title	description	author	ms.topic	ms.date	ms.reviewer
Create your first durable function in Azure Functions using PowerShell	Create and publish an Azure Durable Function in PowerShell using Visual Studio Code.	anthonychu	quickstart	08/10/2020	azfuncdf, antchu

Create your first durable function in PowerShell

Durable Functions is an extension of Azure Functions that lets you write stateful functions in a serverless environment. The extension manages state, checkpoints, and restarts for you.

In this article, you learn how to use the Visual Studio Code Azure Functions extension to locally create and test a "hello world" durable function. This function will orchestrate and chain together calls to other functions. You then publish the function code to Azure.

Prerequisites

To complete this tutorial:

Install Visual Studio Code.
Install the Azure Functions VS Code extension
Make sure you have the latest version of the Azure Functions Core Tools.
Durable Functions require an Azure storage account. You need an Azure subscription.

[!INCLUDE quickstarts-free-trial-note]

Create your local project

In this section, you use Visual Studio Code to create a local Azure Functions project.

In Visual Studio Code, press F1 (or Ctrl/Cmd+Shift+P) to open the command palette. In the command palette, search for and select Azure Functions: Create New Project....
Choose an empty folder location for your project and choose Select.

Following the prompts, provide the following information:

Prompt	Value	Description
Select a language for your function app project	PowerShell	Create a local PowerShell Functions project.
Select a version	Azure Functions v3	You only see this option when the Core Tools aren't already installed. In this case, Core Tools are installed the first time you run the app.
Select a template for your project's first function	Skip for now
Select how you would like to open your project	Open in current window	Reopens VS Code in the folder you selected.

Visual Studio Code installs the Azure Functions Core Tools, if needed. It also creates a function app project in a folder. This project contains the host.json and local.settings.json configuration files.

A package.json file is also created in the root folder.

Configure function app to use PowerShell 7

Open the local.settings.json file and confirm that a setting named FUNCTIONS_WORKER_RUNTIME_VERSION is set to ~7. If it is missing or set to another value, update the contents of the file.

{
  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "",
    "FUNCTIONS_WORKER_RUNTIME": "powershell",
    "FUNCTIONS_WORKER_RUNTIME_VERSION" : "~7"
  }
}

Create your functions

The most basic Durable Functions app contains three functions:

Orchestrator function - describes a workflow that orchestrates other functions.
Activity function - called by the orchestrator function, performs work, and optionally returns a value.
Client function - a regular Azure Function that starts an orchestrator function. This example uses an HTTP triggered function.

Orchestrator function

You use a template to create the durable function code in your project.

In the command palette, search for and select Azure Functions: Create Function....

Following the prompts, provide the following information:

Prompt	Value	Description
Select a template for your function	Durable Functions orchestrator	Create a Durable Functions orchestration
Provide a function name	HelloOrchestrator	Name of your durable function

You've added an orchestrator to coordinate activity functions. Open HelloOrchestrator/run.ps1 to see the orchestrator function. Each call to the Invoke-ActivityFunction cmdlet invokes an activity function named Hello.

Next, you'll add the referenced Hello activity function.

Activity function

In the command palette, search for and select Azure Functions: Create Function....
Following the prompts, provide the following information:

Prompt Value Description

Select a template for your function Durable Functions activity Create an activity function

Provide a function name Hello Name of your activity function

You've added the Hello activity function that is invoked by the orchestrator. Open Hello/run.ps1 to see that it's taking a name as input and returning a greeting. An activity function is where you'll perform actions such as making a database call or performing a computation.

Finally, you'll add an HTTP triggered function that starts the orchestration.

Client function (HTTP starter)

In the command palette, search for and select Azure Functions: Create Function....

Following the prompts, provide the following information:

Prompt	Value	Description
Select a template for your function	Durable Functions HTTP starter	Create an HTTP starter function
Provide a function name	HttpStart	Name of your activity function
Authorization level	Anonymous	For demo purposes, allow the function to be called without authentication

You've added an HTTP triggered function that starts an orchestration. Open HttpStart/run.ps1 to see that it uses the Start-NewOrchestration cmdlet to start a new orchestration. Then it uses the New-OrchestrationCheckStatusResponse cmdlet to return an HTTP response containing URLs that can be used to monitor and manage the new orchestration.

You now have a Durable Functions app that can be run locally and deployed to Azure.

Test the function locally

Azure Functions Core Tools lets you run an Azure Functions project on your local development computer. You're prompted to install these tools the first time you start a function app from Visual Studio Code.

To test your function, set a breakpoint in the Hello activity function code (Hello/run.ps1). Press F5 or select Debug: Start Debugging from the command palette to start the function app project. Output from Core Tools is displayed in the Terminal panel.

[!NOTE] Refer to the Durable Functions Diagnostics for more information on debugging.
Durable Functions requires an Azure Storage account to run. When VS Code prompts you to select a storage account, choose Select storage account.

Following the prompts, provide the following information to create a new storage account in Azure.

Prompt	Value	Description
Select subscription	name of your subscription	Select your Azure subscription
Select a storage account	Create a new storage account
Enter the name of the new storage account	unique name	Name of the storage account to create
Select a resource group	unique name	Name of the resource group to create
Select a location	region	Select a region close to you

In the Terminal panel, copy the URL endpoint of your HTTP-triggered function.
Using your browser, or a tool like Postman or cURL, send an HTTP POST request to the URL endpoint. Replace the last segment with the name of the orchestrator function (HelloOrchestrator). The URL should be similar to http://localhost:7071/api/orchestrators/HelloOrchestrator.

The response is the initial result from the HTTP function letting you know the durable orchestration has started successfully. It is not yet the end result of the orchestration. The response includes a few useful URLs. For now, let's query the status of the orchestration.

Copy the URL value for statusQueryGetUri and paste it in the browser's address bar and execute the request. Alternatively you can also continue to use Postman to issue the GET request.

The request will query the orchestration instance for the status. You should get an eventual response, which shows us the instance has completed, and includes the outputs or results of the durable function. It looks like:

{
    "name": "HelloOrchestrator",
    "instanceId": "9a528a9e926f4b46b7d3deaa134b7e8a",
    "runtimeStatus": "Completed",
    "input": null,
    "customStatus": null,
    "output": [
        "Hello Tokyo!",
        "Hello Seattle!",
        "Hello London!"
    ],
    "createdTime": "2020-03-18T21:54:49Z",
    "lastUpdatedTime": "2020-03-18T21:54:54Z"
}

To stop debugging, press Shift + F5 in VS Code.

After you've verified that the function runs correctly on your local computer, it's time to publish the project to Azure.

[!INCLUDE functions-create-function-app-vs-code]

Publish the project to Azure

In this section, you create a function app and related resources in your Azure subscription and then deploy your code.

Important

Publishing to an existing function app overwrites the content of that app in Azure.

Choose the Azure icon in the Activity bar, then in the Azure: Functions area, choose the Deploy to function app... button.
Provide the following information at the prompts:
- Select folder: Choose a folder from your workspace or browse to one that contains your function app. You won't see this if you already have a valid function app opened.
- Select subscription: Choose the subscription to use. You won't see this if you only have one subscription.
- Select Function App in Azure: Choose + Create new Function App. (Don't choose the Advanced option, which isn't covered in this article.)
- Enter a globally unique name for the function app: Type a name that is valid in a URL path. The name you type is validated to make sure that it's unique in Azure Functions.
- Select a runtime: Choose the version of PowerShell you've been running on locally. You can use the pwsh -version command to check your version.
  
  [!NOTE] The Azure Functions VS Code extension may not support PowerShell 7 yet. If PowerShell 7 is not available as an option, select PowerShell 6.x for now and update the version manually after the function app has been created.
- Select a location for new resources: For better performance, choose a region near you.
When completed, the following Azure resources are created in your subscription, using names based on your function app name:
- A resource group, which is a logical container for related resources.
- A standard Azure Storage account, which maintains state and other information about your projects.
- A consumption plan, which defines the underlying host for your serverless function app.
- A function app, which provides the environment for executing your function code. A function app lets you group functions as a logical unit for easier management, deployment, and sharing of resources within the same hosting plan.
- An Application Insights instance connected to the function app, which tracks usage of your serverless function.
A notification is displayed after your function app is created and the deployment package is applied.
If you were unable to select PowerShell 7 earlier when creating the function app, press F1 (or Ctrl/Cmd+Shift+P) to open the command palette. In the command palette, search for and select Azure Functions: Upload Local Settings.... Follow the prompts to select the function app you created. If prompted to overwrite existing settings, select No to all.
Select View Output in this notification to view the creation and deployment results, including the Azure resources that you created. If you miss the notification, select the bell icon in the lower right corner to see it again.

Test your function in Azure

Copy the URL of the HTTP trigger from the Output panel. The URL that calls your HTTP-triggered function should be in this format: http://<functionappname>.azurewebsites.net/api/orchestrators/HelloOrchestrator
Paste this new URL for the HTTP request into your browser's address bar. You should get the same status response as before when using the published app.

Next steps

You have used Visual Studio Code to create and publish a PowerShell durable function app.

[!div class="nextstepaction"] Learn about common durable function patterns

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quickstart-powershell-vscode.md

quickstart-powershell-vscode.md

Create your first durable function in PowerShell

Prerequisites

Create your local project

Configure function app to use PowerShell 7

Create your functions

Orchestrator function

Activity function

Client function (HTTP starter)

Test the function locally

Publish the project to Azure

Test your function in Azure

Next steps

Prompt	Value	Description
Select a template for your function	Durable Functions activity	Create an activity function
Provide a function name	Hello	Name of your activity function

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quickstart-powershell-vscode.md

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quickstart-powershell-vscode.md

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Create your first durable function in PowerShell

Prerequisites

Create your local project

Configure function app to use PowerShell 7

Create your functions

Orchestrator function

Activity function

Client function (HTTP starter)

Test the function locally

Publish the project to Azure

Test your function in Azure

Next steps