feat: Update cert_generation mgmt command with ability to read arguments from config model

[MICROBA-1100]
* Add CertificationGenerationCommandConfiguration model that will store the command arguments for the `cert_generation` mgmt command
* Add ability to add entries to the CertificationGenerationCommandConfiguration through Django admin
* Update mgmt command with ability to read arguments from the config model/database
* Fix failing test in `test_cert_generation.py`
* Add new test for missing `users` argument in `test_cert_generation.py`

lms/djangoapps/certificates/admin.py

@@ -15,6 +15,7 @@ from organizations.api import get_organizations
 from lms.djangoapps.certificates.models import (
     AllowListGenerationConfiguration,
     CertificateGenerationConfiguration,
+    CertificateGenerationCommandConfiguration,
     CertificateGenerationCourseSetting,
     CertificateHtmlViewConfiguration,
     CertificateTemplate,
@@ -95,6 +96,11 @@ class CertificateGenerationCourseSettingAdmin(admin.ModelAdmin):
 class AllowListGenerationConfigurationAdmin(ConfigurationModelAdmin):
     pass
 
+
+@admin.register(CertificateGenerationCommandConfiguration)
+class CertificateGenerationCommandConfigurationAdmin(ConfigurationModelAdmin):
+    pass
+
 admin.site.register(CertificateGenerationConfiguration)
 admin.site.register(CertificateGenerationCourseSetting, CertificateGenerationCourseSettingAdmin)
 admin.site.register(CertificateHtmlViewConfiguration, ConfigurationModelAdmin)

lms/djangoapps/certificates/management/commands/cert_generation.py

@@ -3,6 +3,7 @@ Management command to generate course certificates for one or more users in a gi
 """
 
 import logging
+import shlex
 
 from django.contrib.auth import get_user_model
 from django.core.management.base import BaseCommand, CommandError
@@ -10,6 +11,7 @@ from opaque_keys import InvalidKeyError
 from opaque_keys.edx.keys import CourseKey
 
 from lms.djangoapps.certificates.generation_handler import generate_certificate_task
+from lms.djangoapps.certificates.models import CertificateGenerationCommandConfiguration
 
 User = get_user_model()
 log = logging.getLogger(__name__)
@@ -33,18 +35,40 @@ class Command(BaseCommand):
             nargs='+',
             metavar='USER',
             dest='user',
-            required=True,
             help='user_id or space-separated list of user_ids for whom to generate course certificates'
         )
         parser.add_argument(
             '-c', '--course-key',
             metavar='COURSE_KEY',
             dest='course_key',
-            required=True,
             help='course run key'
         )
+        parser.add_argument(
+            '--args-from-database',
+            action='store_true',
+            help='Use arguments from the CertificateGenerationCommandConfiguration model instead of the command line'
+        )
+
+    def get_args_from_database(self):
+        """
+        Returns an options dictionary from the current CertificateGenerationCommandConfiguration model.
+        """
+        config = CertificateGenerationCommandConfiguration.current()
+        if not config.enabled:
+            raise CommandError(
+                "CertificateGenerationCommandConfiguration is disabled, but --args-from-database was requested"
+            )
+
+        args = shlex.split(config.arguments)
+        parser = self.create_parser("manage.py", "cert_generation")
+
+        return vars(parser.parse_args(args))
 
     def handle(self, *args, **options):
+        # database args will override cmd line args
+        if options['args_from_database']:
+            options = self.get_args_from_database()
+
         if not options.get('user'):
             raise CommandError('You must specify a list of users')
 

lms/djangoapps/certificates/management/commands/tests/test_cert_generation.py

@@ -43,13 +43,20 @@ class CertGenerationTests(ModuleStoreTestCase):
             mode="verified",
         )
 
-    def test_command_with_missing_param(self):
+    def test_command_with_missing_param_course_key(self):
         """
-        Verify command with a missing param
+        Verify command with a missing param -- course key.
         """
-        with pytest.raises(CommandError, match="Error: the following arguments are required"):
+        with pytest.raises(CommandError, match="You must specify a course-key"):
             call_command("cert_generation", "--u", self.user.username)
 
+    def test_command_with_missing_param_users(self):
+        """
+        Verify command with a missing param -- users.
+        """
+        with pytest.raises(CommandError, match="You must specify a list of users"):
+            call_command("cert_generation", "--c", "blah")
+
     def test_command_with_invalid_key(self):
         """
         Verify command with an invalid course run key

lms/djangoapps/certificates/migrations/0023_certificategenerationcommandconfiguration.py

@@ -0,0 +1,29 @@
+# Generated by Django 2.2.19 on 2021-03-30 19:37
+
+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),
+        ('certificates', '0022_add_unique_constraints_to_certificatewhitelist_model'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='CertificateGenerationCommandConfiguration',
+            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="Arguments for the 'cert_generation' management command. Specify like '-u <user_id> -c <course_run_key>'")),
+                ('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': 'cert_generation argument',
+            },
+        ),
+    ]

lms/djangoapps/certificates/models.py

@@ -1245,3 +1245,26 @@ class AllowListGenerationConfiguration(ConfigurationModel):
 
     def __str__(self):
         return str(self.arguments)
+
+
+class CertificateGenerationCommandConfiguration(ConfigurationModel):
+    """
+    Manages configuration for a run of the cert_generation management command.
+
+    .. no_pii:
+    """
+
+    class Meta(object):
+        app_label = "certificates"
+        verbose_name = "cert_generation argument"
+
+    arguments = models.TextField(
+        blank=True,
+        help_text=(
+            "Arguments for the 'cert_generation' management command. Specify like '-u <user_id> -c <course_run_key>'"
+        ),
+        default="",
+    )
+
+    def __str__(self):
+        return str(self.arguments)