How to Solve Sessions Related Issues When Magento-1.x is Running over Ssl and Configured with Varnish-Cache and Turpentine Extension?

To solve sessions related issues for Turpentine when run over ssl, add the following to magento root directory:

mkdir -p /var/www/magento/app/code/community/SupportDesk/CartFormKey/Model

mkdir /var/www/magento/app/code/community/SupportDesk/CartFormKey/etc

nano /var/www/magento/app/code/community/SupportDesk/CartFormKey/Model/Observer.php

<?php

class SupportDesk_CartFormKey_Model_Observer
{
function disableCsrf($observer)
{
$events = array(
'checkout_cart_add',
'checkout_cart_addgroup',
'checkout_cart_updatepost',
'review_product_post',
'sendfriend_product_sendmail',
'wishlist_index_add',
'wishlist_index_update',
'wishlist_index_cart',
'wishlist_index_send',
'catalog_product_compare_add',
);
$route = $observer->getEvent()->getControllerAction()->getFullActionName();

if (in_array($route, $events)) {
$key = Mage::getSingleton('core/session')->getFormKey();
Mage::app()->getRequest()->setParam('form_key', $key);
}
}
}

nano /var/www/magento/app/code/community/SupportDesk/CartFormKey/etc/config.xml

<?xml version="1.0" ?>
<config>
<modules>
<SupportDesk_CartFormKey>
<version>1.0.0</version>
</SupportDesk_CartFormKey>
</modules>
<global>
<models>
<supportdesk_cartformkey>
<class>SupportDesk_CartFormKey_Model</class>
</supportdesk_cartformkey>
</models>

<events>
<controller_action_predispatch>
<observers>
<controller_action_before>
<class>supportdesk_cartformkey/observer</class>
<method>disableCsrf</method>
</controller_action_before>
</observers>
</controller_action_predispatch>
</events>
</global>
</config>

nano /var/www/magento/app/etc/modules/SupportDesk_CartFormKey.xml

<?xml version="1.0" ?>
<config>
<modules>
<SupportDesk_CartFormKey>
<active>true</active>
<codePool>community</codePool>
</SupportDesk_CartFormKey>
</modules>
</config>


Now clear all cache and sessions.