Archive for Perl
I had fun writing about how I work with Git yesterday. I thought I’d continue on that thread.
I have a solid set of code libraries that I’ve written that latch into the WordPress themes we produce at iThemes. Each time code is duplicated across different repositories, I break that code out and make it into a separate repository. I then link it back into the project as a submodule. This makes it extremely-easy to keep duplicated code across numerous repositories updated with little or no fuss.
After cloning a repository, simply run git submodule init followed by git submodule update in order to initialize all the submodules and update their container folder with the content of the submodule’s repository. For a long time, this is exactly what I did when I would clone a theme repository to start working on it. However, this quickly wasn’t enough.
The problem happened as soon as I added a submodule to a repository that was also a submodule of other repositories. Doing the submodule init and update process wouldn’t do everything I needed in this case as there would be submodules in some subfolder that haven’t been set up.
I didn’t want to get into a habit of always switching to other directories and doing the submodule processes there as well since I 1) knew that I would forget all-too-often, thus wasting my time, and 2) knew that this would not be the last time that a submodule had submodules. Heck, there is even the possibility that I’ll have a submodule that has a submodule that has a submodule. It was immediately clear that I needed a script to do all this dirty work for me. The rest of this post will be about the script I created.
I work for a company that has a proprietary CMS software package written in Perl. We have a number of servers that run this code, and everything has been fine for a number of years and many different versions and customizations. A few months back, something changed. One of our servers started producing completely empty files for all uploads. This affected all of our code, all of our versions, and every site.
After some time debugging and testing, I finally found the problem. Apparently some code was updated, either Perl itself or one of its packages, and that caused my CGI object to be recylced before the upload code ran. When the CGI object gets recylced, all the file handles are closed resulting in reading and saving an empty file.
The solution was deceptively simple. All I had to do was store the CGI object in a persistent variable that has scope throughout the end of the program execution.