✨(marketing) create tooling to help backend initialization

Like we did for the malware_detection module, we want helpers allowing
use to instantiate a backend without knowing in the code how to do it,
just importing a module and the marketing service is ready to be used.

src/lasuite/marketing/__init__.py

@@ -1 +1,17 @@
 """Marketing module."""
+
+from django.utils.functional import LazyObject
+
+from .handler import MarketingHandler
+
+
+class DefaultMarketing(LazyObject):
+    """Lazy object to handle the marketing backend."""
+
+    def _setup(self):
+        """Configure the marketing backend."""
+        self._wrapped = marketing_handler()
+
+
+marketing_handler = MarketingHandler()
+marketing = DefaultMarketing()

src/lasuite/marketing/exceptions.py

@@ -0,0 +1,13 @@
+"""Marketing exceptions module."""
+
+
+class MarketingError(Exception):
+    """Base exception for all marketing exceptions."""
+
+
+class MarketingInvalidBackendError(MarketingError):
+    """Exception raised when the backend is invalid."""
+
+
+class ContactCreationError(MarketingError):
+    """Exception raised when the contact creation fails."""

src/lasuite/marketing/handler.py

@@ -0,0 +1,46 @@
+"""marketing backendhandler."""
+
+from django.conf import settings
+from django.core.exceptions import ImproperlyConfigured
+from django.utils.functional import cached_property
+from django.utils.module_loading import import_string
+
+from lasuite.marketing.exceptions import MarketingInvalidBackendError
+
+
+class MarketingHandler:
+    """Marketing handler managing the backend instantiation."""
+
+    def __init__(self, backend=None):
+        """Initialize the marketing handler."""
+        # backend is an optional dict of marketing backend definitions
+        # (structured like settings.LASUITE_MARKETING).
+        self._backend = backend
+        self._marketing = None
+
+    @cached_property
+    def backend(self):
+        """Put in cache the backend properties from the settings."""
+        if self._backend is None:
+            try:
+                self._backend = settings.LASUITE_MARKETING.copy()
+            except AttributeError as e:
+                raise ImproperlyConfigured("settings.LASUITE_MARKETING is not configured") from e
+        return self._backend
+
+    def __call__(self):
+        """Create if not existing the backend and then return it."""
+        if self._marketing is None:
+            self._marketing = self.create_marketing(self.backend)
+        return self._marketing
+
+    def create_marketing(self, params):
+        """Instantiate and configure the marketing backend."""
+        params = params.copy()
+        backend = params.pop("BACKEND")
+        parameters = params.pop("PARAMETERS", {})
+        try:
+            klass = import_string(backend)
+        except ImportError as e:
+            raise MarketingInvalidBackendError(f"Could not find backend {backend!r}: {e}") from e
+        return klass(**parameters)

tests/marketing/__init__.py

@@ -0,0 +1 @@
+"""Marketing tests module."""

tests/marketing/test_handler.py

@@ -0,0 +1,34 @@
+"""Test the marketing handler."""
+
+import pytest
+from django.core.exceptions import ImproperlyConfigured
+
+from lasuite.marketing.backends.dummy import DummyBackend
+from lasuite.marketing.handler import MarketingHandler
+
+
+def test_marketing_handler_from_settings(settings):
+    """Test the marketing handler from the settings."""
+    settings.LASUITE_MARKETING = {
+        "BACKEND": "lasuite.marketing.backends.dummy.DummyBackend",
+    }
+    handler = MarketingHandler()
+    assert isinstance(handler(), DummyBackend)
+
+
+def test_marketing_handler_from_backend():
+    """Test the marketing handler from the backend."""
+    handler = MarketingHandler(
+        backend={
+            "BACKEND": "lasuite.marketing.backends.dummy.DummyBackend",
+        }
+    )
+    assert isinstance(handler(), DummyBackend)
+
+
+def test_marketing_backend_no_config(settings):
+    """Test the marketing handler when no config set should raise an error."""
+    settings.LASUITE_MARKETING = None
+    handler = MarketingHandler()
+    with pytest.raises(ImproperlyConfigured):
+        handler()

tests/marketing/test_marketing_detection_lazy_handler.py

@@ -0,0 +1,12 @@
+"""Test the marketing lazy handler."""
+
+from lasuite.marketing import marketing
+from lasuite.marketing.backends.dummy import DummyBackend
+
+
+def test_marketing_lazy_handler(settings):
+    """Test the marketing lazy handler."""
+    settings.LASUITE_MARKETING = {
+        "BACKEND": "lasuite.marketing.backends.dummy.DummyBackend",
+    }
+    assert isinstance(marketing, DummyBackend)