.. _script-output:

==============================
ska-tango-event-monitor output
==============================

The ``ska-tango-event-monitor`` script takes snapshots of the :term:`event supplier` and :term:`event consumer` of every :term:`Tango device server` passed as arguments to the script.  The script prints summaries of these snapshots highlighting the differences from the previous snapshot.

:ref:`Listing 1 <output-list1>` shows possible output for a single snapshot while monitoring two device servers.  Lines from this output will be omitted if there are no changes.

.. _output-list1:
.. literalinclude :: ../../build/reference/output-example.txt
    :linenos:
    :caption: Listing 1: Synthetic output from the ska-tango-event-monitor script while monitoring the ``dserver/MyServer/1`` and ``dserver/MyServer/2`` device servers.  The output for ``dserver/MyServer/2`` is omitted for brevity.


.. list-table :: Output breakdown
    :header-rows: 1

    * - Lines
      - Description
      - Format
    * - 1, 49
      - Time stamp when the snapshot was taken.
      - 
    * - 2, 47
      - Headers for each device server, identified by :term:`admin device` name.
      - 
    * - 4 - 5
      - Newly published :term:`event streams <event stream>` with most recently pushed :term:`server counter` values.
      - ``<event stream>: <server counter> is the last pushed server counter``
    * - 7
      - Pushed events by :term:`event stream` for this snapshot.
      - ``<event stream> : <old value> -> <new value> (<delta>) last pushed server counter``
    * - 9
      - Removed publishers as they no longer have a subscriber.
      - ``<event stream>``
    * - 12
      - Statistical summary of the time between events being pushed by the :term:`event supplier`.
      - 
    * - 13
      - Statistical summary of the time taken to push events by the :term:`event supplier`.
      - 
    * - 15
      - Number of events processed by this subscription.
      - ``<event topic>: <count> events already processed``
    * - 16
      - The most recently received :term:`server counter` value.
      - ``: <count> is the last received server counter``
    * - 17
      - Number of callbacks registered for subscription.
      - ``: <count> callbacks registered``
    * - 18
      - Number of :term:`missed events <missed event>` detected.
      - ``: <count> missed events detected``
    * - 19
      - Number of :term:`duplicate events <discarded event>` discarded.
      - ``: <count> events discarded``
    * - 26
      - Changes to the number of events processed by this subscription.
      - ``<event topic>: <old_value> -> <new_value> (<delta>) events already processed``
    * - 27
      - Changes to the most recently received :term:`server counter` value.
      - ``: <old_value> -> <new_value> (<delta>) is the last received server counter``
    * - 28
      - Changes to the number of callbacks registered for subscription.
      - ``: <old_value> -> <new_value> (<delta>) callbacks registered``
    * - 29
      - Changes to the number of :term:`missed events <missed event>` detected.
      - ``: <old_value> -> <new_value> (<delta>) missed events deteceted``
    * - 30
      - Changes to the number of :term:`duplicate events <discarded event>` discarded.
      - ``: <old_value> -> <new_value> (<delta>) discarded events``
    * - 32
      - Removed subscription topics
      - ``<event topic>``
    * - 34 - 35
      - :term:`Event streams <event stream>` the :term:`event consumer` is actively connecting to for the first time.
      - ``<event stream>``
    * - 37
      - :term:`Event streams <event stream>` the :term:`event consumer` is no longer attempting to connect to.  Either client has given up, or the connection has been successful.
      - ``<event stream>``
    * - 40
      - Statistical summary of the time between events being received by the :term:`event consumer`.
      -
    * - 41
      - Statistical summary of the time spent sleeping between events being received by the :term:`event consumer`.
      -
    * - 42
      - Statistical summary of the :term:`latency <event latency>` between the event being pushed by the :term:`event supplier` and being received by the :term:`event consumer`.
      -
    * - 43
      - Statistical summary of the number of callbacks called per event.
      -
    * - 44
      - Statistical summary of the number of times the :term:`event consumer` was woken from sleeping while waiting for the event.
      -
    * - 45
      - Statistical summary of the processing time for the events relating to the "state" attribute.
      -
    * - 46
      - Statistical summary of the processing time for the events relating to the "status" attribute.
      -