Developing on Bedrock

Managing Dependencies

For Python we use hashin to pin dependencies in requirements files. To use hashin it must first be installed using pip:

pip install hashin

See the hashin documentation for how to install new packages.

For Node packages we use NPM, which should already be installed alongside Node.js.

Asset Management and Bundling

Bedrock uses Webpack to manage front-end asset processing and bundling. This includes processing and minifying JavaScript and SCSS/CSS bundles, as well as managing static assets such as images, fonts, and other common file types.

When developing on bedrock you can start Webpack by running make run when using Docker, or npm start when running bedrock locally.

Once Webpack has finished compiling, a local development server will be available at localhost:8000. When Webpack detects changes to a JS/SCSS file, it will automatically recompile the bundle and then refresh any page running locally in the browser.

Webpack Configuration

We have two main Webpack config files in the root directory:

The webpack.static.config.js file is responsible for copying static assets, such as images and fonts, from the /media/ directory over to the /assets/ directory. This is required so Django can serve them correctly.

The webpack.config.js file is responsible for processing JS and SCSS files in the /media/ directory and compiling them into the /assets/ directory. This config file also starts a local development server and watches for file changes.

We use two separate config files to keep responsibilities clearly defined, and to make the configs both shorter and easier to follow.

Note

Because of the large number of files used in bedrock, only JS and SCSS files managed by webpack.config.js are watched for changes when in development mode. This helps save on memory consumption. The implication of this is that files handled by webpack.static.config.js are only copied over when Webpack first runs. If you update an image for example, then you will need to stop and restart Webpack to pick up the change. This is not true for JS and SCSS files, which will be watched for change automatically.

Asset Bundling

Asset bundles for both JS and SCSS are defined in ./media/static-bundles.json. This is the file where you can define the bundle names that will get used in page templates. For example, a CSS bundle can be defined as:

"css": [
    {
        "files": [
            "css/firefox/new/basic/download.scss"
        ],
        "name": "firefox_new_download"
    }
]

Which can then be referenced in a page template using:

{{ css_bundle('firefox_new_download') }}

A JS bundle can be defied as:

"js": [
    {
        "files": [
            "protocol/js/protocol-modal.js",
            "js/firefox/new/basic/download.js"
        ],
        "name": "firefox_new_download"
    }
]

Which can then be referenced in a page template using:

{{ js_bundle('firefox_new_download') }}

Once you define a bundle in static-bundles.json, the webpack.config.js file will use these as entrypoints for compiling JS and CSS and watching for changes.

Writing JavaScript

Bedrock’s Webpack configuration supports some different options for writing JavaScript:

Default Configuration

Write example-script.js using ES5 syntax and features. Webpack will bundle the JS as-is, without any additional pre-processing.

Babel Configuration

Write example-script.es6.js using ES2015+ syntax. Webpack will transpile the code to ES5 using Babel. This is useful when you want to write modern syntax but still support older browsers.

Important

Whilst Babel will transpile most modern JS syntax to ES5 when suitable fallbacks exist, it won’t automatically include custom polyfills for everything since these can start to greatly increase bundle size. If you want to use Promise or async/await functions for example, then you will need to load polyfills for those. This can be done either at the page level, or globally in lib.js if it’s something that multiple pages would benefit from. But please pick and choose wisely, and be concious of performance.

For pages that are served to Firefox browsers only, such as /whatsnew, it is also possible to write native ES2015+ syntax and serve that directly in production. Here there is no need to include the .es6.js file extension. Instead, you can simply use .js instead. The rules that which files you can do this in are defined in our ESLint config.

Writing URL Patterns

URL patterns should be as strict as possible. It should begin with a ^ and end with /$ to make sure it only matches what you specifiy. It also forces a trailing slash. You should also give the URL a name so that other pages can reference it instead of hardcoding the URL. Example:

url(r'^channel/$', channel, name='mozorg.channel')

Bedrock comes with a handy shortcut to automate all of this:

from bedrock.mozorg.util import page
page('channel', 'mozorg/channel.html')

You don’t even need to create a view. It will serve up the specified template at the given URL (the first parameter). You can also pass template data as keyword arguments:

page('channel', 'mozorg/channel.html',
     latest_version=product_details.firefox_versions['LATEST_FIREFOX_VERSION'])

The variable latest_version will be available in the template.

Optimizing Images

Images can take a long time to load and eat up a lot of bandwidth. Always take care to optimize images before uploading them to the site.

The script img.sh can be used to optimize images locally on the command line:

  1. Before you run it for the first time you will need to run npm install to install dependencies

  2. Add the image files to git’s staging area git add *

  3. Run the script ./bin/img.sh

  4. The optimized files will not automatically be staged, so be sure to add them before commiting

The script will:

  • optimize JPG and PNG files using tinypng (
    • this step is optional since running compression on the same images over and over degrades them)

    • you will be prompted to add a TinyPNG API key

  • optimize SVG images locally with svgo

  • check that SVGs have a viewbox (needed for IE support)

  • check that images that end in -high-res have low res versions as well

Embedding Images

Images should be included on pages using helper functions.

static()

For a simple image, the static() function is used to generate the image URL. For example:

<img src="{{ static('img/firefox/new/firefox-logo.png') }}" alt="Firefox" />

will output an image:

<img src="/media/img/firefox/new/firefox-logo.png" alt="Firefox">

high_res_img()

For images that include a high-resolution alternative for displays with a high pixel density, use the high_res_img() function:

high_res_img('img/firefox/new/firefox-logo.png', {'alt': 'Firefox', 'width': '200', 'height': '100'})

The high_res_img() function will automatically look for the image in the URL parameter suffixed with ‘-high-res’, e.g. img/firefox/new/firefox-logo-high-res.png and switch to it if the display has high pixel density.

high_res_img() supports localized images by setting the ‘l10n’ parameter to True:

high_res_img('img/firefox/new/firefox-logo.png', {'l10n': True, 'alt': 'Firefox', 'width': '200', 'height': '100'})

When using localization, high_res_img() will look for images in the appropriate locale folder. In the above example, for the de locale, both standard and high-res versions of the image should be located at media/img/l10n/de/firefox/new/.

l10n_img()

Images that have translatable text can be handled with l10n_img():

<img src="{{ l10n_img('firefox/os/have-it-all/messages.jpg') }}" />

The images referenced by l10n_img() must exist in media/img/l10n/, so for above example, the images could include media/img/l10n/en-US/firefox/os/have-it-all/messages.jpg and media/img/l10n/es-ES/firefox/os/have-it-all/messages.jpg.

platform_img()

Finally, for outputting an image that differs depending on the platform being used, the platform_img() function will automatically display the image for the user’s browser:

platform_img('img/firefox/new/browser.png', {'alt': 'Firefox screenshot'})

platform_img() will automatically look for the images browser-mac.png, browser-win.png, browser-linux.png, etc. Platform image also supports hi-res images by adding ‘high-res’: True to the list of optional attributes.

platform_img() supports localized images by setting the ‘l10n’ parameter to True:

platform_img('img/firefox/new/firefox-logo.png', {'l10n': True, 'alt': 'Firefox screenshot'})

When using localization, platform_img() will look for images in the appropriate locale folder. In the above example, for the es-ES locale, all platform versions of the image should be located at media/img/l10n/es-ES/firefox/new/.

qrcode()

This is a helper function that will output SVG data for a QR Code at the spot in the template where it is called. It caches the results to the data/qrcode_cache directory, so it only generates the SVG data one time per data and box_size combination.

qrcode('https://accounts.firefox.com', 30)

The first argument is the data you’d like to encode in the QR Code (usually a URL), and the second is the “box size”. It’s a parameter that tells the generator how large to set the height and width parameters on the XML SVG tag, the units of which are “mm”. This can be overriden with CSS so you may not need to use it at all. The box_size parameter is optional.

Using Large Assets

We don’t want to (and if large enough GitHub won’t let us) commit large files to the bedrock repo. Files such as large PDFs or very-high-res JPG files (e.g. leadership team photos), or videos are not well-tracked in git and will make every checkout after they’re added slower and this diffs less useful. So we have another domain at which we upload these files: assets.mozilla.net

This domain is simply an AWS S3 bucket with a CloudFront CDN in front of it. It is highly available and fast. We’ve made adding files to this domain very simple using git-lfs. You simply install git-lfs, clone our assets.mozilla.net repo, and then add and commit files under the assets directory there as usual. Open a PR, and once it’s merged it will be automatically uploaded to the S3 bucket and be available on the domain.

For example, if you add a file to the repo under assets/pdf/the-dude-abides.pdf, it will be available as https://assets.mozilla.net/pdf/the-dude-abides.pdf. Once that is done you can link to that URL from bedrock as you would any other URL.

Writing Migrations

Bedrock uses Django’s built-in Migrations framework for its database migrations, and has no custom database routing, etc. So, no big surprises here – write things as you regularly would.

However, as with any complex system, care needs to be taken with schema changes that drop or rename database columns. Due to the way the rollout process works (ask for details directly from the team), an absent column can cause some of the rollout to enter a crashloop.

To avoid this, split your changes across releases, such as below.

For column renames:

  • Release 1: Add your new column

  • Release 2: Amend the codebase to use it instead of the old column

  • Release 3: Clean up - drop the old, deprecated column, which should not be referenced in code at this point.

For column drops:

  • Release 1: Update all code that uses the relevant column, so that nothing interacts with it any more.

  • Release 2: Clean up - drop the old, deprecated column.

With both paths, check for any custom schema or data migrations that might reference the deprecated column.

Writing Views

You should rarely need to write a view for mozilla.org. Most pages are static and you should use the page function documented above.

If you need to write a view and the page is translated or translatable then it should use the l10n_utils.render() function to render the template.

from lib import l10n_utils

def my_view(request):
    # do your fancy things
    ctx = {'template_variable': 'awesome data'}
    return l10n_utils.render(request, 'app/template.html', ctx)

Make sure to namespace your templates by putting them in a directory named after your app, so instead of templates/template.html they would be in templates/blog/template.html if blog was the name of your app.

If you prefer to use Django’s Generic View classes we have a convenient helper for that. You can use it either to create a custom view class of your own, or use it directly in a urls.py file.

# app/views.py
from lib.l10n_utils import L10nTemplateView

class FirefoxRoxView(L10nTemplateView):
    template_name = 'app/firefox-rox.html'

# app/urls.py
urlpatterns = [
    # from views.py
    path('firefox/rox/', FirefoxRoxView.as_view()),
    # directly
    path('firefox/sox/', L10nTemplateView.as_view(template_name='app/firefox-sox.html')),
]

The L10nTemplateView functionality is mostly in a template mixin called LangFilesMixin which you can use with other generic Django view classes if you need one other than TemplateView.

Variation Views

We have a generic view that allows you to easily create and use a/b testing templates. If you’d like to have either separate templates or just a template context variable for switching, this will help you out. For example.

# urls.py

from django.conf.urls import url

from bedrock.utils.views import VariationTemplateView

urlpatterns = [
    url(r'^testing/$',
        VariationTemplateView.as_view(template_name='testing.html',
                                      template_context_variations=['a', 'b']),
        name='testing'),
]

This will give you a context variable called variation that will either be an empty string if no param is set, or a if ?v=a is in the URL, or b if ?v=b is in the URL. No other options will be valid for the v query parameter and variation will be empty if any other value is passed in for v via the URL. So in your template code you’d simply do the following:

{% if variation == 'b' %}<p>This is the B variation of our test. Enjoy!</p>{% endif %}

If you’d rather have a fully separate template for your test, you can use the template_name_variations argument to the view instead of template_context_variations.

# urls.py

from django.conf.urls import url

from bedrock.utils.views import VariationTemplateView

urlpatterns = [
    url(r'^testing/$',
        VariationTemplateView.as_view(template_name='testing.html',
                                      template_name_variations=['1', '2']),
        name='testing'),
]

This will not provide any extra template context variables, but will instead look for alternate template names. If the URL is testing/?v=1, it will use a template named testing-1.html, if v=2 it will use testing-2.html, and for everything else it will use the default. It simply puts a dash and the variation value between the template file name and file extension.

It is theoretically possible to use the template name and template context versions of this view together, but that would be an odd situation and potentially inappropriate for this utility.

You can also limit your variations to certain locales. By default the variations will work for any localization of the page, but if you supply a list of locales to the variation_locales argument to the view then it will only set the variation context variable or alter the template name (depending on the options explained above) when requested at one of said locales. For example, the template name example above could be modified to only work for English or German like so

# urls.py

from django.conf.urls import url

from bedrock.utils.views import VariationTemplateView

urlpatterns = [
    url(r'^testing/$',
        VariationTemplateView.as_view(template_name='testing.html',
                                      template_name_variations=['1', '2'],
                                      variation_locales=['en-US', 'de']),
        name='testing'),
]

Any request to the page in for example French would not use the alternate template even if a valid variation were given in the URL.

Note

If you’d like to add this functionality to an existing Class-Based View, there is a mixin that implements this pattern that should work with most views: bedrock.utils.views.VariationMixin.

Geo Template View

Now that we have our CDN configured properly, we can also just swap out templates per request country. This is very similar to the above, but it will simply use the proper template for the country from which the request originated.

from bedrock.base.views import GeoTemplateView

class CanadaIsSpecialView(GeoTemplateView):
    geo_template_names = {
        'CA': 'mozorg/canada-is-special.html',
    }
    template_name = 'mozorg/everywhere-else-is-also-good.html'

For testing purposes while you’re developing or on any deployment that is not accessed via the production domain (www.mozilla.org) you can append your URL with a geo query param (e.g. /firefox/?geo=DE) and that will take precedence over the country from the request header.

Other Geo Stuff

There are a couple of other tools at your disposal if you need to change things depending on the location of the user. You can use the bedrock.base.geo.get_country_from_request function in a view and it will return the country code for the request (either from the CDN or the query param, just like above).

from bedrock.base.geo import get_country_from_request

def dude_view(request):
    country = get_country_from_request(request)
    if country == 'US':
        # do a thing for the US
    else:
        # do the default thing

The other convenience available is that the country code, either from the CDN or the query param, is avilable in any template in the country_code variable. This allows you to change anything about how the template renders based on the location of the user.

{% if country_code == 'US' %}
    <h1>GO MURICA!</h1>
{% else %}
    <h1>Yay World!</h1>
{% endif %}

Coding Style

Bedrock uses the following open source tools to follow coding styles and conventions, as well as applying automatic code formatting:

  • black for Python code formatting.

  • flake8 for Python style and code quality rules.

  • isort for Python import ordering consistency.

  • Prettier for JavaScript code formatting.

  • ESLint for JavaScript code quality rules.

  • Stylelint for Sass/CSS style and code quality rules.

For front-end HTML & CSS conventions, bedrock uses Mozilla’s Protocol design system for building components. You can read the Protocol documentation site for more information.

Mozilla also has some more general coding styleguides available, although some of these are now rather outdated:

Test coverage

When the Python tests are run, a coverage report is generated, showing which lines of the codebase have tests that execute them, and which do not. You can view this report in your browser at file:///path/to/your/checkout/of/bedrock/python_coverage/index.html.

When adding code, please aim to provide solid test coverage, using the coverage report as a guide. This doesn’t necessarily mean every single line needs a test, and 100% coverage doesn’t mean 0% defects.

Configuring your Code Editor

Bedrock includes an .editorconfig file in the root directory that you can use with your code editor to help maintain consistent coding styles. Please see editorconfig.org. for a list of supported editors and available plugins.

Working with Protocol

Bedrock uses the Protocol Design System to quickly produce consistent, stable components.

When we find we are frequently re-using code for a particular Protocol component (i.e. Split), we convert it to a macro template with parameters for customization.

You can find parameter definitions for the available Protocol macros below.

Picto

  • title

    String indicating heading text (usually a translation id wrapped in ftl function)

    Default: None

    Example: title=ftl('misinformation-why-trust-firefox')

  • heading_level

    Number indicating heading level for title text. Should be based on semantic meaning, not presentational styling.

    Default: 3

    Example: heading_level=2

  • body

    A boolean attribute. If true, it will show the contents of the card, if false, it will hide the contents.

    Default: False

    Example: body=True

  • image_url

    image location to be used. Start it off with ‘img/…’.

    Default: ‘’

    Example: image_url='img/icons/mountain-purple.svg'

  • base_el

    The element the content of the picto will be read as in HTML. For example, if the Picto macro is wrapped in a ul tag, the base_el would be an li tag.

    Default: div

    Example: base_el='li'

  • class

    String adding class(es) to the base el tag.

    Default: None

    Example: class='trust'

  • image_width

    Number indicating width of image.

    Default: 64

    Example: image_width='153px'

  • include_highres_image

    Boolean that determines whether the image can also appear in high res.

    Default: False

    Example: include_highres_image=True

  • l10n_image

    Boolean to indicate if image has translatable text.

    Default: False

    Example: l10n_image=True

  • lazy_loading

    Boolean to provide “lazy” value for “loading” attribute. This will be “eager” by default. Lazy loading defers fetching of images to a browser decision based on user scroll and connection.

    Default: False

    Example: lazy_loading=True

Call out

  • title

    Required. String indicating heading text (usually a translation id wrapped in ftl function).

    Default: N/A

    Example: title=ftl('firefox-privacy-hub-read-the-privacy-notice-for')

  • desc

    String indicating paragraph text (usually a translation id wrapped in ftl function).

    Default: None

    Example: desc=ftl('firefox-channel-test-beta-versions-of-firefox-ios')

  • class

    String adding class(es) to the section tag.

    Default: None

    Example: class='mzp-t-firefox ' + product_class

  • include_cta

    Boolean indicating whether or not to include the body of the macro call (usually a mix of text and html).

    Default: None

    Example: include_cta=True

  • heading_level

    Number indicating heading level for title text. Should be based on semantic meaning, not presentational styling.

    Default: 2

    Example: heading_level=1

Split

  • block_id

    String providing id to the section tag (usually if it needs to be used as an in-page link).

    Default: None

    Example: id='nextgen

  • base_el

    String for block HTML tag not required.

    Default: section

    Example: base_el='aside'

  • block_class

    String providing class(es) to the section tag.

    Default: None

    Example: block_class='mzp-l-split-reversed mzp-l-split-center-on-sm-md

  • theme_class

    String providing theme class(es) to a container div tag inside the section.

    Default: None

    Example: theme_class='mzp-t-dark'

  • body_class

    String providing class(es) to the body (text content) div inside the section.

    Default: None

    Example: Not currently in use

  • image_url

    Path to image location.

    Default: None

    Example: image_url=’img/firefox/accounts/trailhead/value-respect.jpg’

  • media_class

    String providing class(es) to the media div inside the section.

    Default: None

    Example: media_class='mzp-l-split-h-center'

  • include_highres_image

    Boolean that determines whether the image can also appear in high res.

    Default: False

    Example: include_highres_image=True

  • l10n_image

    Boolean to indicate if image has translatable text.

    Default: False

    Example: l10n_image=True

  • image_alt

    String providing alt text to the image.

    Default: ‘’

    Example: Not currently in use

  • media_after

    Boolean to determine if image appears before or after text when stacked on mobile size screens.

    Default: False

    Example: media_after=True

  • media_include

    Path to video media.

    Default: None

    Example: media_include='firefox/facebookcontainer/includes/video.html'

Billboard

  • title

    Required. String indicating heading text (usually a translation id wrapped in ftl function).

    Default: N/A

    Example: title=ftl('about-the-mozilla-manifesto')

  • ga_title

    Required. String providing value for data-link-name attribute on cta.

    Default: N/A

    Example: ga_title='The Mozilla Manifesto'

  • desc

    Required.String indicating paragraph text (usually a translation id wrapped in ftl function).

    Default: N/A

    Example: desc=ftl('about-the-principles-we-wrote-in')

  • link_cta

    Required. String indicating link text (usually a translation id wrapped in an ftl function).

    Default: N/A

    Example: link_cta=ftl('about-read-the-manifesto')

  • link_url

    Required. String or url helper function provides href value for cta link.

    Default: N/A

    Example: link_url=url('mozorg.about.manifesto')

  • image_url

    Required. Path to image location.

    Default: N/A

    Example: image_url='img/home/2018/billboard-healthy-internet.png'

  • include_highres_image

    Boolean that determines whether the image can also appear in high res.

    Default: False

    Example: include_highres_image=True

  • reverse

    Uses default layout: mzp-l-billboard-rightReverse will switch to billboard (text) left.

    Default: False

    Example: reverse=True

  • heading_level

    Number indicating heading level for title text. Should be based on semantic meaning, not presentational styling.

    Default: 2

    Example: heading_level=1

Feature Card

  • title

    String indicating heading text (usually a translation id wrapped in ftl function).

    Default: None

    Example: title=ftl('firefox-home-firefox-browser')

  • ga_title

    String used as an identifying name on a link for google analytics. Only used if link_url and link_cta are provided as well.

    Default: None

    Example: ga_title='Firefox Windows'

  • image_url

    Path to image location.

    Default: N/A

    Example: image_url=’img/firefox/accounts/trailhead/value-respect.jpg’

  • class

    String adding class(es) to the section tag.

    Default: None

    Example: class=’mzp-l-card-feature-left-half t-mozvpn’

  • link_url

    String or url helper function provides href value for cta link. Only used if link_cta is provided as well.

    Default: None

    Example: link_url=url('firefox.privacy.index')

  • link_cta

    String indicating link text (usually a translation id wrapped in an ftl function). Only used if link_url is provided as well.

    Default: None

    Example: link_cta=ftl('ui-learn-more')

  • include_highres_image

    Boolean that determines whether the image can also appear in high res.

    Default: False

    Example: include_highres_image=True

  • l10n_image

    Boolean to indicate if image has translatable text.

    Default: False

    Example: l10n_image=True

  • aspect_ratio

    aspect_ratio String with an mzp class name indicating desired aspect ratio (adds class to section tag).

    Default: False

    Example: aspect_ratio='mzp-has-aspect-3-2'

  • heading_level

    Number indicating heading level for title text. Should be based on semantic meaning, not presentational styling.

    Default: 2

    Example: heading_level=3

  • media_after

    Boolean to determine if image appears before or after text when stacked on mobile size screens.

    Default: False

    Example: media_after=True

Card

  • youtube_id

    String indicating the Youtube ID found at the end of a Youtube video URL. Used when we are embedding a video to the card rather than an image.

    Default: N/A

    Example: youtube_id='aHpCLDQ_2ns'

  • title

    Required. String indicating heading text (usually a translation id wrapped in ftl function).

    Default: N/A

    Example: title=ftl('about-the-mozilla-manifesto')

  • ga_title

    Required. String providing value for data-link-name attribute on cta.

    Default: N/A

    Example: ga_title='The Mozilla Manifesto'

  • desc

    Required. String indicating paragraph text (usually a translation id wrapped in ftl function).

    Default: N/A

    Example: desc=ftl('about-the-principles-we-wrote-in')

  • aspect_ratio

    String indicating size/aspect ratio of the card (make sure to have it even if it’s in a defined Card Layout.

    Default: N/A

    Example: aspect_ratio=’mzp-has-aspect-16-9’

  • link_url

    Required. String or url helper function provides href value for cta link.

    Default: N/A

    Example: link_url=url('mozorg.about.manifesto')

  • image_url

    Required. Path to image location.

    Default: N/A

    Example: image_url='img/home/2018/billboard-healthy-internet.png'

  • include_highres_image

    Required. Boolean that determines whether the image can also appear in high res.

    Default: N/A

    Example: include_highres_image=True

  • l10n_image

    Boolean to indicate if image has translatable text.

    Default: False

    Example: l10n_image=True

  • heading_level

    Number indicating heading level for title text. Should be based on semantic meaning, not presentational styling.

    Default: 3

    Example: heading_level=2