Override default icon tag

[oniko94]

I have an application that uses Weblate to manage translations. I use weblate/weblate Docker image, with my own customizations built as a separate Python package extending this image and built on top of it. The problem is that in the Weblate HTML templates there is an icon template tag that is supposed to load SVG icons from a STATIC_ROOT or a CACHE_DIR location - but my application runs in a serverless setup and as such offloads all of the static resources to a S3 bucket. For most of the resources it works fine, but due to that template tag logic the icons are not loaded and I get these error messages -

weblate-1   | gunicorn stderr | [2025-01-21 12:41:08,913: WARNING/1540] Could not load icon: FileNotFoundError: [Errno 2] No such file or directory: '/app/cache/static/icons/weblate.svg'
weblate-1   | gunicorn stderr | [2025-01-21 12:41:08,918: WARNING/1540] Could not load icon: FileNotFoundError: [Errno 2] No such file or directory: '/app/cache/static/icons/wrench.svg'
weblate-1   | gunicorn stderr | [2025-01-21 12:41:08,919: WARNING/1540] Could not load icon: FileNotFoundError: [Errno 2] No such file or directory: '/app/cache/static/icons/plus.svg'
weblate-1   | gunicorn stderr | [2025-01-21 12:41:08,923: WARNING/1540] Could not load icon: FileNotFoundError: [Errno 2] No such file or directory: '/app/cache/static/icons/dots.svg'

I wrote my custom template tag, which I placed in my custom module weblate_customization/templatetags/icon.py, but it does not override weblate default icon loading logic, and I cannot access the default templates in my code, unless I monkey-patch. The code for the default icon template tag exists within weblate.utils app, which is included within the base image and loads all of the utility functionality required by the application to function, so I can't just throw it out. Is there a way to make Django load my custom version of this template tag, instead of the one provided by weblate?

The logic of the default template tag goes like this:

weblate/weblate/utils/templatetags/icon.py

@register.simple_tag()
def icon(name):
    """
    Inlines SVG icon.

    Inlining is necessary to be able to apply CSS styles on the path.
    """
    if not name:
        msg = "Empty icon name"
        raise ValueError(msg)

    if name not in CACHE:
        if name.startswith("state/"):
            icon_file = os.path.join(settings.STATIC_ROOT, name)
        else:
            icon_file = os.path.join(settings.STATIC_ROOT, "icons", name)
        try:
            with open(icon_file) as handle:
                CACHE[name] = mark_safe(handle.read())  # noqa: S308
        except OSError:
            report_error("Could not load icon")
            return ""

    return CACHE[name]

Whereas the logic I am trying to implement is the following:

weblate_customization/templatetags/icon.py

@register.simple_tag()
def icon(name: str) -> str:
    """
    Inlines SVG icon.

    Inlining is necessary to be able to apply CSS styles on the path.
    """
    if not name:
        msg = "Empty icon name"
        raise ValueError(msg)

    if name not in CACHE:
        if name.startswith("state/"):
            icon_url = os.path.join(settings.STATIC_URL, name)
        else:
            icon_url = os.path.join(settings.STATIC_URL, "icons", name)

        try:
            icon_file = request.urlopen(icon_url)
        except OSError:
            report_error("Could not load icon")
            return ""
        else:
            CACHE[name] = ""
            for line in icon_file.readlines():
                CACHE[name] += line

    return mark_safe(CACHE[name])

How do I make Django to use the simple tag I specify instead of the default one? I cannot rename it to something like "new_icon" and overwrite the templates since the templates come from the base docker image, as well as the weblate.utils module itself, where the template tags are defined and registered.

[nijel]

Would the following code work in your case?

from django.contrib.staticfiles.storage import staticfiles_storage
staticfiles_storage.open('icons/plus.svg')

[oniko94]

@nijel Thanks for the suggestion! I'm not sure where I would put this code.

Just in case, here are my custom storage settings:

CDN_ROOT = get_env_str("CDN_ROOT")
if CDN_ROOT:
    AWS_S3_CUSTOM_DOMAIN = f"{CDN_ROOT}/weblate"
else:
    AWS_S3_CUSTOM_DOMAIN = f"{AWS_STORAGE_BUCKET_NAME}.s3.amazonaws.com"

CDN_URL = f"https://{AWS_S3_CUSTOM_DOMAIN}"

AWS_LOCATION = "static"
STATIC_URL = f"https://{AWS_S3_CUSTOM_DOMAIN}/{AWS_LOCATION}/"
#CACHE_DIR = STATIC_URL
STATICFILES_STORAGE = "weblate_zoop.ext.backends.StaticStorage"
# Serve media from storage
PUBLIC_MEDIA_LOCATION = "media"
MEDIA_URL = f"https://{AWS_S3_CUSTOM_DOMAIN}/{PUBLIC_MEDIA_LOCATION}/"
DEFAULT_FILE_STORAGE = "weblate_zoop.ext.backends.MediaStorage"

STORAGES = {
    "default": {
        "BACKEND": DEFAULT_FILE_STORAGE,
    },
    "staticfiles": {
        "BACKEND": STATICFILES_STORAGE,
    },
}

And here are my custom storage classes:

weblate_customization/ext/backends.py

from django.conf import settings
from storages.backends.s3boto3 import S3Boto3Storage


class StaticStorage(S3Boto3Storage):
    location = getattr(settings, "AWS_LOCATION", "static")
    default_acl = "public-read"
    querystring_auth = False


class MediaStorage(S3Boto3Storage):
    location = getattr(settings, "PUBLIC_MEDIA_LOCATION", "media")
    default_acl = "public-read"
    file_overwrite = False
    querystring_auth = False

[nijel]

I've rewritten icons loading to be compatible with such static file storage in #13619.