One of the features about ETW I liked was LoggingLevel. It meant I no longer had to worry about whether something might be too overly verbose to log. Or that certain important messages might get buried in a lot of usually-unimportant verbose details. By assigning a logging level, developers have the option to filter messages by level during later examination. Unfortunately I got lost with ETW and had to take a step back with my own primitive logger, but that didn’t make the usefulness go away. In fact I quickly found that I wanted it as things got complex.
In my first experiment
Hello3DP I put a big text box on the application to dump data. For the second experiment
PollingComms I have a much smaller text area so I could put some real UI on the screen. However, the limited area meant the verbose messages quickly overflowed the area, pushing potentially important information off screen. I still want to have everything in the log file, but I only need a subset displayed live in the application.
I was motivated to take another stab at ETW but was similarly unsuccessful. In order to resolve my immediate needs I started hacking away at my simple logger. I briefly toyed with the idea of using a small database like SQLite. Microsoft even put in the work for easy SQLite integration in UWP applications. Putting everything into a database would allow me to query by LoggingLevel, but I thought it was overkill for solving the problem at hand.
I ended up adding a separate list of strings. Whenever the logger receives a message, it looks at the level and decides if it should be added to the subset of string as well. By default I limited the subset to 5 entries, and only at
LoggingLevel.Information or higher. This was something I could pass into the on screen text box to display and notify me in real time (or at least within ~1 second) what is going wrong in my application.
Once again I avoided putting in the work to learn how to work with ETW. I know I can’t put it off forever but this simple hack kicked that can further down the road.
[This kick-the-can exercise is publicly available on GitHub]