Download fonts at app startup instead

We can't bake the font into the Docker image as such, because we mount
the volumes which blows away anything we have in the app tree
beforehand.

We could stash it somewhere in the image and then copy it from there on
app startup or something, but at that point we might as well just
download it as part of the app startup.

Dockerfile

@@ -6,13 +6,6 @@ RUN mkdir /app /app/static /app/images
 
 WORKDIR /app
 
-# Use RUN curl because ADD will re-download the file every time to make sure it
-# hasn't changed, which is exactly what we don't want
-RUN mkdir -p /app/static/fonts/source_han_sans
-RUN curl \
-  https://github.com/adobe-fonts/source-han-sans/raw/release/Variable/OTC/SourceHanSans-VF.ttf.ttc \
-  -o /app/static/fonts/source_han_sans/SourceHanSans-VF.ttf.ttc
-
 COPY requirements.txt /app/
 RUN pip install -r requirements.txt --no-cache-dir
 RUN apt-get update && apt-get install -y gettext libgettextpo-dev tidy && apt-get clean

bookwyrm/apps.py

@@ -0,0 +1,35 @@
+import os
+import urllib
+import logging
+
+from django.apps import AppConfig
+
+from bookwyrm import settings
+
+logger = logging.getLogger(__name__)
+
+def download_file(url, destination):
+    try:
+        stream = urllib.request.urlopen(url)
+        with open(destination, "b+w") as f:
+            f.write(stream.read())
+    except (urllib.error.HTTPError, urllib.error.URLError):
+        logger.error("Failed to download file %s", url)
+
+
+class BookwyrmConfig(AppConfig):
+    name = "bookwyrm"
+    verbose_name = "BookWyrm"
+
+    def ready(self):
+        if settings.ENABLE_PREVIEW_IMAGES and settings.FONTS:
+            # Download any fonts that we don't have yet
+            logger.debug("Downloading fonts..")
+            for name, config in settings.FONTS.items():
+                font_path = os.path.join(
+                    settings.FONT_DIR, config["directory"], config["filename"]
+                )
+
+                if "url" in config and not os.path.exists(font_path):
+                    logger.info("Just a sec, downloading %s", name)
+                    download_file(config["url"], font_path)

bookwyrm/preview_images.py

@@ -4,6 +4,8 @@ import os
 import textwrap
 from io import BytesIO
 from uuid import uuid4
+import urllib
+import logging
 
 import colorsys
 from colorthief import ColorThief
@@ -17,29 +19,37 @@ from django.db.models import Avg
 from bookwyrm import models, settings
 from bookwyrm.tasks import app
 
+logger = logging.getLogger(__name__)
 
 IMG_WIDTH = settings.PREVIEW_IMG_WIDTH
 IMG_HEIGHT = settings.PREVIEW_IMG_HEIGHT
 BG_COLOR = settings.PREVIEW_BG_COLOR
 TEXT_COLOR = settings.PREVIEW_TEXT_COLOR
 DEFAULT_COVER_COLOR = settings.PREVIEW_DEFAULT_COVER_COLOR
+DEFAULT_FONT = settings.PREVIEW_DEFAULT_FONT
 TRANSPARENT_COLOR = (0, 0, 0, 0)
 
 margin = math.floor(IMG_HEIGHT / 10)
 gutter = math.floor(margin / 2)
 inner_img_height = math.floor(IMG_HEIGHT * 0.8)
 inner_img_width = math.floor(inner_img_height * 0.7)
-font_dir = os.path.join(settings.STATIC_ROOT, "fonts/source_han_sans")
+
+
+def get_imagefont(name, size):
+    try:
+        config = settings.FONTS[name]
+        path = os.path.join(settings.FONT_DIR, config["directory"], config["filename"])
+        return ImageFont.truetype(path, size)
+    except KeyError:
+        logger.error("Font %s not found in config", name)
+    except OSError:
+        logger.error("Could not load font %s from file", name)
+
+    return ImageFont.load_default()
 
 
 def get_font(weight, size=28):
-    """Loads custom font"""
+    font = get_imagefont(DEFAULT_FONT, size)
-    font_path = os.path.join(font_dir, "SourceHanSans-VF.ttf.ttc")
-
-    try:
-        font = ImageFont.truetype(font_path, size)
-    except OSError:
-        font = ImageFont.load_default()
 
     try:
         if weight == "light":

bookwyrm/settings.py

@@ -35,6 +35,9 @@ LOCALE_PATHS = [
 ]
 LANGUAGE_COOKIE_NAME = env.str("LANGUAGE_COOKIE_NAME", "django_language")
 
+STATIC_ROOT = os.path.join(BASE_DIR, env("STATIC_ROOT", "static"))
+MEDIA_ROOT = os.path.join(BASE_DIR, env("MEDIA_ROOT", "images"))
+
 DEFAULT_AUTO_FIELD = "django.db.models.AutoField"
 
 # Preview image
@@ -44,6 +47,16 @@ PREVIEW_TEXT_COLOR = env.str("PREVIEW_TEXT_COLOR", "#363636")
 PREVIEW_IMG_WIDTH = env.int("PREVIEW_IMG_WIDTH", 1200)
 PREVIEW_IMG_HEIGHT = env.int("PREVIEW_IMG_HEIGHT", 630)
 PREVIEW_DEFAULT_COVER_COLOR = env.str("PREVIEW_DEFAULT_COVER_COLOR", "#002549")
+PREVIEW_DEFAULT_FONT = env.str("PREVIEW_DEFAULT_FONT", "Source Han Sans")
+
+FONTS = {
+    "Source Han Sans": {
+        "directory": "source_han_sans",
+        "filename": "SourceHanSans-VF.ttf.ttc",
+        "url": "https://github.com/adobe-fonts/source-han-sans/raw/release/Variable/OTC/SourceHanSans-VF.ttf.ttc",
+    }
+}
+FONT_DIR = os.path.join(STATIC_ROOT, "fonts")
 
 # Quick-start development settings - unsuitable for production
 # See https://docs.djangoproject.com/en/3.2/howto/deployment/checklist/
@@ -310,13 +323,8 @@ if USE_S3:
     MEDIA_FULL_URL = MEDIA_URL
     STATIC_FULL_URL = STATIC_URL
     DEFAULT_FILE_STORAGE = "bookwyrm.storage_backends.ImagesStorage"
-    # I don't know if it's used, but the site crashes without it
-    STATIC_ROOT = os.path.join(BASE_DIR, env("STATIC_ROOT", "static"))
-    MEDIA_ROOT = os.path.join(BASE_DIR, env("MEDIA_ROOT", "images"))
 else:
     STATIC_URL = "/static/"
-    STATIC_ROOT = os.path.join(BASE_DIR, env("STATIC_ROOT", "static"))
     MEDIA_URL = "/images/"
     MEDIA_FULL_URL = f"{PROTOCOL}://{DOMAIN}{MEDIA_URL}"
     STATIC_FULL_URL = f"{PROTOCOL}://{DOMAIN}{STATIC_URL}"
-    MEDIA_ROOT = os.path.join(BASE_DIR, env("MEDIA_ROOT", "images"))