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Discussion on: Logging done right, makes your life bright!

pedromanoel profile image
Pedro Manoel Fabiano Alves Evangelista

Your article is really well written and easy to understand! I would say I'm a beginner in logging and this article really helped.

I'm curious if you have a guideline for how to write log messages and what should be logged. Just like writing commit messages, I have a hard time with this. For instance, sometimes the name of the function is clear enough, and writing a message that simply states the function name with different wording seems to be redundant. What's your experience with this?

grhegde09 profile image
Gajanan H Author

Glad that the article helped you.

We have set up our logging macros in such a way that we get the function name which generated the log for each line of the log file. So mentioning from which function the log got generated is totally redundant.
When a function I called returns failure, I generally log the function name which returned failure along with the error code and if possible a brief description of the error code.

void myStupidFunction()
    char *fileName = "myFile.txt";
    File *pFile = fopen (fileName,"w");
    if(NULL == pFile)
        LOG_ERROR("fopen failed for file:%s with error code:%d and error description:%s",fileName,errno,std::strerror(errno));

phlash909 profile image
Phil Ashby

The principle Gajanan demonstrates here is simple: "never hide information from the logs" (credentials being the only exception to this rule!). In this case a function that returns an error.

I would also suggest using a machine parseable textual log format, defined in a logging story for the team, that will make life much easier for operations and your monitoring tools (SIEM, protective monitoring, etc.)

The use of macros (in C anyway) or similar language features to add consistent source code traceability is also a Good Thing (tm), that's what the FILE and LINE macros are for :)