HTTP triggered functions in GCP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an HTTP triggered function in cloud computing?

An HTTP triggered function is a small piece of code that runs in the cloud when it receives an HTTP request, like when you visit a website or call an API.

beginner

How does an HTTP triggered function receive input?

It receives input through the HTTP request's URL, headers, query parameters, or body sent by the client.

beginner

What happens after an HTTP triggered function finishes running?

It sends back an HTTP response to the caller, which can include data like text, JSON, or status codes.

beginner

Why are HTTP triggered functions useful for beginners?

Because they let you run code easily without managing servers, just by calling a web address, making it simple to build apps or APIs.

beginner

What is a common use case for HTTP triggered functions?

They are often used to create APIs, handle form submissions, or respond to webhooks from other services.

What triggers an HTTP triggered function in GCP?

A An incoming HTTP request

B A file upload to storage

C A scheduled timer

D A database update

HTTP triggered functions run when they receive an HTTP request from a client.

Which of these can be part of the input to an HTTP triggered function?

A CPU usage of the server

B Query parameters in the URL

C User's screen resolution

D Local file system data

Query parameters in the URL are sent as part of the HTTP request and can be used as input.

What does an HTTP triggered function return after execution?

A A cloud storage bucket

B A new virtual machine

C An HTTP response

D A database record

It returns an HTTP response to the caller, which can include data or status codes.

Which is NOT a typical use of HTTP triggered functions?

A Running background batch jobs without HTTP

B Handling API requests

C Responding to webhooks

D Processing form submissions

Background batch jobs usually use other triggers, not HTTP requests.

Why do HTTP triggered functions not require managing servers?

A Because they only run once a year

B Because they run on your local machine

C Because they use physical servers you manage

D Because they run on serverless platforms

They run on serverless platforms that handle servers automatically for you.

Explain how an HTTP triggered function works from receiving a request to sending a response.

Think about the journey of a web request to a cloud function and back.

List three common use cases for HTTP triggered functions and why they are suitable for those tasks.

Consider simple web tasks that need quick responses without managing servers.

Practice

1. What happens when an HTTP triggered function in GCP receives a web request?

easy

A. The function only logs the request but does not respond.

B. The function stores the request without running any code.

C. The function runs the code and sends back a response.

D. The function waits for a manual trigger to run.

Solution

1. Step 1: Understand the trigger type

   HTTP triggered functions run automatically when they receive a web request.

2. Step 2: Identify the function behavior

   They process the request and return a response to the caller.

3. Final Answer:

   The function runs the code and sends back a response. -> Option C

4. Quick Check:

   HTTP trigger = runs code + responds [OK]

Hint: HTTP trigger means code runs on web request [OK]

Common Mistakes:

• Thinking the function only logs requests
• Assuming manual trigger is needed
• Believing the function stores requests without running

2. Which of the following is the correct way to define an HTTP triggered function in Python for GCP Cloud Functions?

easy

A. def my_function(data, context):

B. def my_function(event, context):

C. def my_function():

D. def my_function(request):

Solution

1. Step 1: Recall function signature for HTTP triggers

   HTTP triggered functions accept a single 'request' parameter representing the web request.

2. Step 2: Match the correct signature

   Only 'def my_function(request):' matches this pattern.

3. Final Answer:

   def my_function(request): -> Option D

4. Quick Check:

   HTTP function signature = def func(request) [OK]

Hint: HTTP functions take one 'request' parameter [OK]

Common Mistakes:

• Using event and context parameters (for background triggers)
• Defining function without parameters
• Using wrong parameter names

3. Given this Python HTTP function code snippet, what will be the HTTP response body when a GET request is made?

def hello_world(request):
    if request.method == 'GET':
        return 'Hello, World!'
    else:
        return 'Unsupported method', 405

medium

A. "Hello, World!"

B. "Unsupported method"

C. Error: Missing return statement

D. Empty response

Solution

1. Step 1: Check the request method

   The function checks if the request method is 'GET'.

2. Step 2: Determine response for GET

   For 'GET', it returns the string 'Hello, World!'.

3. Final Answer:

   "Hello, World!" -> Option A

4. Quick Check:

   GET request returns greeting [OK]

Hint: GET request returns 'Hello, World!' string [OK]

Common Mistakes:

• Confusing method names case sensitivity
• Expecting a JSON response without formatting
• Ignoring else branch

4. Identify the error in this HTTP triggered function code snippet:

def process_request(request):
    if request.method == 'POST'
        return 'Received POST'
    else:
        return 'Only POST allowed', 405

medium

A. Missing colon ':' after if statement

B. Incorrect return type for HTTP function

C. Wrong parameter name for request

D. No error in the code

Solution

1. Step 1: Check syntax of if statement

   The if statement is missing a colon ':' at the end.

2. Step 2: Confirm syntax error impact

   Without the colon, the code will cause a syntax error and fail to deploy.

3. Final Answer:

   Missing colon ':' after if statement -> Option A

4. Quick Check:

   if statement needs ':' [OK]

Hint: Check colons after if statements [OK]

Common Mistakes:

• Ignoring syntax errors
• Assuming return types are wrong
• Confusing parameter names

5. You want to create an HTTP triggered function that accepts JSON data in a POST request and returns the value of the 'name' field. Which code snippet correctly handles this in Python?

hard

A. def get_name(request):
data = request.get_json()
return f"Hello, {data.name}!"

B. def get_name(request):
data = request.get_json()
return f"Hello, {data['name']}!"

C. def get_name(request):
data = request.get_json
return f"Hello, {data['name']}!"

D. def get_name(request):
data = request.json()
return f"Hello, {data.name}!"

Solution

1. Step 1: Use correct method to parse JSON

   request.get_json() is the correct method to parse JSON body in GCP HTTP functions.

2. Step 2: Access JSON data correctly

   JSON data is a dictionary, so access fields with data['name'], not data.name.

3. Final Answer:

   def get_name(request): data = request.get_json() return f"Hello, {data['name']}!" -> Option B

4. Quick Check:

   Use get_json() and dict access [OK]

Hint: Use get_json() and dict keys for JSON data [OK]

Common Mistakes:

• Using request.json() instead of get_json()
• Accessing JSON fields with dot notation
• Forgetting parentheses on get_json