The Path From APIs to Containers: How Microservices Fueled the Journey

This is an article from DZone's 2023 Software Integration Trend Report.

For more:

Read the Report

In recent years, the rise of microservices has drastically changed the way we build and deploy software. The most important aspect of this shift has been the move from traditional API architectures driven by monolithic applications to containerized microservices. This shift not only improved the scalability and flexibility of our systems, but it has also given rise to new ways of software development and deployment approaches. 

In this article, we will explore the path from APIs to containers and examine how microservices have paved the way for enhanced API development and software integration.

The Two API Perspectives: Consumer and Provider

The inherent purpose of building an API is to exchange information. Therefore, APIs require two parties: consumers and providers of the information. However, both have completely different views. 

For an API consumer, an API is nothing more than an interface definition and a URL. It does not matter to the consumer whether the URL is pointing to a mainframe system or a tiny IoT device hosted on the edge. Their main concern is ease of use, reliability, and security. 

An API provider, on the other hand, is more focused on the scalability, maintainability, and monetization aspects of an API. They also need to be acutely aware of the infrastructure behind the API interface. This is the place where APIs actually live, and it can have a lot of impact on their overall behavior. For example, an API serving millions of consumers would have drastically different infrastructure requirements when compared to a single-consumer API. The success of an API offering often depends on how well it performs in a production-like environment with real users. 

With the explosion of the internet and the rise of always-online applications like Netflix, Amazon, Uber, and so on, API providers had to find ways to meet the increasing demand. They could not rely on large monolithic systems that were difficult to change and scale up as and when needed. This increased focus on scalability and maintainability, which led to the rise of microservices architecture. 

The Rise of Microservices Architecture

Microservices are not a completely new concept. They have been around for many years under various names, but the official term was actually coined by a group of software architects at a workshop near Venice in 2011/2012. The goal of microservices has always been to make a system flexible and maintainable. This is an extremely desirable target for API providers and led to the widespread adoption of microservices architecture styles across a wide variety of applications. 

The adoption of microservices to build and deliver APIs addressed several challenges by providing important advantages: 

• Since microservices are developed and deployed independently, they allow developers to work on different parts of the API in parallel. This reduces the time to market for new features.
• Microservices can be scaled up or down to meet the varying demands of specific API offerings. This helps to improve resource use and cost savings.
• There is a much better distribution of API ownership as different teams can focus on different sets of microservices. 
• By breaking down an API into smaller and more manageable services, it becomes theoretically easier to manage outages and downtimes. This is because one service going down does not mean the entire application goes down. 

The API consumers also benefit due to the microservices-based APIs. In general, consumer applications can model better interactions by integrating a bunch of smaller services rather than interfacing with a giant monolith. 

Figure 1: APIs perspectives for consumer and provider

Since each microservice has a smaller scope when compared to a monolith, there is less impact on the client application in case of changes to the API endpoints. Moreover, testing for individual interactions becomes much easier. 

Ultimately, the rise of microservices enhanced the API-development landscape. Building an API was no longer a complicated affair. In fact, APIs became the de facto method of communication between different systems. Nonetheless, despite the huge number of benefits provided by microservices-based APIs, they also brought some initial challenges in terms of deployments and managing dependencies. 

Streamlining Microservices Deployment With Containers

The twin challenges of deployment and managing dependencies in a microservices architecture led to the rise in container technologies. Over the years, containers have become increasingly popular, particularly in the context of microservices. With containers, we can easily package the software with its dependencies and configuration parameters in a container image and deploy it on a platform. This makes it trivial to manage and isolate dependencies in a microservices-based application. 

Containers can be deployed in parallel, and each deployment is predictable since everything that is needed by an application is present within the container image. Also, containers make it easier to scale and load balance resources, further boosting the scalability of microservices and APIs. Figure 2 showcases the evolution from monolithic to containerized microservices: 

Figure 2: Evolution of APIs from monolithic to containerized microservices 

Due to the rapid advancement in cloud computing, container technologies and orchestration frameworks are now natively available on almost all cloud platforms. In a way, the growing need for microservices and APIs boosted the use of containers to deploy them in a scalable manner. 

The Future of Microservices and APIs

Although APIs and microservices have been around for numerous years, they have yet to reach their full potential. Both are going to evolve together in this decade, leading to some significant trends. One of the major trends is around API governance. Proper API governance is essential to make your APIs discoverable, reusable, secure, and consistent. In this regard, OpenAPI, a language-agnostic interface to RESTful APIs, has more or less become the prominent and standard way of documenting APIs. It can be used by both humans and machines to discover and understand an API's capabilities without access to the source code. 

Another important trend is the growth in API-powered capabilities in the fields of NLP, image recognition, sentiment analysis, predictive analysis, chatbot APIs, and so on. With the increased sophistication of models, this trend is only going to grow stronger, and we will see many more applications of APIs in the coming years. The rise of tools like ChatGPT and Google Bard shows that we are only at the beginning of this journey. 

A third trend is the increased use of API-driven DevOps for deploying microservices. With the rise of cloud computing and DevOps, managing infrastructure is an extremely important topic in most organizations. API-driven DevOps is a key enabler for Infrastructure as Code tools to provision infrastructure and deploy microservices. Under the covers, these tools rely on APIs exposed by the platforms.

Apart from major ones, there are also other important trends when it comes to the future of microservices and APIs: 

• There is a growing role of API enablement on the edge networks to power millions of IoT devices.
• API security practices have become more important than ever in a world of unprecedented integrations and security threats.
• API ecosystems are expanding as more companies develop a suite of APIs that can be used in a variety of situations to build applications. Think of API suites like Google Maps API.
• There is an increased use of API gateways and service meshes to improve reliability, observability, and security of microservices-based systems.

Conclusion

The transition from traditional APIs delivered via monolithic applications to microservices running on containers has opened up a world of possibilities for organizations. The change has enabled developers to build and deploy software faster and more reliably without compromising on the scalability aspects. They have made it possible to build extremely complex applications and operate them at an unprecedented scale. 

Developers and architects working in this space should first focus on the key API trends such as governance and security. However, as these things become more reliable, they should explore cutting-edge areas such as API usage in the field of artificial intelligence and DevOps. This will keep them abreast with the latest innovations. Despite the maturity of the API and microservices ecosystem, there is a lot of growth potential in this area. With more advanced capabilities coming up every day and DevOps practices making it easier to manage the underlying infrastructure, the future of APIs and microservices looks bright. 

References:

• "A Brief History of Microservices" by Keith D. Foote
• "The Future of APIs: 7 Trends You Need to Know" by Linus Håkansson
• "Why Amazon, Netflix, and Uber Prefer Microservices over Monoliths" by Nigel Pereira 
• "Google Announces ChatGPT Rival Bard, With Wider Availability in 'Coming Weeks'" by James Vincent 
• "Best Practices in API Governance" by Janet Wagner
•  "APIs Impact on DevOps: Exploring APIs Continuous Evolution," xMatters Blog

This is an article from DZone's 2023 Software Integration Trend Report.

For more:

Read the Report