grafana/public/app/plugins/datasource/postgres/module.ts

import { PostgresDatasource } from './datasource';
import { PostgresQueryCtrl } from './query_ctrl';
import { PostgresConfigCtrl } from './config_ctrl';
import { PostgresQuery } from './types';
import { DataSourcePlugin } from '@grafana/data';

const defaultQuery = `SELECT
  extract(epoch from time_column) AS time,
  text_column as text,
  tags_column as tags
FROM
  metric_table
WHERE
  $__timeFilter(time_column)
`;

class PostgresAnnotationsQueryCtrl {
  static templateUrl = 'partials/annotations.editor.html';

  declare annotation: any;

  /** @ngInject */
  constructor($scope: any) {
    this.annotation = $scope.ctrl.annotation;
    this.annotation.rawQuery = this.annotation.rawQuery || defaultQuery;
  }
}

export const plugin = new DataSourcePlugin<PostgresDatasource, PostgresQuery>(PostgresDatasource)
  .setQueryCtrl(PostgresQueryCtrl)
  .setConfigCtrl(PostgresConfigCtrl)
  .setAnnotationQueryCtrl(PostgresAnnotationsQueryCtrl);