domotz-remote-pawn/src/external_processes/queue.js

Domotz Agent

/** This file is part of Domotz Agent.
 * Copyright (C) 2016  Domotz Ltd
 *
 * Domotz Agent is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Domotz Agent 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Domotz Agent.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Created by Tommaso Latini <tommaso@domotz.com> on 20/09/16.
 */

const PROMISE = 0;
const COMMAND = 1;
const ARGS = 2;
const OPTIONS = 3;
const SPAWN_HARD_TIMEOUT = 180000;
var startTime;

module.exports = function (index, childProcess, lodash, myConsole) {
    var prefix = 'EXECUTOR - (' + index + '):',
        queue = [],
        current = null;

    function describe(command, args, options) {
        return command + (args ? ' ' + args.join(' ') + '' : '') + (options ? '. Options: ' + JSON.stringify(options) : '');
    }

    function finalize(id) {
        clearTimeout(id);
        dequeue();
    }

    function resolve(deferred, response, id) {
        deferred.resolve(response);
        finalize(id);
    }

    function reject(deferred, error, id) {
        deferred.reject(error);
        finalize(id);
    }

    function enqueue(task) {
        queue.push(task);
        if (!current) {
            dequeue();
        }
    }

    function dequeue() {
        current = queue.shift();

        if (!current) {
            myConsole.verbose('%s Empty queue.', prefix);
            return;
        }

        var options = current[OPTIONS] || {};
        var timeOut;

        if (options.timeout === undefined && options.ttl === undefined) {
            timeOut = SPAWN_HARD_TIMEOUT;
        } else {
            timeOut = options.timeout || options.ttl || null;
        }

        var deferred = current[PROMISE],
            command = current[COMMAND],
            args = current[ARGS] || [],
            description = (options && options.description) || describe(command, args, options),
            id = null,
            err = null,
            stdout = '',
            stderr = '',
            pid = undefined,
            child = undefined;

        try {
            startTime = new Date();
            child = childProcess.spawn(command, args, options);
            pid = child.pid;
        } catch (err) {
            myConsole.warn('%s Process pid:%s "%s" exited with unexpected error', prefix, pid, description);
            reject(deferred, err.stack, undefined);
            return;
        }

        if (child) {
            if (timeOut) {
                myConsole.debug('%s pid:%s Set timeOut %s to %s', prefix, pid, timeOut, description);
                id = setTimeout(function () {
                    myConsole.debug('Timeout expired for pid:%s', pid);
                    child.kill();
                    err = new Error(prefix + ' - Process "' + description + '" killed after timeout: ' + timeOut);
                    reject(deferred, err, id);
                }, timeOut);
            } else {
                myConsole.info('%s Spawned child pid: %s. Path: %s', prefix, pid, description);
            }
            if (child.stdout) {
                child.stdout.on('data', function (data) {
                    stdout += data;
                    if (options.onStdout) {
                        options.onStdout(data, deferred);
                    }
                });
            }

            if (child.stderr) {
                child.stderr.on('data', function (data) {
                    stderr += data;
                    if (options.onStderr) {
                        options.onStderr(data, deferred);
                    }
                });
            }

            child.on('error', function (err) {
                myConsole.warn('%s Process pid:%s "%s" exited with unexpected error', prefix, pid, description);
                reject(deferred, err, id);
            });

            child.on('close', function (code) {
                var duration = new Date() - startTime;
                myConsole.debug('%s Process with pid:%s exited after %dms', prefix, pid, duration);
                if (stdout.length > 0) {
                    myConsole.verbose('%s pid:%s STDOUT: %s ', prefix, pid, stdout);
                }
                if (stderr.length > 0) {
                    myConsole.verbose('%s pid:%s STDERR: %s ', prefix, pid, stderr);
                }
                if (code !== 0 || (stderr && !stdout)) {
                    stderr = stderr.toString().trim();
                    err = new Error(stderr);
                    err.code = code;
                    err.message = stderr || stdout;
                    myConsole.error('%s Process with pid:%s "%s" exited with code: %s. "%s"', prefix, pid, description, code, stderr);
                    reject(deferred, err, id);
                } else {
                    stdout = stdout.toString().trim();
                    resolve(deferred, stdout, id);
                }
            });
        }
    }

    function status() {
        var length = queue.length;
        if (current) {
            var processTimeout = lodash.get(current, '[' + OPTIONS + '].timeout', undefined);
            if (processTimeout === null) {
                myConsole.debug('%s Executor %s is busy with long running process', prefix, index);
                return null;
            }
        }
        return current ? length + 1 : length;
    }

    function getIndex() {
        return index;
    }

    this.enqueue = enqueue;
    this.dequeue = dequeue;
    this.status = status;
    this.getIndex = getIndex;
};