Amazon AWS Simple Workflow Service SWF PHP Samples

Question

I was wondering if there are any SWF workflow PHP sample code available for the AWS PHPSDK 2+ ?

Answer 1

I looked for a tutorial and wasn't able to find one. Eventually, I went through the docs and examples using Ruby and the web API and pieced together the nuts and bolts of working with the PHP SDK.

The first thing you need to do is register your domain, workflow, and activities. This can be done either through the AWS console or using the PHP SDK. Using the SDK, use the following:

<?php

require_once "path/to/aws.phar";

use Aws\Swf\SwfClient;

// Create an instance of the SWF class
$client = SwfClient::factory(array(
    "key" => "your_aws_key",
    "secret" => "your_aws_secret_key",
    "region" => "your_aws_region"
));

// Register your domain
$client->registerDomain(array(
    "name" => "domain name you want",
    "description" => "this is a test domain",
    "workflowExecutionRetentionPeriodInDays" => "7"
));

// Register your workflow
$client->registerWorkflowType(array(
    "domain" => "domain name you registered in previous call",
    "name" => "workflow name you want",
    "version" => "1.0",
    "description" => "this is a sample",
    "defaultTaskList" => array(
        "name" => "mainTaskList"
    ),
    "defaultChildPolicy" => "TERMINATE"
));

// Register an activity
$client->registerActivityType(array(
    "domain" => "domain name you registered above",
    "name" => "activity name you want",
    "version" => "1.0",
    "description" => "first activity in our workflow",
    "defaultTaskList" => array(
        "name" => "mainTaskList"
    )
));

// Follow activity registration example above and register 
// more activities as you wish

The next step is to create a decider. This is the script that acts as the coordinating node for your activity (worker) nodes.

// Ask SWF for things the decider needs to know
$result = $client->pollForDecisionTask(array(
    "domain" => "your domain name",
    "taskList" => array(
        "name" => "mainTaskList"
    ),
    "identify" => "default",
    "maximumPageSize" => 50,
    "reverseOrder" => true
));

// Current version of activity types we are using
$activity_type_version = "1.0";

// Parse info we need returned from the pollForDecisionTask call
$task_token = $result["taskToken"];
$workflow_id = $result["workflowExecution"]["workflowId"];
$run_id = $result["workflowExecution"]["runId"];
$last_event = $result["events"][0]["eventId"];

// Our logic that decides what happens next
if($last_event == "3"){
    $activity_type_name = "activity to start if last event ID was 3";
    $task_list = "mainTaskList";
    $activity_id = "1";
    $continue_workflow = true;
}
elseif($last_event == "8"){
    $activity_type_name = "activity to start if last event ID was 8";
    $task_list = "mainTaskList";
    $activity_id = "2";
    $continue_workflow = false;
}

// Now that we populated our variables based on what we received 
// from SWF, we need to tell SWF what we want to do next
if($continue_workflow === true){
    $client->respondDecisionTaskCompleted(array(
        "taskToken" => $task_token,
        "decisions" => array(
            array(
                "decisionType" => "ScheduleActivityTask",
                "scheduleActivityTaskDecisionAttributes" => array(
                    "activityType" => array(
                        "name" => $activity_type_name,
                        "version" => $activity_type_version
                    ),
                    "activityId" => $activity_id,
                    "control" => "this is a sample message",
                    // Customize timeout values
                    "scheduleToCloseTimeout" => "360",
                    "scheduleToStartTimeout" => "300",
                    "startToCloseTimeout" => "60",
                    "heartbeatTimeout" => "60",
                    "taskList" => array(
                        "name" => $task_list
                    ),
                    "input" => "this is a sample message"
                )
            )
        )
    ));
}
// End workflow if last event ID was 8
else if($continue_workflow === false){
    $client->respondDecisionTaskCompleted(array(
        "taskToken" => $task_token,
        "decisions" => array(
            array(
                "decisionType" => "CompleteWorkflowExecution"
            )
        )
    ));
}

The final step is to create your activity workers. You can spin them up using the following format:

// Check with SWF for activities
$result = $client->pollForActivityTask(array(
    "domain" => "domain name you registered",
    "taskList" => array(
        "name" => "mainTaskList"
    )
));

// Take out task token from the response above
$task_token = $result["taskToken"];

// Do things on the computer that this script is saved on
exec("my program i want to execute");

// Tell SWF that we finished what we need to do on this node
$client->respondActivityTaskCompleted(array(
    "taskToken" => $task_token,
    "result" => "I've finished!"
));

The scripts for your activity workers and decider can be put on any server. These scripts all call SWF in order to communicate with each other.

Finally, to start the workflow you just created, use:

// Generate a random workflow ID
$workflowId = mt_rand(1000, 9999);

// Starts a new instance of our workflow
$client->startWorkflowExecution(array(
    "domain" => "your domain name",
    "workflowId" => $workflowId,
    "workflowType" => array(
        "name" => "your workflow name",
        "version" => "1.0"
    ),
    "taskList" => array(
        "name" => "mainTaskList"
    ),
    "input" => "a message goes here",
    "executionStartToCloseTimeout" => "300",
    'taskStartToCloseTimeout' => "300",
    "childPolicy" => "TERMINATE"
));