fix(log): ES 7.2.0 time format .SSSZ + index dropdown + demo always visible

- ES query 502 fix: remove +00:00 conversion, use native .SSSZ format
  (ES 7.2.0 date_time = strict_date_optional_time only, rejects +00:00/epoch)
- parseLogTime: use time.RFC3339Nano for fractional seconds
- new API GET /log-datasources/indices to list ES indices via proxy
- LogDatasourceDialog: add '获取索引' button + Select dropdown for ES
- LogDatasourcePage: always show demo sources alongside real ones

frontend/src/api/monitor/log-center.ts

@@ -34,6 +34,9 @@ export const logCenterApi = {
   deleteDatasource: (id: number | string) => http.delete(`/log-datasources/${id}`),
   setDefaultDatasource: (id: number | string) => http.post(`/log-datasources/${id}/default`),
   testDatasource: (data: Record<string, unknown>) => http.post('/log-datasources/test', data),
+  /** 通过代理查询 ES 集群索引列表 // Logan.Li */
+  listIndices: (params: Record<string, string>) =>
+    http.get<string[]>('/log-datasources/indices', params),
   queryLoki: (data: {
     datasource_id: number;
     query: string;

frontend/src/components/monitor/log-center/LogDatasourceDialog.tsx

@@ -7,7 +7,10 @@ import { Button } from '@/components/ui/button';
 import { Input } from '@/components/ui/input';
 import { Label } from '@/components/ui/label';
 import { Switch } from '@/components/ui/switch';
-import { Loader2, Plug } from 'lucide-react';
+import {
+  Select, SelectContent, SelectItem, SelectTrigger, SelectValue,
+} from '@/components/ui/select';
+import { Loader2, Plug, RefreshCw } from 'lucide-react';
 import { useToast } from '@/hooks/use-toast';
 import { logCenterApi, type LogDataSource } from '@/api/monitor/log-center';
 import type { LogEngine } from './log-center-types';
@@ -32,6 +35,9 @@ export function LogDatasourceDialog({
   const [isDefault, setIsDefault] = useState(false);
   const [saving, setSaving] = useState(false);
   const [testing, setTesting] = useState(false);
+  // 索引下拉: ES 索引列表 + 加载状态 // Logan.Li
+  const [indices, setIndices] = useState<string[]>([]);
+  const [loadingIndices, setLoadingIndices] = useState(false);
 
   useEffect(() => {
     if (!open) return;
@@ -44,6 +50,10 @@ export function LogDatasourceDialog({
       setPass('');
       setSkipTLS(!!editing.skip_tls_verify);
       setIsDefault(!!editing.is_default);
+      // 编辑 ES 源时预加载索引列表
+      if (editing.type === 'elasticsearch' && editing.url) {
+        fetchIndices(editing.url, !!editing.basic_auth, editing.basic_auth_user || '', '');
+      }
     } else {
       setName(engine === 'loki' ? 'Loki' : 'Elasticsearch');
       setUrl(engine === 'loki' ? 'http://localhost:3100' : 'http://localhost:9200');
@@ -53,9 +63,30 @@ export function LogDatasourceDialog({
       setPass('');
       setSkipTLS(false);
       setIsDefault(false);
+      setIndices([]);
     }
   }, [open, editing, engine]);
 
+  const fetchIndices = async (esUrl: string, auth: boolean, authUser: string, authPass: string) => {
+    if (!esUrl) return;
+    setLoadingIndices(true);
+    try {
+      const result = await logCenterApi.listIndices({
+        url: esUrl,
+        basic_auth: auth ? 'true' : 'false',
+        basic_auth_user: authUser,
+        basic_auth_pass: authPass,
+        skip_tls_verify: skipTLS ? 'true' : 'false',
+      });
+      setIndices(Array.isArray(result) ? result : []);
+    } catch {
+      // 静默失败，仍可手动输入
+      setIndices([]);
+    } finally {
+      setLoadingIndices(false);
+    }
+  };
+
   const payload = () => ({
     name: name.trim(),
     type: engine,
@@ -121,8 +152,39 @@ export function LogDatasourceDialog({
           </div>
           {engine === 'elasticsearch' && (
             <div>
-              <Label className="text-xs text-[var(--dg-text-muted)]">默认索引</Label>
-              <Input value={defaultIndex} onChange={e => setDefaultIndex(e.target.value)} className="mt-1 h-9 font-mono text-xs bg-[var(--dg-bg-tertiary)] border-[var(--dg-border)]" />
+              <div className="flex items-center justify-between">
+                <Label className="text-xs text-[var(--dg-text-muted)]">默认索引</Label>
+                <Button
+                  variant="ghost"
+                  size="sm"
+                  className="h-6 px-1.5 text-[10px] text-[var(--dg-text-muted)] hover:text-[var(--dg-text-primary)]"
+                  onClick={() => fetchIndices(url, basicAuth, user, pass)}
+                  disabled={!url || loadingIndices}
+                >
+                  {loadingIndices ? (
+                    <Loader2 className="h-3 w-3 animate-spin mr-0.5" />
+                  ) : (
+                    <RefreshCw className="h-3 w-3 mr-0.5" />
+                  )}
+                  获取索引
+                </Button>
+              </div>
+              {indices.length > 0 ? (
+                <Select value={defaultIndex} onValueChange={setDefaultIndex}>
+                  <SelectTrigger className="mt-1 h-9 w-full font-mono text-xs bg-[var(--dg-bg-tertiary)] border-[var(--dg-border)]">
+                    <SelectValue />
+                  </SelectTrigger>
+                  <SelectContent className="bg-[var(--dg-bg-secondary)] border-[var(--dg-border)] max-h-48">
+                    {indices.map((idx) => (
+                      <SelectItem key={idx} value={idx} className="font-mono text-xs">
+                        {idx}
+                      </SelectItem>
+                    ))}
+                  </SelectContent>
+                </Select>
+              ) : (
+                <Input value={defaultIndex} onChange={e => setDefaultIndex(e.target.value)} placeholder="索引名或通配符，如 logstash-*" className="mt-1 h-9 font-mono text-xs bg-[var(--dg-bg-tertiary)] border-[var(--dg-border)]" />
+              )}
             </div>
           )}
           <div className="flex items-center justify-between">
@@ -157,4 +219,4 @@ export function LogDatasourceDialog({
       </DialogContent>
     </Dialog>
   );
-}
+}

frontend/src/components/monitor/log-center/LogDatasourcePage.tsx

@@ -32,8 +32,8 @@ export function LogDatasourcePage() {
     try {
       const res = await logCenterApi.listDatasources();
       const apiList: LogDataSource[] = Array.isArray(res) ? res : [];
-      // API 有数据 → 展示真实数据源；无数据 → demo 兜底 // Logan.Li
-      setSources(apiList.length > 0 ? apiList : DEMO_FALLBACK);
+      // 真实数据源在前 + demo 兜底在后 // Logan.Li
+      setSources([...apiList, ...DEMO_FALLBACK]);
     } catch {
       setSources(DEMO_FALLBACK);
     } finally {