.. _User Manual: https://docs.zeek.org/projects/broker

================================
Broker: Zeek's Messaging Library
================================

The Broker library implements Zeek's high-level communication patterns:

    - remote logging
    - remote events
    - distributed data stores

Remote logging and events all follow a pub/sub communication model
between Broker endpoints that are directly peered with each other.  An
endpoint also has the option of subscribing to its own messages.
Subscriptions are matched prefix-wise and endpoints have the capability
of fine-tuning the subscription topic strings they wish to advertise to
peers as well as the messages they wish to send to them.

The distributed data store functionality allows a master data store
associated with one Broker endpoint to be cloned at peer endpoints which
may then perform lightweight, local queries against the clone, which
automatically stays synchronized with the master store.  Clones
cannot modify their content directly, instead they send modifications
to the centralized master store which applies them and then broadcasts
them to all clones.

Applications which integrate the Broker library may communicate with
each other using the above-mentioned patterns which are common to Zeek.

See the `User Manual`_ for more information.  For offline reading, it's
also available in the ``doc/`` directory of the source tree.

See the NEWS file for the most important release notes and the CHANGES
file for the complete history of changes.

Dependencies
------------

Compiling Broker requires the following libraries/tools to already be
installed:

    * C++ compiler with C++17 support    (GCC 7+, Clang 4+, MSVC 19.14+)
    * OpenSSL headers/libraries          (http://www.openssl.org)
    * CMake 3.0 or greater               (https://cmake.org)

The optional Python bindings also require Python 2.7 or greater
along with Python development packages.  For Python 2.7, you'll
also need the ``ipaddress`` backport from Python 3.

By default, Broker will use an integrated version of the C++ Actor
Framework (CAF; https://actor-framework.org), though there's still the
option to specify an exernal CAF version via the ``--with-caf=``
configure script option.

Compiling/Installing
--------------------

On UNIX, we provide a ``configure`` script to automate the CMake setup. To
compile and install into ``/usr/local``::

    ./configure
    make
    make install

See ``./configure --help`` for more advanced configuration options.

On Windows, we support MSVC natively. We do not support builds via MinGW or
Cygwin. For Windows builds, please use CMake directly and use the CMake
generator for your Visual Studio version. Afterwards, you can either open the
project file with Visual Studio to build Broker, or you can build directly from
the command line using CMake::

    cmake --build <build-dir> --target install --config release

Please note that Broker currently only supports *static* builds on MSVC.
