Microservices and related component concepts

1. Reference material

Microservices （Microservices）——Martin Flower

https://www.bilibili.com/video/BV1LQ4y127n4?spm_id_from=333.999.0.0&vd_source=c581024b8cd9585ec6a75c56ac05571a

2. Microservice related concepts

1. Monomer architecture

Develop all the functions of the business in one project , Deploy as a package .

advantage ： Simple architecture 、 Low deployment cost 、 Suitable for small projects .

Inferiority ： High coupling degree 、 Expandability of .

2. Distributed architecture

Split the system according to business functions , Each business function module is developed as an independent project , It's called a service .

advantage ： loose coupling 、 Good scalability 、 Suitable for large Internet projects .

shortcoming ： The architecture is complex 、 Difficulty .

3. Microservice architecture

Microservice is a well-designed distributed architecture .

characteristic ：

• Single responsibility ： Microservices have smaller granularity , Each service corresponds to a unique business capability , Single responsibility .
• autonomous ： Team independence 、 Technology independence 、 Data independence , Independent deployment and delivery .
• Service oriented ： The service provides a unified standard interface , It has nothing to do with language and Technology .
• Strong isolation ： Isolate service calls 、 Fault tolerance 、 Downgrade , Avoid cascading problems .

advantage ： Smaller split granularity 、 The service is more independent 、 Less coupling .

shortcoming ： The architecture is very complex 、 Operation and maintenance 、 monitor 、 Deployment is more difficult .

Service splitting principle

• Different microservices , Don't develop the same business repeatedly
• Microservice data independence , Do not access databases of other microservices
• Microservices can expose their business as interfaces , For other microservices to call

Call between services

service A Can pass Http Request call service B.

3. Microservice framework and technical components

2.1 Registry Center

problem :

• service A When initiating a remote call , How to know about the service B Example of ip Address and port ？（ Register at the service center 、 Pull the service list ）
• There are multiple services B Address of the instance , service A How to choose when calling ？（ Load balancing algorithm ）
• service A How to know about a service B Whether the instance is still healthy , Is it down ？（ The heartbeat detection ）

The role of the registry is , Save the list of services 、 Detect service status through heartbeat 、 Allocate service instances through load balancing algorithm .

2.2 The remote invocation

Realize the call between services (HTTP agreement )

2.3 Configuration center

When there are more and more instances of microservice deployment , Up to dozens 、 Hundreds of hours , Modifying the microservice configuration one by one will drive people crazy , And it's easy to make mistakes . We need a unified configuration management solution , Sure Centrally manage the configuration of all instances .

2.4 gateway

Front end requests do not allow direct access to microservices , You must go through the gateway first .

The gateway has the functions of routing and filtering , Routing is to distribute requests to a micro service , Filtering will directly intercept unqualified requests .

2.5 Service monitoring 、 Protect

Protect service callers , Protect service calls from cascading failures , It is possible to quickly return to the service failure , Don't let users wait for a long time .

Protect service providers , Interface current limiting .