Let notify_credentials get args from db

To allow the notify_credentials management command to run from a
jenkins job, we want to allow the command to pull its arguments
from the database, rather than the jenkins interface.

So this adds a table that admins can adjust in the DB and a new
argument for notify_credentials to tell it to go look there.

LEARNER-6196
LEARNER-6197

openedx/core/djangoapps/credentials/admin.py

@@ -5,11 +5,14 @@ Django admin pages for credentials support models.
 from config_models.admin import ConfigurationModelAdmin
 from django.contrib import admin
 
-from openedx.core.djangoapps.credentials.models import CredentialsApiConfig
+from openedx.core.djangoapps.credentials.models import CredentialsApiConfig, NotifyCredentialsConfig
 
 
+@admin.register(CredentialsApiConfig)
 class CredentialsApiConfigAdmin(ConfigurationModelAdmin):
     pass
 
 
-admin.site.register(CredentialsApiConfig, CredentialsApiConfigAdmin)
+@admin.register(NotifyCredentialsConfig)
+class NotifyCredentialsConfigAdmin(ConfigurationModelAdmin):
+    pass

openedx/core/djangoapps/credentials/management/commands/notify_credentials.py

@@ -24,6 +24,7 @@ from pytz import UTC
 
 from lms.djangoapps.certificates.models import GeneratedCertificate
 from lms.djangoapps.grades.models import PersistentCourseGrade
+from openedx.core.djangoapps.credentials.models import NotifyCredentialsConfig
 from openedx.core.djangoapps.credentials.signals import handle_cert_change, send_grade_if_interesting
 from openedx.core.djangoapps.programs.signals import handle_course_cert_changed
 from openedx.core.djangoapps.site_configuration.models import SiteConfiguration
@@ -134,8 +135,28 @@ class Command(BaseCommand):
             default=100,
             help="Number of items to query at once.",
         )
+        parser.add_argument(
+            '--args-from-database',
+            action='store_true',
+            help='Use arguments from the NotifyCredentialsConfig model instead of the command line.',
+        )
+
+    def get_args_from_database(self):
+        """ Returns an options dictionary from the current NotifyCredentialsConfig model. """
+        config = NotifyCredentialsConfig.current()
+        if not config.enabled:
+            raise CommandError('NotifyCredentialsConfig is disabled, but --args-from-database was requested.')
+
+        # We don't need fancy shell-style whitespace/quote handling - none of our arguments are complicated
+        argv = config.arguments.split()
+
+        parser = self.create_parser('manage.py', 'notify_credentials')
+        return parser.parse_args(argv).__dict__   # we want a dictionary, not a non-iterable Namespace object
 
     def handle(self, *args, **options):
+        if options['args_from_database']:
+            options = self.get_args_from_database()
+
         log.info(
             "notify_credentials starting, dry-run=%s, site=%s, delay=%d seconds",
             options['dry_run'],

openedx/core/djangoapps/credentials/management/commands/tests/test_notify_credentials.py

@@ -14,6 +14,7 @@ from freezegun import freeze_time
 
 from lms.djangoapps.certificates.tests.factories import GeneratedCertificateFactory
 from lms.djangoapps.grades.models import PersistentCourseGrade
+from openedx.core.djangoapps.credentials.models import NotifyCredentialsConfig
 from openedx.core.djangoapps.site_configuration.tests.factories import SiteConfigurationFactory
 from openedx.core.djangolib.testing.utils import skip_unless_lms
 from student.tests.factories import UserFactory
@@ -131,3 +132,30 @@ class TestNotifyCredentials(TestCase):
         call_command(Command(), '--site', site_config.site.domain, '--start-date', '2017-01-01')
         self.assertEqual(mock_grade_interesting.call_count, 1)
         self.assertEqual(mock_cert_change.call_count, 1)
+
+    @mock.patch(COMMAND_MODULE + '.Command.send_notifications')
+    def test_args_from_database(self, mock_send):
+        # Nothing in the database, should default to disabled
+        with self.assertRaisesRegex(CommandError, 'NotifyCredentialsConfig is disabled.*'):
+            call_command(Command(), '--start-date', '2017-01-01', '--args-from-database')
+
+        # Add a config
+        config = NotifyCredentialsConfig.current()
+        config.arguments = '--start-date 2017-03-01'
+        config.enabled = True
+        config.save()
+
+        # Not told to use config, should ignore it
+        call_command(Command(), '--start-date', '2017-01-01')
+        self.assertEqual(len(mock_send.call_args[0][0]), 3)
+
+        # Told to use it, and enabled. Should use config in preference of command line
+        call_command(Command(), '--start-date', '2017-01-01', '--args-from-database')
+        self.assertEqual(len(mock_send.call_args[0][0]), 1)
+
+        config.enabled = False
+        config.save()
+
+        # Explicitly disabled
+        with self.assertRaisesRegex(CommandError, 'NotifyCredentialsConfig is disabled.*'):
+            call_command(Command(), '--start-date', '2017-01-01', '--args-from-database')

openedx/core/djangoapps/credentials/migrations/0004_notifycredentialsconfig.py

@@ -0,0 +1,31 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.15 on 2018-08-17 18:14
+from __future__ import unicode_literals
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('credentials', '0003_auto_20170525_1109'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='NotifyCredentialsConfig',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('change_date', models.DateTimeField(auto_now_add=True, verbose_name='Change date')),
+                ('enabled', models.BooleanField(default=False, verbose_name='Enabled')),
+                ('arguments', models.TextField(blank=True, default='', help_text='Useful for manually running a Jenkins job. Specify like "--start-date=2018 --courses A B".')),
+                ('changed_by', models.ForeignKey(editable=False, null=True, on_delete=django.db.models.deletion.PROTECT, to=settings.AUTH_USER_MODEL, verbose_name='Changed by')),
+            ],
+            options={
+                'verbose_name': 'notify_credentials argument',
+            },
+        ),
+    ]

openedx/core/djangoapps/credentials/models.py

@@ -108,3 +108,22 @@ class CredentialsApiConfig(ConfigurationModel):
     def is_cache_enabled(self):
         """Whether responses from the Credentials API will be cached."""
         return self.cache_ttl > 0
+
+
+class NotifyCredentialsConfig(ConfigurationModel):
+    """
+    Manages configuration for a run of the notify_credentials management command.
+    """
+
+    class Meta(object):
+        app_label = 'credentials'
+        verbose_name = 'notify_credentials argument'
+
+    arguments = models.TextField(
+        blank=True,
+        help_text='Useful for manually running a Jenkins job. Specify like "--start-date=2018 --courses A B".',
+        default='',
+    )
+
+    def __unicode__(self):
+        return unicode(self.arguments)