The central focus of attention of Event-driven architecture (EDA) is events. Events can arise from different locations, such as knowledge base or answering service. They inform us of any occasions, illustrate changes and show the user’s activity within the application.
The appearance of the events is usually a simple tap, text input, typewritten facts, voice instructions (messages), and any other actions within the software that show the change of state and demand a reaction from the system. If you are looking for professional development consultation about your project, ask for advice on this domain.
1. Event-driven architecture in comparison with a request-driven architecture
The first distinctive feature of the event-driven architecture is being asynchronous. That helps make applications with little effort. API- architectures, on the contrary, are synchronous. When you request one service in such architectures, you always have to wait for a response of more than one following service. That makes the process last long. In an event-driven architecture, this is different: the process is more straightforward and faster for the client (EDA does not demand any long-waited response from distant services, and the application reacts to the event as far as it occurs).
2. Profitable qualities of EDA
1) Autonomy
One of the most beneficial qualities of EDA is autonomy. Indifference from the request-driven architecture, every constituent preserves all the necessary information. This quality makes interconnected microservices of the event-driven architecture work independently.
- Side benefits:
It turns out microservices in EDA have the competence to respond to the events autonomously. Individual services are in charge of their specific occasion.
Imagine that we have an event router that distributes events to their services, defining them by the role they perform. Several events like orders and questions handled simultaneously, and each of them directed to its specific system. Then the app responds to it.
It seems that EDA and request-driven architecture are parallels to each other, but one is efficient the other is vice versa. One architecture is framed by services bounds, while the other uses services independently. So that’s the point.
- How is it useful for a customer?
The independence and asynchronous nature of event-driven architecture increase the process’ speed. Event-driven architecture works faster than request-driven architecture because the events within a software don’t have to wait for the reaction of more responsible and competent services for a long time. Fast response, in its turn, guarantees immediate remedial action. Especially if we talk about the problem of fraud.
2) Flexibility (produce and consume nature)
The flexibility of event-driven architectures is evident in the work of its structural components. Event-driven architecture’s structural constituents are publishers (participate in handling and storing necessary data); subscribers (participate in absorbing and reacting to the happening event); data origins (where the information is derived from) and destination spots (the sense is apparent in this case). Generally, EDA constituents’ role is not only to respond to events but also to publish them and update information in microservices after the change of state (events that happened).
- Side benefits
Events happened⇒ in reaction to changes in state⇒ updated database in all microservices
The information in microservices of event-driven architecture is constantly being updated. As a result, if service fails to respond to an event, this solution can be fixed with no harm to the productiveness of the whole process. According to the fact that every service has access to the necessary info, other services perform their function while the broken service is being repaired. Moreover, EDA can increase the number of benefits in time of need (when demanded).
- How is it useful for a customer?
With such qualities, event-driven architecture adapts to Cloud computing. EDA can save its broadband and microservices can be scaled if necessary (small code units joined in an eCommerce system that deals with inventory).
3) Recovery and analyzing
One more specific pattern of event-driven architecture is the ability to analyze an expanded database, including previous taken acts and events. Due to all services involved, the application becomes transparent and enables us to track the changes in state and data tracings. This advantage helps to analyze consumed information during the process.
- Side benefits
Tracking operations with events and handling data gives access to the previously stored data. We can always get back to some previous events and recover the data of that period lossless.
For example, when we put the mosaic together, we can see the shape of the unpracticed pieces and the pieces in the puzzle. Their topography is always visible. Embossed seams pieces do not disappear anywhere, even when the puzzle pieces turn into a picture, and it helps us to remove them at any moment or put another piece between them.
- How is it useful for a customer?
Tracking events helps decision-makers view the information about consumer actions within the system needed to target. This information, in its turn, is applied to the IoT tools. It is also helpful for manipulations. In a business approach it helps to direct consumers at the right time to sell something.
3. Disadvantages
Even such a developed contemporary architecture has different sides of the same coin.
1) As we already know, microservices within the software are asynchronous and automatic, independent of each other. This feature increases the flexibility of the system. This is a beneficial side.
The negative side is the impossibility of predicting events that occur in different periods.
Thus, it takes extra time to check if the responses to the events are correct in each direction of the services. There is a compulsory process of deep system analysis that helps to avoid the risk of data loss.
2) It is also difficult to predict any results when the incoming data sources are not defined. Information comes from everywhere and the unframed nature of EDA makes the recording of info more complicated.
3) In event-driven architecture events the order is relative. It only depends on the context and there’s no way to predict the result. Moreover, any preconditions to the problem are out of sight.
4) Many services= many events. There is an enormous range of directions. One cannot trace all the changes of state that happen within a system. Not so easy. Moreover, the flexibility of the application suffers. It takes too much time to find a malicious occasion in a long list of events.
4. Summary
In the popular board game Jenga, we can see that by building a tower up and using the same bars, we leave space behind and make the tower vulnerable. In the same way, we have an event-oriented leap up to meet new trends and requirements but still need to refine and fill these vulnerabilities. Event-driven architecture has made a gigantic leap up to modern trends. This architecture is flexible, asynchronous, self-reliant, and constantly updated, but still needs further elaboration.
