Drab as a fool, aloof as a bard

A new month nearly upon us, and the only thing I can think to blog is about the difficulty I had configuring the logging in piece of in-house software recently. The software was written in Java, and used the very configurable log4j library for logging. In an almost textbook use case of the library, I was tasked with converting the software from logging to stdout, to logging to a file which would be more permanent. There are, of course, several things to consider when logging to file, not least security, but another major concern was the size of the log file created. These are not new concerns however, and I decided to make use of the standard syslog facility used in conjunction with the logrotate program, both of which were available on the machine in question.

Of course, log4j supported outputting to syslog, which meant that with a simple configuration change based on any good example on the Web, I could get syslog logging instead of (or as well as) stdout logging. I could even exploit syslog’s network-transparency to log to another host, but I didn’t need that. In theory everything was now ready to go, but when I restarted the Java program, the problems started.

I recently found myself in a position of having to produce some pretty impressive line graphs, based on constantly updated data from a [MySQL] database, and made available to authenticated users over the Web. Having worked with a PHP graphing library before, I knew the problem could be solved with PHP, but I looked around to find the most professional-looking solution. In terms of features, and active development, I found the PEAR package Image_Graph to have everything I needed, and with a good history, being based on GraPHPite. There were many excellent examples showing the power of the package, and there were only a few issues I had to solve to get a [Debian] GNU/Linux test machine to produce graphs with it. Unfortunately, even after I had got a graph to appear, the graph was wrong in subtle ways and it took quite some time to realise this and find what the cause was. I am now more than satisfied with the results, and even had a woman say “Your graphs are looking nice.” to me today, so if you’re thinking of creating graphs with PHP (or you have found this page in a desperate trawl through Google results pages) then I hope your problems are solved below.