This week is UC Berkeley’s Spring Break. Obviously I’m not on vacation, because I actually need Spring Break to catch up on research due to how much time my GSI is consuming; it is taking 25-ish hours a week if I’m tracking my work hours correctly. (I’m not sure if students realize this, but teaching assistants, and probably professors, look forward to the Spring Break just as much as they do.) But I figured that since since the week would give me leeway to step off the gas pedal just a tad bit, I should use the time to tinker and improve my development environment. Broadly speaking, this means improving how I code, since my normal daily activity involves lots and lots of programming. Therefore, a proper investment in a development environment should pay for itself.

Almost two years ago, I wrote a blog post stating how I organized my GitHub repositories. That’s technically part of my development environment, but perhaps more important than GitHub repository organization is how I design my .bashrc files (or .bash_profile if I use my Mac OS X laptop) and how I organize my Python virtual environments. Those two are the subject of this blog post.

After reading my fellow lab-mate Roshan Rao’s development environment on GitHub, I realized that I was missing out on a key feature: having the git branch explicitly listed in the command line, like this where the text (master) is located after the name of this repository:

danielseita@dhcp-46-186:~/ (master) $ ls 
Gemfile			_config.yml		_posts		css
Gemfile.lock		_includes		_sass		feed.xml		_layouts		_site			assets			index.html
danielseita@dhcp-46-186:~/ (master) $ 

Having the branch listed this way is helpful because otherwise it is easy to forget which one I’m on when coding across multiple projects and multiple machines, and I’d rather not have to keep typing git status to reveal the branch name. Branches are useful for a variety of reasons. In particular, I use them for testing new features and fixing bugs, while keeping my master branch stable for running experiments. Though, even that’s not technically true: I’ll often make “archived” branches solely for the purpose of reproducing experiments. Finally, the value of branches for a project arguably increases when there are multiple collaborators, since each can work on their own feature and then make a pull request from their branch.

All that’s needed for the above change are a couple of lines in the .bashrc file, which I copied from Roshan earlier. No extra “plugins” or fancy installations are needed. Incidentally, I am putting my development environment online, and you can see the relevant changes in .bashrc. I used to have a vimrc repository, but I am deprecating that in favor of putting my vimrc details in the development environment. Note that I won’t be discussing vimrc in this post.

There was one annoying issue after implementing the above fix. I noticed that calling an alias which activates a virtualenv caused the git branch detail to disappear, and additionally reverted some of the .bashrc color changes. To be clear on the “alias” part, as of yesterday (heh!) I organized my Python virutual environments (“virualenvs”) by saving them all in a directory like this:

danielseita@dhcp-46-186:~ $ ls -lh seita-venvs/
drwxr-xr-x  7 danielseita  staff   224B Feb  4 21:18 py2-cs182
drwxr-xr-x  7 danielseita  staff   224B Mar  8 18:09 py2-cython-tests
drwxr-xr-x  8 danielseita  staff   256B Mar 12 21:45 py3-hw3-cs182
drwxr-xr-x  7 danielseita  staff   224B Mar  8 13:36 py3.6-mujoco
danielseita@dhcp-46-186:~ $

and then putting this in my .bashrc file:

alias  env182='source ~/seita-venvs/py2-cs182/bin/activate'
alias  cython='source ~/seita-venvs/py2-cython-tests/bin/activate'
alias hw3_182='source ~/seita-venvs/py3-hw3-cs182/bin/activate'
alias  mujoco='source ~/seita-venvs/py3.6-mujoco/bin/activate'

So that, for example, if I wanted to go to my environment which I use to test Python MuJoCo bindings, I just type in mujoco on the command line. Otherwise, it’s really annoying to have to type in source <env_path>/bin/activate each time!

But of course people must have settled on a solution to avoiding that. During the process of trying to fix the puzzling issue above of aliases “resetting” some of my .bashrc changes, I came across virtualenvwrapper, a package to manage multiple virtualenvs. I’m embarrassed that I didn’t know about it before today!

Now, instead of doing the silly thing with all the aliases, I installed virtualenvwrapper, adjusted my ~/.bashrc accordingly, and made a new directory ~/Envs in my home level directory which now stores all my environents. Then, I create virtualenvs which are automatically inserted in ~/Envs/. For example, the Python2 virtualenv that I use for testing CS 182 homework could be created like this:

mkvirtualenv py2-cs182

I often put in py2 and similar stuff to prefix the virtualenv to make it easy to remember what Python versions I’m using. Nowadays, I normally need Python3 environments, because Python2 is finally going to be deprecated as of January 1, 2020. Let’s dump Python 2, everyone!!

For Python 3 virtualenvs, the following command works for both Mac OS X and Ubuntu systems:

mkvirtualenv --python=`which python3` py3.6-mujoco

To switch my virtualenv, all I need to do is type workon <ENV>, and this will tab-complete as needed. And fortunately, it seems like this will preserve the colors and git branch changes from my .bashrc file changes.

One weakness of the virtualenvwrapper solution is that it does require a global pip installation for installing it in the first place, via:

pip install --user virtualenvwrapper

So that you can even start using it. I’m not sure how else to do this without having someone install pip with sudo access. But that should be the only requirement. The --user option means virtualenvwrapper is only applied locally to you, but it also means you have to change your .bashrc to source the local directory, not the global one. It works, but I wish there was an easy option that didn’t require a global pip installation.

As a second aside, I also have a new .bash_aliases file that I use for aliases, mostly for ssh-ing into machines without having to type the full ID, but I’ll be keeping that private for obvious reasons. Previously, I would put them in my .bashrc, but for organizational purposes, it now makes sense to put them in a separate file.

Whew. I don’t know how I managed to work without these changes above. I use multiple machines for research, so I’ll be converting all of my user accounts and file organization to follow the above.

Of course, in about six more months, I will probably be wondering how I managed to work without features XYZ … there’s just so much to learn, yet time is just so limited.