add django system checks for path configuration

imagetagger/imagetagger/base/__init__.py

@@ -0,0 +1 @@
+from imagetagger.base.checks import *

imagetagger/imagetagger/base/checks.py

@@ -0,0 +1,40 @@
+from typing import List
+from os.path import join, dirname
+from django.core.checks import register, CheckMessage, Error
+from django.conf import settings
+from fs.base import FS
+from . import filesystem
+
+
+def _create_check_file(fs: FS, path: str):
+    fs.makedirs(dirname(path), recreate=True)
+    fs.create(path, wipe=True)
+    fs.writebytes(path, bytes('This is a demo file content', encoding='ASCII'))
+    fs.remove(path)
+
+
+@register
+def check_fs_root_config(app_configs, **kwargs) -> List[CheckMessage]:
+    try:
+        _create_check_file(filesystem.root(), join(settings.IMAGE_PATH, 'check.tmp.jpeg'))
+        _create_check_file(filesystem.root(), join(settings.TOOLS_PATH, 'check.tmp.py'))
+        return []
+    except Exception as e:
+        return [Error(
+            'Persistent filesystem is incorrectly configured. Could not create and delete a temporary check file',
+            hint=f'Check your FS_URL settings (currently {settings.FS_URL})',
+            obj=e,
+        )]
+
+
+@register
+def check_tmp_fs_config(app_configs, **kwargs) -> List[CheckMessage]:
+    try:
+        _create_check_file(filesystem.tmp(), join(settings.TMP_IMAGE_PATH, 'check.tmp.jpeg'))
+        return []
+    except Exception as e:
+        return [Error(
+            'Persistent filesystem is incorrectly configured. Could not create and delete a temporary check file',
+            hint=f'Check your TMP_FS_URL settings (currently {settings.TMP_FS_URL})',
+            obj=e,
+        )]

imagetagger/imagetagger/base/filesystem.py

@@ -6,7 +6,7 @@
 def root() -> fs.base.FS:
     """Get the root filesystem object or create one by opening `settings.FS_URL`."""
     if root._instance is None:
-        root._instance = fs.open_fs(settings.FS_URL)
+        root._instance = fs.open_fs(settings.FS_URL, writeable=True)
     return root._instance
 
 root._instance = None
@@ -15,7 +15,7 @@ def root() -> fs.base.FS:
 def tmp() -> fs.base.FS:
     """Get the tmp filesystem object or create one by opening `settings.TMP_FS_URL`."""
     if tmp._instance is None:
-        tmp._instance = fs.open_fs(settings.TMP_FS_URL)
+        tmp._instance = fs.open_fs(settings.TMP_FS_URL, writeable=True)
     return tmp._instance
 
 tmp._instance = None

imagetagger/imagetagger/settings.py

@@ -216,7 +216,7 @@ def post_setup(cls):
     TOOL_UPLOAD_NOTICE = values.Value(environ_prefix='IT', default='')
     ENABLE_ZIP_DOWNLOAD = values.BooleanValue(environ_prefix='IT', default=is_in_docker())
     USE_NGINX_IMAGE_PROVISION = values.BooleanValue(environ_prefix='IT', default=is_in_docker())
-    FS_URL = values.Value(environ_prefix='IT', default=path_join(os.path.dirname(BASE_DIR), 'data'))
+    FS_URL = values.Value(environ_prefix='IT', default=path_join(BASE_DIR, 'data'))
     TMP_FS_URL = values.Value(environ_prefix='IT', default='temp://imagetagger')
 
     SENTRY_REPORTING_ENABLED = values.BooleanValue(environ_prefix='IT', default=False)