Serverless Web Application and Eventing

What is Serverless?

Serverless is an application architecture where the cloud provider provides a service where the developer only has to focus on building features. The features run inside a container that is triggered by a specific event, such as a user request to access a certain API endpoint or database query. The developer doesn’t have to worry about the underlying infrastructure to run the application because the cloud provider takes care of that. One of the major benefits of serverless is that there is no need to provision capacity ahead of time as with a traditional application deployment model. The cloud provider dynamically scales up and down based on demand. Therefore, serverless is ideally suited for web apps with a high rate of change, such as heavily user-facing apps.

Cloud Eventing and Why It’s Important

A key feature of serverless functions is that they trigger based on events. These events are emitted by other services or triggered by a database query. Many cloud-based event sources are available as APIs. For example, you can create a database table that triggers an event when a new row is added to the table. The table can emit an event of type “row inserted” or “row deleted” and include the new row data. That event can be used in a serverless function to update a user profile, add a new row to a table, or trigger an email to be sent to an advertiser.

Serverless Web Apps and Cloud Events

Serverless web applications are event-driven applications. A developer identifies a specific event that triggers a function that performs a specific task. For example, the developer can create a function that is triggered when a new user signs up and the function stores the user data in a database. The developer can also create a function triggered when a user requests their profile. The user-profile function can retrieve the user data from the database and return it to the user. When a user signs up, the user-signup function is triggered and creates a new row in the database with the user data. The user-profile function uses the database events to retrieve the user data and return it to the user. Multiple database tables can trigger multiple events. In fact, there can be events triggered by other services: a serverless web application is an event-driven application.

Serverless Web Application Uses

● Database event triggers serverless function - A user signs up for an application and a new row is added to the database where the user data is stored.
● Cloud event triggers serverless function - A user sends a request for user data and the database triggers an event that is used to populate a table with the user data.
● Serverless function triggers another function - A user-signup function triggers another function that creates a new user profile.
● Serverless function triggers an API call - A user-profile function retrieves the user data from the database and returns it to the user.

Serverless Web Architecture

The serverless architecture is a distributed application that is comprised of multiple microservices, each of which runs in its own container on a distributed infrastructure. A single service may communicate with other services within the same architecture or with services hosted by other architectures. The diagram below shows an example of a distributed application that is comprised of multiple services, each of which runs in its own container. This architecture is referred to as a serverless architecture because it does not rely on a dedicated server. Over the past decade, many architectural trends have emerged and vanished. One that continues to grow in popularity is event-driven or serverless architecture. Using event-driven architectures has many benefits, including reduced latency and breaking up applications into smaller, more discrete pieces that can be deployed independently.