grafana/public/app/plugins/datasource/graphite/utils.ts

import { last } from 'lodash';

/**
 * Graphite-web before v1.6 returns HTTP 500 with full stack traces in an HTML page
 * when a query fails. It results in massive error alerts with HTML tags in the UI.
 * This function removes all HTML tags and keeps only the last line from the stack
 * trace which should be the most meaningful.
 */
export function reduceError(error: any): any {
  if (error && error.status === 500 && error.data?.message?.startsWith('<body')) {
    // Remove all HTML tags and take the last line from the stack trace
    const newMessage = last<string>(
      error.data.message
        .replace(/(<([^>]+)>)/gi, '')
        .trim()
        .split(/\n/)
    )!.replace(/u?&#[^;]+;/g, '');
    error.data.message = `Graphite encountered an unexpected error while handling your request. ${newMessage}`;
  }
  return error;
}