Entity service is an anti pattern

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In the microservices architecture , The most important thing is to keep the isolation between services . Physical services （Entity Service） It is a model widely used in micro service architecture , But in fact, it is a kind of Anti pattern , Because it deviates from the principle of service isolation .Michael Nygard He mentioned this in his micro service series blog .

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Nygard yes “Release It!” The author of , He said that physical services are used to solve a very common problem , In a Microsoft book about E-book of microservice architecture neutralization Spring Of the two course This mode is used in .

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stay Nygard It seems , Antipatterns only make things worse . To illustrate that entity services are an anti pattern , He uses a large legacy monomer as an example . There are multiple instances of this application , Each instance contains all the features ：

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according to Spring A tutorial for , Refactoring this application using a microservice architecture , Decompose features into separate services . but Nygard say , Most features still require multiple entities , This will create dependencies between multiple entities . such as , Calculating the price of the shopping cart requires the involvement of all services ：

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Nygard Think , These dependencies cause coupling , This affects usability 、 Performance and capacity . He also stressed that , These dependencies lead to semantic coupling , The change of one service will affect other services . In the worst case , This will cause a service to deal with different versions of services .

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Nygard It summarizes the results of using entity services in microservice architecture ：

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• Teams can still deliver services at their pace .\\\t
• Semantic coupling leads to cross team negotiation .\\\t
• A large number of requests need to call entity Services , Increased traffic load .\\\t
• The overall availability depends on more services .\

Based on the above ,Nygard Think that entity service is an anti pattern .

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come from Fourth.com Chief architect of Ben Morris In another blog post Nygard The article , He said , Using entity services in microservice architecture is worse than single architecture .Morris Think , One of the advantages of microservice is its autonomy , But the more fine-grained Services , The greater the coupling between them , Thus reducing autonomy . He stressed that , Process changes can become difficult , Because difficulties involve a lot of services , If the service is maintained by different development teams , Then change will become more difficult . Another risk of using a large number of small coupled services is , A service failure will produce cascading effects , Affect more services .

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Nygard Your blog post has triggered a long discussion . The author of Microsoft's ebook said , They have targeted the use of HTTP Calling to couple microservices provides a warning . He also stressed , Using the domain model correctly can improve the autonomy of microservices .

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stay Nygard In subsequent blog posts , He will introduce alternatives to physical services .

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Check the English text ：Entity Services is an Antipattern

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