====== MSMQ Event Source/Sink ======

===== Overview =====

Data Core can read and write Alarm & Event (A&E) data from Microsoft message queues. This can be used for temporary data caching when configuring resilient data flows.

For example, imagine a Data Core Node is responsible for subscribing to A&E data from an ephemeral data source such as a serial printer feed, then sending it to a downstream server. Introducing an intermediate message queue will protect us from data loss if the downstream network connection is interupted.


===== Getting Started =====

==== 1. Enable MSMQ on Windows Server ====

Enable Message Queuing Services via Server Features.

{{ :data_core:msmq01.png?600 |}}


==== 2. Create Queue(s) ====

Create a queue using Computer Management.

**NB.** Data Core can only communicate with private queues on the local server.

{{ :data_core:msmq02.png?500 |}}

==== 3. Queue Config ====

We recommend configuring transactional queues with an explicit storage capacity.

{{ :data_core:msmq03.png?500 |}}

If "Authenticated" is selected and [[data_core:how_to_run_app_store_connect_under_a_service_account|Data Core is running under a service account]], then the service account must have send/receive/delete security privileges.

==== 4. Configure an Event Sink ====

A //Microsoft Message Queue// Event Sink will write any messages arriving on an event subscription flow to a MSMQ.

The key settings are listed under //Message Queue Settings//. Configure these to reference your local queue with equivalent properties.

{{ :data_core:msmq04.png?600 |}}


==== 5. Configure an Event Source ====

A //Microsoft Message Queue// Event Source reads messages from the MSMQ and relays to downstream subscribers. Note that the message will only be removed from the queue if all subscribers respond with a successful acknowledgement, therefore we recommended one event sink subscription per MSMQ event source.

The key settings are listed under //Message Queue Settings//. Configure these to reference your local queue.


{{ :data_core:msmq05.png?600 |}}

===== Optional Settings =====

==== Set MSMQ to use custom storage location ====

By default MSMQ created in system partition, use the following method to move MSMQ files to a different location.

  * Open "Computer Manager" and expand "Services and Applications"
  * Right-click on "Message Queuing" mouse over "All Task" then click "Take Message Queuing Offline" \\ Click "Yes"
  * Use xcopy command to copy MSMQ directory to different volume. \\ Xcopy c:\windows\system32\msmq d:\msmq /O/X/E/H/K \\ //This copies contents and security settings.//

After copying to new location.

  * Right click on "Message queuing" and click on "Properties"
  * Click on the "Storage" tab
  * Change the folder locations and select new location.
  * Click "OK" and a prompt will appear to reboot the system.
  * Reboot the system for the changes to take effect.
  * Open "Computer Manager" and expand "Services and Applications"
  * Right click on "Message Queuing" mouse over "All Task" then click "Bring Message Queuing Online"


===== Further Notes =====

  * [[https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2003/cc738047(v=ws.10)?redirectedfrom=MSDN|Administer Security for Message Queuing]]