abstractor
Version:
Node.js abstraction layer and automation framework.
216 lines (153 loc) • 7.57 kB
JavaScript
/* ------------------------------------------------------------------------------------
Abstractor - MIT License - Hexagon <github.com/Hexagon>
Node.js abstraction layer and automation framework.
------------------------------------------------------------------------------------
License:
MIT:
Copyright (c) 2016 Hexagon <github.com/Hexagon>
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
------------------------------------------------------------------------------------ */
"use strict";
var extend = require("util")._extend,
uuid = require("uuid"),
qbus = require("qbus"),
clone = require("klon");
class Pipe {
constructor(parameters, defaults) {
this.bus = new qbus();
// Default, is overridden by abstractor.createNode
this.log = console;
// Message tracking
// Every instance of a node gets their own uuid, which is appendeded to the _trace array every time a message passes the node
this._trace = [];
this.uuid = uuid.v4();
// Normal operation
if (typeof parameters == "object" || parameters == undefined) {
this.config = extend(defaults || {}, parameters);
// Special case for generic nodes which just pass their function instead of object { fn: function () { ... } }
} else {
this.config = defaults || {};
this.config.fn = parameters;
}
this.instant && this.instant();
}
on(event, destination) {
var self = this;
this.bus.on(event, function() {
// If destination is a node, or a function
if ( destination._invoke || typeof destination === 'function' ) {
// Qbus passes payload (message) second to last, we want it first
let tmpMsg = arguments[arguments.length - 2],
callback = arguments[arguments.length - 1];
// Move the first argument back second to last
arguments[arguments.length - 2] = arguments[0];
// Make a deep copy of the incoming message
tmpMsg = clone(tmpMsg);
// Add trace of old node to new copy of message
if (tmpMsg.__trace === undefined) tmpMsg.__trace = [];
tmpMsg.__trace.push(self.uuid);
// Place new message back in arguments
arguments[0] = tmpMsg;
// Run callback before invoking actual function
callback && callback();
// Invoke destination node. Remove callback from argument list before passing it
if ( destination._invoke) {
destination._invoke.apply(destination, Array.prototype.slice.call(arguments,0,-1));
// Run destination function. Remove callback from argument list before passing it
} else {
destination.apply(destination, Array.prototype.slice.call(arguments,0,-1));
}
// If destination is a string, log it
} else if (Object.prototype.toString.call(destination) === '[object String]') {
self.log.log(self.constructor.name, destination, undefined,this.config);
}
});
// Return this for chaining
return this;
}
trigger(event, msg, callback) {
// Print node description on invocation
this.log.notice(this.constructor.name, event, this.config.describe ,this.config);
// Place event on private queue, find out if a listener was found, pass callback if requested
var foundListener = false,
_callback = function () { foundListener = true; callback && callback(); };
if (this.config.bypass) {
this.bus.emit(event, this.originalMsg, _callback);
} else {
this.bus.emit(event, msg, _callback);
}
if( !foundListener && (event == "warning" || event == "error") ) {
this.log[event](this.constructor.name, "Unhandled " + event + ": " + (msg.error ? msg.error : "") , msg, this.config);
}
// ALWAYS trigger "always", don't log it though
this.bus.emit("always", msg, false);
return foundListener;
}
error(msg, errMsg) {
msg.error = errMsg;
this.trigger( "error", msg);
}
success(msg, payload) {
msg.payload = payload;
this.trigger( "success", msg);
}
getConfig(entry, msg, mandatory) {
var result = undefined;
// - use msg.`entry` primarily
if (msg[entry] !== undefined) {
result = msg[entry];
// - config.`entry` is used if msg.`entry` is not privided
} else if (this.config[entry] !== undefined) {
result = this.config[entry];
// - abort if we did not get a path at all
} else {
if (mandatory) {
return this.error("Configuration entry `"+entry+"` provided, please supply through msg."+entry+" or <node config>."+entry+".");
}
}
return result;
}
// Just a cleaner entry point than _invoke when invoking a node manually
start(msg) {
this._invoke(msg || {});
}
// Return true if supplied message has visited this node before
traceback( msg ) {
return (msg && msg.__trace && msg.__trace.indexOf(this.uuid) !== -1);
}
_invoke() {
// Warning on empty message
if (arguments[0] === undefined) {
this.log.warning(this.constructor.name, "Invoked without message!",undefined,this.config);
arguments[0] = {};
}
// Save a copy of message for later use
if (!this.traceback(arguments[0])) {
if ( this.config.bypass )
this.originalMsg = clone(arguments[0]);
else
this.originalMsg = arguments[0];
}
// Print node description on invoke, if available
if ( this.config.describe ) {
this.log.notice(this.constructor.name, this.config.describe, arguments[0], this.config);
}
// Incoke it for real
this.invoke && this.invoke.apply(this, arguments);
}
}
module.exports = Pipe;