Data Management Patterns for Microservices Architecture


Data is the primary requirement of any software. Thus, efficient and effective data management can make or break a business. For starters, you have to ensure that data is available to the end user at the right time. Monolithic systems are notorious for their complex handling of data management. In contrast, microservices architecture paints a different picture. Here are some of data management patterns for this type of architecture.

Database Per Service

In this model, data is managed separately by each microservice. This means that one microservice cannot access or use the data of another one directly. In order to exchange data or communicate with each other, a number of well-designed APIs are required by the microservices.

However, the pattern is one of the trickiest to implement. Applications are not always properly demarcated. Microservices require a continuous exchange of data to apply the logic. As a result, spaghetti-like interactions develop with different application services.

The pattern’s success is reliant on carefully specifying the application’s bounded content. While this is easier in newer applications, large systems present a major problem at hand.

Among the challenges of the pattern, one is to implement queries that can result in the exposure of data for various bounded contexts. Other options include the implementation of business transactions that cover multiple microservices.

When this pattern is applied correctly, the notable benefit of it includes loose coupling for microservices. In this way, your application can be saved from the impact-analysis-hell. Moreover, it helps in the individual scaling up of microservices. It is flexible for software architects to select a certain DB solution while working with a specific service.

Shared Database

When the complexity of database per service is too high, then a shared database can be a good option. A shared database is used to resolve similar issues while using a more relaxed approached as a single database receives access by several microservices. Usually, this pattern is considered safe for developers because they can make use of existing techniques. Conversely, doing such always restricts them from using microservices at its best. Software architects from separate teams require cooperation to modify the schema of tables. It is possible that the runtime conflicts occur in case two or more services attempt using a single database resource.

API Composition

In a microservices architecture, while working with the implementation of complex queries, API composition can be one of the best solutions. It helps in the invocation of microservices for the needed arrangement. When results are fetched, a join (in-memory) is executed of the data after which the consumer receives it. The pattern’s drawback is its utilization of in-memory joins—particularly when they are unnecessary—for bigger datasets.

Command Query Responsibility Segregation

Command Query Responsibility Segregation (CQRS) becomes useful while dealing with the API composition’s issues.

In this pattern, the domain events of microservices are ‘listened’ by an application which then updates the query or view database accordingly. Such a database can allow you to handle those aggregation queries which are deemed complex. It is also possible to go with the performance optimization and go for the scaling up of the query microservices.

On the flipside, this pattern is known for adding more complexity. Suddenly it forces that all the events should be managed by the microservice. As a consequence, it is prone to get latency issues as the view DB exercises consistency in the end. The duplication of code increases in this pattern.

Event Sourcing

Event sourcing is used in order to update the DB and publish an event atomically. In this pattern, the entity’s state or the entity’s aggregate in the form of events—where states continue to change—are stored. Insert and update operations cause the generation of a new event. Events are stored in the event store.

This pattern can be used in tandem with the command query responsibility segregation. Such a combination can help you fix issues related to the maintenance of data and event handling. On the other hand, it has a shortcoming as well; the imposition of an unconventional programming style. Moreover, eventually, the data is consistent, not always the best factor for all the applications.

Saga

When business transactions extend over several microservices, then the saga pattern is one of the best data management patterns in a microservices architecture. A saga can be seen as simply local transactions—in a sequence or order. When Saga is used to perform a transaction, an event is published by its service. Consequently, other transactions follow after being invoked due to the prior transaction’s output. In case, failure arises for any of the chain’s transactions, a number of transactions (as compensation) are executed by the Saga to repair the previous transactions’ effect.

In order to see how Saga works, let’s consider an instance. Consider an app which is used for food delivery. If a customer requests for an order of food, then the following steps happen.

  1. The service of ‘orders’ generates an order. In this specific time period, a pending state marks the order. The events chain is managed by a saga.
  2. The service of ‘restaurant’ is contacted by the saga.
  3. The service of ‘restaurant’ begins the process to start the order for the selected eatery. When the eatery confirms, a response is generated and sent back.
  4. The response is received by the Saga. Considering the response contents, it can either proceed with the approval or rejection of the order.
  5. The service of ‘orders’ modifies the order state accordingly. In the scenario of the order approval, the customer receives the relevant details. In the scenario of order rejection, the customer receives the bad news in the form of an apology.

By now, you might have realized that such an approach is too distinct from the point-to-point strategy. While this pattern may add complexity, it is a highly formidable solution to respond to several tricky issues. Though, it is best to use it occasionally.

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Are Microservices the Right Fit For You?


The term Microservices was originally coined in 2011. Since then it has been on the radars of modern development organizations.  In the following years, software architecture has gained traction in various IT circles. According to a survey, the enterprises which used microservices were around 36 percent while 26 percent were thinking to include it in the future.

So, why exactly should you use microservices your company? There has to be something unique and more rewarding in it that can compel you to leave your traditional architecture in favor of it. Consider the following reasons to decide for yourself.

Enhance Resilience

Microservices can help to decouple and decentralize your complete application into multiple services. These services are distinct because they operate independently and are separate from each other. As opposed to the conventional monolithic architecture in which code failure can disrupt one function or service, there are little to no possibilities a single service failure to affect another. Moreover, even if you have to do maintain code for multiple systems, it will not be noted by your users.

More Scalability

In a monolithic architecture, when developers have to scale a single function, they have to tweak and adjust other functions as well. Perhaps, one of the biggest advantages of microservices is the scalability which it brings to the table. Since all the services in microservices architecture are separate, therefore it is possible to scale one service or function without having to worry about scaling up the complete application. You can deploy critical business services on different servers to improve the performance and availability of your application whereas your other services remain unaffected.

Right Tool for the Right Task

Microservices ensure that a single vendor does not make you pigeonholed. It can help you to infuse greater flexibility for your projects so rather than trying to make things work with a single tool, you can instead look up for the right tool which can fit your requirements. Each of your services can use any framework, programming language, technology stack, or ancillary services. Despite this heterogeneousness, they can still communicate and connect easily.

Promotion of Services

In microservices, there is no need to rewrite and adjust the complete codebase if you have to change or incorporate a new feature in your application. This is because microservices are ‘loosely coupled’. Therefore, you only have to modify a single service if it is required. The strategy to code your project in smaller increments can help you to test and deploy them independently. In this way, you can promote your services and application quickly, as soon as you complete one service after another.

Maintenance and Debugging

Microservices can help you to test and debug applications easily. The use of smaller modules via continuously testing and delivery means that you can create applications from bugs and errors, thereby improving the reliability and quality of your projects.

Better ROI

With microservices, your resource optimization is instantly improved. They allow different teams to operate by using independent services. As a result, the time needed to deploy is reduced. Moreover, the time for development is also significantly decreased while you can achieve greater reusability as well for your project. The decoupling of services also means that you do not have to spend much on high-priced machines. You can use the standard x86 machines as well. The efficiency which you get from microservices can minimize the costs of infrastructure along with the downtime.

Continuous Delivery

While working with a monolithic architecture, dedicated teams are needed to code discrete modules like front-end, back-end, database, and other parts of the application. On the other hand, microservices allow project managers to add cross-functional teams in the mix who can manage the application lifecycle through a delivery model which is entirely continuous in nature. When testing, operations, and development teams use a single service at the same time, debugging and testing is quickened and made easier. This strategy can help you to develop, test, and deploy your code ‘continuously’. Moreover, you do not have to write new code, instead, you can write code with the help of the existing libraries.

Considerations before Deciding to Use Microservices

If you have decided to use a microservices-based architecture, then review the following considerations.

The State of Your Business

To begin with, you have to think if your business is big enough that it warrants your IT team to work on complex projects independently. If you are not, then it is better to avoid microservices.

Assess the Deployment of Components

Analyze the components and functions of your software. If there are two or more components which you deploy in your project which are completely separate from each other in terms of business processes and capabilities, then it is a wise option to use microservices.

Decide if Your Team Is Skilled for the Project

The use of microservices allows project managers to use smaller teams for development that are well-skilled in their respective expertise. As a result, it helps to quickly generate new functionalities and release it.

Before you adopt the microservices architecture, you have to make sure that your team members are well positioned to operate with continuous integration and deployment. Similarly, you have to see if they can work in a DevOps culture and are experienced enough to work with microservices. In case, they are not good enough yet, you can focus on creating a group who is able to fulfill your requirements to work with microservices architecture. Alternatively, you can also hire experienced individuals to make up a new team.

Define Realistic Roadmap

Exponential scaling is the key to success. Despite the importance of businesses to be agile, it is not necessary for all businesses to scale. If you feel that complexity cannot help you much, then it is better to avoid a microservices architecture. You have to decide on some realistic goals about how your business is going to operate in the future to decide if the adoption of microservices architecture can reap your benefits.