Introduction
Azure Functions is a serverless compute service that enables you to run event-driven code without having to explicitly provision or manage infrastructure. It allows you to focus on building and deploying your applications without worrying about the underlying servers.
Key Concepts
- Serverless Architecture: No need to manage infrastructure; Azure handles the scaling and maintenance.
- Event-Driven: Functions are triggered by events such as HTTP requests, database changes, or messages in a queue.
- Pay-per-Use: You only pay for the time your code runs, making it cost-effective.
Setting Up Azure Functions
Prerequisites
- An active Azure account.
- Azure CLI installed on your local machine.
- Visual Studio Code with the Azure Functions extension (optional but recommended).
Steps to Create an Azure Function
-
Create a Function App:
az functionapp create --resource-group <ResourceGroupName> --consumption-plan-location <Location> --runtime <Runtime> --functions-version 3 --name <FunctionAppName> --storage-account <StorageAccountName> -
Create a Function:
func init <FunctionAppName> --worker-runtime <Runtime> cd <FunctionAppName> func new -
Deploy the Function:
func azure functionapp publish <FunctionAppName>
Example: HTTP Trigger Function
Code Example
# __init__.py
import logging
import azure.functions as func
def main(req: func.HttpRequest) -> func.HttpResponse:
logging.info('Python HTTP trigger function processed a request.')
name = req.params.get('name')
if not name:
try:
req_body = req.get_json()
except ValueError:
pass
else:
name = req_body.get('name')
if name:
return func.HttpResponse(f"Hello, {name}!")
else:
return func.HttpResponse(
"Please pass a name on the query string or in the request body",
status_code=400
)Explanation
- Logging: Logs the function execution for monitoring.
- Request Handling: Retrieves the
nameparameter from the query string or request body. - Response: Returns a greeting message if the
nameparameter is provided; otherwise, returns an error message.
Practical Exercise
Exercise: Create and Deploy an HTTP Trigger Function
-
Create a new Function App:
az functionapp create --resource-group MyResourceGroup --consumption-plan-location westeurope --runtime python --functions-version 3 --name MyFunctionApp --storage-account mystorageaccount -
Initialize a new Function:
func init MyFunctionApp --worker-runtime python cd MyFunctionApp func new --name HttpTrigger --template "HTTP trigger" --authlevel "anonymous" -
Replace the content of
__init__.pywith the example code above. -
Deploy the Function:
func azure functionapp publish MyFunctionApp -
Test the Function:
- Open a browser and navigate to
https://<FunctionAppName>.azurewebsites.net/api/HttpTrigger?name=YourName. - You should see the message: "Hello, YourName!".
- Open a browser and navigate to
Solution
The solution involves following the steps outlined in the exercise. Ensure that you replace placeholders like <FunctionAppName>, <ResourceGroupName>, and <StorageAccountName> with your actual values.
Common Mistakes and Tips
- Incorrect Runtime: Ensure you specify the correct runtime (e.g.,
python,node,dotnet) when creating the function app. - Missing Parameters: Always check for required parameters in the request to avoid errors.
- Deployment Issues: Verify that your Azure CLI is authenticated and has the necessary permissions to deploy resources.
Conclusion
In this section, you learned about Azure Functions, a powerful serverless compute service. You explored how to create, deploy, and test an HTTP trigger function. This knowledge will enable you to build scalable, event-driven applications without worrying about infrastructure management. In the next module, we will dive into Azure Logic Apps, another essential service for building automated workflows.