Write Code

Know What You Want to Write Code to Do

Do you want to write code to resolve an open issue (bug)? Which one?

Do you want to implement a BigchainDB Enhancement Proposal (BEP)? Which one?

You should know why you want to write code before you go any farther.

Refresh Yourself about the C4 Process

C4 is the Collective Code Construction Contract. It’s quite short: re-reading it will only take a few minutes.

Set Up Your Local Machine. Here’s How.

  • Make sure you have Git installed.
  • Get a text editor. Internally, we like:
    • Vim
    • PyCharm
    • Visual Studio Code
    • Atom
    • GNU Emacs (Trent is crazy)
    • GNU nano (Troy has lost his mind)
  • If you plan to do JavaScript coding, get the latest JavaScript stuff (npm etc.).
  • If you plan to do Python coding, get the latest Python, and get the latest pip.

Warning

Don’t use apt or apt-get to get the latest pip. It won’t work properly. Use get-pip.py from the pip website.

  • Use the latest pip to get the latest virtualenv:

    $ pip install virtualenv

  • Create a Python Virttual Environment (virtualenv) for doing BigchainDB Server development. There are many ways to do that. Google around and pick one. An old-fashioned but fine way is:

    $ virtualenv -p $(which python3.6) NEW_ENV_NAME
$ . NEW_ENV_NAME/bin/activate

    Be sure to use Python 3.6.x as the Python version for your virtualenv. The virtualenv creation process will actually get the latest pip, wheel and setuptools and put them inside the new virtualenv.

Before You Start Writing Code

Read BEP-24 so you know what to do to ensure that your changes (i.e. your future pull request) can be merged. It’s easy and will save you some hassle later on.

Start Writing Code

Use the Git Fork and Pull Request Workflow. Tip: You could print that page for reference.

Your Python code should follow our Python Style Guide. Similarly for JavaScript.

Make sure pre-commit actually checks commits. Do:

$ pip install pre-commit  # might not do anything if it is already installed, which is okay
$ pre-commit install

That will load the pre-commit settings in the file .pre-commit-config.yaml. Now every time you do git commit <stuff>, pre-commit will run all those checks.

To install BigchainDB Server from the local code, and to keep it up to date with the latest code in there, use:

$ pip install -e .[dev]

The -e tells it to use the latest code. The . means use the current directory, which should be the one containing setup.py. The [dev] tells it to install some extra Python packages. Which ones? Open setup.py and look for dev in the extras_require section.

Remember to Write Tests

We like to test everything, if possible. Unit tests and also integration tests. We use the pytest framework to write Python tests. Read all about it.

Most tests are in the tests/ folder. Take a look around.

Running a Local Node/Network for Dev and Test

This is tricky and personal. Different people do it different ways. We documented some of those on separate pages:

Create the PR on GitHub

Git push your branch to GitHub so as to create a pull request against the branch where the code you want to change lives.

Travis and Codecov will run and might complain. Look into the complaints and fix them before merging. Travis gets its configuration and setup from the files:

Read about the Travis CI build lifecycle to understand when those scripts run and what they do. You can have even more scripts!

Codecov gets its configuration from the file codeocov.yaml which is also documented at docs.codecov.io. Codecov might also use setup.cfg.

Merge!

Ideally, we like your PR and merge it right away. We don’t want to keep you waiting.

If we want to make changes, we’ll do them in a follow-up PR.