feat: adds a LicenseTransferJob model and admin

Also installs django-autocomplete-light for help to support
advanced admin autocomplete field filtering, and therefore
runs make upgrade to pull in some other new package versions.

.annotation_safe_list.yml

@@ -39,6 +39,8 @@ subscriptions.HistoricalCustomerAgreement:
   ".. no_pii:": "This model has no PII"
 subscriptions.HistoricalLicense:
   ".. no_pii:": "This model has no PII"
+subscriptions.HistoricalLicenseTransferJob:
+  ".. no_pii:": "This model has no PII"
 subscriptions.HistoricalNotification:
   ".. no_pii:": "This model has no PII"
 subscriptions.HistoricalSubscriptionPlan:

docs/decisions/0015-license-transfer-job.rst

@@ -0,0 +1,54 @@
+15. License Transfer Jobs
+#########################
+
+Status
+******
+Accepted (October 2023)
+
+Context
+*******
+There are some customer agreements for which we want to support transferring
+licenses between Subscription Plans, particularly in the following scenario:
+
+* A learner is assigned (and activates) a license in Plan A.
+* By some threshold date for Plan A, like a "lock" or "cutoff" time,
+  the plan is closed (meaning no more licenses will be assigned from that plan).
+* There’s a new, rolling Subscription Plan B that starts directly
+  after the lock time of Plan A.
+
+In this scenario, We want to give the learner an opportunity to
+continue learning via a subscription license under Plan B.
+Furthermore, we want the enrollment records to continue to be associated
+with the original license, but for the license to now be associated with plan B
+(which may be necessary for back-office reporting purposes).
+
+Decision
+********
+We've introuduced a ``LicenseTransferJob`` model that, given a set of
+activated or assigned license UUIDs, will transfer the licenses from
+an old plan to a new plan via a ``process()`` method.  This method
+has several important properties:
+
+1. It support dry-runs, so that we can see which licenses **would** be
+   transferred without actually transferring them.
+2. It's idempotent: calling ``process()`` twice on the same input
+   will leave the licenses in the same output state (provided no other
+   rouge process has mutated the licenses outside of these ``process()`` calls.).
+3. It's reversible: If you transfer licenses from plan A to plan B, you
+   can reverse that action by creating a new job to transfer from plan B
+   back to plan A.
+
+The Django Admin site supports creation, management, and processing of
+``LicenseTransferJobs``.
+
+Consequences
+************
+Supporting the scenario above via LicenseTransferJobs allows us
+to some degree to satisfy agreements for rolling-window subscription access;
+that is, subscriptions where the license expiration time is determined
+from the perspective of the license's activation time, **not** the plan's
+effective date.
+
+Alternatives Considered
+***********************
+None in particular.

license_manager/apps/subscriptions/admin.py

@@ -19,13 +19,15 @@
 from license_manager.apps.subscriptions.exceptions import CustomerAgreementError
 from license_manager.apps.subscriptions.forms import (
     CustomerAgreementAdminForm,
+    LicenseTransferJobAdminForm,
     ProductForm,
     SubscriptionPlanForm,
     SubscriptionPlanRenewalForm,
 )
 from license_manager.apps.subscriptions.models import (
     CustomerAgreement,
     License,
+    LicenseTransferJob,
     Notification,
     PlanType,
     Product,
@@ -657,3 +659,66 @@ class NotificationAdmin(admin.ModelAdmin):
 
     def has_change_permission(self, request, obj=None):
         return False
+
+
+@admin.register(LicenseTransferJob)
+class LicenseTransferJobAdmin(admin.ModelAdmin):
+    form = LicenseTransferJobAdminForm
+
+    list_display = (
+        'id',
+        'customer_agreement',
+        'old_subscription_plan',
+        'new_subscription_plan',
+        'completed_at',
+        'is_dry_run',
+    )
+
+    list_filter = (
+        'is_dry_run',
+    )
+
+    search_fields = (
+        'customer_agreement__enterprise_customer_uuid__startswith',
+        'customer_agreement__enterprise_customer_slug__startswith',
+        'customer_agreement__enterprise_customer_name__startswith',
+        'old_subscription_plan',
+        'new_subscription_plan',
+    )
+
+    sortable_by = (
+        'id',
+        'completed_at',
+        'is_dry_run',
+        'customer_agreement',
+    )
+
+    actions = ['process_transfer_jobs']
+
+    def get_readonly_fields(self, request, obj=None):
+        """
+        Makes all fields except ``notes`` read-only
+        when ``completed_at`` is not null.
+        """
+        if obj and obj.completed_at:
+            return list(
+                # pylint: disable=no-member
+                set(self.form.base_fields) - {'notes'}
+            )
+        else:
+            return [
+                'completed_at',
+                'processed_results',
+            ]
+
+    def get_queryset(self, request):
+        return super().get_queryset(request).select_related(
+            'customer_agreement',
+            'old_subscription_plan',
+            'new_subscription_plan',
+        )
+
+    @admin.action(description="Process selected license transfer jobs")
+    def process_transfer_jobs(self, request, queryset):
+        for transfer_job in queryset:
+            transfer_job.process()

license_manager/apps/subscriptions/forms.py

@@ -1,9 +1,9 @@
 """
 Forms to be used in the subscriptions django app.
 """
-
 import logging
 
+from dal import autocomplete
 from django import forms
 from django.conf import settings
 from django.utils.translation import gettext as _
@@ -22,6 +22,7 @@
 )
 from license_manager.apps.subscriptions.models import (
     CustomerAgreement,
+    LicenseTransferJob,
     Product,
     SubscriptionPlan,
     SubscriptionPlanRenewal,
@@ -401,3 +402,37 @@ def is_valid(self):
             return False
 
         return True
+
+
+class LicenseTransferJobAdminForm(forms.ModelForm):
+    class Meta:
+        model = LicenseTransferJob
+        fields = '__all__'
+        # Use django-autocomplete-light to filter the available
+        # subscription_plan choices to only those related to
+        # the selected customer agreement.  Works for both
+        # records that don't yet exist (on transfer job creation)
+        # and for modification of existing transfer job records.
+        # See urls_admin.py for the view that does this filtering,
+        # and see static/filtered_subscription_admin.js for
+        # the jQuery code that clears subscription plan selections
+        # when the selected customer agreement is changed.
+        widgets = {
+            'old_subscription_plan': autocomplete.ModelSelect2(
+                url='filtered_subscription_plan_admin',
+                # forward the customer_agreement field's value
+                # into our custom autocomplete field in urls_admin.py
+                forward=['customer_agreement'],
+            ),
+            'new_subscription_plan': autocomplete.ModelSelect2(
+                url='filtered_subscription_plan_admin',
+                # forward the customer_agreement field's value
+                # into our custom autocomplete field in urls_admin.py
+                forward=['customer_agreement'],
+            ),
+        }
+
+    class Media:
+        js = (
+            'filtered_subscription_admin.js',
+        )

license_manager/apps/subscriptions/migrations/0062_add_license_transfer_job.py

@@ -0,0 +1,70 @@
+# Generated by Django 4.2.6 on 2023-10-24 15:52
+
+from django.conf import settings
+import django.core.serializers.json
+from django.db import migrations, models
+import django.db.models.deletion
+import django.utils.timezone
+import model_utils.fields
+import simple_history.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('subscriptions', '0061_auto_20230927_1119'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='LicenseTransferJob',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('created', model_utils.fields.AutoCreatedField(default=django.utils.timezone.now, editable=False, verbose_name='created')),
+                ('modified', model_utils.fields.AutoLastModifiedField(default=django.utils.timezone.now, editable=False, verbose_name='modified')),
+                ('completed_at', models.DateTimeField(blank=True, help_text='The time at which the job was successfully processed.', null=True)),
+                ('notes', models.TextField(blank=True, help_text='Optionally, say something about why the licenses are being transferred.', null=True)),
+                ('is_dry_run', models.BooleanField(default=False, help_text='If true, will report which licenses will be transferred in processed_results, without actually transferring them.')),
+                ('delimiter', models.CharField(choices=[('newline', 'Newline character'), ('comma', 'Comma character'), ('pipe', 'Pipe character')], default='newline', max_length=8)),
+                ('license_uuids_raw', models.TextField(help_text='Delimitted (with newlines by default) list of license_uuids to transfer')),
+                ('processed_results', models.JSONField(blank=True, encoder=django.core.serializers.json.DjangoJSONEncoder, help_text='Raw results of what licenses were changed, either in dry-run form, or actual form.', null=True)),
+                ('customer_agreement', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='license_transfer_jobs', to='subscriptions.customeragreement')),
+                ('new_subscription_plan', models.ForeignKey(help_text='SubscriptionPlan to which licenses will be transferred.', on_delete=django.db.models.deletion.CASCADE, related_name='license_transfer_jobs_new', to='subscriptions.subscriptionplan')),
+                ('old_subscription_plan', models.ForeignKey(help_text='SubscriptionPlan from which licenses will be transferred.', on_delete=django.db.models.deletion.CASCADE, related_name='license_transfer_jobs_old', to='subscriptions.subscriptionplan')),
+            ],
+            options={
+                'verbose_name': 'License Transfer Job',
+                'verbose_name_plural': 'License Transfer Jobs',
+            },
+        ),
+        migrations.CreateModel(
+            name='HistoricalLicenseTransferJob',
+            fields=[
+                ('id', models.IntegerField(auto_created=True, blank=True, db_index=True, verbose_name='ID')),
+                ('created', model_utils.fields.AutoCreatedField(default=django.utils.timezone.now, editable=False, verbose_name='created')),
+                ('modified', model_utils.fields.AutoLastModifiedField(default=django.utils.timezone.now, editable=False, verbose_name='modified')),
+                ('completed_at', models.DateTimeField(blank=True, help_text='The time at which the job was successfully processed.', null=True)),
+                ('notes', models.TextField(blank=True, help_text='Optionally, say something about why the licenses are being transferred.', null=True)),
+                ('is_dry_run', models.BooleanField(default=False, help_text='If true, will report which licenses will be transferred in processed_results, without actually transferring them.')),
+                ('delimiter', models.CharField(choices=[('newline', 'Newline character'), ('comma', 'Comma character'), ('pipe', 'Pipe character')], default='newline', max_length=8)),
+                ('license_uuids_raw', models.TextField(help_text='Delimitted (with newlines by default) list of license_uuids to transfer')),
+                ('processed_results', models.JSONField(blank=True, encoder=django.core.serializers.json.DjangoJSONEncoder, help_text='Raw results of what licenses were changed, either in dry-run form, or actual form.', null=True)),
+                ('history_id', models.AutoField(primary_key=True, serialize=False)),
+                ('history_date', models.DateTimeField()),
+                ('history_change_reason', models.CharField(max_length=100, null=True)),
+                ('history_type', models.CharField(choices=[('+', 'Created'), ('~', 'Changed'), ('-', 'Deleted')], max_length=1)),
+                ('customer_agreement', models.ForeignKey(blank=True, db_constraint=False, null=True, on_delete=django.db.models.deletion.DO_NOTHING, related_name='+', to='subscriptions.customeragreement')),
+                ('history_user', models.ForeignKey(null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='+', to=settings.AUTH_USER_MODEL)),
+                ('new_subscription_plan', models.ForeignKey(blank=True, db_constraint=False, help_text='SubscriptionPlan to which licenses will be transferred.', null=True, on_delete=django.db.models.deletion.DO_NOTHING, related_name='+', to='subscriptions.subscriptionplan')),
+                ('old_subscription_plan', models.ForeignKey(blank=True, db_constraint=False, help_text='SubscriptionPlan from which licenses will be transferred.', null=True, on_delete=django.db.models.deletion.DO_NOTHING, related_name='+', to='subscriptions.subscriptionplan')),
+            ],
+            options={
+                'verbose_name': 'historical License Transfer Job',
+                'verbose_name_plural': 'historical License Transfer Jobs',
+                'ordering': ('-history_date', '-history_id'),
+                'get_latest_by': ('history_date', 'history_id'),
+            },
+            bases=(simple_history.models.HistoricalChanges, models.Model),
+        ),
+    ]