✨ [#4908] Add config checks for JSON registration plugin

Will check the connection to the configured service

src/openforms/fixtures/admin_index_unlisted.json

@@ -19,6 +19,7 @@
     "haalcentraal.HaalCentraalConfig",
     "qmatic.QmaticConfig",
     "registrations_email.EmailConfig",
+    "registrations_json.JSONConfig",
     "registrations_microsoft_graph.MSGraphRegistrationConfig",
     "objects_api.ObjectsAPIGroupConfig",
     "registrations_objects_api.ObjectsAPIConfig",

src/openforms/registrations/contrib/json/admin.py

@@ -0,0 +1,10 @@
+from django.contrib import admin
+
+from solo.admin import SingletonModelAdmin
+
+from .models import JSONConfig
+
+
+@admin.register(JSONConfig)
+class JSONConfigAdmin(SingletonModelAdmin):
+    pass

src/openforms/registrations/contrib/json/migrations/0001_initial.py

@@ -0,0 +1,44 @@
+# Generated by Django 4.2.17 on 2024-12-30 12:49
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+        ("zgw_consumers", "0022_set_default_service_slug"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="JSONConfig",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+                (
+                    "service",
+                    models.OneToOneField(
+                        help_text="Service for JSON registration plugin",
+                        limit_choices_to={"api_type": "orc"},
+                        null=True,
+                        on_delete=django.db.models.deletion.PROTECT,
+                        to="zgw_consumers.service",
+                        verbose_name="Service",
+                    ),
+                ),
+            ],
+            options={
+                "verbose_name": "JSON registration configuration",
+            },
+        ),
+    ]

src/openforms/registrations/contrib/json/models.py

@@ -0,0 +1,30 @@
+from django.db import models
+from django.utils.translation import gettext_lazy as _
+
+from solo.models import SingletonModel
+from zgw_consumers.constants import APITypes
+
+
+class JSONConfigManager(models.Manager):
+    def get_queryset(self):
+        return super().get_queryset().select_related("service")
+
+
+class JSONConfig(SingletonModel):
+    """
+    Global configuration and defaults
+    """
+
+    service = models.OneToOneField(
+        "zgw_consumers.Service",
+        verbose_name=_("Service"),
+        on_delete=models.PROTECT,
+        limit_choices_to={"api_type": APITypes.orc},
+        null=True,
+        help_text=_("Service for JSON registration plugin"),
+    )
+
+    objects = JSONConfigManager()
+
+    class Meta:
+        verbose_name = _("JSON registration configuration")

src/openforms/registrations/contrib/json/plugin.py

@@ -1,15 +1,19 @@
 import base64
 
 from django.utils.translation import gettext_lazy as _
+from django.urls import reverse
 
+from requests import RequestException
 from zgw_consumers.client import build_client
 
+from openforms.plugins.exceptions import InvalidPluginConfiguration
 from openforms.submissions.models import Submission
 from openforms.variables.service import get_static_variables
 
 from ...base import BasePlugin  # openforms.registrations.base
 from ...registry import register  # openforms.registrations.registry
 from .config import JSONOptions, JSONOptionsSerializer
+from .models import JSONConfig
 
 
 @register("json")
@@ -58,8 +62,27 @@ def register_submission(self, submission: Submission, options: JSONOptions) -> d
 
         return result
 
-    def check_config(self):
-        # TODO-4908: check if it's possible to connect to the service
-        #  (using the 'connection check endpoint' of the service)
-        # TODO-4908: check anything else?
-        pass
+    def check_config(self) -> None:
+        # Get service
+        config = JSONConfig.get_solo()
+        if (service := config.service) is None:
+            raise InvalidPluginConfiguration(_("Please configure a service"))
+
+        # Check connection to service
+        with build_client(service) as client:
+            try:
+                res = client.get(service.api_connection_check_path)
+                res.raise_for_status()
+            except RequestException as exc:
+                raise InvalidPluginConfiguration(_(f"Invalid response: {exc}")) from exc
+
+    def get_config_actions(self) -> list[tuple[str, str]]:
+        return [
+            (
+                _("Configuration"),
+                reverse(
+                    "admin:registrations_json_jsonconfig_change",
+                    args=(JSONConfig.singleton_instance_id,)
+                )
+            )
+        ]