I’ve been thinking about logging in the context of OpenStack and containerized service deployments. I’d like to lay out some of my thoughts on this topic and see if people think I am talking crazy or not.

There are effectively three different mechanisms that an application can use to emit log messages:

• Via some logging-specific API, such as the legacy syslog API
• By writing a byte stream to stdout/stderr
• By writing a byte stream to a file

A substantial advantage to the first mechanism (using a logging API) is that the application is logging messages rather than bytes. This means that if you log a message containing embedded newlines (e.g., python or java tracebacks), you can collect that as a single message rather than having to impose some sort of structure on the byte stream after the fact in order to reconstruct those message.

As part of a project I’m working on I wanted to get a rough idea of the activity of the Apache virtual hosts on the system. I wasn’t able to find exactly what I wanted, so I refreshed my memory of curses to bring you vhoststats.

This tools reads an Apache log file (with support for arbitrary formats) and generates a dynamic bar chart showing the activity (in number of requests and bytes transferred) of hosts on the system. The output might look something like this (but with colors):