<aura:component controller="PrdConfigCls">
  <aura:attribute name="paramProductId" type="String"/>
  <aura:attribute name="product" type="PrdConfigCls.Product"/>
  <aura:handler name="change" value="{!v.paramProductId}" action="{!c.paramProductIdChangeEventHandler}"/>

  <aura:iteration items="{!v.product.attributes}" var="attr">
      <c:ChildComponent attributeParam="{!attr}"/>
  </aura:iteration>

</aura:component>

<aura:handler name="change" value="{!v.paramProductId}" action="{!c.paramProductIdChangeEventHandler}"/>

({
    paramProductIdChangeEventHandler : function(component, event, helper) {
        var paramProductId = component.get("v.paramProductId");
        if (paramProductId != null && paramProductId != '') {
            helper.loadProductConfiguration(component);
        }
    }
})

({
    loadProductConfiguration : function(component) {

        var action = component.get("c.getProjectProductDefinition");
        action.setParams({  "projectProductId": component.get("v.paramProductId") });
        var self = this;

        action.setCallback(this, function(a) {
            var productResp = a.getReturnValue();
            var product = JSON.parse(productResp);
            component.set("v.product", product);
        });
        $A.enqueueAction(action);

    }
})