I am using Nodejs for the backend. I tried this npm package to create a simple work flow (AMAZON-SWF). The package has an example folder which contains files which I put in my node project so that I understand how it works.
The problem is that the Decider is not receiving any task from the SWF server. because of which my work flow never runs. Is there some configuration problem. Please point out what errors I have done.
Below is the code for quick reference. The only change the code has is the version number change and change in the domain name. Otherwise it is the same code as the code which you can find here.
Following is the decider code.
var swf = require('./index');
var myDecider = new swf.Decider({
"domain": "test-domain",
"taskList": {"name": "my-workflow-tasklist"},
"identity": "Decider-01",
"maximumPageSize": 100,
"reverseOrder": false // IMPORTANT: must replay events in the right order, ie. from the start
});
myDecider.on('decisionTask', function (decisionTask) {
console.log("Got a new decision task !");
if(!decisionTask.eventList.scheduled('step1')) {
decisionTask.response.schedule({
name: 'step1',
activity: 'simple-activity'
});
}
else {
decisionTask.response.stop({
result: "some workflow output data"
});
}
decisionTask.response.respondCompleted(decisionTask.response.decisions, function(err, result) {
if(err) {
console.log(err);
return;
}
console.log("responded with some data !");
});
});
myDecider.on('poll', function(d) {
//console.log(_this.config.identity + ": polling for decision tasks...");
console.log("polling for tasks...", d);
});
// Start polling
myDecider.start();
/**
* It is not recommanded to stop the poller in the middle of a long-polling request,
* because SWF might schedule an DecisionTask to this poller anyway, which will obviously timeout.
*
* The .stop() method will wait for the end of the current polling request,
* eventually wait for a last decision execution, then stop properly :
*/
process.on('SIGINT', function () {
console.log('Got SIGINT ! Stopping decider poller after this request...please wait...');
myDecider.stop();
});
Following is activity code:
/**
* This simple worker example will respond to any incoming task
* on the 'my-workflow-tasklist, by setting the input parameters as the results of the task
*/
var swf = require('./index');
var activityPoller = new swf.ActivityPoller({
domain: 'test-domain-newspecies',
taskList: { name: 'my-workflow-tasklist' },
identity: 'simple-activity'
});
activityPoller.on('error',function() {
console.log('error');
});
activityPoller.on('activityTask', function(task) {
console.log("Received new activity task !");
var output = task.input;
task.respondCompleted(output, function (err) {
if(err) {
console.log(err);
return;
}
console.log("responded with some data !");
});
});
activityPoller.on('poll', function(d) {
console.log("polling for activity tasks...", d);
});
activityPoller.on('error', function(error) {
console.log(error);
});
// Start polling
activityPoller.start();
/**
* It is not recommanded to stop the poller in the middle of a long-polling request,
* because SWF might schedule an ActivityTask to this poller anyway, which will obviously timeout.
*
* The .stop() method will wait for the end of the current polling request,
* eventually wait for a last activity execution, then stop properly :
*/
process.on('SIGINT', function () {
console.log('Got SIGINT ! Stopping activity poller after this request...please wait...');
activityPoller.stop();
});
Following is the code which registers:
var awsswf = require('./index');
var swf = awsswf.createClient();
/**
* Register the domain "test-domain"
*/
swf.registerDomain({
name: "test-domain-newspecies",
description: "this is a just a test domain",
workflowExecutionRetentionPeriodInDays: "3"
}, function (err, results) {
if (err && err.code != 'DomainAlreadyExistsFault') {
console.log("Unable to register domain: ", err);
return;
}
console.log("'test-domain-newspecies' registered !")
/**
* Register the WorkflowType "simple-workflow"
*/
swf.registerWorkflowType({
domain: "test-domain-newspecies",
name: "simple-workflow",
version: "2.0"
}, function (err, results) {
if (err && err.code != 'TypeAlreadyExistsFault') {
console.log("Unable to register workflow: ", err);
return;
}
console.log("'simple-workflow' registered !")
/**
* Register the ActivityType "simple-activity"
*/
swf.registerActivityType({
domain: "test-domain-newspecies",
name: "simple-activity",
version: "2.0"
}, function (err, results) {
if (err && err.code != 'TypeAlreadyExistsFault') {
console.log("Unable to register activity type: ", err);
return;
}
console.log("'simple-activity' registered !");
});
});
});
Following is the code which starts the workflow execution:
var swf = require('./index');
var workflow = new swf.Workflow({
"domain": "test-domain-newspecies",
"workflowType": {
"name": "simple-workflow",
"version": "2.0"
},
"taskList": { "name": "my-workflow-tasklist" },
"executionStartToCloseTimeout": "1800",
"taskStartToCloseTimeout": "1800",
"tagList": ["example"],
"childPolicy": "TERMINATE"
});
var workflowExecution = workflow.start({ input: "any data ..."}, function (err, runId) {
if (err) { console.log("Cannot start workflow : ", err); return; }
console.log("Workflow started, runId: " +runId);
});
Following is index.js file
var basePath = "../node_modules/aws-swf/lib/";
exports.AWS = require('aws-swf').AWS;
exports.AWS.config.loadFromPath(__dirname + '/../config/awsConfig.json');
exports.createClient = require(basePath+"swf").createClient;
exports.Workflow = require(basePath+"workflow").Workflow;
exports.WorkflowExecution = require(basePath+"workflow-execution").WorkflowExecution;
exports.ActivityPoller = require(basePath+"activity-poller").ActivityPoller;
exports.ActivityTask = require(basePath+"activity-task").ActivityTask;
exports.Decider = require(basePath+"decider").Decider;
exports.DecisionTask = require(basePath+"decision-task").DecisionTask;
exports.EventList = require(basePath+"event-list").EventList;
exports.DecisionResponse = require(basePath+"decision-response").DecisionResponse;
exports.Poller = require(basePath+"poller").Poller;
