Cloud Functions

Question 1

What is Cloud Functions?

Answer 1

Cloud Functions is a FaaS solution offered by GCP.

Question 1

For which type of applications should Cloud Functions be used for?

Answer 1

Lightweight, single-purpose, event-driven applications.

Question 2

What are the 2 main differences between Cloud Run 1st generation and 2nd generation?

Answer 2

1. First generation is not built on Cloud Run and Eventarc. Second Generation is built on Cloud Run and Eventarc.
2. First generation does not support concurrency. Second generation supports up to 1000 concurrent requests.

Question 3

What is the billing structure for Cloud Functions 2nd generation?

Answer 3

The same as Cloud Run

Question 4

What are the 2 different types of Cloud Functions and what are their execution guarantees?

Answer 4

1. HTTP Functions, they are invoked at most once. This is because in the case of an error, the caller of the HTTP function should decide to retry if needed.
2. Event-driven functions, they are invoked at least once. This is because event-driven functions are asynchronous.

Question 5

By default, when an event-driven function fails with an error, will the function be invoked again automatically?

Answer 5

No. An event-driven function will only be re-invoked if Retries on Failure is enabled. This can be enabled when creating a Cloud Functions instance. Keep in mind, retries will occur up to 7 days.

Question 6

Which HTTP methods does an HTTP Function support?

Answer 6

GET
POST
PUT
DELETE
OPTIONS

Question 7

What is CloudEvents and how is it associated with Cloud Functions?

Answer 7

CloudEvents is a specification for describing event data in a common way. This is what Event-driven Cloud Functions uses to handle events. Essentially, you import the CloudEvents package into your source code and use its classes and interfaces in your function code.

Question 8

When are event-driven function executions considered complete?

Answer 8

When the function returns.

Question 9

What is a background activity and what is Google’s stand on it when using Cloud Functions?

Answer 9

A background activity is anything that happens after your function has terminated. Google recommends not running any background activity code when using Cloud Functions. However, if you do, it is imperative that you make sure all asynchronous activity are finished before you terminate the function.

Question 10

When you write to local disk using Cloud Functions, where are you actually writing data?

Answer 10

To a temporary directory which consumes memory resources. This is important to remember because data that you write to this directory can sometimes persist between invocations potentially leading to an out-of-memory error. Make sure to delete temporary files if you write to them when using Cloud Functions.

Question 11

What are the 2 ways to develop and test Cloud Functions locally?

Answer 11

1. Functions Framework
2. Functions Emulator

Question 12

What are the 3 ways to deploy your code to Cloud Functions second generation?

Answer 12

1. From local source code
2. From Cloud Storage
3. From Cloud Console inline

Question 13

What happens to your source code when you deploy to Cloud Functions?

Answer 13

When you deploy to Cloud Functions, your source code is stored in a Cloud Storage Bucket. Then, Cloud Build automatically builds a container image and pushes that image to Artifact Registry. Cloud Functions then uses that image to create instances to run your code.

Question 14

Does Cloud Functions have the ability to integrate with Cloud Secret Manager like Cloud Run?

Answer 14

Yes.

Question 15

What is the default timeout for Cloud Functions invocations?

Answer 15

60 seconds

Question 16

Does Cloud Functions support split traffic?

Answer 16

Yes. It’s exactly the same as Cloud Run.

Question 17

Spring Cloud Function has out-of-the-box support for Cloud Functions.

Question 18

What is an event?

Answer 18

An event is something that happens at a specific point in time.

Question 19

What is a webhook?

Answer 19

A webhook is a push request from a server to a client specific endpoint. In other words, the client gives the server an endpoint to call whenever a specific event occurs, and the server pushes a request tot the client.

Question 20

Depending on the programming language used, a Cloud Functions Entry Point is either a …

Answer 20

Function or class

Question 21

What is the Functions Framework?

Answer 21

The Functions framework is an open source FaaS (function as a service) framework and library that lets you write lightweight functions that run in different environments that include Cloud Functions, your local development machine, and Cloud Run.

Question 22

Since Cloud Functions 2nd generation uses Cloud Run, is it possible to navigate to Cloud Run on Cloud Console and inspect your deployed revisions?

Answer 22

Yes

Question 23

Is it possible to bind a function to more than 1 trigger at a time?

Answer 23

No. However, the same event can trigger multiple functions that have the same trigger.

Question 24

Is it possible to use a YAML file to provide environment variables when deploying a Cloud Function?

Answer 24

Yes. However, this is only possible when deploying using gcloud.

Question 25

If you declare a variable in global scope, its value can be reused in subsequent invocations to a function instance without having to be recomputed resulting in significant performance improvements.

You can use this approach to cache objects like API client objects and network connections that may be expensive to recreate on each function invocation.

When accessing URLs from your functions, you should create persistent HTTP connections to those URLs. By creating persistent connections and caching them in your function’s global scope, you can reduce the CPU time spent to establish a new connection with each function invocation. You can also reduce the likelihood of exhausting your connection quota.