Log writing specification

Log purpose

1. Problem tracking ： When debugging the program , Through the log tracker bug, It can also be found by the user bug after , Analyze and locate problems through logs .
2. Condition monitoring ： The running status of the system can be viewed through the log , Find and locate problems .
3. Security audit ： By analyzing the log , You can find out whether there are unauthorized operations .

Log type

1. Safety information ： Record system boundary interaction behavior and information .
2. Business information ： Record the internal business processing behavior and information of the system .
3. Performance information ： Record the supporting ability of the system hardware for business processing .

The level of logging

1. ERROR（ error ）： It has affected the normal operation of the system , And the system cannot recover to the normal operation state by itself .
2. WARN（ Warning ）： There is a problem with the general module of the system , It does not affect the operation of the system .
3. INFO（ notice ）： Change of system operation status during system operation , Or key business processing records and other information concerned by users or administrators during system operation .
4. DEBUG（ debugging ）： The most detailed record , Generally, it is the system execution process , And function parameters and return values , It is mainly used to assist programmers in developing .
5. TRACE（ track ）： similar debug, Rarely used in general .

Log output

1. ERROR： A short description of the error , Key parameters related to this error , If there is any abnormality , There should be an exception StackTrace.
2. WARN： A brief description of the alarm , Key parameters related to this error , If there is any abnormality , There should be an exception StackTrace.
3. INFO： Brief and comprehensive information description , If there is relevant dynamic key data , To be output together , For example, related ID、 Name, etc .
4. DEBUG： A brief description , related data , If there is any abnormality , There should be an exception StackTrace.

        Pay special attention to the protection of sensitive information when outputting log related data , For example, when changing the password , Cannot output password to log .

log Writing norms

1. For most foreseeable cases, a single instance of class, Can not add static Prefix ; Most of the cases may be multiple , Especially those that need to be created frequently class, We ask to add static Prefix .
   
2. System startup parameters 、 To configure 、 environment variable 、System.Properties Such information is very important for the normal operation of the software , The output of this information helps the installation and configuration personnel to quickly locate problems through logs , Therefore, it is necessary for the program to use the key parameters in the startup process 、 Variables are output in the log . Attention should be paid to when outputting , Not all the output of one brain , Instead, the configuration information involved in software operation is output .
   
3. Function start and end add log, It is convenient to view the program running process .
4. The function passes in parameters and returns parameters using log Print , It is convenient to check whether the parameter is passed incorrectly .
5. log Data with unclear meaning in （ Such as ： Simple numbers, etc ） It can be converted to a string that can express meaning for printing .
6. log use the same pattern , Such as case , Same data name, etc .
7. log Print by level , Easy to debug and view .

This article is a summary of some information on the Internet , And some of my own experience , If there are any deficiencies, please correct .

This article is only for reference and learning ！