Azure Functions Java HTTP Trigger using AZD

This repository contains an Azure Functions HTTP trigger reference sample written in Java and deployed to Azure using Azure Developer CLI (azd). The sample uses managed identity and a virtual network to make sure deployment is secure by default. You can opt out of a VNet being used in the sample by setting VNET_ENABLED to false in the parameters.

This source code supports the article Quickstart: Create and deploy functions to Azure Functions using the Azure Developer CLI.

Prerequisites

• Java Developer Kit (JDK) version 17:
  • Other supported Java versions require updates to the pom.xml file.
  • The local JAVA_HOME environment variable must be set to the install location of the correct version of the JDK.
• Apache Maven, version 3.0 or above.
• Azure Functions Core Tools
• Azure Developer CLI (azd)
• To use Visual Studio Code to run and debug locally:
  • Visual Studio Code
  • Azure Functions extension

Initialize the local project

You can initialize a project from this azd template in one of these ways:

• Use this azd init command from an empty local (root) folder:

  azd init --template azure-functions-java-flex-consumption-azd

  Supply an environment name, such as flexquickstart when prompted. In azd, the environment is used to maintain a unique deployment context for your app.

• Clone the GitHub template repository locally using the git clone command:

  git clone https://github.com/Azure-Samples/azure-functions-java-flex-consumption-azd.git
  cd azure-functions-java-flex-consumption-azd

  You can also clone the repository from your own fork in GitHub.

Prepare your local environment

Navigate to the http app folder and create a file in that folder named local.settings.json that contains this JSON data:

{
    "IsEncrypted": false,
    "Values": {
        "AzureWebJobsStorage": "UseDevelopmentStorage=true",
        "FUNCTIONS_WORKER_RUNTIME": "java"
    }
}

Run your app from the terminal

1. From the http folder, run these commands to start the Functions host locally:

   mvn clean package
   mvn azure-functions:run

2. From your HTTP test tool in a new terminal (or from your browser), call the HTTP GET endpoint: http://localhost:7071/api/httpget

3. Test the HTTP POST trigger with a payload using your favorite secure HTTP test tool. This example runs in the http folder and uses the curl tool with payload data from the testdata.json project file:

   curl -i http://localhost:7071/api/httppost -H "Content-Type: text/json" -d "@testdata.json"

4. When you're done, press Ctrl+C in the terminal window to stop the func.exe host process.

Run your app using Visual Studio Code

1. From the root directory run the code . code command to open the project in Visual Studio Code.
2. Press Run/Debug (F5) to run in the debugger.
3. Send GET and POST requests to the httpget and httppost endpoints respectively using your HTTP test tool (or browser for httpget). If you have the RestClient extension installed, you can execute requests directly from the test.http project file.

Source Code

The source code for the GET and POST functions is found in the Function.java file. The function is identified as an Azure Function by use of the @FunctionName and @HttpTrigger annotations from the azure.functions.java.library.version library in the POM.

This code defines an HTTP GET triggered function:

@FunctionName("httpget")
public HttpResponseMessage run(
        @HttpTrigger(
            name = "req",
            methods = {HttpMethod.GET},
            authLevel = AuthorizationLevel.FUNCTION)
            HttpRequestMessage<Optional<String>> request,
        final ExecutionContext context) {
    context.getLogger().info("Java HTTP trigger processed a request.");

    // Parse query parameter
    String name = Optional.ofNullable(request.getQueryParameters().get("name")).orElse("World");

    return request.createResponseBuilder(HttpStatus.OK).body("Hello, " + name).build();
}

This code defines an HTTP POST triggered function, which expects a JSON payload with name and age values in the request.

@FunctionName("httppost")
public HttpResponseMessage runPost(
        @HttpTrigger(
            name = "req",
            methods = {HttpMethod.POST},
            authLevel = AuthorizationLevel.FUNCTION)
            HttpRequestMessage<Optional<String>> request,
        final ExecutionContext context) {
    context.getLogger().info("Java HTTP trigger processed a POST request.");

    // Parse request body
    String name;
    Integer age;
    try {
        ObjectMapper mapper = new ObjectMapper();
        JsonNode jsonNode = mapper.readTree(request.getBody().orElse("{}"));
        name = Optional.ofNullable(jsonNode.get("name")).map(JsonNode::asText).orElse(null);
        age = Optional.ofNullable(jsonNode.get("age")).map(JsonNode::asInt).orElse(null);
        if (name == null || age == null) {
            return request.createResponseBuilder(HttpStatus.BAD_REQUEST)
                    .body("Please provide both name and age in the request body.").build();
        }
    } catch (Exception e) {
        context.getLogger().severe("Error parsing request body: " + e.getMessage());
        return request.createResponseBuilder(HttpStatus.BAD_REQUEST)
                .body("Error parsing request body").build();
    }

    return request.createResponseBuilder(HttpStatus.OK).body("Hello, " + name +"! You are " + age +" years old.").build();
}

Deploy to Azure

Run this command to provision the function app, with any required Azure resources, and deploy your code:

azd up

By default, this sample uses a virtual network to ensure your deployment is secure by default. You can opt-out of a VNet being used by setting VNET_ENABLED to false before running azd up:

azd env set VNET_ENABLED false
azd up

You're prompted to supply these required deployment parameters:

Parameter	Description
Environment name	An environment that's used to maintain a unique deployment context for your app. You won't be prompted if you created the local project using azd init.
Azure subscription	Subscription in which your resources are created.
Azure location	Azure region in which to create the resource group that contains the new Azure resources. Only regions that currently support the Flex Consumption plan are shown.

After publish completes successfully, azd provides you with the URL endpoints of your new functions, but without the function key values required to access the endpoints. To learn how to obtain these same endpoints along with the required function keys, see Invoke the function on Azure in the companion article Quickstart: Create and deploy functions to Azure Functions using the Azure Developer CLI.

Redeploy your code

You can run the azd up command as many times as you need to both provision your Azure resources and deploy code updates to your function app.

Note

Deployed code files are always overwritten by the latest deployment package.

Clean up resources

When you're done working with your function app and related resources, you can use this command to delete the function app and its related resources from Azure and avoid incurring any further costs:

azd down