build: move collectstatic ignore patterns into configuration

Django provides the `collectstatic` management command, which collects static
assets into the STATIC_ROOT so that they can be served by some system external
to Django (like nginx or caddy), as is usually desired in production environments.

edx-platform contains several types of files that we don't want to be collected
into the STATIC_ROOT. Previously, these files had to be supplied to the manageme
nt command using the `--ignore` option:

    ./manage.py lms collectstatic --ignore geoip --ignore sass ...etc
    ./manage.py cms collectstatic --ignore geoip --ignore sass ...etc

This yields a long, hard-to-remember command. Paver wrapped the command in its
big `paver update_assets` task, but that task also builds assets, which is totally
overkill when you're just trying to collect them.

Fortunately, `collectstatic`'s default ignore patterns can be configured by
defining a custom AppConfig class. We define such an config
(`EdxPlatformStaticFilesConfig`) for LMS and CMS. Now, devs can collect LMS and
CMS assets with just:

    ./manage.py lms collectstatic
    ./manage.py cms collectstatic

Further reading on collecstatic and --ignore:
https://docs.djangoproject.com/en/3.2/ref/contrib/staticfiles/#customizing-the-i
gnored-pattern-list

Further reading on eschewing Paver:
https://github.com/openedx/edx-platform/blob/master/docs/decisions/0017-reimplem
ent-asset-processing.rst

Closes: openedx#31658

cms/envs/common.py

@@ -1565,8 +1565,12 @@
     'django.contrib.sessions',
     'django.contrib.sites',
     'django.contrib.messages',
-    'django.contrib.staticfiles',
+
+    # Tweaked version of django.contrib.staticfiles
+    'openedx.core.lib.staticfiles_config.EdxPlatformStaticFilesConfig',
+
     'django_celery_results',
+
     'method_override',
 
     # Common Initialization

lms/envs/common.py

@@ -2955,7 +2955,10 @@ def _make_locale_paths(settings):  # pylint: disable=missing-function-docstring
     'django.contrib.redirects',
     'django.contrib.sessions',
     'django.contrib.sites',
-    'django.contrib.staticfiles',
+
+    # Tweaked version of django.contrib.staticfiles
+    'openedx.core.lib.staticfiles_config.EdxPlatformStaticFilesConfig',
+
     'django_celery_results',
 
     # Common Initialization

openedx/core/lib/staticfiles_config.py

@@ -0,0 +1,31 @@
+"""
+Configuration utilities for static assets. Shared by LMS and CMS.
+"""
+from django.contrib.staticfiles.apps import StaticFilesConfig
+
+
+class EdxPlatformStaticFilesConfig(StaticFilesConfig):
+    """
+    A thin wrapper around the standard django.contrib.staticfiles app
+    which adds the proper file & folder ignore patterns for edx-platform
+    static asset collection.
+
+    This allows devs & operators to run:
+        ./manage.py [lms|cms] collectstatic
+
+    instead of:
+        ./manage.py [lms|cms] collectstatic --ignore geoip --ignore sass ... etc.
+    """
+    ignore_patterns = StaticFilesConfig.ignore_patterns + [
+
+        "geoip",  # Geo-IP data, only accessed in Python
+        "sass",  # We compile these out, don't need the source files in staticfiles
+        "xmodule_js",  # Symlink for tests.
+
+        # Karma test related files:
+        "fixtures",
+        "karma_*.js",
+        "spec",
+        "spec_helpers",
+        "spec-helpers",
+    ]

pavelib/assets.py

@@ -692,30 +692,9 @@ def collect_assets(systems, settings, **kwargs):
     `settings` is the Django settings module to use.
     `**kwargs` include arguments for using a log directory for collectstatic output. Defaults to /dev/null.
     """
-    ignore_patterns = [
-        # Karma test related files...
-        "fixtures",
-        "karma_*.js",
-        "spec",
-        "spec_helpers",
-        "spec-helpers",
-        "xmodule_js",  # symlink for tests
-
-        # Geo-IP data, only accessed in Python
-        "geoip",
-
-        # We compile these out, don't need the source files in staticfiles
-        "sass",
-    ]
-
-    ignore_args = " ".join(
-        f'--ignore "{pattern}"' for pattern in ignore_patterns
-    )
-
     for sys in systems:
         collectstatic_stdout_str = _collect_assets_cmd(sys, **kwargs)
-        sh(django_cmd(sys, settings, "collectstatic {ignore_args} --noinput {logfile_str}".format(
-            ignore_args=ignore_args,
+        sh(django_cmd(sys, settings, "collectstatic --noinput {logfile_str}".format(
             logfile_str=collectstatic_stdout_str
         )))
         print(f"\t\tFinished collecting {sys} assets.")