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---
type: docs
title: "Quickstart: Workflow"
linkTitle: Workflow
weight: 73
description: Get started with the Dapr Workflow building block
---
{{% alert title="Note" color="primary" %}}
Redis is currently used as the state store component for Workflows in the Quickstarts. However, Redis does not support transaction rollbacks and should not be used in production as an actor state store.
{{% /alert %}}
Let's take a look at the Dapr [Workflow building block]({{< ref workflow-overview.md >}}). In this Quickstart, you'll create a simple console application to demonstrate Dapr's workflow programming model and the workflow management APIs.
In this guide, you'll:
- Run the `order-processor` application.
- Start the workflow and watch the workflow activites/tasks execute.
- Review the workflow logic and the workflow activities and how they're represented in the code.
<img src="/images/workflow-quickstart-overview.png" width=800 style="padding-bottom:15px;">
Select your preferred language-specific Dapr SDK before proceeding with the Quickstart.
{{< tabs "Python" "JavaScript" ".NET" "Java" Go >}}
<!-- Python -->
{{% codetab %}}
The `order-processor` console app starts and manages the `order_processing_workflow`, which simulates purchasing items from a store. The workflow consists of five unique workflow activities, or tasks:
- `notify_activity`: 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.
- `process_payment_activity`: Processes and authorizes the payment.
- `verify_inventory_activity`: Checks the state store to ensure there is enough inventory present for purchase.
- `update_inventory_activity`: Removes the requested items from the state store and updates the store with the new remaining inventory value.
- `request_approval_activity`: 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](https://docs.dapr.io/getting-started).
- [Python 3.7+ installed](https://www.python.org/downloads/).
<!-- IGNORE_LINKS -->
- [Docker Desktop](https://www.docker.com/products/docker-desktop)
<!-- END_IGNORE -->
### Step 2: Set up the environment
Clone the [sample provided in the Quickstarts repo](https://github.com/dapr/quickstarts/tree/master/workflows/python/sdk).
```bash
git clone https://github.com/dapr/quickstarts.git
```
In a new terminal window, navigate to the `order-processor` directory:
```bash
cd workflows/python/sdk/order-processor
```
Install the Dapr Python SDK package:
```bash
pip3 install -r requirements.txt
```
Return to the `python/sdk` directory:
```bash
cd ..
```
### Step 3: Run the order processor app
In the terminal, start the order processor app alongside a Dapr sidecar using [Multi-App Run]({{< ref multi-app-dapr-run >}}). From the `python/sdk` directory, run the following command:
```bash
dapr run -f .
```
This starts the `order-processor` app with unique workflow ID and runs the workflow activities.
Expected output:
```bash
== APP == Starting order workflow, purchasing 10 of cars
== APP == 2023-06-06 09:35:52.945 durabletask-worker INFO: Successfully connected to 127.0.0.1:65406. Waiting for work items...
== APP == INFO:NotifyActivity:Received order f4e1926e-3721-478d-be8a-f5bebd1995da for 10 cars at $150000 !
== APP == INFO:VerifyInventoryActivity:Verifying inventory for order f4e1926e-3721-478d-be8a-f5bebd1995da of 10 cars
== APP == INFO:VerifyInventoryActivity:There are 100 Cars available for purchase
== APP == INFO:RequestApprovalActivity:Requesting approval for payment of 165000 USD for 10 cars
== APP == 2023-06-06 09:36:05.969 durabletask-worker INFO: f4e1926e-3721-478d-be8a-f5bebd1995da Event raised: manager_approval
== APP == INFO:NotifyActivity:Payment for order f4e1926e-3721-478d-be8a-f5bebd1995da has been approved!
== APP == INFO:ProcessPaymentActivity:Processing payment: f4e1926e-3721-478d-be8a-f5bebd1995da for 10 cars at 150000 USD
== APP == INFO:ProcessPaymentActivity:Payment for request ID f4e1926e-3721-478d-be8a-f5bebd1995da processed successfully
== APP == INFO:UpdateInventoryActivity:Checking inventory for order f4e1926e-3721-478d-be8a-f5bebd1995da for 10 cars
== APP == INFO:UpdateInventoryActivity:There are now 90 cars left in stock
== APP == INFO:NotifyActivity:Order f4e1926e-3721-478d-be8a-f5bebd1995da has completed!
== APP == 2023-06-06 09:36:06.106 durabletask-worker INFO: f4e1926e-3721-478d-be8a-f5bebd1995da: Orchestration completed with status: COMPLETED
== APP == Workflow completed! Result: Completed
== APP == Purchase of item is Completed
```
### (Optional) Step 4: View in Zipkin
Running `dapr init` launches the [openzipkin/zipkin](https://hub.docker.com/r/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/`).
<img src="/images/workflow-trace-spans-zipkin.png" width=800 style="padding-bottom:15px;">
### What happened?
When you ran `dapr run -f .`:
1. A unique order ID for the workflow is generated (in the above example, `f4e1926e-3721-478d-be8a-f5bebd1995da`) and the workflow is scheduled.
1. The `NotifyActivity` workflow activity sends a notification saying an order for 10 cars has been received.
1. 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.
1. Your workflow starts and notifies you of its status.
1. The `ProcessPaymentActivity` workflow activity begins processing payment for order `f4e1926e-3721-478d-be8a-f5bebd1995da` and confirms if successful.
1. The `UpdateInventoryActivity` workflow activity updates the inventory with the current available cars after the order has been processed.
1. The `NotifyActivity` workflow activity sends a notification saying that order `f4e1926e-3721-478d-be8a-f5bebd1995da` has completed.
1. The workflow terminates as completed.
#### `order-processor/app.py`
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
```python
class WorkflowConsoleApp:
def main(self):
# Register workflow and activities
workflowRuntime = WorkflowRuntime(settings.DAPR_RUNTIME_HOST, settings.DAPR_GRPC_PORT)
workflowRuntime.register_workflow(order_processing_workflow)
workflowRuntime.register_activity(notify_activity)
workflowRuntime.register_activity(requst_approval_activity)
workflowRuntime.register_activity(verify_inventory_activity)
workflowRuntime.register_activity(process_payment_activity)
workflowRuntime.register_activity(update_inventory_activity)
workflowRuntime.start()
print("==========Begin the purchase of item:==========", flush=True)
item_name = default_item_name
order_quantity = 10
total_cost = int(order_quantity) * baseInventory[item_name].per_item_cost
order = OrderPayload(item_name=item_name, quantity=int(order_quantity), total_cost=total_cost)
# Start Workflow
print(f'Starting order workflow, purchasing {order_quantity} of {item_name}', flush=True)
start_resp = daprClient.start_workflow(workflow_component=workflow_component,
workflow_name=workflow_name,
input=order)
_id = start_resp.instance_id
def prompt_for_approval(daprClient: DaprClient):
daprClient.raise_workflow_event(instance_id=_id, workflow_component=workflow_component,
event_name="manager_approval", event_data={'approval': True})
approval_seeked = False
start_time = datetime.now()
while True:
time_delta = datetime.now() - start_time
state = daprClient.get_workflow(instance_id=_id, workflow_component=workflow_component)
if not state:
print("Workflow not found!") # not expected
elif state.runtime_status == "Completed" or\
state.runtime_status == "Failed" or\
state.runtime_status == "Terminated":
print(f'Workflow completed! Result: {state.runtime_status}', flush=True)
break
if time_delta.total_seconds() >= 10:
state = daprClient.get_workflow(instance_id=_id, workflow_component=workflow_component)
if total_cost > 50000 and (
state.runtime_status != "Completed" or
state.runtime_status != "Failed" or
state.runtime_status != "Terminated"
) and not approval_seeked:
approval_seeked = True
threading.Thread(target=prompt_for_approval(daprClient), daemon=True).start()
print("Purchase of item is ", state.runtime_status, flush=True)
def restock_inventory(self, daprClient: DaprClient, baseInventory):
for key, item in baseInventory.items():
print(f'item: {item}')
item_str = f'{{"name": "{item.item_name}", "quantity": {item.quantity},\
"per_item_cost": {item.per_item_cost}}}'
daprClient.save_state("statestore-actors", key, item_str)
if __name__ == '__main__':
app = WorkflowConsoleApp()
app.main()
```
#### `order-processor/workflow.py`
In `workflow.py`, the workflow is defined as a class with all of its associated tasks (determined by workflow activities).
```python
def order_processing_workflow(ctx: DaprWorkflowContext, order_payload_str: OrderPayload):
"""Defines the order processing workflow.
When the order is received, the inventory is checked to see if there is enough inventory to
fulfill the order. If there is enough inventory, the payment is processed and the inventory is
updated. If there is not enough inventory, the order is rejected.
If the total order is greater than $50,000, the order is sent to a manager for approval.
"""
order_id = ctx.instance_id
order_payload=json.loads(order_payload_str)
yield ctx.call_activity(notify_activity,
input=Notification(message=('Received order ' +order_id+ ' for '
+f'{order_payload["quantity"]}' +' ' +f'{order_payload["item_name"]}'
+' at $'+f'{order_payload["total_cost"]}' +' !')))
result = yield ctx.call_activity(verify_inventory_activity,
input=InventoryRequest(request_id=order_id,
item_name=order_payload["item_name"],
quantity=order_payload["quantity"]))
if not result.success:
yield ctx.call_activity(notify_activity,
input=Notification(message='Insufficient inventory for '
+f'{order_payload["item_name"]}'+'!'))
return OrderResult(processed=False)
if order_payload["total_cost"] > 50000:
yield ctx.call_activity(requst_approval_activity, input=order_payload)
approval_task = ctx.wait_for_external_event("manager_approval")
timeout_event = ctx.create_timer(timedelta(seconds=200))
winner = yield when_any([approval_task, timeout_event])
if winner == timeout_event:
yield ctx.call_activity(notify_activity,
input=Notification(message='Payment for order '+order_id
+' has been cancelled due to timeout!'))
return OrderResult(processed=False)
approval_result = yield approval_task
if approval_result["approval"]:
yield ctx.call_activity(notify_activity, input=Notification(
message=f'Payment for order {order_id} has been approved!'))
else:
yield ctx.call_activity(notify_activity, input=Notification(
message=f'Payment for order {order_id} has been rejected!'))
return OrderResult(processed=False)
yield ctx.call_activity(process_payment_activity, input=PaymentRequest(
request_id=order_id, item_being_purchased=order_payload["item_name"],
amount=order_payload["total_cost"], quantity=order_payload["quantity"]))
try:
yield ctx.call_activity(update_inventory_activity,
input=PaymentRequest(request_id=order_id,
item_being_purchased=order_payload["item_name"],
amount=order_payload["total_cost"],
quantity=order_payload["quantity"]))
except Exception:
yield ctx.call_activity(notify_activity,
input=Notification(message=f'Order {order_id} Failed!'))
return OrderResult(processed=False)
yield ctx.call_activity(notify_activity, input=Notification(
message=f'Order {order_id} has completed!'))
return OrderResult(processed=True)
```
{{% /codetab %}}
<!-- JavaScript -->
{{% codetab %}}
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](https://docs.dapr.io/getting-started).
- [Latest Node.js installed](https://nodejs.org/download/).
<!-- IGNORE_LINKS -->
- [Docker Desktop](https://www.docker.com/products/docker-desktop)
<!-- END_IGNORE -->
### Step 2: Set up the environment
Clone the [sample provided in the Quickstarts repo](https://github.com/dapr/quickstarts/tree/master/workflows/javascript/sdk).
```bash
git clone https://github.com/dapr/quickstarts.git
```
In a new terminal window, navigate to the `order-processor` directory:
```bash
cd workflows/javascript/sdk/order-processor
```
Install the dependencies:
```bash
cd ./javascript/sdk
npm install
npm run build
```
### Step 3: Run the order processor app
In the terminal, start the order processor app alongside a Dapr sidecar using [Multi-App Run]({{< ref multi-app-dapr-run >}}). From the `javascript/sdk` directory, run the following command:
```bash
dapr run -f .
```
This starts the `order-processor` app with unique workflow ID and runs the workflow activities.
Expected output:
```log
== 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](https://hub.docker.com/r/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/`).
<img src="/images/workflow-trace-spans-zipkin.png" width=800 style="padding-bottom:15px;">
### 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.
1. The `notifyActivity` workflow activity sends a notification saying an order for 10 cars has been received.
1. 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.
1. Your workflow starts and notifies you of its status.
1. The `processPaymentActivity` workflow activity begins processing payment for order `0c332155-1e02-453a-a333-28cfc7777642` and confirms if successful.
1. The `updateInventoryActivity` workflow activity updates the inventory with the current available cars after the order has been processed.
1. The `notifyActivity` workflow activity sends a notification saying that order `0c332155-1e02-453a-a333-28cfc7777642` has completed.
1. 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
```javascript
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);
});
```
{{% /codetab %}}
<!-- .NET -->
{{% codetab %}}
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](https://docs.dapr.io/getting-started).
- [.NET SDK or .NET 6 SDK installed](https://dotnet.microsoft.com/download).
<!-- IGNORE_LINKS -->
- [Docker Desktop](https://www.docker.com/products/docker-desktop)
<!-- END_IGNORE -->
### Step 2: Set up the environment
Clone the [sample provided in the Quickstarts repo](https://github.com/dapr/quickstarts/tree/master/workflows/csharp/sdk).
```bash
git clone https://github.com/dapr/quickstarts.git
```
In a new terminal window, navigate to the `order-processor` directory:
```bash
cd workflows/csharp/sdk/order-processor
```
Install the dependencies:
```bash
dotnet restore
dotnet build
```
Return to the `csharp/sdk` directory:
```bash
cd ..
```
### Step 3: Run the order processor app
In the terminal, start the order processor app alongside a Dapr sidecar using [Multi-App Run]({{< ref multi-app-dapr-run >}}). From the `csharp/sdk` directory, run the following command:
```bash
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](https://hub.docker.com/r/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/`).
<img src="/images/workflow-trace-spans-zipkin.png" width=800 style="padding-bottom:15px;">
### 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.
1. The `NotifyActivity` workflow activity sends a notification saying an order for 10 cars has been received.
1. 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.
1. Your workflow starts and notifies you of its status.
1. The `ProcessPaymentActivity` workflow activity begins processing payment for order `6d2abcc9` and confirms if successful.
1. The `UpdateInventoryActivity` workflow activity updates the inventory with the current available cars after the order has been processed.
1. The `NotifyActivity` workflow activity sends a notification saying that order `6d2abcc9` has completed.
1. 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
```csharp
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 daprWorkflowClient.ScheduleNewWorkflowAsync(
name: nameof(OrderProcessingWorkflow),
input: orderInfo,
instanceId: orderId);
// Wait for the workflow to start and confirm the input
WorkflowState state = await daprWorkflowClient.WaitForWorkflowStartAsync(
instanceId: orderId);
Console.WriteLine($"{nameof(OrderProcessingWorkflow)} (ID = {orderId}) started successfully with {state.ReadInputAs<OrderPayload>()}");
// Wait for the workflow to complete
using var ctx = new CancellationTokenSource(TimeSpan.FromSeconds(5));
state = await daprClient.WaitForWorkflowCompletionAsync(
instanceId: orderId,
cancellation: ctx.Token);
Console.WriteLine("Workflow Status: {0}", state.ReadCustomStatusAs<string>());
```
#### `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).
```csharp
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 (WorkflowTaskFailedException)
{
// 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](https://youtu.be/BxiKpEmchgQ?t=2564):
<iframe width="560" height="315" src="https://www.youtube-nocookie.com/embed/BxiKpEmchgQ?start=2564" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>
{{% /codetab %}}
<!-- Java -->
{{% codetab %}}
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](https://docs.dapr.io/getting-started).
- Java JDK 17 (or greater):
- [Microsoft JDK 17](https://docs.microsoft.com/java/openjdk/download#openjdk-17)
- [Oracle JDK 17](https://www.oracle.com/technetwork/java/javase/downloads/index.html#JDK17)
- [OpenJDK 17](https://jdk.java.net/17/)
- [Apache Maven](https://maven.apache.org/install.html) version 3.x.
<!-- IGNORE_LINKS -->
- [Docker Desktop](https://www.docker.com/products/docker-desktop)
<!-- END_IGNORE -->
### Step 2: Set up the environment
Clone the [sample provided in the Quickstarts repo](https://github.com/dapr/quickstarts/tree/master/workflows/java/sdk).
```bash
git clone https://github.com/dapr/quickstarts.git
```
Navigate to the `order-processor` directory:
```bash
cd workflows/java/sdk/order-processor
```
Install the dependencies:
```bash
mvn clean install
```
Return to the `java/sdk` directory:
```bash
cd ..
```
### Step 3: Run the order processor app
In the terminal, start the order processor app alongside a Dapr sidecar using [Multi-App Run]({{< ref multi-app-dapr-run >}}). From the `java/sdk` directory, run the following command:
```bash
cd workflows/java/sdk
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](https://hub.docker.com/r/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/`).
<img src="/images/workflow-trace-spans-zipkin.png" width=800 style="padding-bottom:15px;">
### 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.
1. The `NotifyActivity` workflow activity sends a notification saying an order for 10 cars has been received.
1. 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.
1. Once approved, your workflow starts and notifies you of its status.
1. The `ProcessPaymentActivity` workflow activity begins processing payment for order `edceba90-9c45-4be8-ad40-60d16e060797` and confirms if successful.
1. The `UpdateInventoryActivity` workflow activity updates the inventory with the current available cars after the order has been processed.
1. The `NotifyActivity` workflow activity sends a notification saying that order `edceba90-9c45-4be8-ad40-60d16e060797` has completed.
1. 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
```java
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).
```java
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`](https://github.com/dapr/quickstarts/tree/master/workflows/java/sdk/order-processor/src/main/java/io/dapr/quickstarts/workflows/activities/NotifyActivity.java)
- [`RequestApprovalActivity`](https://github.com/dapr/quickstarts/tree/master/workflows/java/sdk/order-processor/src/main/java/io/dapr/quickstarts/workflows/activities/RequestApprovalActivity.java)
- [`ReserveInventoryActivity`](https://github.com/dapr/quickstarts/tree/master/workflows/java/sdk/order-processor/src/main/java/io/dapr/quickstarts/workflows/activities/ReserveInventoryActivity.java)
- [`ProcessPaymentActivity`](https://github.com/dapr/quickstarts/tree/master/workflows/java/sdk/order-processor/src/main/java/io/dapr/quickstarts/workflows/activities/ProcessPaymentActivity.java)
- [`UpdateInventoryActivity`](https://github.com/dapr/quickstarts/tree/master/workflows/java/sdk/order-processor/src/main/java/io/dapr/quickstarts/workflows/activities/UpdateInventoryActivity.java)
{{% /codetab %}}
<!-- Go -->
{{% codetab %}}
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](https://docs.dapr.io/getting-started).
- [Latest version of Go](https://go.dev/dl/).
<!-- IGNORE_LINKS -->
- [Docker Desktop](https://www.docker.com/products/docker-desktop)
<!-- END_IGNORE -->
### Step 2: Set up the environment
Clone the [sample provided in the Quickstarts repo](https://github.com/dapr/quickstarts/tree/master/workflows/go/sdk).
```bash
git clone https://github.com/dapr/quickstarts.git
```
In a new terminal window, navigate to the `sdk` directory:
```bash
cd workflows/go/sdk
```
### Step 3: Run the order processor app
In the terminal, start the order processor app alongside a Dapr sidecar using [Multi-App Run]({{< ref multi-app-dapr-run >}}). From the `go/sdk` directory, run the following command:
```bash
dapr run -f .
```
This starts the `order-processor` app with unique workflow ID and runs the workflow activities.
Expected output:
```bash
== 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:
```bash
dapr stop -f .
```
### (Optional) Step 4: View in Zipkin
Running `dapr init` launches the [openzipkin/zipkin](https://hub.docker.com/r/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/`).
<img src="/images/workflow-trace-spans-zipkin.png" width=800 style="padding-bottom:15px;">
### 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.
1. The `NotifyActivity` workflow activity sends a notification saying an order for 10 cars has been received.
1. 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.
1. Your workflow starts and notifies you of its status.
1. The `ProcessPaymentActivity` workflow activity begins processing payment for order `48ee83b7-5d80-48d5-97f9-6b372f5480a5` and confirms if successful.
1. The `UpdateInventoryActivity` workflow activity updates the inventory with the current available cars after the order has been processed.
1. The `NotifyActivity` workflow activity sends a notification saying that order `48ee83b7-5d80-48d5-97f9-6b372f5480a5` has completed.
1. 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
```go
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`](https://github.com/dapr/quickstarts/workflows/go/sdk/order-processor/workflow.go)
{{% /codetab %}}
{{< /tabs >}}
## Tell us what you think!
We're continuously working to improve our Quickstart examples and value your feedback. Did you find this Quickstart helpful? Do you have suggestions for improvement?
Join the discussion in our [discord channel](https://discord.com/channels/778680217417809931/953427615916638238).
## Next steps
- Set up Dapr Workflow with any programming language using [HTTP instead of an SDK]({{< ref howto-manage-workflow.md >}})
- Walk through a more in-depth [.NET SDK example workflow](https://github.com/dapr/dotnet-sdk/tree/master/examples/Workflow)
- Learn more about [Workflow as a Dapr building block]({{< ref workflow-overview >}})
{{< button text="Explore Dapr tutorials >>" page="getting-started/tutorials/_index.md" >}}
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