What is Function as a Service (FaaS)?

Key takeaways:

• Function as a Service (FaaS) is a core component of serverless computing that allows developers to run code in response to events without managing infrastructure.

• FaaS operates on an event-driven basis, meaning it executes functions automatically in response to specific triggers, such as HTTP requests or database changes.

• FaaS offers significant benefits, including scalability, cost efficiency due to pay-per-use billing, and elimination of server management tasks.

• FaaS increases development efficiency and allows for faster deployment; it presents challenges such as server control loss, debugging complexities, and potential vendor lock-in.

What is FaaS?

Function as a service (FaaS) is a serverless way of executing modular pieces of code on the edge. FaaS enables developers to write and update a piece of code on the go, which can then be performed in response to an event, such as a user entering data in the text field in a web application. This makes it easy to scale code and is a cost-efficient way to implement microservices.

Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and FaaS are all cloud computing offerings. The difference lies in the level of abstraction they provide between the user and the infrastructure.

FaaS and serverless

FaaS helps developers work better by removing the need to maintain application infrastructure. When developers leverage FaaS, they use a FaaS platform to build, run, and oversee application packages.

At this point, you might think that FaaS sounds like serverless computing—and it is. Serverless computing allows developers to outsource managing databases, API gateways, storage, messaging, and other infrastructure to a third-party provider. FaaS is a type of serverless computing.

Here are the key difference between FaaS and serverless:

Key characteristics of FaaS

FaaS provides numerous benefits to its users, which include:

• Event-driven execution: FaaS is known for its event-driven execution nature. It follows microservices architecture, enabling the user to divide tasks into functions. A specific block of code (function) is executed on the occurrence of a particular event, making it event-driven. An example of this would be an HTTP request or changes in the data of a database. Each request/event serves as a trigger for the execution of a function.

• Stateless nature of functions: Functions in FaaS are designed to be stateless to ensure they can handle events independently. Each invocation is isolated and does not retain any information from previous invocations, promoting modularity and scalability.

• Automatic scalability: FaaS platforms automatically handle the scaling of function instances based on the incoming workload. When there are more events or requests, the platform automatically provisions additional instances of the function to handle the load, and when the load decreases, it scales down accordingly.

• Pay-per-use billing: FaaS platforms typically charge based on the number of invocations and the duration of each invocation. Since developers don’t need to manage servers or infrastructure, they only pay for the actual execution time of their functions.

• No server management: With FaaS, developers don’t have to worry about provisioning or managing servers. It provides the functionality to divide the server into functions and not worry about the infrastructure. They can focus solely on writing the code for individual functions.

Working of FaaS

To understand the workings of FaaS, there are two terms that you must know about:

• Monolithic architecture

• Microservices architecture

As the image explains, in monolithic architecture, the whole code or program is given as one, whereas in the case of microservices architecture, each service is divided into modules. A microservices architecture executes only a specified part when the event occurs.

Example of FaaS

To better explain the workings of FaaS, let’s take a daily life example.

Event: Smart home automation

Response scenario: Motion-activated lights

1. Event: You enter a room in your smart home equipped with motion sensors. The motion sensors detect your presence and trigger an event.

2. FaaS function trigger: The smart home system is integrated with a FaaS platform like AWS Lambda or Microsoft Azure Functions. The FaaS platform is configured to trigger a specific function whenever the sensors detect motion.

3. Function execution: The FaaS platform detects the motion event and automatically invokes the designated function responsible for controlling the room’s lighting.

4. Light control: The function receives the motion event as input and determines the appropriate action based on the current lighting status and time of day. If the room’s lights are off or set to a dim level, the function will turn on or brighten the lights. If the lights are already on and there is no motion for a certain period, the function might turn off the lights to conserve energy.

5. Statelessness: The function processes the motion event independently without relying on previous data. Each motion detection event is treated as a unique occurrence.

6. Automated response: As the function executes, the room’s lights respond in real-time to your presence. They adjust automatically based on the predefined rules set up by the smart home automation system.

7. Resource management: Once the function has completed its execution, the FaaS platform releases the allocated resources, making them available for other tasks.

Popular FaaS platforms

Some known platforms for FaaS include:

• AWS Lambda

• Azure Functions

• Google Cloud Functions

• IBM Cloud Functions

Benefits of FaaS

FaaS is very efficient, and you don’t need to worry about maintenance as the cloud service providers are available and responsible for taking necessary measures to keep it all updated. Its event-driven approach makes it cost-effective, as functions are not always executed. They are only executed when an event triggers them. Here is the list of benefits provided by FaaS:

• Deploy code faster.

• Provisioning takes milliseconds.

• Code in any language.

• Automated Disaster Recovery (DR)

• Cost-efficient

• Scalable

Disadvantages of FaaS

But, FaaS is not all about pros. There exist a few drawbacks that it holds. With FaaS, you don’t have complete control over the server. Moreover, debugging is tricky as you let the third party interfere and manage the infrastructure. Also, revamping a code block in the FaaS development environment is challenging. It is more suitable for writing a new block of code than changing the existing one. Here is list of disadvantages provided by FaaS:

• Loose control over the server.

• Debugging is harder.

• Testing takes longer.

• You are locked into your vendor.

• You must write FaaS-suitable code.

Conclusion

Function as a Service (FaaS) enables running code responding to specific events without managing infrastructure. Stateless functions execute independently, triggered by events like HTTP requests or database updates. FaaS offers real-time responsiveness, scalability, and cost-effectiveness. Examples include image processing, email notifications, and smart home automation. FaaS revolutionizes cloud computing and application development.