Add variable $__from_oid and $__to_oid

Author: haohanyang

src/datasource.ts

@@ -19,6 +19,7 @@ import {
   getMetricValues,
   datetimeToJson,
   base64UrlEncode,
+  unixTsToMongoID
 } from './utils';
 import { MongoQuery, MongoDataSourceOptions, DEFAULT_QUERY, QueryLanguage, VariableQuery } from './types';
 import { firstValueFrom, merge, Observable, of } from 'rxjs';
@@ -46,6 +47,10 @@ export class DataSource extends DataSourceWithBackend<MongoQuery, MongoDataSourc
     const from = getTemplateSrv().replace('$__from', {});
     const to = getTemplateSrv().replace('$__to', {});
 
+    queryText = queryText
+      .replaceAll(/"\$__from_oid"/g, `"${unixTsToMongoID(from, '0')}"`)
+      .replaceAll(/"\$__to_oid"/g, `"${unixTsToMongoID(to, 'f')}"`);
+
     // Compatible with legacy plugin $from
     if (from !== '$__from') {
       queryText = queryText.replaceAll(/"\$from"/g, datetimeToJson(from));

src/utils.ts

@@ -141,3 +141,23 @@ export function base64UrlEncode(input: string | undefined) {
   let base64Url = base64.replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/, '');
   return base64Url;
 }
+
+export function unixTsToMongoID(utc: string, rightPadding: string) {
+  const val = Math.trunc(parseInt(utc, 10) / 1000)
+
+  if (val < 0 || val > 0xFFFFFFFF) {
+    return '';
+  }
+
+  let hexString = val.toString(16)
+
+  while (hexString.length < 8) {
+    hexString = '0' + hexString;
+  }
+
+  while (hexString.length < 24) {
+    hexString = hexString + rightPadding;
+  }
+
+  return hexString;
+}