Application Logging on your way

Development and Debug are two most important phase in Software developers life. Whenever we talk about debugging we come across so many tools, best practices, coding styles etc. Logging is one of the most popular and mandatory concept of debugging the application. I will say that this is one of the most crucial elements for monitoring and analyzing the application. Using proper logging mechanism, we can not only find out the description about errors but also could take certain decisions for improving system performance. It helps in identifying the issue and their cause. Sometimes we can also generate metrics based on current logs to set the target for future road map for the application.

Types of Logging:

Use Log for Debug - To know the issue, for recording request and responses, for knowing system performance and many more. Logs could contain the end to end session for an user. 

Use Log for Knowing Stats - You can log for counting number of visitor came to the site, for voice application, it can be used to know the call details of the user, database hits and/or anything that could be used for audits etc.

Based on my work experience and knowledge I would outline some of the best practices that we should follow for Logging:

#1- Use categories - Use the severity values like INFO, WARN, ERROR, and DEBUG for each message.

#2- Proper Name inclusion - Include the Name of Method,Function,Class etc.

#3- Use Time information - Timing information and context information can be very useful.

#4- Log the messages to some Local Files

#5- Try to log events for all possible resources. For example 

Application logs

DB logs

Any Network logs

All Configuration files details

Performance data details (example - iostat, vmstat, ps, etc.)

Any other time component

#6- Use user friendly messages

#7- Use time-stamps for every log messages

#8- For DB debugging, use some log table to store the activity from DB procedure, functions etc. It will help to determine if everything worked well during DB processing. Some Autonomous function/procedure for logging will also be good to design to have.

#9- Try to log the end to end flow for a request. Try not to log unnecessary stuff, for example some details may be duplicate/redundant.

#10- Do not use sysout for showing messages in console.

#11- You can log messages in XML format as well, but you have take some extra care for this.

#12- Log both errors and behavior of the application.

#13- As it takes too much space, it is advisable to Keep the time limit for storage of Log file in local system.

#14- In case of try-catch, use as follows:

Do not use the following, it is an anti-pattern:

  try {

    toDBOperations();

  } catch (SQLException cnce) {

    log("Exception in toDBOperations()");

  }

Following ussae is good to go:

  try {

    toDBOperations();

  } catch (SQLException cnce) {

    log("Exception in toDBOperations()");

    rollbackDBData();

  }

Hope you enjoyed reading the blog!!!