DPS909/OSD600 Fall 2017 Lab 6/7

GitHub Repos and Pull Requests

This lab is all about practicing the git/GitHub workflow we discussed on Tuesday. By the end of this lab, you will have successfully done the following:

• Created a new repo for a project
• Written new code, committed it locally, and pushed it to GitHub
• Contributed a Pull Request to another student's repo
• Reviewed and Merged a Pull Request from another student to your repo

This process will give you some exposure to the entire process of creating, maintaining, and contributing to an open source project.

If you have trouble with any of the steps below, or need help, please use our Slack channel to ask your questions. Don't suffer in silence.

Step 1: Design a Library for File Info

You are asked to create a new open source library. The purpose of this library is to make it easy to get various pieces of info about a given file. You will write functions in your library that do the following:

• filename without path. For example: given a path like "/home/kim/mydata.txt", return "mydata.txt"
• file size in bytes. For example, given a path like "/home/kim/mydata.txt", return 129 (e.g., the file is 129 bytes on disk)
• sha1 digest for a file at the given path. For example, given a path like "/home/kim/mydata.txt", which contains the text The quick brown fox jumps over the lazy dog, return 2fd4e1c67a2d28fced849ee1bb76e7391b93eb12
• [https://en.wikipedia.org/wiki/MD5 MD5 digest) for a file at the given path. For example, given a path like "/home/kim/mydata.txt", which contains the text The quick brown fox jumps over the lazy dog, return 9e107d9d372bb6826bd81d3542a419d6

Step 2: Pick a Language

You can write your library in any language you want, with the single condition that you cannot use C/C++/Java and must choose a language you don't usually use or have never used before. Challenge yourself to learn something new, and push yourself out of your comfort zone. Here are some suggestions:

• JavaScript and node.js
• TypeScript (a version of JS with static types)
• Python
• Rust
• Go

When you choose your language, that you are going to need to convince another student to contribute to your repo, and shouldn't pick something that no other developer uses or wants to learn. Choose wisely!

Step 3: Pick a License

Pick a license for your project. You can use any open source license you want. Be careful what you choose, since you don't want to limit your ability to use existing code (e.g., make sure you pick something that can be combined with other open source licenses).

If you're not sure what to pick, consider using BSD, MIT, or Apache.

Step 3: Look for Existing Modules/Libraries/Packages to Help

You can use any existing open source code that will help you write your library. For example, if you can find a module that already implements the MD5 digest algorithm, use it. Don't write any code you don't have to, don't reinvent the wheel.

Make sure that any open source code you choose is compatible with the license you've chosen. You may need to adjust your license or language choice depending on what you find.

Step 4. Create a Repo on GitHub

Follow the instructions on GitHub to create a repo for your library. Make sure you choose a name that hasn't already been used by another project, company, or product. Try doing a Google search before you settle on your name.

Step 5. Clone your Repo Locally and Start Coding

Clone your repo on your local computer.

Step 6. Plan your Library by Filing Bugs

Begin by planning your work as a series of bugs. Each bug should be small enough to capture a single feature, improvement, or task. For example, you might file bugs for each of the main functions of your library. You might also choose to break those down into a smaller bugs. Do what feels right for you. Fixing many small bugs is often easier than a few large ones.

Step 7. Start coding

Now that you have bugs filed, pick one and start coding it. Remember to do each fix on a separate branch. Once you get a feature finished, and you're happy with it, you can merge it into your master branch. Here's an example of what this might look like:

git checkout -b issue-1
...write the code...
git add <filename>
git commit -m "Fix #1: Added code to do feature X"
git checkout master
git merge issue-1

Step 8. Publish your master branch

When you've got a few of your bugs fixed and merged into master, it's time to publish your work on GitHub. To do this, you want to push your master branch:

git checkout master
git push origin master

Now visit your GitHub repo and make sure you can see your commits, and the code you've written. If anything looks wrong, do another commit to fix it, and push again.

Step 6. Invite people in the Class to Contribute

When you're ready to have people contribute to your project, add your name and GitHub Repo URL to the table below. File any additional Issues in your project repo on GitHub for things you'd like help doing (see suggestions in step 7 below). You can also use the Slack channel to tell people about your project, and how they can get involved.

Step 7. Contribute to Another Project

In addition to creating and maintaining your own library, you are asked to contribute to at least one other project in the class. You can work on a different language than you wrote your own project using, and are free to work with anyone in the class (e.g., don't limit yourself to people you know).

Here are some suggestions of things you could do:

• Write the README.md file, with instructions on how to setup and use the library
• Add automated tests (e.g., unit tests) to make sure the library does what it's supposed to do
• Add automated code quality checks (e.g., linting) to help find bugs before they happen
• Add a build system to make it easier to perform common tasks (e.g., build or minify the code, run tests, do various checks)
• Write a simple command line tool shows an example of how you use the library
• Improve the code to make it cleaner, faster, or more simple (e.g., remove duplication, add documentation)
• Test the code and fix a bug if there are any. Does the code do the right thing in all cases? What happens if you give it data that's different from how the original author wrote it (e.g., run the code on macOS or Linux instead of Windows)?

Before you contribute to another project, make sure there is either an existing bug, or file one yourself. Make sure the project owner knows you're working on this issue.

Next, fork and clone their repo. Create a branch for the issue you're fixing, make your changes, add, and commit. Then push your branch to your fork</code.

Finally, create a Pull Request for your change. In your Pull Request's description, make sure you use the pattern <code>Fix #...: <desc> to have GitHub automatically close the associated issue when your Pull Request is merged. For example, if you are working on Issue 14, you might say, Fix #14: add md5 unit test. Also include a useful discussion of what you've done, how to test it, etc.

Step 7. Code Review

Every Pull Request will need to be reviewed by the project maintainer. When someone submit a Pull Request to your repo, you'll get an email. You should go and read their code, and make any suggestions for how you want it to be fixed (if necessary). Remember that as a maintainer, it's your job to help new contributors feel welcome and valued in your project--you want them to stick around and fix more bugs.

When you submit your own Pull Request, if there are changes requested, please make them and then commit and push your branch again. Any new commits will get added to the pull request. You should let your reviewer know when you've added more commits so that he/she can go and re-review your work.

When everything is complete, the maintainer will merge the pull request. When this happens, the commits on the branch will get added to master. The maintainer should then pull these commits to their local cloned repo:

git checkout master
git pull origin master

Step 8. Record your Contribution(s)

Once you've submitted one or more Pull Requests, make sure you add links in the table below beside your name.

Step 9. Blog

Write a blog post about your experiences in this lab. In particular, discuss each of the following:

• Why did you choose the language you chose? What did you think of it? Would you use it again?
• Were you able to find any existing open source code that you could re-use? How did that go? Did you have any technical or licensing issues?
• What was it like contributing to another project?
• What was it like having people contribute to your project?
• Did you learn anything during your own experience as a maintainer or contributor that will impact you when you do this again?
• Did you run into any issues with git as you managed your project? What did you learn in the process, and what do you still need to learn more about?

Submission

#	Name	GitHub Repo (URL)	Contribution Pull Request(s) (URLs)	Blog Post (URL)
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