Use a django model for managing experiments (#24)

Author: adinhodovic

django_google_optimize/admin.py

@@ -0,0 +1,18 @@
+from django.contrib import admin
+
+from .models import ExperimentVariant, GoogleExperiment
+
+
+class ExperimentVariantInline(admin.StackedInline):
+    model = ExperimentVariant
+
+
+@admin.register(GoogleExperiment)
+class GoogleExperimentAdmin(admin.ModelAdmin):
+    list_display = (
+        "experiment_id",
+        "experiment_alias",
+    )
+    inlines = [
+        ExperimentVariantInline,
+    ]

django_google_optimize/middleware.py

@@ -1,13 +1,9 @@
-from django.conf import settings
-
 from .utils import get_experiments_variants
 
-experiments = getattr(settings, "GOOGLE_OPTIMIZE_EXPERIMENTS", None)
-
 
 def google_optimize(get_response):
     def middleware(request):
-        request.google_optimize = get_experiments_variants(request, experiments)
+        request.google_optimize = get_experiments_variants(request)
         return get_response(request)
 
     return middleware

django_google_optimize/migrations/0001_initial.py

@@ -0,0 +1,41 @@
+# Generated by Django 3.0.2 on 2020-01-28 16:33
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='GoogleExperiment',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('experiment_id', models.CharField(max_length=50, unique=True)),
+                ('experiment_alias', models.CharField(blank=True, max_length=30, null=True, unique=True)),
+                ('active', models.BooleanField()),
+            ],
+        ),
+        migrations.CreateModel(
+            name='ExperimentVariant',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('index', models.IntegerField()),
+                ('alias', models.CharField(blank=True, max_length=50, null=True)),
+                ('experiment', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='experiment_variant', to='django_google_optimize.GoogleExperiment')),
+            ],
+        ),
+        migrations.AddConstraint(
+            model_name='experimentvariant',
+            constraint=models.UniqueConstraint(fields=('alias', 'experiment'), name='Can not have the same alias within an experiment_variant'),
+        ),
+        migrations.AddConstraint(
+            model_name='experimentvariant',
+            constraint=models.UniqueConstraint(fields=('index', 'experiment'), name='Can not have the same index within an experiment_variant'),
+        ),
+    ]

django_google_optimize/migrations/__init__.py

@@ -0,0 +1,33 @@
+from django.db import models
+
+
+class GoogleExperiment(models.Model):
+    experiment_id = models.CharField(max_length=50, unique=True)
+    experiment_alias = models.CharField(
+        max_length=30, unique=True, blank=True, null=True
+    )
+    active = models.BooleanField()
+
+
+class ExperimentVariant(models.Model):
+    index = models.IntegerField()
+    alias = models.CharField(max_length=50, blank=True, null=True)
+    experiment = models.ForeignKey(
+        GoogleExperiment,
+        null=True,
+        blank=True,
+        on_delete=models.CASCADE,
+        related_name="experiment_variant",
+    )
+
+    class Meta:
+        constraints = [
+            models.UniqueConstraint(
+                fields=["alias", "experiment"],
+                name="Can not have the same alias within an experiment_variant",
+            ),
+            models.UniqueConstraint(
+                fields=["index", "experiment"],
+                name="Can not have the same index within an experiment_variant",
+            ),
+        ]

django_google_optimize/models.py

@@ -1,53 +1,64 @@
 import logging
 
+from .models import GoogleExperiment
+
 logger = logging.getLogger()
 
 
-def get_experiments_variants(request, experiments):
+# pylint: disable=too-many-return-statements
+def get_experiments_variants(request):
+    experiments = GoogleExperiment.objects.all()
     if not experiments:
-        logger.error("Setting GOOGLE_OPTIMIZE_EXPERIMENTS not defined")
+        logger.warning("No experiment added")
         return None
 
     try:
-        experiment_variants = _parse_experiments(request)
+        cookie_data = _parse_experiments(request)
     except Exception:  # pylint: disable=broad-except
-        logger.error("Failed to parse _gaexp %s", request.COOKIES.get("_gaexp"))
+        logger.warning("Failed to parse _gaexp %s", request.COOKIES.get("_gaexp"))
         return None
 
-    if not experiment_variants:
+    if not cookie_data:
         logger.debug("Missing _ga_exp cookie")
         return None
 
     active_experiments = {}
 
     for experiment in experiments:
 
-        experiment_id = experiment.get("id", None)
-        experiment_alias = experiment.get("alias", None)
-        variant_aliases = experiment.get("variant_aliases", None)
-
-        if not experiment_id:
-            logger.warning("experiment id not found in experiment settings")
-            return None
+        experiment_id = experiment.experiment_id
 
-        if experiment_id not in experiment_variants:
+        if experiment_id not in cookie_data:
             logger.warning(
                 "experiment id %s not found in experiments cookie %s",
                 experiment_id,
                 request.COOKIES["_gaexp"],
             )
             return None
 
-        variant = experiment_variants[experiment_id]
+        variant_name = cookie_data[experiment_id]
 
-        if variant_aliases:
-            if variant in variant_aliases:
-                variant = variant_aliases[variant]
+        experiment_variants = experiment.experiment_variant.all()
+
+        if experiment_variants:
+            variant = experiment_variants.filter(index=variant_name).first()
+            if variant:
+                if variant.alias:
+                    variant_name = variant.alias
+            else:
+                logger.warning(
+                    "No experiment variant added with the index %s", variant_name
+                )
+                return None
+        else:
+            logger.warning("No variants added")
+            return None
 
+        experiment_alias = experiment.experiment_alias
         if experiment_alias:
-            active_experiments[experiment_alias] = variant
+            active_experiments[experiment_alias] = variant_name
         else:
-            active_experiments[experiment_id] = variant
+            active_experiments[experiment_id] = variant_name
 
     return active_experiments
 

django_google_optimize/utils.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python
+"""Django's command-line utility for administrative tasks."""
+import os
+import sys
+
+
+def main():
+    os.environ.setdefault("DJANGO_SETTINGS_MODULE", "tests.settings")
+    try:
+        from django.core.management import execute_from_command_line
+    except ImportError as exc:
+        raise ImportError(
+            "Couldn't import Django. Are you sure it's installed and "
+            "available on your PYTHONPATH environment variable? Did you "
+            "forget to activate a virtual environment?"
+        ) from exc
+    execute_from_command_line(sys.argv)
+
+
+if __name__ == "__main__":
+    main()