Running Azure Functions Locally Step by Step

Running Azure Functions locally allows you to test and debug your code without incurring Azure costs.

First, you need to install the Azure Functions Core Tools, which can be done by running the command `dotnet tool install -g Azure.Functions.Cli` in your terminal or command prompt.

This will install the necessary tools to create, run, and debug Azure Functions locally.

To create a new Azure Function project, you can use the `func new` command, which will create a new directory with the basic files and folders needed for an Azure Function project.

To start building .NET-based Azure Functions, you need to install the .NET SDK and Azure Functions Core Tools on your machine. This is a prerequisite to get started.

You can install the .NET SDK and Azure Functions Core Tools from the official Microsoft documentation. Make sure to follow the installation instructions carefully.

Once you have installed the required tools, you can proceed with configuring your project to run locally. This involves setting the Azure Storage account connection string, which is used by the Functions runtime internally for all trigger types other than HTTP and webhooks.

To set the storage account connection string, you need to follow these steps:

To get started with Azure Functions, you need to have Visual Studio Code installed on one of the supported platforms.

An active Azure subscription is also required, and you can create one from the extension in Visual Studio Code if you don't already have an account.

You'll also need to install the Azure Functions extension, and the Azure Tools extension pack is recommended for working with Azure resources.

Here's a quick rundown of the required tools:

You may need additional tools depending on the programming language you're using, such as the C# extension for Visual Studio Code, or Node.js and Maven for Java development.

To start a new project, you can create an Azure Functions project in Visual Studio Code. Press F1 to open the command palette and search for and run the command Azure Functions: Create New Project.

You'll need to select the directory location for your project workspace, and then choose Select. You can create a new folder or choose an empty folder for the project workspace.

Select the HTTP trigger function template to create an HTTP-triggered function. You can also select Skip for now to create a project without a function.

For the function name, enter HttpExample, select Enter, and then select Function authorization. This requires that you provide a function key when you call the function endpoint.

To create a new Azure Functions project using the .NET SDK and Azure Functions Core Tools, you can select the runtime: dotnet (isolated process) and the language: C#.

Here are the steps to create a new Azure Functions project in Visual Studio Code:

Download from Azure is a convenient option if you've already created application settings in Azure. You can use the Azure Functions: Download Remote Settings command to get the settings into your local file.

If your local file is encrypted, it will be decrypted and updated with the new settings, and then encrypted again to keep your data secure. This ensures that your sensitive information remains protected.

You'll be prompted to choose how to proceed if there are settings with conflicting values in both locations, so be prepared to make a decision about what to do.

To configure your Azure Function project for local development, you'll need to set up the necessary files and connections. The project root folder should contain a host.json file, which provides more information when referenced.

The local.settings.json file is used by Core Tools when running locally, and it includes app settings. This file is also prevented from being published to a Git repository by the .gitignore file.

To run your project locally, you'll need to set the AzureWebJobsStorage key to a valid Azure Storage account connection string. This can be done by copying the Primary Connection String value from the Azure Storage Account properties in Visual Studio, and then adding it to the local.settings.json file.

Here are the steps to set up the storage account connection string:

To create a new Azure Functions project, you can use Visual Studio Code with the Azure Functions extension. To start, press F1 to open the command palette and search for and run the command Azure Functions: Create New Project.

You can either create a new folder or choose an empty folder for the project workspace, but don't choose a project folder that's already part of a workspace. You can instead run the command Azure Functions: Create New Containerized Project to also get a Dockerfile generated for the project.

Select the HTTP trigger function template, or you can select Skip for now to create a project without a function. You can always add a function to your project later.

To select the HTTP trigger function template, follow these steps:

You can also create a C# script project by selecting C# script as the default language in the Azure Functions extension settings. To do this, follow these steps:

After setting the default language, all projects you create will default to C# script projects. However, if you want to create projects in other languages, you must change this setting or remove it from the user settings.json file.

To configure the project, you'll need to set up the local project files. These include host.json, local.settings.json, .gitignore, and .vscode\extensions.json.

The host.json file is used to learn more about the host.json reference. It's essential to understand its purpose and how it works.

local.settings.json is used by Core Tools when running locally, including app settings. You can find more information about it in the local settings file.

The .gitignore file prevents the local.settings.json file from being accidentally published to a Git repository. This is a crucial step to avoid any potential issues.

In Visual Studio, you can open Cloud Explorer, expand Storage Account > Your Storage Account, and then select Properties and copy the Primary Connection String value. This is necessary to set up the storage account connection string.

To set up the storage account connection string, you'll need to open the local.settings.json file and set the value of the AzureWebJobsStorage key to the connection string you copied. You'll also need to repeat this step to add unique keys to the Values array for any other connections required by your functions.

Here's a summary of the steps to set up the storage account connection string:

To check if the Azure Functions Core Tools are installed, you can run the func --version command. This will ask you a few questions to set up the project.

You'll need to install the Azure Functions Core Tools on your system. You can find the installation instructions in the Install the Azure Functions Core Tools section of the Core Tools Development documentation.

You can run individual functions with the Azure Functions extension, either locally on your development computer or in your Azure subscription.

To run functions locally, you'll need to meet specific requirements and use the local runtime, which is the same as the one hosting your function app in Azure.

The local settings are read from the local.settings.json file, which is a crucial file for local development.

You can run your Functions project locally by using the Azure Functions Core Tools, which are simple to use and allow you to run the function based on the same trigger it would use if hosted in Azure.

For HTTP trigger functions, the extension calls the HTTP endpoint, while for other triggers, it calls administrator APIs to start the function.

The message body of the request sent to the function depends on the trigger type, and you may be prompted to enter test data in a specific JSON format.

To run your function, simply copy the local.settings.json file to the root of the Functions project next to the DLL, open a command prompt from there, and run "func start."

You can debug your Azure Functions locally using the Core Tools. To do this, select F5, which will prompt you to install Core Tools if it's not already available.

With Core Tools installed and running, you can see the output in the Terminal. This is the same as running the func start Core Tools command from the Terminal, but with extra build tasks and an attached debugger.

You can use the Execute Function Now... feature of the extension to trigger your functions as you would when the project is deployed to Azure. To do this, follow these steps:

Debugging from Visual Studio is also possible by setting the function project as the startup project for the Visual Studio solution. This requires an Azure Storage account for handling triggers and logging, which can be replaced with an installed emulator.

Local development environments, such as Visual Studio Code, Command prompt or terminal, and Visual Studio, support local development of Azure Functions. The environments in the following table support local development:

Note that keys aren't required when running locally, which applies to both function keys and admin-level keys.