Getting Set Up¶

The Bokeh project encompasses two major components: the Bokeh package source code, written in Python, and the BokehJS client-side library, written in TypeScript. Accordingly, development of Bokeh is slightly complicated by the explicit compilation step required to generate deployable JavaScript.

For this reason, in order to develop Bokeh from a source checkout, you must first be able to build BokehJS. This chapter will walk you through getting a full development environment set up.

Preliminaries
- Git
- Conda
Cloning the Repository
Creating a Conda Environment
Installing Node Packages
Configuring Git
- Git Hooks
- Git Aliases
Building and Installing
Downloading Sample Data
Next Steps

Preliminaries ¶

Git ¶

The Bokeh source code is stored in a Git source control repository. The first step to working on Bokeh is to install Git on to your system. There are different ways to do this depending on whether, you are using Windows, OSX, or Linux.

To install Git on any platform, refer to the Installing Git section of the Pro Git Book.

Conda ¶

Developing Bokeh requires installing some software packages that are not Python packages (e.g. Selenium, NodeJS, etc.). To make this more manageable, core developers rely heavily on the conda package manager for the free Anaconda Python distribution. However, conda can also install non-Python package dependencies, which helps streamline Bokeh development greatly. It is strongly recommended that anyone developing Bokeh also use conda, and the remainder of the instructions will assume that conda is available.

To install Conda on any platform, see the Downloading conda section of the conda documentation.

Cloning the Repository ¶

The source code for the Bokeh project is hosted on GitHub. To clone the main source repository, issue the following command:

git clone https://github.com/bokeh/bokeh.git

Note

Active @bokeh/dev contributors should clone the main source repository to make sure the complete CI testing automation runs successfully.

New or casual contributors are required to clone their forks of the bokeh source repository. To fork and clone Github repositories, refer to Fork a repo section of GitHub Help.

This will create a bokeh directory at your file system location. This bokeh directory is referred to as the source checkout for the remainder of this document.

Creating a Conda Environment ¶

The Bokeh repo contains an environment.yml file that can be used to create a conda environment named bkdev with all the packages necessary for basic Bokeh development.

At the top level of the repository, issue the following command in a terminal:

conda env create environment.yml

Then, to activate the environment:

conda activate bkdev

Installing Node Packages ¶

Building BokehJS also requires installing JavaScript dependencies using the Node Package Manager. If you have followed the instructions above, conda has already installed the necessary npm and node.js packages to your system.

Bokeh is typically updated to require the latest major revision of npm in order to build. To install the lastest version globally, start from the top level of the source checkout directory, and execute the following commands

cd bokehjs
npm install -g npm

If you do not wish to install globally (i.e. with -g) then all subsequent npm commands will need to be adjusted to use the local version installed under bokehjs/node_modules.

Next, still in the bokehjs subdirectory, execute the following command to install all of BokehJS JavaScript dependencies:

npm ci

This command will install the necessary packages into the node_modules subdirectory.

Typically, these instructions only need to be followed once, when you are first getting set up. Occasionally, however, dependencies may be added or changed, in which case these instructions will need to be followed again.

Configuring Git ¶

There are a few configurations you can make locally that will help make working with the repository safer and easier.

Note

The optional instructions in this section are specific to OSX and Linux.

Git Hooks ¶

In order to help prevent some accidental errors, here are some git hooks that may be useful. The scripts below should be placed in the .git/hooks subdirectory in the top level of the source checkout directory and be marked executable with e.g. chmod +x pre-commit. For more information on git hooks, see this tutorial.

pre-commit

This git hook runs all the codebase tests before allowing a commit to proceed. Note that all the standard testing dependencies must be installed in order for this hook to function.
#!/bin/bash

py.test tests/codebase
exit $?

pre-push

This git hook prevents accidental pushes to master on GitHub.

#!/bin/bash

protected_branch='master'
current_branch=$(git symbolic-ref HEAD | sed -e 's,.*/\(.*\),\1,')

if [ $protected_branch = $current_branch ]
then
    read -p "You're about to push master, is that what you intended? [y|n] " -n 1 -r < /dev/tty
    echo
    if echo $REPLY | grep -E '^[Yy]$' > /dev/null
    then
        exit 0 # push will execute
    fi
    exit 1 # push will not execute
else
    exit 0 # push will execute
fi

Git Aliases ¶

There are also some useful aliases that can be added to the .gitconfig file located in your home directory.

The following alias adds a git resolve command that will automatically open up your editor to resolve any merge conflicts.

[alias]
    resolve = !sh -c 'vim -p $(git status -s | grep "^UU" | cut -c4-)'

You can replace vim with whatever your favorite editor command is.

Building and Installing ¶

Once you have all the required depencies installed, the simplest way to build and install Bokeh and BokehJS is to use the setup.py script at the top level of the source checkout directory.

The setup.py script has two main modes of operation:

python setup.py install

Bokeh will be installed in your Python site-packages directory. In this mode, any changes to the python source code will not show up until setup.py install is run again.

python setup.py develop

Bokeh will be installed to refer to the source directory. Any changes you make to the python source code will be available immediately without any additional steps.

With either mode, you will be prompted for how to install BokehJS, e.g.:

python setup.py develop

Bokeh includes a JavaScript library (BokehJS) that has its own
build process. How would you like to handle BokehJS:

1) build and install fresh BokehJS
2) install last built BokehJS from bokeh/bokehjs/build

Choice?

You may skip this prompt by supplying the appropriate command line option to setup.py, e.g.

python setup.py develop --build-js
python setup.py develop --install-js

Note that you will need to build BokehJS any time that the BokehJS source code changes (either by you or by pulling new revisions from GitHub). In particular, at the very least, you must build BokehJS the first time you install.

Note

Occasionally the list of JavaScript dependencies also changes. If this occurs, you will also need to re-run the instructions in the Installing Node Packages section above.

Downloading Sample Data ¶

Several tests and examples require Bokeh’s sample data to be available. Once Bokeh is installed, the simplest way that sample data can be obtained is by executing the following command at a Bash or Windows prompt:

bokeh sampledata

It’s also possible to configue the download location, or to start the download programmatically. For full details see the Sample Data section of the User’s Guide.

Next Steps ¶

You can check that everything is installed and set up correctly by executing the command:

python -m bokeh info

You should see output similar to:

Python version      :  3.8.3 | packaged by conda-forge | (default, Jun  1 2020, 17:21:09)
IPython version     :  7.15.0
Tornado version     :  6.0.4
Bokeh version       :  2.0.2-95-g8e0b447c0-dirty
BokehJS static path :  /Users/bryan/work/bokeh/bokeh/server/static
node.js version     :  v14.4.0
npm version         :  6.14.5

The next check that can be made is to run some of the examples. There are different ways in which bokeh can be used which suit a variety of use cases.

To create an html file,

BOKEH_RESOURCES=inline python examples/plotting/file/iris.py

which will create a file iris.html locally and open up a web browser.

The variable BOKEH_RESOURCES determines where the css and JavaScript resources required by bokeh are found. By specifying inline we are using the version of BokehJS we just built to include the resources inline as part of the html file. The BOKEH_RESOURCES variable is required as the default behaviour is to use CDN resources.

Another method of running bokeh is as a server. An example of this mode of operation can be run using the command

python -m bokeh serve --show examples/app/sliders.py

which will open up a browser with an interactive figure.

All the sliders allow interactive control of the sine wave, with each update redrawing the line with the new parameters. The --show option opens the web browser to the appropriate address, the default is localhost:5006.

If you have any problems with the steps here, please contact the developers.