Development

Git Branches

On the parent repo for NSoT, there are two important branches:

  • develop is the branch that all Pull Requests are opened against and represents the bleeding edge of work being done on NSoT.
  • master is considered to be the ‘stable’ branch and no PRs should be merged directly in to this branch. As features are merged into develop, releases are created off of that branch and then merged into master. See Release Process for more information on how this is done.

When developing on NSoT, you should be basing your work on the develop branch.

Setting up Your Environment

Note: You’ll need to have a reasonably recent version of npm to build front-end dependencies. (Minimum version tested is 1.3.24)

We suggest setting up your test environment in a Python virtualenv:

$ virtualenv nsot
$ source nsot/bin/activate

Or, if you use virtualenvwrapper:

$ mkvirtualenv nsot

If you haven’t already, make sure you set up git and add an SSH key to your GitHub account before proceeding!

After that, clone the repository into whichever directory you use for development and install the dependencies:

$ git clone git@github.com:dropbox/nsot.git
$ cd nsot
$ pip install -r requirements-dev.txt
$ python setup.py develop

Running a Test Instance

For developement and testing, it’s easiest to run NSoT behind a reverse proxy that handles authentication and sends a username via a special HTTP header. We’ve included a test proxy for running on development instances.

To get started, follow these steps:

# Initialize the config
$ nsot-server init

# Setup the database.
$ nsot-server upgrade

# Run the development reverse proxy (where $USER is the desired username)
$ nsot-server user_proxy $USER

# (In another terminal) Run the front-end server, remember to activate your
# virtualenv first if you need to
$ nsot-server start

Note: This quick start assumes that you’re installing and running NSoT on your local system (aka localhost).

Now, point your web browser to http://localhost:8991 and explore the documentation!

Running Unit Tests

All tests will automatically be run on Travis CI when pull requests are sent. However, it’s beneficial to run the tests often during development:

$ py.test -v tests/

Working with Database Migrations

If you make any changes to the database models you’ll need to generate a new migration. We use Django’s built-in support for database migrations underneath, so for general schema changes is should be sufficient to just run:

$ nsot-server makemigrations

This will generate a new schema version. You can then sync to the latest version:

$ nsot-server migrate

Working with Docs

Documentation is generated using Sphinx. If you just want to build and view the docs | you cd into the docs directory and run make html. Then point your browser | to docs/\_build/html/index.html on your local filesystem.

If you’re actively modifying the docs it’s useful to run the autobuild server:

$ sphinx-autobuild docs docs/_build/html/

This will start a server listening on a port that you can browse to and will be automatically reloaded when you change any rst files. One downside of this approach is that is doesn’t refresh when docstrings are modified.

Front-end Development

We use a combination JavaScript utilities to do front-end development:

  • npm - npm is used to manage our build dependencies
  • bower - bower to manage our web dependencies
  • gulp - gulp for building, linting, testing

Note: You do not have to install these yourself! When you run setup.py develop, it will install and build all front-end components for you!

Adding New Build Dependencies

For the most part you shouldn’t need to care about these details though if you want to add new build dependencies, for example gulp-concat, you would run the followiing:

# Install gulp-concat, updating package.json with a new devDependency
$ npm install gulp-concat --save-dev

# Writes out npm-shrinkwrap.json, including dev dependencies, so consistent
# build tools are used
$ npm shrinkwrap --dev

Adding New Web Dependencies

Adding new web dependencies are done through bower:

# Install lodaash, updating bower.json with the new dependency
$ bower install lodash --save

Unfortunately, bower doesn’t have a shrinkwrap/freeze feature so you’ll want to update the version string to make the version explicit for repeatable builds.

We make use of bower’s “main file” concept to distribute only “main” files. Most packages don’t consider consider the minified versions of their project to be their main files so you’ll likely also need to update the overrides section of bower.json with which files to distribute.

Versioning

We use semantic versioning. Version numbers will follow this format:

{Major version}.{Minor version}.{Revision number}.{Build number (optional)}

Patch version numbers (0.0.x) are used for changes that are API compatible. You should be able to upgrade between minor point releases without any other code changes.

Minor version numbers (0.x.0) may include API changes, in line with the Deprecation policy. You should read the release notes carefully before upgrading between minor point releases.

Major version numbers (x.0.0) are reserved for substantial project milestones.

Release Process

When a new version is to be cut from the commits made on the develop branch, the following process should be followed. This is meant to be done by project maintainers, who have push access to the parent repository.

  1. Create a branch off of the develop branch called release-vX.Y.Z where vX.Y.Z is the version you are releasing
  2. Use bump.sh to update the version in nsot/version.py and the Dockerfile. Example:
$ ./bump.sh -v X.Y.Z
  1. Update CHANGELOG.rst with what has changed since the last version. A one-line summary for each change is sufficient, and often the summary from each PR merge works.
  2. Commit these changes to your branch.
  3. Merge the release branch into develop and push that branch up
  4. Merge the release branch into master
  5. Create a new git tag with this verison in the format of vX.Y.Z
  6. Push the master branch up along with the new tag
  7. Create a new package and push it up to PyPI:
$ python setup.py sdist upload

Deprecation policy

NSoT releases follow a formal deprecation policy, which is in line with Django’s deprecation policy.

The timeline for deprecation of a feature present in version 1.0 would work as follows:

  • Version 1.1 would remain fully backwards compatible with 1.0, but would raise Python PendingDeprecationWarning warnings if you use the feature that are due to be deprecated. These warnings are silent by default, but can be explicitly enabled when you’re ready to start migrating any required changes.

    Additionally, a WARN message will be logged to standard out from the nsot-server process.

    Finally, a Warning header will be sent back in any response from the API. For example:

    Warning: 299 - "The `descendents` API endpoint is pending deprecation. Use
    the `descendants` API endpoint instead."
    
  • Version 1.2 would escalate the Python warnings to DeprecationWarning, which is loud by default.

  • Version 1.3 would remove the deprecated bits of API entirely and accessing any deprecated API endoints will result in a 404 error.

Note that in line with Django’s policy, any parts of the framework not mentioned in the documentation should generally be considered private API, and may be subject to change.