Refactor dashboard data serialization and mock context for improved clarity

- Introduced `serialize_audit_for_response` and `serialize_current_cluster_for_template` functions to handle JSON serialization of audit and cluster data, enhancing data consistency for API responses and template rendering.
- Updated `get_mock_context` in `mock_data.py` to utilize the new serialization functions, simplifying the mock data structure and improving readability.
- Refactored `collect_context` and `collect_audits` in `views.py` to leverage the new serialization methods, ensuring a cleaner and more maintainable codebase.
- Added unit tests for the new serialization functions to ensure correctness and reliability of data formatting.

dashboard/mock_data.py

@@ -1,6 +1,9 @@
 """Mock context for dashboard when USE_MOCK_DATA is enabled (no OpenStack/Prometheus)."""
 
-import json
+from dashboard.serializers import (
+    serialize_audit_for_response,
+    serialize_current_cluster_for_template,
+)
 
 
 def get_mock_context():
@@ -38,7 +41,7 @@ def get_mock_context():
     cpu_current = [45.2, 38.1, 52.0, 41.3, 29.8, 32.1, 36.4, 29.2, 42.2, 41.3, 28.3, 33.3]
     cpu_projected = [42.0, 40.0, 48.0, 44.0, 35.0, 46.0, 43.0, 43.0, 44.0, 48.0, 47.0, 49.0]
 
-    audits = [
+    audits_raw = [
         {
             "id": "mock-audit-uuid-1",
             "name": "Mock audit (balanced)",
@@ -49,20 +52,18 @@ def get_mock_context():
             "scope": "Full Cluster",
             "cpu_weight": "1.0",
             "ram_weight": "1.0",
-            "migrations": json.dumps(
-                [
-                    {
-                        "instanceName": "instance-1",
-                        "source": "compute-0",
-                        "destination": "compute-3",
-                        "flavor": "m1.small",
-                        "impact": "Low",
-                    }
-                ]
-            ),
-            "host_labels": json.dumps(host_labels),
-            "cpu_current": json.dumps(cpu_current),
-            "cpu_projected": json.dumps(cpu_projected),
+            "migrations": [
+                {
+                    "instanceName": "instance-1",
+                    "source": "compute-0",
+                    "destination": "compute-3",
+                    "flavor": "m1.small",
+                    "impact": "Low",
+                }
+            ],
+            "host_labels": host_labels,
+            "cpu_current": cpu_current,
+            "cpu_projected": cpu_projected,
         },
         {
             "id": "mock-audit-uuid-2",
@@ -74,12 +75,13 @@ def get_mock_context():
             "scope": "Full Cluster",
             "cpu_weight": "1.0",
             "ram_weight": "1.0",
-            "migrations": json.dumps([]),
-            "host_labels": json.dumps(host_labels),
-            "cpu_current": json.dumps(cpu_current),
-            "cpu_projected": json.dumps([40.0, 42.0, 50.0, 43.0, 36.0, 45.0]),
+            "migrations": [],
+            "host_labels": host_labels,
+            "cpu_current": cpu_current,
+            "cpu_projected": [40.0, 42.0, 50.0, 43.0, 36.0, 45.0],
         },
     ]
+    audits = [serialize_audit_for_response(a) for a in audits_raw]
 
     return {
         "region": {
@@ -128,8 +130,7 @@ def get_mock_context():
             "third_common_flavor": {"name": "m1.large", "count": 4},
         },
         "audits": audits,
-        "current_cluster": {
-            "host_labels": json.dumps(host_labels),
-            "cpu_current": json.dumps(cpu_current),
-        },
+        "current_cluster": serialize_current_cluster_for_template(
+            {"host_labels": host_labels, "cpu_current": cpu_current}
+        ),
     }

dashboard/openstack_utils/audits.py

@@ -49,41 +49,81 @@ def get_current_cluster_cpu(connection: Connection) -> dict:
     }
 
 
+def _fetch_audits_and_action_plans(session, watcher_endpoint):
+    """GET audits and action_plans from Watcher API. Returns (audits_list, action_plans_list)."""
+    audits_resp = session.get(f"{watcher_endpoint}/v1/audits")
+    audits_resp.raise_for_status()
+    audits_list = audits_resp.json().get("audits") or []
+
+    actionplans_resp = session.get(f"{watcher_endpoint}/v1/action_plans")
+    actionplans_resp.raise_for_status()
+    action_plans_list = actionplans_resp.json().get("action_plans") or []
+
+    return audits_list, action_plans_list
+
+
+def _fetch_migrations_for_audit(
+    connection, session, watcher_endpoint, audit_resp, actionplan, actions_resp
+):
+    """
+    Fetch action details for the given action plan and build migrations list and
+    instance->destination mapping. Returns (migrations, mapping).
+    """
+    migrations = []
+    mapping = {}
+    for action in actions_resp:
+        action_resp = session.get(f"{watcher_endpoint}/v1/actions/{action['uuid']}")
+        action_resp.raise_for_status()
+        action_resp = action_resp.json()
+
+        server = connection.get_server_by_id(action_resp["input_parameters"]["resource_id"])
+        params = action_resp["input_parameters"]
+        mapping[params["resource_name"]] = params["destination_node"]
+
+        migrations.append(
+            {
+                "instanceName": params["resource_name"],
+                "source": params["source_node"],
+                "destination": params["destination_node"],
+                "flavor": server.flavor.name,
+                "impact": "Low",
+            }
+        )
+    return migrations, mapping
+
+
+def _build_projected_cpu_metrics(cpu_data, mapping):
+    """
+    Apply instance->destination mapping to a copy of cpu_data and return
+    aggregated CPU metrics DataFrame (host, cpu_usage).
+    """
+    projected_cpu_data = copy(cpu_data)
+    for entry in projected_cpu_data:
+        if (instance := entry["metric"]["instanceName"]) in mapping:
+            entry["metric"]["host"] = mapping[instance]
+    return convert_cpu_data(projected_cpu_data)
+
+
 def get_audits(connection: Connection) -> list[dict] | None:
     session = connection.session
-
     watcher_endpoint = connection.endpoint_for(
         service_type=WATCHER_ENDPOINT_NAME, interface=WATCHER_INTERFACE_NAME
     )
 
-    # Collect instances prometheus metrics
     cpu_data = query_prometheus(PROMETHEUS_METRICS["cpu_usage"])
-
     cpu_metrics = convert_cpu_data(data=cpu_data)
 
-    # Fetch audit list
-    audits_resp = session.get(f"{watcher_endpoint}/v1/audits")
-    audits_resp.raise_for_status()
-    audits_resp = audits_resp.json().get("audits") or []
-
-    # Fetch action plan list
-    actionplans_resp = session.get(f"{watcher_endpoint}/v1/action_plans")
-    actionplans_resp.raise_for_status()
-    actionplans_resp = actionplans_resp.json().get("action_plans") or []
-
-    # Filtering audits by PENDING state
-    pending_audits = [plan for plan in actionplans_resp if plan["state"] == "RECOMMENDED"]
+    _, action_plans_list = _fetch_audits_and_action_plans(session, watcher_endpoint)
+    pending_audits = [plan for plan in action_plans_list if plan["state"] == "RECOMMENDED"]
 
     result = []
     for item in pending_audits:
-        projected_cpu_data = copy(cpu_data)
-
         audit_resp = session.get(f"{watcher_endpoint}/v1/audits/{item['audit_uuid']}")
         audit_resp.raise_for_status()
         audit_resp = audit_resp.json()
 
         actionplan = next(
-            filter(lambda x: x.get("audit_uuid") == audit_resp["uuid"], actionplans_resp), None
+            filter(lambda x: x.get("audit_uuid") == audit_resp["uuid"], action_plans_list), None
         )
         if actionplan is None:
             continue
@@ -94,32 +134,10 @@ def get_audits(connection: Connection) -> list[dict] | None:
         actions_resp.raise_for_status()
         actions_resp = actions_resp.json().get("actions") or []
 
-        migrations = []
-        mapping = {}
-        for action in actions_resp:
-            action_resp = session.get(f"{watcher_endpoint}/v1/actions/{action['uuid']}")
-            action_resp.raise_for_status()
-            action_resp = action_resp.json()
-
-            server = connection.get_server_by_id(action_resp["input_parameters"]["resource_id"])
-            params = action_resp["input_parameters"]
-            mapping[params["resource_name"]] = params["destination_node"]
-
-            migrations.append(
-                {
-                    "instanceName": action_resp["input_parameters"]["resource_name"],
-                    "source": action_resp["input_parameters"]["source_node"],
-                    "destination": action_resp["input_parameters"]["destination_node"],
-                    "flavor": server.flavor.name,
-                    "impact": "Low",
-                }
-            )
-
-        for entry in projected_cpu_data:
-            if (instance := entry["metric"]["instanceName"]) in mapping:
-                entry["metric"]["host"] = mapping[instance]
-
-        projected_cpu_metrics = convert_cpu_data(projected_cpu_data)
+        migrations, mapping = _fetch_migrations_for_audit(
+            connection, session, watcher_endpoint, audit_resp, actionplan, actions_resp
+        )
+        projected_cpu_metrics = _build_projected_cpu_metrics(cpu_data, mapping)
 
         result.append(
             {

dashboard/serializers.py

@@ -0,0 +1,32 @@
+"""Serialization helpers for dashboard context and API responses."""
+
+import json
+
+
+def _ensure_json_str(value):
+    """Return value as JSON string; if already a string, return as-is."""
+    return value if isinstance(value, str) else json.dumps(value)
+
+
+def serialize_audit_for_response(audit: dict) -> dict:
+    """
+    Return a copy of the audit dict with migrations, host_labels, cpu_current,
+    and cpu_projected serialized as JSON strings (for template/API response).
+    """
+    result = dict(audit)
+    result["migrations"] = _ensure_json_str(audit.get("migrations"))
+    result["host_labels"] = _ensure_json_str(audit.get("host_labels"))
+    result["cpu_current"] = _ensure_json_str(audit.get("cpu_current"))
+    result["cpu_projected"] = _ensure_json_str(audit.get("cpu_projected"))
+    return result
+
+
+def serialize_current_cluster_for_template(current_cluster: dict) -> dict:
+    """
+    Return current_cluster with host_labels and cpu_current as JSON strings
+    for template embedding (e.g. in index.html).
+    """
+    return {
+        "host_labels": _ensure_json_str(current_cluster.get("host_labels")),
+        "cpu_current": _ensure_json_str(current_cluster.get("cpu_current")),
+    }

dashboard/tests/test_serializers.py

@@ -0,0 +1,57 @@
+"""Tests for dashboard.serializers."""
+
+import json
+
+from django.test import TestCase
+
+from dashboard.serializers import (
+    serialize_audit_for_response,
+    serialize_current_cluster_for_template,
+)
+
+
+class SerializeAuditForResponseTest(TestCase):
+    def test_serializes_list_fields_to_json_strings(self):
+        audit = {
+            "id": "audit-1",
+            "name": "Test",
+            "migrations": [{"instanceName": "i1", "source": "h1", "destination": "h2"}],
+            "host_labels": ["h1", "h2"],
+            "cpu_current": [10.0, 20.0],
+            "cpu_projected": [15.0, 25.0],
+        }
+        result = serialize_audit_for_response(audit)
+        self.assertEqual(result["id"], "audit-1")
+        self.assertEqual(result["name"], "Test")
+        self.assertEqual(json.loads(result["migrations"]), audit["migrations"])
+        self.assertEqual(json.loads(result["host_labels"]), audit["host_labels"])
+        self.assertEqual(json.loads(result["cpu_current"]), audit["cpu_current"])
+        self.assertEqual(json.loads(result["cpu_projected"]), audit["cpu_projected"])
+
+    def test_leaves_already_serialized_strings_unchanged(self):
+        audit = {
+            "id": "a",
+            "migrations": "[1,2]",
+            "host_labels": "[]",
+            "cpu_current": "[0]",
+            "cpu_projected": "[0]",
+        }
+        result = serialize_audit_for_response(audit)
+        self.assertEqual(result["migrations"], "[1,2]")
+        self.assertEqual(result["host_labels"], "[]")
+        self.assertEqual(result["cpu_current"], "[0]")
+        self.assertEqual(result["cpu_projected"], "[0]")
+
+
+class SerializeCurrentClusterForTemplateTest(TestCase):
+    def test_serializes_lists_to_json_strings(self):
+        cluster = {"host_labels": ["c0", "c1"], "cpu_current": [30.0, 40.0]}
+        result = serialize_current_cluster_for_template(cluster)
+        self.assertEqual(json.loads(result["host_labels"]), cluster["host_labels"])
+        self.assertEqual(json.loads(result["cpu_current"]), cluster["cpu_current"])
+
+    def test_leaves_already_serialized_strings_unchanged(self):
+        cluster = {"host_labels": "[]", "cpu_current": "[]"}
+        result = serialize_current_cluster_for_template(cluster)
+        self.assertEqual(result["host_labels"], "[]")
+        self.assertEqual(result["cpu_current"], "[]")

dashboard/views.py

@@ -1,5 +1,3 @@
-import json
-
 from django.conf import settings
 from django.core.cache import cache
 from django.http import JsonResponse
@@ -10,6 +8,10 @@ from dashboard.openstack_utils.audits import get_audits, get_current_cluster_cpu
 from dashboard.openstack_utils.connect import check_openstack, get_connection
 from dashboard.openstack_utils.flavor import get_flavor_list
 from dashboard.prometheus_utils.query import check_prometheus, fetch_dashboard_metrics
+from dashboard.serializers import (
+    serialize_audit_for_response,
+    serialize_current_cluster_for_template,
+)
 from dashboard.stats import (
     CACHE_KEY_AUDITS,
     CACHE_KEY_CURRENT_CLUSTER,
@@ -44,17 +46,9 @@ def collect_context():
     audits = get_audits(connection=connection)
     metrics = fetch_dashboard_metrics()
     context = build_stats(metrics, region_name, flavors)
-    context["audits"] = audits
+    context["audits"] = [serialize_audit_for_response(a) for a in audits]
     current_cluster = get_current_cluster_cpu(connection)
-    context["current_cluster"] = {
-        "host_labels": json.dumps(current_cluster["host_labels"]),
-        "cpu_current": json.dumps(current_cluster["cpu_current"]),
-    }
-    for audit in context["audits"]:
-        audit["migrations"] = json.dumps(audit["migrations"])
-        audit["host_labels"] = json.dumps(audit["host_labels"])
-        audit["cpu_current"] = json.dumps(audit["cpu_current"])
-        audit["cpu_projected"] = json.dumps(audit["cpu_projected"])
+    context["current_cluster"] = serialize_current_cluster_for_template(current_cluster)
     return context
 
 
@@ -71,12 +65,7 @@ def collect_audits():
     """Build audits list with serialized fields for frontend."""
     connection = get_connection()
     audits = get_audits(connection=connection)
-    for audit in audits:
-        audit["migrations"] = json.dumps(audit["migrations"])
-        audit["host_labels"] = json.dumps(audit["host_labels"])
-        audit["cpu_current"] = json.dumps(audit["cpu_current"])
-        audit["cpu_projected"] = json.dumps(audit["cpu_projected"])
-    return audits
+    return [serialize_audit_for_response(a) for a in audits]
 
 
 def _skeleton_context():

docs/api_context.md

@@ -0,0 +1,80 @@
+# Dashboard API and context contract
+
+This document describes the structure of data passed to the index template and returned by the dashboard API endpoints. Cache keys are defined in `dashboard/stats.py`.
+
+## Index page context (server-rendered)
+
+When the index is rendered with full data (e.g. `USE_MOCK_DATA=True` or after JS loads from API), the template receives a context with these top-level keys:
+
+| Key | Description |
+|-----|-------------|
+| `region` | `{ "name": str, "hosts_total": int }` |
+| `pcpu` | Physical CPU: `total`, `usage`, `free`, `used_percentage` |
+| `vcpu` | Virtual CPU: `total`, `allocated`, `free`, `allocated_percentage`, `overcommit_ratio`, `overcommit_max` |
+| `pram` | Physical RAM (bytes): `total`, `usage`, `free`, `used_percentage` |
+| `vram` | Virtual RAM (bytes): `total`, `allocated`, `free`, `allocated_percentage`, `overcommit_ratio`, `overcommit_max` |
+| `vm` | VMs: `count`, `active`, `stopped`, `avg_cpu`, `avg_ram`, `density` |
+| `flavors` | `first_common_flavor`, `second_common_flavor`, `third_common_flavor` — each `{ "name": str, "count": int }` or `None`. The `name` may be a human-readable flavor name or a flavor UUID depending on OpenStack. |
+| `audits` | List of audit objects (see below). For template, `migrations`, `host_labels`, `cpu_current`, `cpu_projected` are JSON strings. |
+| `current_cluster` | `{ "host_labels": str (JSON array), "cpu_current": str (JSON array) }` for embedding in the page. |
+| `skeleton` | Optional boolean; when true, stats placeholders are shown and data is loaded via API. |
+
+## Single audit object (for template / API response)
+
+When serialized for the template or for `api/audits`, each audit has:
+
+| Field | Type | Description |
+|-------|------|-------------|
+| `id` | str | Audit UUID |
+| `name` | str | Audit name |
+| `created_at` | str | ISO 8601 datetime |
+| `strategy` | str | Strategy name |
+| `goal` | str | Goal name |
+| `type` | str | e.g. `ONESHOT` |
+| `scope` | str | e.g. `Full Cluster` |
+| `cpu_weight` | str | Weight parameter |
+| `ram_weight` | str | Weight parameter |
+| `migrations` | str (template) / list (API raw) | JSON string of migration list, or list of `{ instanceName, source, destination, flavor, impact }` |
+| `host_labels` | str (template) / list (API raw) | JSON string of host names, or list |
+| `cpu_current` | str (template) / list (API raw) | JSON string of CPU usage per host, or list of numbers |
+| `cpu_projected` | str (template) / list (API raw) | JSON string of projected CPU per host, or list of numbers |
+
+For the **index template**, `migrations`, `host_labels`, `cpu_current`, and `cpu_projected` are always JSON strings so they can be embedded in the page. For **api/audits**, `audits` are returned with these four fields as JSON strings (same as template). The **current_cluster** in the API response uses raw lists (see below).
+
+## GET /api/stats/
+
+Returns a JSON object with the same keys as the index context, **excluding** `audits`, `current_cluster`, and `skeleton`: `region`, `pcpu`, `vcpu`, `pram`, `vram`, `vm`, `flavors`. All numeric values are numbers; sizes are in bytes where applicable.
+
+## GET /api/audits/
+
+Returns:
+
+```json
+{
+  "audits": [ /* list of audit objects with migrations, host_labels, cpu_current, cpu_projected as JSON strings */ ],
+  "current_cluster": {
+    "host_labels": [ "compute-0", "compute-1", ... ],
+    "cpu_current": [ 30.5, 42.1, ... ]
+  }
+}
+```
+
+Here `audits` use the same serialized form as the template (JSON strings for list fields). The `current_cluster` is with **raw lists** (not JSON strings) so the frontend can use them directly without parsing.
+
+## GET /api/source-status/
+
+Returns:
+
+```json
+{
+  "prometheus": { "status": "ok" | "error" | "mock", "message"?: "..." },
+  "openstack": { "status": "ok" | "error" | "mock", "message"?: "..." }
+}
+```
+
+## Cache keys (dashboard/stats.py)
+
+- `CACHE_KEY_STATS` — stats for `/api/stats/`
+- `CACHE_KEY_AUDITS` — serialized audits list
+- `CACHE_KEY_CURRENT_CLUSTER` — raw current_cluster (host_labels, cpu_current lists)
+- `CACHE_KEY_SOURCE_STATUS` — source status result

static/js/dashboard.js

@@ -1,11 +1,29 @@
 /**
  * Dashboard logic: stats rendering, audit selector, CPU chart, migration table.
- * Expects globals: SKELETON_MODE, CURRENT_CLUSTER, auditData (set by index.html).
- * Depends on: utils.js (formatBytes, getCSSVar, calculateStats)
+ *
+ * Expected globals (set by index.html / inline script):
+ *   - SKELETON_MODE (boolean): whether to fetch data from API instead of using embedded context
+ *   - CURRENT_CLUSTER: { host_labels, cpu_current } for "current" cluster chart when no audits
+ *   - auditData: object keyed by audit id, each value { name, migrations, hostData: { labels, current, projected } }
+ *   - INITIAL_AUDIT_ID: first audit id to select when not in skeleton mode
+ *
+ * Required DOM element ids:
+ *   - auditSelector, previewCpu, previewRam, previewScope, previewStrategy
+ *   - regionBadge, auditsCount, migrationTableBody, migrationCount, cpuDistributionChart
+ *   - currentCpuMean, currentCpuStd, currentCpuStdBlock
+ *   - elements with data-stats="..." for renderStats()
+ *
+ * Depends on: utils.js (formatBytes, getCSSVar, calculateStats, escapeHtml, formatAuditDate)
  */
 (function() {
     var cpuDistributionChart = null;
+    var escapeHtml = typeof window.escapeHtml === 'function' ? window.escapeHtml : function(text) {
+        if (text == null) return '';
+        var s = String(text);
+        return s.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;').replace(/'/g, '&#39;');
+    };
 
+    // --- Initialization: audit selector change (preview panel) ---
     document.getElementById('auditSelector').addEventListener('change', function(e) {
         var option = this.options[this.selectedIndex];
         if (!option) return;
@@ -15,6 +33,7 @@
         document.getElementById('previewStrategy').textContent = option.dataset.strategy || 'Balanced';
     });
 
+    // --- Stats: setStat, setProgress, renderStats ---
     function setStat(key, text) {
         document.querySelectorAll('[data-stats="' + key + '"]').forEach(function(el) {
             el.textContent = text;
@@ -85,6 +104,7 @@
         document.querySelectorAll('[data-stats]').forEach(function(n) { n.classList.remove('animate-pulse'); });
     }
 
+    // --- Audits: renderAudits, loadSelectedAudit ---
     function renderAudits(auditsList) {
         if (!auditsList || !auditsList.length) {
             var countEl = document.getElementById('auditsCount');
@@ -117,7 +137,7 @@
                 opt.setAttribute('data-scope', audit.scope || 'Full Cluster');
                 opt.setAttribute('data-strategy', audit.strategy || 'Balanced');
                 opt.setAttribute('data-goal', audit.goal || '');
-                var dateStr = audit.created_at ? new Date(audit.created_at).toLocaleDateString('en-US', { month: 'short', day: 'numeric' }) : '';
+                var dateStr = formatAuditDate(audit.created_at);
                 opt.textContent = audit.name + ' (' + dateStr + ')';
                 sel.appendChild(opt);
             });
@@ -136,6 +156,7 @@
         updateCPUCharts(auditId);
     };
 
+    // --- Migration table: updateMigrationTable ---
     function updateMigrationTable(auditId) {
         var tbody = document.getElementById('migrationTableBody');
         var migrationCount = document.getElementById('migrationCount');
@@ -151,12 +172,13 @@
         data.migrations.forEach(function(migration) {
             var impact = migration.impact || 'Low';
             var impactClass = { 'Low': 'badge-success', 'Medium': 'badge-warning', 'High': 'badge-error' }[impact] || 'badge-neutral';
-            html += '<tr><td class="font-medium"><div>' + migration.instanceName + '</div></td><td><div class="flex items-center gap-2"><span class="badge badge-outline badge-xs">' + migration.source + '</span><svg class="w-3 h-3 text-base-content/30" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M13 7l5 5m0 0l-5 5m5-5H6"/></svg><span class="badge badge-primary badge-outline badge-xs">' + migration.destination + '</span></div></td><td><code class="text-xs bg-base-200 px-2 py-1 rounded">' + migration.flavor + '</code></td><td><span class="badge ' + impactClass + ' badge-xs">' + impact + '</span></td></tr>';
+            html += '<tr><td class="font-medium"><div>' + escapeHtml(migration.instanceName) + '</div></td><td><div class="flex items-center gap-2"><span class="badge badge-outline badge-xs">' + escapeHtml(migration.source) + '</span><svg class="w-3 h-3 text-base-content/30" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M13 7l5 5m0 0l-5 5m5-5H6"/></svg><span class="badge badge-primary badge-outline badge-xs">' + escapeHtml(migration.destination) + '</span></div></td><td><code class="text-xs bg-base-200 px-2 py-1 rounded">' + escapeHtml(migration.flavor) + '</code></td><td><span class="badge ' + impactClass + ' badge-xs">' + escapeHtml(impact) + '</span></td></tr>';
         });
         tbody.innerHTML = html;
         migrationCount.textContent = data.migrations.length + ' action' + (data.migrations.length !== 1 ? 's' : '');
     }
 
+    // --- CPU charts: updateCPUCharts ---
     function updateCPUCharts(auditId) {
         var data = window.auditData && window.auditData[auditId];
         if (!data || !data.hostData) return;
@@ -289,6 +311,7 @@
             : [ data.hostData.current.slice() ];
     }
 
+    // --- Initialization: DOMContentLoaded (skeleton vs embedded data) ---
     document.addEventListener('DOMContentLoaded', function() {
         if (typeof SKELETON_MODE !== 'undefined' && SKELETON_MODE) {
             Promise.all([
@@ -325,6 +348,7 @@
         }
     });
 
+    // --- Initialization: theme change (recreate chart) ---
     document.addEventListener('themechange', function() {
         if (cpuDistributionChart) {
             var auditId = document.getElementById('auditSelector').value;

static/js/utils.js

@@ -1,3 +1,15 @@
+// Escape for safe HTML text content (prevents XSS when inserting into HTML)
+function escapeHtml(text) {
+    if (text == null) return '';
+    const s = String(text);
+    return s
+        .replace(/&/g, '&')
+        .replace(/</g, '&lt;')
+        .replace(/>/g, '&gt;')
+        .replace(/"/g, '&quot;')
+        .replace(/'/g, '&#39;');
+}
+
 // Format bytes to GB (matches Django convert_bytes filter default)
 function formatBytes(bytes, targetUnit = 'GB') {
     if (bytes == null || isNaN(Number(bytes))) return '0';
@@ -24,6 +36,16 @@ function getColorWithOpacity(className) {
     
     return computedColor;
 }
+// Format audit date for display (ISO string -> short date, e.g. "Feb 1")
+function formatAuditDate(isoString) {
+    if (!isoString) return '';
+    try {
+        return new Date(isoString).toLocaleDateString('en-US', { month: 'short', day: 'numeric' });
+    } catch (e) {
+        return '';
+    }
+}
+
 // Utility function to calculate mean and standard deviation
 function calculateStats(data) {
     if (!data || data.length === 0) return { mean: 0, std: 0 };