AWS SWF - How can I pass an argument to a a workflow task?

Question

I am just starting out with the AWS Flow Framework for Java. Essentially I am trying to extend the HelloWorld tutorial but have hit a wall.

I have defined a new method autoScale in the interface which accepts a String arguement as follows

public interface GreeterActivities {
   public String getName();
   public String getGreeting(String name);
   public void say(String what);
   public void autoScale(String groupName);
}

Implementation is fairly straight forward too.

Finally in the GreeterWorkflowImpl class, I am calling the new Task as follows

public void greet() {
   Promise<String> name = operations.getName();
   Promise<String> greeting = operations.getGreeting(name);
   operations.say(greeting);
   operations.autoScale("WebServerScalingGroup");
}

But I get errors such as AWS Error Code: ValidationError, AWS Error Message: 1 validation error detected: Value null at 'autoScalingGroupName' failed to satisfy constraint: Member must not be null

Any ideas on what I am doing wrong? Thanks!

score 0 · Answer 1 · answered Oct 19 '13 at 04:40

The error appears coming from the Auto Scaling API. It probably means that activity was successfully invoked, but an exception was thrown from its implementation. How does your activity implementation looks like? Have you tried logging the fact of activity invocation and its parameters?

AWS SWF - How can I pass an argument to a a workflow task?

1 Answers1