{"id":5043,"date":"2021-08-23T07:44:26","date_gmt":"2021-08-23T07:44:26","guid":{"rendered":"https:\/\/blog.verbat.com\/?p=2752"},"modified":"2024-05-27T10:19:30","modified_gmt":"2024-05-27T10:19:30","slug":"understanding-asynchronous-messaging-for-microservices","status":"publish","type":"post","link":"https:\/\/www.verbat.com\/blog\/understanding-asynchronous-messaging-for-microservices\/","title":{"rendered":"Understanding Asynchronous Messaging For Microservices"},"content":{"rendered":"\n

One of the possible consequences of adopting the microservice architecture is that the communication between components takes place over the network. For all that, the microservice environment is a distributed system. To fulfill the promises of microservices, like being able to scale, operate, and evolve each service, the communication must transpire in a loosely coupled and reliable manner.<\/p>\n\n\n\n\n\n\n\n

A general way to loosely couple services is to\nunmask an API using the REST architecture. REST APIs are founded on the\narchitecture of the web and enable loose coupling between communicating\nparties. It is an excellent way to decouple interfaces from concrete\nimplementations, and to inform clients about the next line of action, by using\nlinks and link relations.<\/p>\n\n\n\n

Also Read: <\/strong>Everything You Want Know About Microservice Architecture <\/strong><\/a><\/p>\n\n\n\n

Although REST APIs are more common and helpful in microservice design, REST APIs are generally designed with synchronous communications, where a response is needed. A request from an end-user client can spark off a complex communication channel within your service landscape, which can successfully incur coupling between the services at runtime. And for this reason, we have mitigation patterns like a circuit breakers.<\/p>\n\n\n\n

Asynchronous Messaging<\/strong><\/p>\n\n\n\n

If losing-coupling is crucial, especially in a\nsystem that needs high resilience and has variability in terms of scale, an\nalternative is asynchronous messaging.<\/p>\n\n\n\n

Asynchronous messaging is a key approach for\nintegrating autonomous systems or assembling a set of loosely coupled systems\nthat can operate, scale and evolve with autonomy and flexibility.<\/p>\n\n\n\n

Single-Receiver Message-Based\nCommunication<\/strong><\/p>\n\n\n\n

Message-based asynchronous communication with a\nsingle receiver implies an end-to-end communication that renders a message to\nexactly one of the users that\u2019s reading from the channel, and the message\nprocessing is done just once.<\/p>\n\n\n\n

Also Read: X-Cart vs Magento: Selecting the Best E-Commerce Platform for Your Business <\/strong><\/a><\/p>\n\n\n\n

Still, there are special cases. For example, in a\ncloud system that attempts to automatically recover from failures, the same\nmessage could resend multiple times. Owing to network or other failures, the\nclient has to be able to repeatedly send messages, and the server has to\nimplement an action to be unchanged to process a specific message just\nonce. <\/p>\n\n\n\n

Single-receiver message-based communication is perfectly suited for sending asynchronous commands from one microservice to another. But one limitation is that when you begin sending message-based communication (either with commands or events), you should steer clear of combining message-based communication with synchronous HTTP communication.<\/p>\n\n\n

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Picture Courtesy: Microsoft<\/strong><\/figcaption><\/figure>\n<\/div>\n\n\n

Multiple- Receiver\nMessage-Based Communication         <\/strong><\/p>\n\n\n\n

As a more flexible strategy, you might also try\nto resort to a publish\/subscribe mechanism so that messages from the sender\nwill be accessible to another subscriber microservice or external applications.<\/p>\n\n\n\n

Thus, it favors an open\/ closed principle in the sending service. While using a publish\/subscribe communication, you might want to use an event bus interface to publish events to any subscriber.    <\/p>\n\n\n\n

Advantages of Asynchronous\nMessaging<\/strong><\/p>\n\n\n\n

Let us examine a few advantages of asynchronous\ncommunication:<\/p>\n\n\n\n