Azure functions documentation examples

Azure Functions is a serverless computing platform that helps developers build small pieces of code, called functions, which are executed in response to various triggers such as HTTP requests, storage changes, or message queues. This guide provides a comprehensive look at several Azure Functions documentation examples, helping developers get started and integrate these functions into broader cloud solutions, including Azure DevOps and Azure admin training processes.

Understanding Azure Functions

Azure Functions allows developers to focus solely on writing code without worrying about the underlying infrastructure. By leveraging the Function as a Service (FaaS) model, Azure Functions automatically scales based on the number of requests and only charges for the resources consumed during execution. This makes it an ideal tool for building lightweight, event-driven applications.

Key Concepts in Azure Functions

Before diving into examples, it’s important to understand a few key concepts:

• Triggers: Every Azure Function is triggered by an event. Common triggers include HTTP requests, timer-based schedules, changes in Azure Storage, or new messages in a queue.


• Bindings: Bindings are a way to declaratively connect Azure Functions to external services, such as databases or queues, without writing boilerplate code.


• Execution Context: Each function has a context object that contains information about the function's execution, such as the trigger input, logs, and output bindings.

Example 1: Creating an HTTP-Triggered Azure Function

One of the most common examples in Azure Functions documentation is the HTTP-triggered function, which allows you to execute a function when an HTTP request is made. This example demonstrates how to create a simple HTTP-triggered function that returns a greeting.

Steps to Create an HTTP-Triggered Azure Function:

1. Create a Function App: First, create a Function App in the Azure portal. This is the hosting environment for your functions.
   
   
   
   • Navigate to Create a Resource.
   
   
   • Select Function App from the Compute section.
   
   
   • Provide the required details like subscription, resource group, function app name, and hosting plan.
   
   
   
   


2. Create a New Function: Once the Function App is created, follow these steps:
   
   
   
   • In the Functions section, select Create Function.
   
   
   • Choose HTTP trigger from the template options.
   
   
   • Name the function and select the desired authorization level (e.g., Anonymous, Function, or Admin).
   
   
   
   


3. Write the Function Code: Here is an example of a simple Azure Function using JavaScript:
   
   
   

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   module.exports = async function (context, req) { context.log('HTTP trigger function executed.'); const name = (req.query.name || (req.body && req.body.name)); const responseMessage = name ? `Hello, ${name}.` : 'Pass a name in the query string or request body for a personalized response.'; context.res = { status: 200, body: responseMessage }; };

   
   
   
   This function extracts a name from the query string or request body and returns a personalized greeting. If no name is provided, it asks the user to include one.


4. Test the Function: Once deployed, you can test the function by sending an HTTP GET request to the function URL (which can be found in the Function URL section of the Azure portal).

Example 2: Timer-Triggered Azure Function

Azure Functions can be scheduled to run at specific times using a timer trigger. This is particularly useful for automated tasks like nightly backups or regular data processing.

Steps to Create a Timer-Triggered Function:

1. Create the Timer-Triggered Function: After creating the Function App, follow these steps:
   
   
   
   • Select Create Function.
   
   
   • Choose Timer trigger from the template options.
   
   
   • Specify the schedule using a CRON expression. For example, to run the function every day at midnight, use 0 0 0 * * *.
   
   
   
   


2. Write the Function Code: Here’s an example of a timer-triggered function using C#:
   
   
   

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   public static void Run(TimerInfo myTimer, ILogger log) { log.LogInformation($"Timer function executed at: {DateTime.Now}"); }

   
   
   
   This function logs the current time whenever it is triggered.


3. Test the Function: You can verify the function's execution by checking the logs in the Azure portal. The logs will show a message each time the function is triggered.

Example 3: Queue-Triggered Azure Function

Azure Functions can also be triggered when new messages are added to an Azure Storage Queue. This is useful for processing data asynchronously.

Steps to Create a Queue-Triggered Function:

1. Set Up Azure Storage: First, create an Azure Storage account if you don’t already have one. Then, create a queue within the storage account.


2. Create the Queue-Triggered Function:
   
   
   
   • In the Function App, select Create Function.
   
   
   • Choose the Queue trigger template.
   
   
   • Provide the name of the queue you created in Azure Storage.
   
   
   
   


3. Write the Function Code: Here’s an example of a queue-triggered function in JavaScript:
   
   
   

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   module.exports = async function (context, myQueueItem) { context.log('Queue trigger function processed:', myQueueItem); };

   
   
   
   This function logs the content of each message processed from the queue.


4. Test the Function: Add a message to the Azure Queue using the Azure portal or Storage Explorer, and verify that the function is triggered by checking the logs.

Example 4: Integrating Azure Functions with Azure DevOps

One of the significant advantages of using Azure Functions is how well they integrate with Azure DevOps for CI/CD (Continuous Integration/Continuous Deployment) processes. By leveraging Azure Pipelines, you can automatically build, test, and deploy your Azure Functions when changes are made to your codebase.

Steps to Set Up Azure DevOps for Azure Functions:

1. Set Up a Git Repository: Store your function code in a Git repository hosted on Azure Repos or GitHub. This provides version control and a collaborative environment for multiple developers.


2. Create a CI/CD Pipeline in Azure DevOps:
   
   
   
   • In Azure DevOps, create a new pipeline and link it to your Git repository.
   
   
   • Use a YAML file to define the pipeline. Here’s an example:
   
   
   
   
   
   

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   trigger: - master pool: vmImage: 'ubuntu-latest' steps: - task: UseDotNet@2 inputs: packageType: 'sdk' version: '6.x' - script: dotnet build displayName: 'Build project' - task: AzureFunctionApp@1 inputs: azureSubscription: 'Your Azure Subscription' appType: 'functionApp' appName: 'Your Function App Name' package: '$(System.DefaultWorkingDirectory)/path-to-your-package.zip'

   
   


3. Deploy Changes Automatically: When changes are pushed to the repository’s master branch, the pipeline will automatically build and deploy the updated function to Azure. This ensures that new features, bug fixes, or enhancements are deployed without manual intervention.


4. Monitor Deployments: Azure DevOps provides detailed logs for each build and deployment. You can monitor the status of your pipeline and quickly identify any errors during the build or deployment phases.

Example 5: Using Azure Functions for Admin Automation

For individuals involved in Azure admin training, learning how to automate administrative tasks with Azure Functions is an essential skill. Admins can use functions to automate processes like resource clean-up, monitoring usage, or managing scaling based on demand.

Steps to Automate Resource Clean-up:

1. Create a Timer-Triggered Function:
   
   
   
   • Follow the same steps as the timer-triggered function example, but this time, you will be writing an administrative automation script.
   
   
   
   


2. Write the Function Code: Here’s a PowerShell script to clean up unused resources:
   
   
   

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   param($Timer) $resources = Get-AzResource | Where-Object { $_.Tags["Unused"] -eq "True" } foreach ($resource in $resources) { Remove-AzResource -ResourceId $resource.ResourceId -Force Write-Host "Deleted unused resource: $($resource.Name)" }

   
   
   
   This function scans all resources for a specific tag ("Unused") and deletes them automatically.


3. Test the Function: Run the function on a schedule (e.g., weekly) to ensure that it correctly identifies and deletes the unused resources.

Best Practices for Azure Functions

To ensure that your Azure Functions are efficient, scalable, and easy to manage, follow these best practices:

• Keep Functions Lightweight: Azure Functions are designed to handle lightweight tasks. Avoid long-running or resource-intensive processes in a single function.


• Optimize Cold Starts: Functions that are infrequently used may experience cold starts, which introduce latency. Use the Premium Plan for pre-warmed instances to reduce cold start times.


• Monitor and Log: Always enable logging and monitoring using Application Insights. This will help track performance, troubleshoot errors, and optimize your function execution.


• Secure Functions: Use proper authorization levels (Function or Admin) to secure access to your functions. For sensitive tasks, avoid the anonymous access level.

Conclusion

Azure Functions is a versatile, scalable, and efficient platform for building event-driven, serverless applications. Whether you're automating processes in Azure admin training, integrating with CI/CD pipelines through **Azure DevOps