Backport FakeStorageSubclass from versions/next

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

HISTORY.rst

@@ -28,6 +28,9 @@
   doing atabase etup.
 - Added support for YAML encoded environment variables to the platform
   templates apps.
+- Move YAML code to its own module.
+- Move Django and Celery settings.
+- Backport FakeStorageSubclass from versions/next.
 
 3.2.6 (2019-07-10)
 ==================

docs/releases/3.3.rst

@@ -38,6 +38,14 @@ Changes
   is now done using MAYAN_DATABASES to mirror Django way of doing database setup.
 - Added support for YAML encoded environment variables to the platform 
   templates apps.
+- Move YAML code to its own module. Code now resides in common.serialization
+  in the form of two new functions: yaml_load and yaml_dump.
+- Move Django and Celery settings. Django settings now reside in the smart
+  settings app. Celery settings now reside in the task manager app.
+- Backport FakeStorageSubclass from versions/next. Placeholder class to allow
+  serializing the real storage subclass to support migrations.
+  Used by all configurable storages.
+
 
 Removals
 --------

mayan/apps/common/storages.py

@@ -1,11 +1,11 @@
 from __future__ import unicode_literals
 
-from django.utils.module_loading import import_string
+from mayan.apps.storage.utils import get_storage_subclass
 
 from .settings import (
     setting_shared_storage, setting_shared_storage_arguments
 )
 
-storage_sharedupload = import_string(
+storage_sharedupload = get_storage_subclass(
     dotted_path=setting_shared_storage.value
 )(**setting_shared_storage_arguments.value)

mayan/apps/document_signatures/migrations/0009_auto_20190711_0544.py

@@ -0,0 +1,22 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.22 on 2019-07-11 05:44
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import mayan.apps.document_signatures.models
+import mayan.apps.storage.classes
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('document_signatures', '0008_auto_20180429_0759'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='detachedsignature',
+            name='signature_file',
+            field=models.FileField(blank=True, null=True, storage=mayan.apps.storage.classes.FakeStorageSubclass(), upload_to=mayan.apps.document_signatures.models.upload_to, verbose_name='Signature file'),
+        ),
+    ]

mayan/apps/document_signatures/storages.py

@@ -1,11 +1,11 @@
 from __future__ import unicode_literals
 
-from django.utils.module_loading import import_string
+from mayan.apps.storage.utils import get_storage_subclass
 
 from .settings import (
     setting_storage_backend, setting_storage_backend_arguments
 )
 
-storage_detachedsignature = import_string(
+storage_detachedsignature = get_storage_subclass(
     dotted_path=setting_storage_backend.value
 )(**setting_storage_backend_arguments.value)

mayan/apps/document_states/storages.py

@@ -1,12 +1,12 @@
 from __future__ import unicode_literals
 
-from django.utils.module_loading import import_string
+from mayan.apps.storage.utils import get_storage_subclass
 
 from .settings import (
     setting_workflowimagecache_storage,
     setting_workflowimagecache_storage_arguments
 )
 
-storage_workflowimagecache = import_string(
+storage_workflowimagecache = get_storage_subclass(
     dotted_path=setting_workflowimagecache_storage.value
 )(**setting_workflowimagecache_storage_arguments.value)

mayan/apps/documents/migrations/0048_auto_20190711_0544.py

@@ -0,0 +1,22 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.22 on 2019-07-11 05:44
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import mayan.apps.documents.models.document_version_models
+import mayan.apps.storage.classes
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('documents', '0047_auto_20180917_0737'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='documentversion',
+            name='file',
+            field=models.FileField(storage=mayan.apps.storage.classes.FakeStorageSubclass(), upload_to=mayan.apps.documents.models.document_version_models.UUID_FUNCTION, verbose_name='File'),
+        ),
+    ]

mayan/apps/documents/storages.py

@@ -1,6 +1,6 @@
 from __future__ import unicode_literals
 
-from django.utils.module_loading import import_string
+from mayan.apps.storage.utils import get_storage_subclass
 
 from .settings import (
     setting_documentimagecache_storage,
@@ -8,10 +8,10 @@ from .settings import (
     setting_storage_backend, setting_storage_backend_arguments
 )
 
-storage_documentversion = import_string(
+storage_documentversion = get_storage_subclass(
     dotted_path=setting_storage_backend.value
 )(**setting_storage_backend_arguments.value)
 
-storage_documentimagecache = import_string(
+storage_documentimagecache = get_storage_subclass(
     dotted_path=setting_documentimagecache_storage.value
 )(**setting_documentimagecache_storage_arguments.value)

mayan/apps/sources/storages.py

@@ -1,12 +1,12 @@
 from __future__ import unicode_literals
 
-from django.utils.module_loading import import_string
+from mayan.apps.storage.utils import get_storage_subclass
 
 from .settings import (
     setting_staging_file_image_cache_storage,
     setting_staging_file_image_cache_storage_arguments,
 )
 
-storage_staging_file_image_cache = import_string(
+storage_staging_file_image_cache = get_storage_subclass(
     dotted_path=setting_staging_file_image_cache_storage.value
 )(**setting_staging_file_image_cache_storage_arguments.value)

mayan/apps/storage/classes.py

@@ -0,0 +1,10 @@
+from __future__ import unicode_literals
+
+
+class FakeStorageSubclass(object):
+    """
+    Placeholder class to allow serializing the real storage subclass to
+    support migrations.
+    """
+    def __eq__(self, other):
+        return True

mayan/apps/storage/utils.py

@@ -5,6 +5,8 @@ import os
 import shutil
 import tempfile
 
+from django.utils.module_loading import import_string
+
 from .settings import setting_temporary_directory
 
 logger = logging.getLogger(__name__)
@@ -39,6 +41,27 @@ def fs_cleanup(filename, file_descriptor=None, suppress_exceptions=True):
                 raise
 
 
+def get_storage_subclass(dotted_path):
+    """
+    Import a storage class and return a subclass that will always return eq
+    True to avoid creating a new migration when for runtime storage class
+    changes.
+    """
+    imported_storage_class = import_string(dotted_path=dotted_path)
+
+    class StorageSubclass(imported_storage_class):
+        def __init__(self, *args, **kwargs):
+            return super(StorageSubclass, self).__init__(*args, **kwargs)
+
+        def __eq__(self, other):
+            return True
+
+        def deconstruct(self):
+            return ('mayan.apps.storage.classes.FakeStorageSubclass', (), {})
+
+    return StorageSubclass
+
+
 def mkdtemp(*args, **kwargs):
     kwargs.update({'dir': setting_temporary_directory.value})
     return tempfile.mkdtemp(*args, **kwargs)