Logging messages from C++ to Java

Question

I have a library in C++ which is being used by a Java app through JNI. In the Java app I'm using logback to produce logs.

Now I need to log the C++ library messages as well and I have to do it in the same file used by Java so I can have everything in chronological order.

My current approach, not yet implemented, is to create a C++ class named Logger that will send the messages to Java through JNI and then Java will log these messages. The disadvantage is that I'm losing Logback functionalities like logging the name of the thread or the line of the code that produced the log.

Is there a better way?

Answer 1

An easy solution would be to use a common service for logging such as syslog. In your Java code, set the appropriate appender to write the logs to syslog. In your C++ code, simply call syslog natively. All logs will be combined in a chronological order by syslog.

Answer 2

A possible solution I've used in the past:-

1. Use logback with a database appender. The DB will ensure transactional commits in order, with a timestamp. In some databases you can make it a trigger and use the native timestamp which may be more efficient.

2. C++ part will need to have a similar appender and/or modified to write to the same table. (log4cpp works, or if you have a proprietary one, it may need to be modified slightly)

3. Select * from table order by timestamp asc output to a file will give you the logs in order.

In my last place we used sqlite for storing these logs as the overhead was tiny compared to oracle or a more heavy duty one and we could delete the file if needed later.