Getting Started Developing

Before writing your first line of code in VOCAL, give the user and developer documentation a read through!

Learn the Code

Make sure your python skills are up to date. Check out the Code Academy website for an interactive python tutorial. Refer to the python 2.7 documentation for help with specific commands. VOCAL is based heavily on Tk/Tkinter. Documetaion and examples can be found on a multitude of sites, but Effbot has some good examples and explanations. Finally, check out the GitHub to see VOCAL’s repository. Try looking through the code to get a feeling for the flow and organization of the program before you start making additions.

Get in Touch

Many DEVELOPers have put their hands on VOCAL’s code and can provide you with some great insight into how the program is structured and what challenges they faced. Join the Slack or just send an email to one of the previous project leads.

Use Git

Before you start making changes, learn how to use Git for version control. GitHub provides an interactive tutorial on using Git, but there a resources all over the web. For VOCAL, we stick to several best practices in order to streamline development. If you plan on developing VOCAL, you must use Git.

Software for Developing

The IDE, Debugger, or text editor you use are all up to you , as long as you use Git. Pycharm is a great IDE with debugging, syntax highlighting, formatting suggestions, and Git capabilities. You can grab the free community version from their website here. If you prefer a more basic environment, you can always use your favorite text editor (Sublime Text is a great option) along with Gitbash to interact with the GitHub repository.

Clone the Repository

If you plan on using an IDE or debugging software, then simply follow the directions provided by their documentation to clone from GitHub. Make sure you select the Anaconda python 2.7 version as your compiler.

Otherwise, you can use Git Bash to clone the repository.

  1. First, open Git Bash
    • Use cd to reach the folder where you would like to develop VOCAL
  2. Then use git clone https://github.com/NASA-DEVELOP/VOCAL.git
    • git fetch to make sure the branches are up to date
  3. To start VOCAL, use python VOCAL/calipso/Calipso.py

Start Developing

To begin developing, you will need a new branch.

Warning

never update the master branch directly unless you are making small changes or it is absolutly necessary.

  1. Use git checkout -b newbranch to create a branch called newbranch
    • You should choose a more relevant name, such as the number of the issue you are fixing or the name of the feature you are adding
    • If you are using an IDE, use their tools to create a new local repository. In Pycharm, you can right-click the project folder and use Git > Repository > Branches > New Branch
  2. You are now free to develop the python files within VOCAL. Before you start, make sure you read the rest of the user and developer documentation, especially the coding conventions. Write lots of comments, keep track of the changes you make in the changelog, and be ready to explain any code to future developers
  3. When you have made some progress on your branch, you should save and commit the changes.
    • If you created new files, use git add newfile to add the file newfile. Similarly, use git rm oldfile to remove a file called oldfile
    • Otherwise, use git commit -m  "Your commit message here" to commit changes to your branch with a short message
      • To make commits on Pycharm, right-click the project folder and select Git > Commit Directory
    • Git will keep track of your changes from one commit to another and allows you to revert if you mess something up. Checkout tutorials online for a more in depth guide on using Git and all of the features it offers.
  4. When you make big commits or after a few small ones, you should upload your commits to the GitHub
    • Use git push origin newbranch (replace newbranch with the name of your branch)

After you work on your branch for a while and find that your changes have not cause any further errors, you can merge it back into the master

Merging a Branch

After you have made updates or fixed bugs on your own branch, you can merge it back into the master. make sure your files are saved and you latest commit is up to date.

  1. Head over to the GitHub page on your web browser and select your branch from the list. Then click New Pull Request
  2. You will be prompted to write a message to accompany the request. Write in your changes and any other relevant information such as known bugs. Then submit the request.
  3. There may be conflicts with the two branches, so resolve those on the GitHub gui before you merge
  4. Once you’ve had another person look over your pull request and it looks good, confirm the merge.

VOCAL’s master branch is now up to date with yours. Once some more people have tested the new master branch, go ahead and delete the newbranch that you created earlier. All of the changes you made are on the master branch now, so you won’t need it anymore

Closing Out

At the end of your session, you should do a few things to make development easier for the next team.

  1. Make sure all of your changes have been uploaded to the GitHub with good comments. Someone new should be able to come along and figure out what the code is supposed to do pretty easily.
  2. Update the documentation considering the updates you made. If you added or removed features, note them in the changelog and make sure the docs explain the feature accurately. Update the contact info in the documentation and the about in the constants.py file.
  3. If you leave behind any unfinished features or code, leave detailed guides on what you attempted and the goal of the code so the next team can either finish it or scrap it quickly.

Versioning

If you believe that the changes you have made to VOCAL constitute a new version, it should be named 1.YY.MM where YY is the year of the release and MM is the month. VOCAL 2 will be deployed as a web app.