First I should mention that of course there are servers involved. I’m just using the term that popularly describes an approach and a set of technologies that abstracts job processing and scheduling from having to manage servers. In a post written for ReadWrite back in 2012 on the future of software and applications, I described “serverless” as the following.
The phrase “serverless” doesn’t mean servers are no longer involved. It simply means that developers no longer have to think that much about them. Computing resources get used as services without having to manage around physical capacities or limits. Service providers increasingly take on the responsibility of managing servers, data stores and other infrastructure resources…Going serverless lets developers shift their focus from the server level to the task level. Serverless solutions let developers focus on what their application or system needs to do by taking away the complexity of the backend infrastructure.
At the time of that post, the term “serverless” was not all that well received, as evidenced by the comments on Hacker News. With the introduction of a number of serverless platforms and a significant groundswell on the wisdom of using microservices and event-driven architectures, that backlash has fortunately subsided.
A Sample Use Case
Since it is useful to have an example in mind as I discuss issues and concerns in developing a serverless app, I will use the example of a serverless pipeline for processing email and detecting spam. It is event-driven in that when an email comes in, it will spawn a series of jobs or functions intended to operate specifically on that email.
In this pipeline, you may have tasks that perform parsing of text, images, links, mail attributes, and other items or embedded objects in the email. Each item or element might have different processing requirements which in turn would entail one or more separate tasks as well as even its own processing pipeline or sequence. An image link, for example, might be analyzed across several different processing vectors to determine the content and veracity of the image. Depending on the message scoring and results — spam or not — various courses of actions will then be taken, which would likely, in turn, involve other serverless functions.