(feature) Add host config editing view

Add a staff-only Django form for editing operational host settings while keeping
host identity stable. Support address, enablement, SSH/source overrides,
include/exclude lists, rsync extra args, and retention settings using the same
SQL-backed HostConfig model consumed by backup and scheduler flows.

Parse newline-separated list fields into JSON lists, preserve nullable
excludes_replace semantics, and cover rendering plus update behavior with view
tests.

src/pobsync_backend/forms.py

@@ -2,10 +2,68 @@ from __future__ import annotations
 
 from django import forms
 
-from .models import ScheduleConfig
+from .models import HostConfig, ScheduleConfig
 from .scheduler import parse_cron_expr
 
 
+class NewlineListField(forms.CharField):
+    widget = forms.Textarea
+
+    def __init__(self, *args, **kwargs) -> None:
+        kwargs.setdefault("required", False)
+        super().__init__(*args, **kwargs)
+
+    def prepare_value(self, value):
+        if isinstance(value, list):
+            return "\n".join(str(item) for item in value)
+        return value
+
+    def to_python(self, value) -> list[str]:
+        if not value:
+            return []
+        if isinstance(value, list):
+            return [str(item).strip() for item in value if str(item).strip()]
+        return [line.strip() for line in str(value).splitlines() if line.strip()]
+
+
+class NullableNewlineListField(NewlineListField):
+    def to_python(self, value) -> list[str] | None:
+        parsed = super().to_python(value)
+        return parsed or None
+
+
+class HostConfigForm(forms.ModelForm):
+    includes = NewlineListField(help_text="One include path per line. Leave empty to include defaults.")
+    excludes_add = NewlineListField(help_text="One additional exclude pattern per line.")
+    excludes_replace = NullableNewlineListField(
+        help_text="Optional. When set, replaces global excludes; one pattern per line."
+    )
+    rsync_extra_args = NewlineListField(help_text="One extra rsync argument per line.")
+
+    class Meta:
+        model = HostConfig
+        fields = (
+            "address",
+            "enabled",
+            "ssh_user",
+            "ssh_port",
+            "source_root",
+            "includes",
+            "excludes_add",
+            "excludes_replace",
+            "rsync_extra_args",
+            "retention_daily",
+            "retention_weekly",
+            "retention_monthly",
+            "retention_yearly",
+        )
+        help_texts = {
+            "ssh_user": "Leave empty to use the global SSH user.",
+            "ssh_port": "Leave empty to use the global SSH port.",
+            "source_root": "Leave empty to use the global default source root.",
+        }
+
+
 class ScheduleConfigForm(forms.ModelForm):
     cron_expr = forms.CharField(
         label="Cron expression",

src/pobsync_backend/templates/pobsync_backend/base.html

@@ -104,13 +104,14 @@
     .form-grid { display: grid; gap: 14px; max-width: 680px; }
     .field { display: grid; gap: 5px; }
     .field label { font-weight: 650; }
-    .field input[type="text"], .field input[type="number"] {
+    .field input[type="text"], .field input[type="number"], .field textarea {
       border: 1px solid var(--border);
       border-radius: 6px;
       font: inherit;
       padding: 8px 10px;
       width: 100%;
     }
+    .field textarea { min-height: 92px; resize: vertical; }
     .field .helptext { color: var(--muted); font-size: 12px; }
     .errorlist {
       color: var(--failed);

src/pobsync_backend/templates/pobsync_backend/host_detail.html

@@ -6,6 +6,7 @@
   <h1>{{ host.host }}</h1>
 
   <section class="actions" aria-label="Host actions">
+    <a class="button-link" href="{% url 'edit_host_config' host.host %}">Edit config</a>
     <form method="post" action="{% url 'discover_host_snapshots' host.host %}">
       {% csrf_token %}
       <button type="submit">Discover snapshots</button>

src/pobsync_backend/templates/pobsync_backend/host_form.html

@@ -0,0 +1,32 @@
+{% extends "pobsync_backend/base.html" %}
+
+{% block title %}Config | {{ host.host }}{% endblock %}
+
+{% block content %}
+  <h1>Config: {{ host.host }}</h1>
+
+  <section class="actions" aria-label="Config actions">
+    <a class="button-link" href="{% url 'host_detail' host.host %}">Back to host</a>
+  </section>
+
+  <section class="panel">
+    <h2>Edit Host Config</h2>
+    <form method="post" class="form-grid">
+      {% csrf_token %}
+      {{ form.non_field_errors }}
+
+      {% for field in form %}
+        <div class="field">
+          {{ field.errors }}
+          <label for="{{ field.id_for_label }}">{{ field.label }}</label>
+          {{ field }}
+          {% if field.help_text %}<div class="helptext">{{ field.help_text }}</div>{% endif %}
+        </div>
+      {% endfor %}
+
+      <div class="actions">
+        <button type="submit">Save config</button>
+      </div>
+    </form>
+  </section>
+{% endblock %}

src/pobsync_backend/tests/test_views.py

@@ -68,6 +68,7 @@ class ViewTests(TestCase):
         self.assertContains(response, "20260519-021500Z__ABCDEFGH")
         self.assertContains(response, "Discover snapshots")
         self.assertContains(response, "Edit schedule")
+        self.assertContains(response, "Edit config")
 
     def test_host_detail_returns_404_for_unknown_host(self) -> None:
         self.client.force_login(self.staff_user)
@@ -231,6 +232,92 @@ class ViewTests(TestCase):
         self.assertContains(response, "cron expression must have exactly 5 fields")
         self.assertFalse(ScheduleConfig.objects.filter(host=host).exists())
 
+    def test_host_config_form_renders_existing_values(self) -> None:
+        self.client.force_login(self.staff_user)
+        host = HostConfig.objects.create(
+            host="web-01",
+            address="web-01.example.test",
+            includes=["/srv"],
+            excludes_add=["*.tmp"],
+            rsync_extra_args=["--numeric-ids"],
+        )
+
+        response = self.client.get(reverse("edit_host_config", args=[host.host]))
+
+        self.assertEqual(response.status_code, 200)
+        self.assertContains(response, "Config: web-01")
+        self.assertContains(response, "web-01.example.test")
+        self.assertContains(response, "/srv")
+        self.assertContains(response, "*.tmp")
+        self.assertContains(response, "--numeric-ids")
+
+    def test_host_config_form_updates_host_config(self) -> None:
+        self.client.force_login(self.staff_user)
+        host = HostConfig.objects.create(host="web-01", address="old.example.test")
+
+        response = self.client.post(
+            reverse("edit_host_config", args=[host.host]),
+            {
+                "address": "new.example.test",
+                "enabled": "on",
+                "ssh_user": "backup",
+                "ssh_port": "2222",
+                "source_root": "/srv",
+                "includes": "/srv/www\n/srv/db",
+                "excludes_add": "*.tmp\ncache/",
+                "excludes_replace": "",
+                "rsync_extra_args": "--numeric-ids\n--delete",
+                "retention_daily": "7",
+                "retention_weekly": "4",
+                "retention_monthly": "2",
+                "retention_yearly": "1",
+            },
+            follow=True,
+        )
+
+        self.assertRedirects(response, reverse("host_detail", args=[host.host]))
+        self.assertContains(response, "Host config saved for web-01.")
+        host.refresh_from_db()
+        self.assertEqual(host.address, "new.example.test")
+        self.assertEqual(host.ssh_user, "backup")
+        self.assertEqual(host.ssh_port, 2222)
+        self.assertEqual(host.source_root, "/srv")
+        self.assertEqual(host.includes, ["/srv/www", "/srv/db"])
+        self.assertEqual(host.excludes_add, ["*.tmp", "cache/"])
+        self.assertIsNone(host.excludes_replace)
+        self.assertEqual(host.rsync_extra_args, ["--numeric-ids", "--delete"])
+        self.assertEqual(host.retention_daily, 7)
+        self.assertEqual(host.retention_yearly, 1)
+
+    def test_host_config_form_can_replace_global_excludes(self) -> None:
+        self.client.force_login(self.staff_user)
+        host = HostConfig.objects.create(host="web-01", address="web-01.example.test")
+
+        response = self.client.post(
+            reverse("edit_host_config", args=[host.host]),
+            {
+                "address": host.address,
+                "ssh_user": "",
+                "ssh_port": "",
+                "source_root": "",
+                "includes": "",
+                "excludes_add": "",
+                "excludes_replace": "*.cache\nnode_modules/",
+                "rsync_extra_args": "",
+                "retention_daily": "14",
+                "retention_weekly": "8",
+                "retention_monthly": "12",
+                "retention_yearly": "0",
+            },
+            follow=True,
+        )
+
+        self.assertRedirects(response, reverse("host_detail", args=[host.host]))
+        host.refresh_from_db()
+        self.assertFalse(host.enabled)
+        self.assertEqual(host.excludes_add, [])
+        self.assertEqual(host.excludes_replace, ["*.cache", "node_modules/"])
+
     def _snapshot(self, host: HostConfig, dirname: str) -> SnapshotRecord:
         started_at = datetime.strptime(dirname.split("__", 1)[0], "%Y%m%d-%H%M%SZ").replace(tzinfo=timezone.utc)
         return SnapshotRecord.objects.create(

src/pobsync_backend/views.py

@@ -8,7 +8,7 @@ from django.views.decorators.http import require_POST
 
 from pobsync.errors import ConfigError
 
-from .forms import ScheduleConfigForm
+from .forms import HostConfigForm, ScheduleConfigForm
 from .models import BackupRun, HostConfig, ScheduleConfig, SnapshotRecord
 from .retention import run_sql_retention_plan
 from .snapshot_discovery import discover_snapshots
@@ -96,6 +96,28 @@ def host_retention_plan(request, host: str):
     return render(request, "pobsync_backend/retention_plan.html", context)
 
 
+@staff_member_required
+def edit_host_config(request, host: str):
+    host_config = get_object_or_404(HostConfig, host=host)
+    if request.method == "POST":
+        form = HostConfigForm(request.POST, instance=host_config)
+        if form.is_valid():
+            form.save()
+            messages.success(request, f"Host config saved for {host_config.host}.")
+            return redirect("host_detail", host=host_config.host)
+    else:
+        form = HostConfigForm(instance=host_config)
+
+    return render(
+        request,
+        "pobsync_backend/host_form.html",
+        {
+            "host": host_config,
+            "form": form,
+        },
+    )
+
+
 @staff_member_required
 def edit_host_schedule(request, host: str):
     host_config = get_object_or_404(HostConfig, host=host)