Getting the ETW messages for a live running instance of a Service Fabric application

As our company has recently discovered, it would be very handy to have a live running stream of diagnostic from a live running Service Fabric application when one is trying to figure out why a Service won't start.

This docs.microsoft.com article provides a handy way to enable the log streaming feature in Visual Studio for a live running service in the same manner as one would get when debugging the Service Fabric Application in your local cluster.

Stupid MySQL tricks

Recently, I found that our secondary server's MySQL partition was starting to get full. After running du -h --max-depth=1 several times recursively, I found that the source was the MySQL binary logs. As it turns out, MySQL comes with a very handy command for purging all log files. If you run :

show master logs

, you'll be given a list of the logs that the MySQL server is currently using. You can clear out old log files (some of which can be very large) by running the command

purge master logs to 'log-name-here -from-display'

. This will remove the old log files from the hard disk and save up some potentially much needed space.

Logging for tests using the Spring Framework

It's been a while since I've posted to the blog 'cause I've been so busy, and it seems fitting that this be a good way to resume posting, as this issue has pissed me off quite a bit and been a major thorn in my side for the longest time.

The Spring Framework has some pretty good support for creating test classes for your application, however it by default does not properly initialize log4j logging when doing tests, and I found out today why. When running your application in a Servlet container, you'd configure Spring logging in web.xml. However, when running in a standalone context, Spring has no way of knowing how you want logging configured, so it leaves it up to log4j to configure itself. On that front, you have to realize what log4j's default configuration strategy is : reading a 'log4j.properties' file from the root of the classpath. Once this hits you (and it took me a while), getting logging running for your test cases becomes a simple matter of placing a valid 'log4j.properties' config file in the root of your test classpath, and logging starts working properly, so now you can read those pesky hibernate generated queries off your test log .