Introduction
Azure Functions is a serverless compute service that enables you to run event-triggered code without having to explicitly provision or manage infrastructure. This tutorial will guide you through creating a simple Python app that demonstrates CRUD (Create, Read, Update, Delete) functionality using Azure Functions. Additionally, we will cover local testing using Azure Functions Core Tools.
Step-by-Step Guide
First, ensure that you have Azure Functions Core Tools installed on your machine. You can install it by following the instructions (for your OS) here: https://learn.microsoft.com/en-us/azure/azure-functions/functions-run-local?tabs=linux%2Cisolated-process%2Cnode-v4%2Cpython-v2%2Chttp-trigger%2Ccontainer-apps&pivots=programming-language-python
For Linux distros:
sudo apt-get update
sudo apt-get install azure-functions-core-tools-4
Step 2: Initialize Your Azure Functions Project
Create a new directory for your project and navigate into it:
mkdir azure-demo
cd azure-demo
Initialize a new Azure Functions project:
func init azure-functions-crud --worker-runtime python --model V2
Step 3: Create HTTP Trigger Functions
Inside your project directory, create new HTTP trigger functions for each CRUD operation. You can create functions using the following command:
func new --template "Http Trigger" --name MyHttpTrigger
Step 4: Implement CRUD Operations
Replace the content of the generated function_app.py file with the following code to implement the CRUD operations:
import azure.functions as func
import logging
import json
app = func.FunctionApp(http_auth_level=func.AuthLevel.ANONYMOUS)
tasks = []
@app.route(route="add-task", methods=["POST"])
def add_task(req: func.HttpRequest) -> func.HttpResponse:
logging.info('Python HTTP trigger function processed a request to add a new task.')
try:
req_body = req.get_json()
task_id = len(tasks) + 1
task = {
'id': task_id,
'title': req_body.get('title')
}
tasks.append(task)
return func.HttpResponse(json.dumps(task), status_code=201, mimetype="application/json")
except ValueError:
return func.HttpResponse("Invalid input", status_code=400)
@app.route(route="get-task", methods=["GET"])
def get_task(req: func.HttpRequest) -> func.HttpResponse:
logging.info('Python HTTP trigger function processed a request to get task by id.')
try:
task_id = int(req.params["id"]) - 1
return func.HttpResponse(json.dumps(tasks[task_id]), status_code=200, mimetype="application/json")
except ValueError:
return func.HttpResponse("Invalid input", status_code=400)
@app.route(route="update-task", methods=["PUT"])
def update_task(req: func.HttpRequest) -> func.HttpResponse:
logging.info('Python HTTP trigger function processed a request to update task by id.')
try:
task_id = int(req.params["id"]) - 1
req_body = req.get_json()
tasks[task_id]['title'] = req_body.get('title')
return func.HttpResponse(json.dumps({"message": "Updated", "task": tasks[task_id]}), status_code=200, mimetype="application/json")
except ValueError:
return func.HttpResponse("Invalid input", status_code=400)
@app.route(route="delete-task", methods=["DELETE"])
def delete_tasks(req: func.HttpRequest) -> func.HttpResponse:
logging.info('Python HTTP trigger function processed a request to delete task by id.')
try:
task_id = int(req.params["id"]) - 1
tasks.pop(task_id)
return func.HttpResponse("Deleted", status_code=200, mimetype="application/json")
except ValueError:
return func.HttpResponse("Invalid input", status_code=400)
@app.route(route="get-all-tasks", methods=["GET"])
def get_all_tasks(req: func.HttpRequest) -> func.HttpResponse:
logging.info('Python HTTP trigger function processed a request to get all tasks.')
return func.HttpResponse(json.dumps(tasks), status_code=200, mimetype="application/json")
Step 5: Test Your Azure Functions Locally and Deploy to Azure
You can test your Azure Functions locally by starting the Azure Functions host. Run the following command in your project directory:
func start
This will start the local Azure Functions runtime, and you will see URLs for each of your functions. You can use tools like curl or Postman to test the HTTP endpoints.
Example Requests
Add Task
curl -X POST http://localhost:7071/api/add-task -H "Content-Type: application/json" -d '{"title": "New Task"}'
Get Task by ID
curl http://localhost:7071/api/get-task?id=1
Update Task
curl -X PUT http://localhost:7071/api/update-task?id=1 -H "Content-Type: application/json" -d '{"title": "Updated Task"}'
Delete Task
curl -X DELETE http://localhost:7071/api/delete-task?id=1
Get All Tasks
curl http://localhost:7071/api/get-all-tasks
You can publish the azure functions by running the following command:
func azure functionapp publish <FunctionAppName>
Conclusion
In this tutorial, we have created a simple Python application that demonstrates CRUD functionality using Azure Functions. We also covered how to test these functions locally using Azure Functions Core Tools. With this setup, you can easily extend the functionality and deploy it to Azure for a scalable, serverless application.
Microsoft documentation on developing Azure functions: https://learn.microsoft.com/en-us/azure/azure-functions/functions-run-local?tabs=linux%2Cisolated-process%2Cnode-v4%2Cpython-v2%2Chttp-trigger%2Ccontainer-apps&pivots=programming-language-python
