After all content management has been done, the manager service sends a request to the initiator requests queue.
This queue is used to relay the request from one stage (applying campaign settings, filling messages with content, etc.) to another (messages personalization, applying tracking fields, processing conditional URLs, etc.) operated by directory-messages
This queue has two different variations: one for spam messages and one for regular messages.
A target queue is determined by campaign interval settings.
If campaign is set to be sent with an interval less then DELIVERY_IS_SPAM_SECONDS threshold (defined as an environment variable), it is considered to be a spam message and is sent to the initiator-spam-requests queue. Otherwise, it is sent to the initiator-requests queue.
Depending on the queue, different versions of directory-messages service will be used to process the request.