| title | description | ms.date | ms.topic | ms.custom | zone_pivot_groups |
|---|---|---|---|---|---|
Create a function in Azure that responds to HTTP requests |
Learn how to create a function from the command line, then publish the local project to serverless hosting in Azure Functions. |
03/30/2020 |
quickstart |
tracking-python |
programming-languages-set-functions |
::: zone pivot="programming-language-csharp"
In this article, you use command-line tools to create a C# class library-based function that responds to HTTP requests. After testing the code locally, you deploy it to the serverless environment of Azure Functions.
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::: zone pivot="programming-language-javascript"
In this article, you use command-line tools to create a JavaScript function that responds to HTTP requests. After testing the code locally, you deploy it to the serverless environment of Azure Functions.
::: zone-end
::: zone pivot="programming-language-typescript"
In this article, you use command-line tools to create a TypeScript function that responds to HTTP requests. After testing the code locally, you deploy it to the serverless environment of Azure Functions.
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::: zone pivot="programming-language-powershell"
In this article, you use command-line tools to create a PowerShell function that responds to HTTP requests. After testing the code locally, you deploy it to the serverless environment of Azure Functions.
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::: zone pivot="programming-language-python"
In this article, you use command-line tools to create a Python function that responds to HTTP requests. After testing the code locally, you deploy it to the serverless environment of Azure Functions.
::: zone-end
::: zone pivot="programming-language-java"
In this article, you use command-line tools to create a Java function that responds to HTTP requests. After testing the code locally, you deploy it to the serverless environment of Azure Functions.
::: zone-end
Completing this quickstart incurs a small cost of a few USD cents or less in your Azure account.
::: zone pivot="programming-language-csharp,programming-language-javascript,programming-language-typescript,programming-language-powershell,programming-language-python"
There is also a Visual Studio Code-based version of this article.
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::: zone pivot="programming-language-java"
Note
If Maven is not your prefered development tool, check out our similar tutorials for Java developers using Gradle, IntelliJ IDEA and Visual Studio Code. ::: zone-end
[!INCLUDE functions-requirements-cli]
[!INCLUDE functions-cli-verify-prereqs]
[!INCLUDE functions-cli-create-venv]
In Azure Functions, a function project is a container for one or more individual functions that each responds to a specific trigger. All functions in a project share the same local and hosting configurations. In this section, you create a function project that contains a single function.
::: zone pivot="programming-language-csharp,programming-language-javascript,programming-language-typescript,programming-language-powershell,programming-language-python"
Run the func init command, as follows, to create a functions project in a folder named LocalFunctionProj with the specified runtime:
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::: zone pivot="programming-language-python"
func init LocalFunctionProj --python
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::: zone pivot="programming-language-csharp"
func init LocalFunctionProj --dotnet
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::: zone pivot="programming-language-javascript"
func init LocalFunctionProj --javascript
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::: zone pivot="programming-language-typescript"
func init LocalFunctionProj --typescript
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::: zone pivot="programming-language-powershell"
func init LocalFunctionProj --powershell
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::: zone pivot="programming-language-java"
In an empty folder, run the following command to generate the Functions project from a Maven archetype.
mvn archetype:generate -DarchetypeGroupId=com.microsoft.azure -DarchetypeArtifactId=azure-functions-archetype mvn archetype:generate "-DarchetypeGroupId=com.microsoft.azure" "-DarchetypeArtifactId=azure-functions-archetype" mvn archetype:generate "-DarchetypeGroupId=com.microsoft.azure" "-DarchetypeArtifactId=azure-functions-archetype" Maven asks you for values needed to finish generating the project on deployment.
Provide the following values when prompted:
| Prompt | Value | Description |
|---|---|---|
| groupId | com.fabrikam |
A value that uniquely identifies your project across all projects, following the package naming rules for Java. |
| artifactId | fabrikam-functions |
A value that is the name of the jar, without a version number. |
| version | 1.0-SNAPSHOT |
Choose the default value. |
| package | com.fabrikam |
A value that is the Java package for the generated function code. Use the default. |
Type Y or press Enter to confirm.
Maven creates the project files in a new folder with a name of artifactId, which in this example is fabrikam-functions.
::: zone-end
Navigate into the project folder:
::: zone pivot="programming-language-csharp,programming-language-javascript,programming-language-typescript,programming-language-powershell,programming-language-python"
cd LocalFunctionProj
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::: zone pivot="programming-language-java"
cd fabrikam-functions
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This folder contains various files for the project, including configurations files named local.settings.json and host.json. Because local.settings.json can contain secrets downloaded from Azure, the file is excluded from source control by default in the .gitignore file.
[!INCLUDE functions-cli-add-function]
If desired, you can skip to Run the function locally and examine the file contents later.
::: zone pivot="programming-language-csharp"
HttpExample.cs contains a Run method that receives request data in the req variable is an HttpRequest that's decorated with the HttpTriggerAttribute, which defines the trigger behavior.
:::code language="csharp" source="~/functions-docs-csharp/http-trigger-template/HttpExample.cs":::
The return object is an ActionResult that returns an response message as either an OkObjectResult (200) or a BadRequestObjectResult (400). To learn more, see Azure Functions HTTP triggers and bindings. ::: zone-end
::: zone pivot="programming-language-java"
Function.java contains a run method that receives request data in the request variable is an HttpRequestMessage that's decorated with the HttpTrigger annotation, which defines the trigger behavior.
:::code language="java" source="~/azure-functions-samples-java/src/main/java/com/functions/Function.java":::
The response message is generated by the HttpResponseMessage.Builder API.
Settings for the Azure resources created to host your app are defined in the configuration element of the plugin with a groupId of com.microsoft.azure in the generated pom.xml file. For example, the configuration element below instructs a Maven-based deployment to create a function app in the java-functions-group resource group in the westus region. The function app itself runs on Windows hosted in the java-functions-app-service-plan plan, which by default is a serverless Consumption plan.
:::code language="java" source="~/azure-functions-samples-java/pom.xml" range="62-102":::
You can change these settings to control how resources are created in Azure, such as by changing runtime.os from windows to linux before initial deployment. For a complete list of settings supported by the Maven plug-in, see the configuration details.
The archetype also generates a unit test for your function. When you change your function to add bindings or add new functions to the project, you'll also need to modify the tests in the FunctionTest.java file.
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::: zone pivot="programming-language-python"
__init__.py contains a main() Python function that's triggered according to the configuration in function.json.
:::code language="python" source="~/functions-quickstart-templates/Functions.Templates/Templates/HttpTrigger-Python/init.py":::
For an HTTP trigger, the function receives request data in the variable req as defined in function.json. req is an instance of the azure.functions.HttpRequest class. The return object, defined as $return in function.json, is an instance of azure.functions.HttpResponse class. To learn more, see Azure Functions HTTP triggers and bindings.
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::: zone pivot="programming-language-javascript"
index.js exports a function that's triggered according to the configuration in function.json.
:::code language="javascript" source="~/functions-quickstart-templates/Functions.Templates/Templates/HttpTrigger-JavaScript/index.js":::
For an HTTP trigger, the function receives request data in the variable req as defined in function.json. The return object, defined as $return in function.json, is the response. To learn more, see Azure Functions HTTP triggers and bindings.
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::: zone pivot="programming-language-typescript"
index.ts exports a function that's triggered according to the configuration in function.json.
:::code language="typescript" source="~/functions-quickstart-templates/Functions.Templates/Templates/HttpTrigger-TypeScript/index.ts":::
For an HTTP trigger, the function receives request data in the variable req of type HttpRequest as defined in function.json. The return object, defined as $return in function.json, is the response.
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::: zone pivot="programming-language-powershell"
run.ps1 defines a function script that's triggered according to the configuration in function.json.
:::code language="powershell" source="~/functions-quickstart-templates/Functions.Templates/Templates/HttpTrigger-PowerShell/run.ps1":::
For an HTTP trigger, the function receives request data passed to the $Request param defined in function.json. The return object, defined as Response in function.json, is passed to the Push-OutputBinding cmdlet as the response.
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::: zone pivot="programming-language-javascript,programming-language-typescript,programming-language-python,programming-language-powershell"
function.json is a configuration file that defines the input and output bindings for the function, including the trigger type.
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::: zone pivot="programming-language-python"
You can change scriptFile to invoke a different Python file if desired.
:::code language="json" source="~/functions-quickstart-templates/Functions.Templates/Templates/HttpTrigger-Python/function.json"::: ::: zone-end
::: zone pivot="programming-language-javascript,programming-language-typescript" :::code language="json" source="~/functions-quickstart-templates/Functions.Templates/Templates/HttpTrigger-JavaScript/function.json"::: ::: zone-end
::: zone pivot="programming-language-powershell" :::code language="json" source="~/functions-quickstart-templates/Functions.Templates/Templates/HttpTrigger-PowerShell/function.json"::: ::: zone-end
::: zone pivot="programming-language-javascript,programming-language-typescript,programming-language-python,programming-language-powershell"
Each binding requires a direction, a type, and a unique name. The HTTP trigger has an input binding of type httpTrigger and output binding of type http.
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[!INCLUDE functions-run-function-test-local-cli]
::: zone pivot="programming-language-javascript,programming-language-typescript,programming-language-python,programming-language-powershell,programming-language-csharp"
Before you can deploy your function code to Azure, you need to create three resources:
- A resource group, which is a logical container for related resources.
- A Storage account, which maintains state and other information about your projects.
- A function app, which provides the environment for executing your function code. A function app maps to your local function project and lets you group functions as a logical unit for easier management, deployment, and sharing of resources.
Use the following Azure CLI commands to create these items. Each command provides JSON output upon completion.
If you haven't done so already, sign in to Azure with the az login command:
az login
Create a resource group with the az group create command. The following example creates a resource group named AzureFunctionsQuickstart-rg in the westeurope region. (You generally create your resource group and resources in a region near you, using an available region from the az account list-locations command.)
az group create --name AzureFunctionsQuickstart-rg --location westeurope
Note
You can't host Linux and Windows apps in the same resource group. If you have an existing resource group named AzureFunctionsQuickstart-rg with a Windows function app or web app, you must use a different resource group.
Create a general-purpose storage account in your resource group and region by using the az storage account create command. In the following example, replace <STORAGE_NAME> with a globally unique name appropriate to you. Names must contain three to 24 characters numbers and lowercase letters only. Standard_LRS specifies a general-purpose account, which is supported by Functions.
az storage account create --name <STORAGE_NAME> --location westeurope --resource-group AzureFunctionsQuickstart-rg --sku Standard_LRS
The storage account incurs only a few cents (USD) for this quickstart.
Create the function app using the az functionapp create command. In the following example, replace <STORAGE_NAME> with the name of the account you used in the previous step, and replace <APP_NAME> with a globally unique name appropriate to you. The <APP_NAME> is also the default DNS domain for the function app.
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::: zone pivot="programming-language-python"
If you are using Python 3.8, change --runtime-version to 3.8 and --functions_version to 3.
If you are using Python 3.6, change --runtime-version to 3.6.
az functionapp create --resource-group AzureFunctionsQuickstart-rg --os-type Linux --consumption-plan-location westeurope --runtime python --runtime-version 3.7 --functions-version 2 --name <APP_NAME> --storage-account <STORAGE_NAME>
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::: zone pivot="programming-language-javascript,programming-language-typescript"
If you are using Node.js 8, also change --runtime-version to 8.
az functionapp create --resource-group AzureFunctionsQuickstart-rg --consumption-plan-location westeurope --runtime node --runtime-version 10 --functions-version 2 --name <APP_NAME> --storage-account <STORAGE_NAME>
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::: zone pivot="programming-language-csharp"
az functionapp create --resource-group AzureFunctionsQuickstart-rg --consumption-plan-location westeurope --runtime dotnet --functions-version 2 --name <APP_NAME> --storage-account <STORAGE_NAME>
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::: zone pivot="programming-language-powershell"
az functionapp create --resource-group AzureFunctionsQuickstart-rg --consumption-plan-location westeurope --runtime powershell --functions-version 2 --name <APP_NAME> --storage-account <STORAGE_NAME>
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::: zone pivot="programming-language-javascript,programming-language-typescript,programming-language-python,programming-language-powershell,programming-language-csharp"
This command creates a function app running in your specified language runtime under the Azure Functions Consumption Plan, which is free for the amount of usage you incur here. The command also provisions an associated Azure Application Insights instance in the same resource group, with which you can monitor your function app and view logs. For more information, see Monitor Azure Functions. The instance incurs no costs until you activate it.
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::: zone pivot="programming-language-typescript"
Before you use Core Tools to deploy your project to Azure, you create a production-ready build of JavaScript files from the TypeScript source files.
The following command prepares your TypeScript project for deployment:
npm run build:production
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::: zone pivot="programming-language-javascript,programming-language-typescript,programming-language-python,programming-language-powershell,programming-language-csharp"
With the necessary resources in place, you're now ready to deploy your local functions project to the function app in Azure by using the func azure functionapp publish command. In the following example, replace <APP_NAME> with the name of your app.
func azure functionapp publish <APP_NAME>
If you see the error, "Can't find app with name ...", wait a few seconds and try again, as Azure may not have fully initialized the app after the previous az functionapp create command.
The publish command shows results similar to the following output (truncated for simplicity):
...
Getting site publishing info...
Creating archive for current directory...
Performing remote build for functions project.
...
Deployment successful.
Remote build succeeded!
Syncing triggers...
Functions in msdocs-azurefunctions-qs:
HttpExample - [httpTrigger]
Invoke url: https://msdocs-azurefunctions-qs.azurewebsites.net/api/httpexample?code=KYHrydo4GFe9y0000000qRgRJ8NdLFKpkakGJQfC3izYVidzzDN4gQ==
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::: zone pivot="programming-language-java"
A function app and related resources are created in Azure when you first deploy your functions project. Settings for the Azure resources created to host your app are defined in the pom.xml file. In this article, you'll accept the defaults.
Tip
To create a function app running on Linux instead of Windows, change the runtime.os element in the pom.xml file from windows to linux. Running Linux in a consumption plan is supported in these regions. You can't have apps that run on Linux and apps that run on Windows in the same resource group.
Before you can deploy, use the az login Azure CLI command to sign in to your Azure subscription.
az login
Use the following command to deploy your project to a new function app.
mvn azure-functions:deploy
This creates the following resources in Azure:
- Resource group. Named as java-functions-group.
- Storage account. Required by Functions. The name is generated randomly based on Storage account name requirements.
- Hosting plan. Serverless hosting for your function app in the westus region. The name is java-functions-app-service-plan.
- Function app. A function app is the deployment and execution unit for your functions. The name is randomly generated based on your your artifactId, appended with a randomly generated number.
The deployment packages the project files and deploys them to the new function app using zip deployment. The code runs from the deployment package in Azure. ::: zone-end
Because your function uses an HTTP trigger, you invoke it by making an HTTP request to its URL in the browser or with a tool like curl. In both instances, the code URL parameter is your unique function key that authorizes the invocation of your function endpoint.
Copy the complete Invoke URL shown in the output of the publish command into a browser address bar, appending the query parameter &name=Functions. The browser should display similar output as when you ran the function locally.
Run curl with the Invoke URL, appending the parameter &name=Functions. The output of the command should be the text, "Hello Functions."
Tip
To view near real-time logs for a published function app, use the Application Insights Live Metrics Stream.
If you continue to the next step, Add an Azure Storage queue output binding, keep all your resources in place as you'll build on what you've already done.
Otherwise, use the following command to delete the resource group and all its contained resources to avoid incurring further costs.
::: zone pivot="programming-language-javascript,programming-language-typescript,programming-language-python,programming-language-powershell,programming-language-csharp"
az group delete --name AzureFunctionsQuickstart-rg
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az group delete --name java-functions-group
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To exit the virtual environment, run deactivate.
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[!div class="nextstepaction"] Connect to an Azure Storage queue