Three principles of architecture design

The principle of appropriateness

1. 
   
   Better fit than industry leader . It is better to fit your business than to use business leading solutions .
2. 
   
   No “ Feet on the ground ” Three types of failure reasons for the architecture of
   1. 
      
      Insufficient human resources , But insist on doing more work . A general cannot fight a war without soldiers
3. 
   
   Want to do when there is no sufficient infrastructure and platform “ Big ” System
   1. 
      
      Every step is worth a thousand miles
4. 
   
   There is not such a big business scenario, but I want to use business leading solutions
   1. 
      
      The leading solution in the industry is to develop the business to a certain extent , In order to solve all kinds of new problems we have to face “ forced ” Coming out
   2. 
      
      BAT There are many excellent architects , But these architects may not be able to do well in small and medium-sized enterprises or start-up teams . stay BAT There are a lot of resources inside 、 infrastructure 、 Various platforms , But small and medium-sized enterprises rarely have such a complete environment , Copying the routines of large companies by rote often leads to a high probability of failure .

Simple principle

1. 
   
   Simple is better than complex . Architecture design is the art of dealing with complexity .
2. 
   
   The embodiment of complexity .

Structural complexity ：

1. Complex system
   1. 
      
      There are many associations between components
   2. 
      
      The number of components is huge
   3. 
      
      Problems caused by structural complexity
      1. 
         
         The more components , The higher the probability of a component failure
      2. 
         
         Suppose the failure rate of the component is 10%（ Yes 10% Time is not available ）, So there are 3 The system availability of the components is （1-10%）×（1-10%）×（1-10%）= 72.9%, Yes 5 The system availability of the components is （1-10%）×（1-10%）×（1-10%）×（1-10%）×（1-10%）=59%, The availability of the two is different 13%.
      3. 
         
         A change in a component may affect all associated components . These effects may spread along the associated link , Impact on more components .
      4. 
         
         Components A Modification or exception , Will affect components B/C/E,D It will affect E. This problem will affect the development efficiency of the whole system , Because once the change involves external systems , It is necessary to coordinate all parties to conduct a unified program evaluation 、 Resource coordination 、 Online cooperation .
      5. 
         
         It will become very difficult to locate a problem in a complex system .

        The more components , Every component can cause problems , It needs to be checked one by one . The relationship between components is complex , It is possible that one of them shows a fault , But this is not the root of the problem .

The complexity of logic .

1. Architectural complexity .
   1. 
      
      Algorithm complexity .
      1. 
         
         The complexity of the algorithm is mainly difficult to understand , And it makes it hard to achieve 、 Difficult to modify , And it's hard to solve problems quickly .
   2. 
      
      The complexity of architecture will run through the whole life cycle of the system .
      1. 
         
         After the system is put into use, there will be an endless demand , Need to constantly modify the system , New complexities will continue to be introduced .

Principles of evolution

1. 
   
   See the architecture from the perspective of evolution .

         The software field is not static , It needs to be constantly adjusted according to the development of the business .

Architecture design is similar to Biology , We also need to adapt to the external environment through evolution （ Business change ）, Natural selection , The survival of the fittest .

         First , The architecture designed to meet the business needs at that time .

secondly , The architecture should be iterative in the process of practical application , Keep good design , Repair defective design , Correct the wrong design , Get rid of useless designs , Gradually improve the architecture .

         Third , When business changes , Architecture to extend 、 restructure , Even rewrite ; The code may rewrite , But valuable experience 、 lesson 、 Logic 、 Such design （ It's like a gene in an organism ） But it can be continued in the new architecture .

The principle of evolution is very important , When doing architecture design, we need to keep in mind . Fast landing to meet demand , Continue to improve the overall structure in the follow-up development , Evolve with the development of business .

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by Prince