easy-xapi/lib/error.ts

express api x-headers service

/**
 * Created by karl on 16/07/15.
 */

'use strict';

import http = require('http');
import cluster = require('cluster');
import express = require('express');

var logMock = {
    error: function (data, msg) {
        console.error(JSON.stringify(data), msg);
    }
};

export function getErrorHandler(server: http.Server): express.ErrorRequestHandler {
    return function errorHandler(err:any, req, res, next) {

        var friendly = {
            message: err.message,
            stack: err.stack
        };
        if(!req.log) {
            req.log = logMock;
        }

        req.log.error({error: friendly}, 'Something went wrong');

        if(cluster.isMaster) {
            res.error(err.message);
            return;
        }

        // Note: we're in dangerous territory!
        // By definition, something unexpected occurred,
        // which we probably didn't want.
        // Anything can happen now!  Be very careful!

        try {
            // make sure we close down within 30 seconds
            var killtimer = setTimeout(function() {
                process.exit(1);
            }, 30000);
            // But don't keep the process open just for that!
            killtimer.unref();

            // stop taking new requests.
            server.close();

            // Let the master know we're dead.  This will trigger a
            // 'disconnect' in the cluster master, and then it will fork
            // a new worker.
            if(cluster.worker) {
                cluster.worker.disconnect();
            }
            // try to send an error to the request that triggered the problem
            res.error(err.message);
        } catch (err2) {
            // oh well, not much we can do at this point.
            var friendly2 = {
                message: err2.message,
                stack: err2.stack
            };
            req.log.error({error: friendly2}, 'Error sending 500!');
            res.end();
        }
    }
}