From 438789f71395e9fff1c1d8c467b694c28446a04e Mon Sep 17 00:00:00 2001
From: Sidney Richards <sidney@maykinmedia.nl>
Date: Fri, 13 Dec 2024 17:22:51 +0100
Subject: [PATCH] Add a validate-only flag to support web-init/CI usage

---
 README.rst                                    | 12 ++++
 .../commands/setup_configuration.py           | 16 +++++
 tests/test_command.py                         | 69 +++++++++++++++++++
 3 files changed, 97 insertions(+)

diff --git a/README.rst b/README.rst
index 8475eb3..a60054d 100644
--- a/README.rst
+++ b/README.rst
@@ -225,6 +225,18 @@ Command Line
 
     python manage.py setup_configuration --yaml-file /path/to/config.yaml
 
+You can also validate that the configuration source can be successfully loaded,
+without actually running the steps, by adding the ``validate-only`` flag:
+
+.. code-block:: bash
+
+    python manage.py setup_configuration --yaml-file /path/to/config.yaml --validate-only
+
+The command will either return 0 and a success message if the configuration file can
+be loaded without issues, otherwise it will return a non-zero exit code and print any
+validation errors. This can be useful e.g. in CI to confirm that your sources are
+valid without actually running any steps.
+
 Programmatically
 ^^^^^^^^^^^^^^^^
 
diff --git a/django_setup_configuration/management/commands/setup_configuration.py b/django_setup_configuration/management/commands/setup_configuration.py
index 118c23b..39abd8d 100644
--- a/django_setup_configuration/management/commands/setup_configuration.py
+++ b/django_setup_configuration/management/commands/setup_configuration.py
@@ -32,9 +32,17 @@ def add_arguments(self, parser):
             required=True,
             help="Path to YAML file containing the configurations",
         )
+        parser.add_argument(
+            "--validate-only",
+            action="store_true",
+            default=False,
+            help="Validate that all the step configurations can be successfully loaded "
+            "from source, without actually executing the steps.",
+        )
 
     @transaction.atomic
     def handle(self, **options):
+        validate_only = options["validate_only"]
         yaml_file = Path(options["yaml_file"]).resolve()
         if not yaml_file.exists():
             raise CommandError(f"Yaml file `{yaml_file}` does not exist.")
@@ -74,6 +82,14 @@ def handle(self, **options):
                 f"Prerequisites for configuration are not fulfilled: {errors.as_text()}"
             )
 
+        if validate_only:
+            self.stdout.write(
+                self.style.SUCCESS(
+                    "All configuration values could be successfully read from source."
+                )
+            )
+            return
+
         self.stdout.write("Executing steps...")
 
         # 2. Configure steps
diff --git a/tests/test_command.py b/tests/test_command.py
index b67cfd3..07f9b65 100644
--- a/tests/test_command.py
+++ b/tests/test_command.py
@@ -147,6 +147,40 @@ def test_command_success(
     step_execute_mock.assert_called_once_with(expected_step_config)
 
 
+def test_command_success_with_validate_only_flag_does_not_run(
+    settings,
+    yaml_file_with_valid_configuration,
+    expected_step_config,
+    step_execute_mock,
+):
+    """
+    test happy flow
+    """
+    assert User.objects.count() == 0
+    stdout = StringIO()
+
+    call_command(
+        "setup_configuration",
+        yaml_file=yaml_file_with_valid_configuration,
+        stdout=stdout,
+        validate_only=True,
+    )
+
+    output = stdout.getvalue().splitlines()
+    expected_output = [
+        f"Loading config settings from {yaml_file_with_valid_configuration}",
+        "The following steps are configured:",
+        "User Configuration",
+        "TestStep",
+        "All configuration values could be successfully read from source.",
+    ]
+
+    assert output == expected_output
+
+    assert User.objects.count() == 0
+    step_execute_mock.assert_not_called()
+
+
 def test_command_with_failing_requirements_reports_errors(
     step_execute_mock, yaml_file_factory
 ):
@@ -181,6 +215,41 @@ def test_command_with_failing_requirements_reports_errors(
     step_execute_mock.assert_not_called()
 
 
+def test_command_with_failing_requirements_and_validate_reports_errors(
+    step_execute_mock, yaml_file_factory
+):
+    yaml_path = yaml_file_factory(
+        {
+            "user_configuration_enabled": True,
+            "user_configuration": {
+                "username": 1874,
+            },
+            "some_extra_attrs": "should be allowed",
+            "test_step_is_enabled": True,
+            "test_step": {
+                "a_string": 42,
+                "username": None,
+            },
+        }
+    )
+
+    with pytest.raises(CommandError) as exc:
+        call_command(
+            "setup_configuration",
+            yaml_file=yaml_path,
+            validate_only=False,
+        )
+
+    assert (
+        "User Configuration: Failed to load config model for User Configuration"
+        in str(exc.value)
+    )
+    assert "Failed to load config model for TestStep" in str(exc.value)
+
+    assert User.objects.count() == 0
+    step_execute_mock.assert_not_called()
+
+
 def test_command_with_failing_execute_reports_errors(
     expected_step_config, step_execute_mock, yaml_file_with_valid_configuration
 ):