payment for order 48ee83b7-5d80-48d5-97f9-6b372f5480a5 has been approved!
== APP - order-processor == ProcessPaymentActivity: 48ee83b7-5d80-48d5-97f9-6b372f5480a5 for 10 - cars (150000USD)
== APP - order-processor == UpdateInventoryActivity: Checking Inventory for order 48ee83b7-5d80-48d5-97f9-6b372f5480a5 for 10 * cars
== APP - order-processor == UpdateInventoryActivity: There are now 90 cars left in stock
== APP - order-processor == NotifyActivity: Order 48ee83b7-5d80-48d5-97f9-6b372f5480a5 has completed!
== APP - order-processor == Workflow completed - result: COMPLETED
== APP - order-processor == Purchase of item is complete

Stop the Dapr workflow with CTRL+C or:

dapr stop -f .

(Optional) Step 4: View in Zipkin

Running dapr init launches the openzipkin/zipkin Docker container. If the container has stopped running, launch the Zipkin Docker container with the following command:

docker run -d -p 9411:9411 openzipkin/zipkin

View the workflow trace spans in the Zipkin web UI (typically at http://localhost:9411/zipkin/).

What happened?

When you ran dapr run:

1. A unique order ID for the workflow is generated (in the above example, 48ee83b7-5d80-48d5-97f9-6b372f5480a5) and the workflow is scheduled.
2. The NotifyActivity workflow activity sends a notification saying an order for 10 cars has been received.
3. The ReserveInventoryActivity workflow activity checks the inventory data, determines if you can supply the ordered item, and responds with the number of cars in stock.
4. Your workflow starts and notifies you of its status.
5. The ProcessPaymentActivity workflow activity begins processing payment for order 48ee83b7-5d80-48d5-97f9-6b372f5480a5 and confirms if successful.
6. The UpdateInventoryActivity workflow activity updates the inventory with the current available cars after the order has been processed.
7. The NotifyActivity workflow activity sends a notification saying that order 48ee83b7-5d80-48d5-97f9-6b372f5480a5 has completed.
8. The workflow terminates as completed.

order-processor/main.go

In the application’s program file:

• The unique workflow order ID is generated
• The workflow is scheduled
• The workflow status is retrieved
• The workflow and the workflow activities it invokes are registered

func main() {
	fmt.Println("*** Welcome to the Dapr Workflow console app sample!")
	fmt.Println("*** Using this app, you can place orders that start workflows.")

  // ...

  // Register workflow and activities
	if err := w.RegisterWorkflow(OrderProcessingWorkflow); err != nil {
		log.Fatal(err)
	}
	if err := w.RegisterActivity(NotifyActivity); err != nil {
		log.Fatal(err)
	}
	if err := w.RegisterActivity(RequestApprovalActivity); err != nil {
		log.Fatal(err)
	}
	if err := w.RegisterActivity(VerifyInventoryActivity); err != nil {
		log.Fatal(err)
	}
	if err := w.RegisterActivity(ProcessPaymentActivity); err != nil {
		log.Fatal(err)
	}
	if err := w.RegisterActivity(UpdateInventoryActivity); err != nil {
		log.Fatal(err)
	}

  // Build and start workflow runtime, pulling and executing tasks
	if err := w.Start(); err != nil {
		log.Fatal(err)
	}

	daprClient, err := client.NewClient()
	if err != nil {
		log.Fatalf("failed to initialise dapr client: %v", err)
	}
	wfClient, err := workflow.NewClient(workflow.WithDaprClient(daprClient))
	if err != nil {
		log.Fatalf("failed to initialise workflow client: %v", err)
	}

  // Check inventory
	inventory := []InventoryItem{
		{ItemName: "paperclip", PerItemCost: 5, Quantity: 100},
		{ItemName: "cars", PerItemCost: 15000, Quantity: 100},
		{ItemName: "computers", PerItemCost: 500, Quantity: 100},
	}
	if err := restockInventory(daprClient, inventory); err != nil {
		log.Fatalf("failed to restock: %v", err)
	}

	fmt.Println("==========Begin the purchase of item:==========")

	itemName := defaultItemName
	orderQuantity := 10

	totalCost := inventory[1].PerItemCost * orderQuantity

	orderPayload := OrderPayload{
		ItemName:  itemName,
		Quantity:  orderQuantity,
		TotalCost: totalCost,
	}

  // Start workflow events, like receiving order, verifying inventory, and processing payment 
	id, err := wfClient.ScheduleNewWorkflow(context.Background(), workflowName, workflow.WithInput(orderPayload))
	if err != nil {
		log.Fatalf("failed to start workflow: %v", err)
	}

	// ...

  // Notification that workflow has completed or failed
	for {
		timeDelta := time.Since(startTime)
		metadata, err := wfClient.FetchWorkflowMetadata(context.Background(), id)
		if err != nil {
			log.Fatalf("failed to fetch workflow: %v", err)
		}
		if (metadata.RuntimeStatus == workflow.StatusCompleted) || (metadata.RuntimeStatus == workflow.StatusFailed) || (metadata.RuntimeStatus == workflow.StatusTerminated) {
			fmt.Printf("Workflow completed - result: %v\n", metadata.RuntimeStatus.String())
			break
		}
		if timeDelta.Seconds() >= 10 {
			metadata, err := wfClient.FetchWorkflowMetadata(context.Background(), id)
			if err != nil {
				log.Fatalf("failed to fetch workflow: %v", err)
			}
			if totalCost > 50000 && !approvalSought && ((metadata.RuntimeStatus != workflow.StatusCompleted) || (metadata.RuntimeStatus != workflow.StatusFailed) || (metadata.RuntimeStatus != workflow.StatusTerminated)) {
				approvalSought = true
				promptForApproval(id)
			}
		}
		// Sleep to not DoS the dapr dev instance
		time.Sleep(time.Second)
	}

	fmt.Println("Purchase of item is complete")
}

// Request approval (RequestApprovalActivity)
func promptForApproval(id string) {
	wfClient, err := workflow.NewClient()
	if err != nil {
		log.Fatalf("failed to initialise wfClient: %v", err)
	}
	if err := wfClient.RaiseEvent(context.Background(), id, "manager_approval"); err != nil {
		log.Fatal(err)
	}
}

// Update inventory for remaining stock (UpdateInventoryActivity)
func restockInventory(daprClient client.Client, inventory []InventoryItem) error {
	for _, item := range inventory {
		itemSerialized, err := json.Marshal(item)
		if err != nil {
			return err
		}
		fmt.Printf("adding base stock item: %s\n", item.ItemName)
		if err := daprClient.SaveState(context.Background(), stateStoreName, item.ItemName, itemSerialized, nil); err != nil {
			return err
		}
	}
	return nil
}

Meanwhile, the OrderProcessingWorkflow and its activities are defined as methods in workflow.go