Currently, CarbonData outputs audit log with other level log together in one log file, it is not easy for user to check the audit. And sometimes the audit information is not complete since it depends on each Command to invoke Logger in its run function.
To improve it, I propose a new audit log implementation by following:
1. Separate the audit log from normal log, user can configure log4j to output the audit log in a separate file
2. The audit log should have a common format that includes at least: time, username, operation name, operation id that identify this operation, status (success or failure), other extra information like data loading size, time spent
3. The audit log should be in JSON format to enable analytic tool support in the future.
For example, the audit log will be look like following