This feature is a clone of -SP-625- which was not completed in PI5.

An initial version of pub/sub has been implemented during PI4, and continued in PI5; this will need to be completed during PI6. This includes developing test suites that cover the new implementation.

I rewrote this feature based on feedback obtained during PI6 Planning, and crossed out the old description.

Benefit:

A webjive user can use the pub/sub functionality and enjoy a more reactive bahavior of Webjive Suite.

Webjive is capable to displaying a user-friendly label of tango attributes when that is made available by the device.

Description:

Complete pub/sub implementation by enabling TangoGQL to pass (and webjive to accept) all attribute names in their lowercase form. Add a new capability to the webjive suite to use the tango label field.

Acceptance Criteria:

• TangoGQL passes attribute names converted to lower case
• TangoGQL reads and passes the label fields to Webjive
• Webjive is able to read and display the label fields in both the dashboard and in the overview

Benefit

We need to integrate code produced by external people (not adhering to our DoD) so that it does not become legacy code and increases our technical debt.  

Acceptance Criteria

• I expect that unit and end-to-end tests excercise TangoGQL so that the following defects are reproduced and possibly fixed (in some cases tests should be used to provide evidence that TangoGQL is not the cause of the problem). Regarding fixing defects, of course the more we fix the better it is.
  • There appears to be an issue where a mixed case representation of attribute names is being turned into a lower case representation - this may be related to the Tango (ZMQ) channel falling over with errors implying that the health check thread is either not getting a response or is getting an error response.
  • Forwarded attributes (where one device refers to an attribute on another device) seem to be problematic in that they always produce errors. 
  • Once one subscribed attribute fails - they all fail.
  • When you visit a device all the attributes for the device are automatically subscribed and they are not unsubscribed when you move to a new device.
  • You can’t currently subscribe to more than one attribute without the channel becoming unstable - either immediately or shortly afterwards the health check times out throwing an error on the Tango ZMQ channel.
  • If events are produced at a frequency higher than 50ms from tango the pub-sub mechanism fails. (Tango allows events as frequently as 5ms).
  • In the Devices tab, open a device with polled attribute(s?) and open the Attributes list of the device. You should observe pub/sub working but refreshing the page should show that pub/sub has stopped working.
• Fixing of bugs causing failures of these tests should be done too. This includes also bugs found by previously developed tests, like tests that check that failures in subscription of different attributes are independent, and tests checking that the subscription mechanism handles events at a frequency higher than 20Hz, period shorter than 50ms. These are tests that are developed within -SP-625.-

Tests that are out of scope:

• handling errors in webjive suite (tangogql should transfer error messages to the frontend, and the frontend should handle them nicely: but this is out of scope for the moment).