Fix #198 -- Allow using Django settings for linter configuration

CHANGELOG.md

@@ -7,6 +7,7 @@
 - Fix index creation detection when table is being created in the transaction (issue #178)
 - Handle unique index creation as adding a unique constraint (issue #183)
 - Allow any option to be set/unset in config file (issue #167)
+- Allow using Django settings for any option to be set/unset (issue #198)
 - Raise when unsupported database vendor, allow passing an option to select SQL analyser (issue #138 and #169)
 
 ## 3.0.1

django_migration_linter/management/commands/lintmigrations.py

@@ -6,6 +6,7 @@ import sys
 from importlib import import_module
 
 import toml
+from django.conf import settings
 from django.core.management.base import BaseCommand
 
 from ...constants import __version__
@@ -151,9 +152,14 @@ class Command(BaseCommand):
         else:
             logging.basicConfig(format="%(message)s")
 
+        django_settings_options = self.read_django_settings(options)
         config_options = self.read_config_file(options)
         toml_options = self.read_toml_file(options)
-        for k, v in itertools.chain(config_options.items(), toml_options.items()):
+        for k, v in itertools.chain(
+            django_settings_options.items(),
+            config_options.items(),
+            toml_options.items(),
+        ):
             if not options[k]:
                 options[k] = v
 
@@ -186,6 +192,19 @@ class Command(BaseCommand):
         if linter.has_errors:
             sys.exit(1)
 
+    @staticmethod
+    def read_django_settings(options):
+        django_settings_options = dict()
+
+        django_migration_linter_settings = getattr(
+            settings, "MIGRATION_LINTER_OPTIONS", dict()
+        )
+        for key in options:
+            if key in django_migration_linter_settings:
+                django_settings_options[key] = django_migration_linter_settings[key]
+
+        return django_settings_options
+
     @staticmethod
     def read_config_file(options):
         config_options = dict()

docs/usage.md

@@ -41,6 +41,17 @@ Below the detailed command line options, which can all also be defined using a c
 | `--warnings-as-errors`                                | Handle warnings as errors and therefore return an error status code if we should.                     |
 | `--sql-analyser`                                      | Specify the SQL analyser that should be used. Allowed values: 'sqlite', 'mysql', 'postgresql'.        |
 
+## Django settings configuration
+
+All settings can be defined in the Django settings:
+
+```
+MIGRATION_LINTER_OPTIONS = {
+    "no_cache": True,
+    "exclude_apps": ["users"]
+}
+```
+
 ## File configuration
 
 Example `setup.cfg` file:

tests/functional/test_lintmigrations_command.py

@@ -2,6 +2,7 @@ from unittest.mock import patch
 
 from django.core.management import call_command
 from django.test import TransactionTestCase
+from django.test.utils import override_settings
 
 
 class LintMigrationsCommandTestCase(TransactionTestCase):
@@ -29,3 +30,7 @@ class LintMigrationsCommandTestCase(TransactionTestCase):
 
             with self.assertRaises(SystemExit):
                 call_command("lintmigrations", app_label="app_drop_table")
+
+    @override_settings(MIGRATION_LINTER_OPTIONS={"app_label": "app_correct"})
+    def test_django_settings_option(self):
+        call_command("lintmigrations")