nklein software

One of the things that my current work does better than anywhere I’ve worked before is logging. When something goes wrong, there is a log file that you can dig through to find all kinds of information about what you were doing and how things were going.

As I move forward programming a game with my UNet library, I want to make sure that I can easily log all the network traffic during testing runs at least.

In looking through the various Lisp logging packages out there, I decided on Nick Levine’s cl-log library.

I installed it in no time with quicklisp.

Then, I set to work trying to figure out how I could use it to log binary data.

Here’s what I ended up with. If you want to do something similar, this should give you a good starting point.

Serializing, unserializing, and categorizing

With my USerial library, I defined a serializer to keep track of the different categories of log messages. And, I made corresponding categories in cl-log.

Specializing the classes

There are two major classes that I specialized: base-message and base-messenger. For my toying around, I didn’t end up adding any functionality to the base-message class. I will show it here though so that you know you can do it.

Then, I overrode the messenger-send-message generic function to create a binary header with my USerial library and then write the header and the message out.

Using it

To get things going, I then made a log manager that accepts my serialized-message type and started one of my serialized-messenger instances.

Once these were started, I made a little utility function to make it easy for me to make test messages and then invoked log-message a few times.

Conclusions

In all, it has taken me about four times as long to write blog post as it did to install cl-log with quicklisp, peek through the cl-log documentation and source code enough to figure out how to do this, and write all of the code.

To really use this, I will probably separate out the category of a message from the serialized type of the message. This will probably involve adding a field to the serialized-message class to track the message type, adding an initialize-instance :before method for that class to look through the arguments to pull out the type, and then adding the type as an extra argument to log-message.