Glossary
========

Settings
--------


.. glossary::

    Actor
        Actors are what exchanges :term:`messages <Message>` through the bus.
        Thay can be an :term:`Emitter`, a :term:`Consumer` or a :term:`Worker`.

        An actor is always associated to a :term:`Actor Account`, to ensure
        security.

        It must have one and only one :term:`Role`.

    Emitter
        A kind of :term:`Actor` that sends envelopes to the bus.

    Consumer
        A kind of :term:`Actor` that receives envelopes from the bus.

    Worker
        A kind of :term:`Actor` that receives envelopes and sends envelopes in
        reaction.

    Role
        An :term:`Actor` property. Pipelines can select actors by roles instead
        of name/id.

    Account
        An account is what allows a person or an application to connect to the
        bus. There are several kinds of accounts: :term:`Actor Account`,
        :term:`User Account` and :term:`Gateway Account`

    Actor Account
        Associated to one or several actors, it is used by :ref:`xbus-client <program-xbus-client>` or
        other connectors to connect to xbus.

    User Account
        Used by users of the :ref:`xbusctl <program-xbusctl>` command, or the
        web interface. It allows configuration of the pipelines, accounts,
        actors and pipelines, as well as viewing, and acting on processes.

    Gateway Account
        An account with very specific privileges needed by a gateway program
        like :ref:`xbus-http <program-xbus-http>`.

    Connector
        A set of actors that connects an application to the bus.

    Pipeline
        A pipeline defines a path between an emitter, workers and consumers, in
        the form of a `directed acyclic graph
        <https://en.wikipedia.org/wiki/Directed_acyclic_graph>`_.

        It 'matches' incoming envelopes based on the message types they contain.


Contents
--------

.. glossary::
    Message
        A message is what applications connected to the bus send and receive. A
        message must have a type, which can be any alphanumeric string, and a
        body that can be anything. A big body will be chunked for transfers.

        It is identified by a GUID.

    Envelope
        An envelope is a container for :term:`messages <Message>`. It can
        contain any positive number of messages.

        It is identified by a GUID.

    Event
        Deprecated term for :term:`Message`



Process
-------

.. glossary::
    Process
        An incoming envelope creates a Process that will track its path within
        the bus. The first step of a process is to match a :term:`Pipeline` in
        order to known which path should be followed.

        Each process has a status, that can be one of :term:`RUNNING`,
        :term:`PAUSED`, :term:`DONE` and :term:`ERROR`.

    RUNNING
        The status of a process that is not yet over. No error has occured, and
        some actors still need to work or are working.

    PAUSED
        The status of a process that has been paused by the operator.

    DONE
        The status of a process that successfully runned.

    ERROR
        The status of a process in which an error occured.