errorhandler.js

// Tradity.de Server
// Copyright (C) 2016 Tradity.de Tech Team <tech@tradity.de>

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version. 

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.

// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

"use strict";

const fs = require('fs');
const util = require('util');
const PSemaphore = require('promise-semaphore');
const ratelimit = require('promise-ratelimit');
const api = require('./api.js');
const debug = require('debug')('sotrade:error');
const promiseUtil = require('./lib/promise-util.js');

class ErrorHandler extends api.Component {
  constructor() {
    super({
      identifier: 'ErrorHandler',
      description: 'Provides methods for handling, logging, and notifying about errors.',
      depends: ['Mailer']
    });
    
    this.sem = new PSemaphore();
    this.throttle = ratelimit(10000);
  }
  
  init() {
    this.load('PubSub').on('error', e => this.handleError(e));
  }

  /**
   * Listener for <code>error</code> events.
   * 
   * This logs the error and sends, if possible, an e-mail
   * to notify about the error.
   * The exact behaviour, such as the e-mail recipient, can be set
   * in the server configuration.
   */
  handleError(e, noemail) {
    if (!e) {
      return this.err(new Error('Error without Error object caught -- abort'), true);
    }
    
    debug('Error', e);
    
    let cfg, longErrorText;
    const catchstack = new Error().stack; // current stack
    
    Promise.resolve().then(() => {
      return this.load('Config').config();
    }).catch(e2 => {
      console.error('Could not get server config due to', e2);
      return null;
    }).then(cfg_ => {
      cfg = cfg_;
      
      return this.throttle();
    }).then(() => {
      return this.sem.add(() => {
        return Promise.resolve().then(() => {
          noemail = noemail || false;
          
          longErrorText = process.pid + ': ' + (new Date().toString()) + ': ' + e + '\n';
          if (e.stack) {
            longErrorText += e.stack + '\n';
          } else { // assume e is not actually an Error instance
            longErrorText += util.inspect(e) + '\n';
          }
          
          // indicating current stack may be helpful
          longErrorText += catchstack + '\n';
          
          if (this.bus) {
            longErrorText += 'Bus: ' + this.bus.id + '\n';
          
            if (e.nonexistentType || (e.name && e.name.match(/^Assertion/i))) {
              longErrorText += '\n' + JSON.stringify(this.bus.busGraph) + '\n';
            }
          }
          
          if (!process.env.SOTRADE_DO_NOT_OUTPUT_ERRORS) {
            console.error(longErrorText);
          }
          
          if (cfg && cfg.errorLogFile) {
            return promiseUtil.ncall(fs.appendFile)(cfg.errorLogFile.replace(/\{\$pid\}/g, process.pid), longErrorText);
          }
        }).then(() => {
          if (cfg && cfg.mail) {
            const opt = Object.assign({}, cfg.mail['errorBase'], {
              text: longErrorText
            });
            
            return this.load('Mailer').sendMail(opt, null, null, 'error').catch(() => {});
          } else {
            console.warn('Could not send error mail due to missing config!');
          }
        });
      });
    }).catch(e2 => {
      console.error('Error while handling other error:\n');
      console.error(e2);
      console.error(e2 && e2.stack);
      console.error('during handling of\n');
      console.error(e);
      console.error(e && e.stack);
      console.trace('aborting');
      process.exit(64);
    });
  }
}

exports.components = [
  ErrorHandler
];