Use already existing rasdaman logging mechanism in rasnet

[George Merticariu]

Right now debugging info is produced in few different ways:

• RMDebug macros (RMDBGENTER, RMDBGEXIT, etc.), very complex and allow fine grained control, but seem somewhat broken
• ENTER/LEAVE/TALK - very simple, provide indentation, but only global control is possible
• The tile cache introduces TENTER/TTALK/TLEAVE which allow to turn on ENTER/LEAVE/TALK selectively only in the tile cache
• RMInit::logOut, RMInit::dbgOut - simple output to the log, no possibility to turn off, typically used for outputing warnings/errors and other important info

These should be harmonized into a single method, which is hopefully both powerful and simple.

The decision in this ticket is to substitute all these with easylogging, already used in rasnet.
The main arguments for using easylogging are the following:

• It provides thread safe logging.
• It can be configured at runtime by providing a configuration file.(e.g. log formats can be configured, log levels can be disabled if they are not of interest)
• It offers a range of different log levels.
• There is no clear documentation on what loggers are available in rasdaman and what capabilities they have.

[Dimitar Misev]

What about replacing the existing rasdaman logging with the easylogging? I assume easylogging is a better solution, otherwise why did you decide to use it?

[Alex Dumitru]

I vote for keeping easylogging as well. Should be simple to replace the current logging mechanism, just redefine the existing rasdaman log macros to easy logging macros.

[Alex Toader]

The main arguments for using easylogging are the following:

1. It provides thread safe logging.
2. It can be configured at runtime by providing a configuration file.(e.g. log formats can be configured, log levels can be disabled if they are not of interest)
3. It offers a range of different log levels.
4. There is no clear documentation on what loggers are available in rasdaman and what capabilities they have.

[Peter Baumann]

Nothing against easylogging - but much against having divergent mechanisms. So we might also go for the new one, _but_ that entails going through the whole code and adjusting RMInit and Debug. From my feeling this is a tremendous work - any resources on the horizon?

[Dimitar Misev]

I think this task would fit for Jinbo, unless someone else is already working on it?

Alex or Vlad, can you give some directions to Jinbo?