WHAT Observability is a concept that refers to the ability to gain insights into the behavior and performance of complex systems. In the context of software engineering, observability involves the collection, analysis, and visualization of data from software applications, infrastructure, and other components of a system. In the animal kingdom, observability plays a critical role in survival, allowing animals to monitor their surroundings, detect threats, and find food. Dolphins use echolocation to observe their surroundings. They emit high-frequency sounds that bounce off objects, allowing them to create a 3D map of their environment. Thanks for reading Knowledge Cafe! Subscribe for free to receive new posts and support my work. Subscribed WHY In today's era, architectures are becoming increasingly large, complex, and fast-paced due to the faster development and deployment of software by distributed teams with the help of DevOps, continuous delivery, and agile development methodo...
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Building Scalable and Resilient Systems
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What is Event Driven Architecture (EDA)
In an event-driven architecture, events are the primary unit of communication between different components of a system. Event producers generate events, which are then sent to an event router or message broker. The event router filters and routes the events to the appropriate event consumers, which take appropriate action based on the events they receive.
This decoupling of event producers and consumers allows for a loosely coupled and asynchronous communication between different parts of the system, making it more scalable, flexible, and resilient. The event-driven architecture is well-suited for real-time systems such as IoT, online gaming, financial trading, and real-time analytics.
Ways to Implement EDA
Event-driven architecture (EDA) can be implemented in a variety of ways, depending on the specific requirements of the system. Here are a few common ways to implement EDA:
Using a message broker: A message broker, such as Apache Kafka or RabbitMQ, can be used to implement an event-driven architecture. Producers can publish events to topics or queues, and consumers can subscribe to one or more topics or queues to receive the events. The message broker provides the messaging infrastructure that allows for the production and consumption of events, and the storage of events for later processing.
Using an event hub: An event hub is a centralized message bus that allows different components of the system to communicate with each other using events. Producers can publish events to the event hub, and consumers can subscribe to events from the event hub.
Using an event store: An event store is a database that is optimized for storing and querying events. Producers can store events in the event store, and consumers can query the event store for events.
Using serverless computing: Serverless computing allows for the creation of event-driven systems without the need for provisioning and managing servers. Producers can send events to a serverless function, which then triggers another serverless function to process the event. Google’s cloud function, Azure function and AWS Lamda is few of the example of serverless options
It’s worth noting that the choice of the implementation method depends on the specific requirements of the project. It’s possible to use a combination of different methods to get the best of both worlds.
One of the most popular ways to implement event-driven architecture (EDA) is by using a message broker. A message broker, such as Apache Kafka or RabbitMQ, can be used to implement an event-driven architecture.
Apache Kafka Vs Rabbit MQ
Apache Kafka and RabbitMQ are both messaging systems, but they have some key differences in terms of their design, architecture, and use cases.
Kafka vs Rabbit MQ
Conclusion
Event-Driven Architecture (EDA) is a design pattern that allows for the decoupling of components in a system by using events as the primary means of communication. It uses the concepts of producers, consumers, events, and streams to model interactions. The events represent changes in the state of the system and are published and consumed asynchronously by components who do not need to be aware of each other’s existence. This allows for the components to operate and evolve independently. While EDA is not a solution for all systems, it can bring significant benefits when implemented correctly. EDA is often considered an essential element of a successful microservices deployment.
There is a way in Spring 3.1 to auto populate a typed List which is very handy when you want to push a bit the decoupling and the cleaning in your code. To show you how it works, I will implement a simple chain of responsibility that will take care of printing some greetings for a passed User. Let start from the (only) domain class we have, the User: package in.softcaretech.springchain; public class User { private final String name; private final char gender; public User(String name, char gender) { super(); this.name = name; this.gender = gender; } public String getName() { return name; } public char getGender() { return gender; } } Then we create an interface that defines the type for our command objects to be used in our chain: package in.softcaretech.springchain; public interface Printer { void print(User user); } This is the generic class (the template) for a Printer implementation. The org.springframework.core.Ordered is used to tell the AnnotationAwareOrderCo...
The HashMap is one of the most useful data structures in the Java programming language. Once you have a HashMap filled with data, you may want to iterate through its keys and values. Below are three different ways to iterate through a Java HashMap. Sample HashMap Here is our sample HashMap. The key is an Integer and the value is a String: HashMap <Integer, String> hm = new HashMap<Integer, String>(); hm.put(0, "zero"); hm.put(1, "one"); hm.put(2, "two"); In the above Java code, we first declare the HashMap. Then we add the values "zero", "one" and "two" with the keys 0, 1 and 2 respectively. Now that the HashMap has data, we can try to iterate over the keys and values. Iteration Example 1 for (int i=0; i < hm.size(); i++) { Integer key = hm.keySet().toArray()[i]; String val = hm.values().toArray()[i]; System.out.println("key,val: " + key + "," + val); } In this example, we use a for loop ...
Gossip Protocol Apache Cassandra is a highly scalable and distributed NoSQL database management system designed to handle large amounts of data across many commodity servers. It was developed at Facebook and later became an Apache Software Foundation project. Cassandra offers a number of key features, including: Linear scalability, high availability, Predictive data consistency, flexible data modeling and high performance. What is Gossip Protocol The Gossip protocol is a key component of the Apache Cassandra distributed database system. It is used for node communication and failure detection within the cluster. The following is how it works: Each node in the Cassandra cluster maintains a list of all other nodes in the cluster and information about their status. The Gossip protocol operates in rounds, where each node sends its state information to a randomly selected set of other nodes. The receiving nodes update their state information based on the information received from their...
