[seiscomp, scanloc] Install, add .gitignore

share/doc/seiscomp/html/_sources/base/concepts/plugins.rst.txt

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+.. _concepts_plugins:
+
+****************
+SeisComP plugins
+****************
+
+
+Scope
+=====
+
+This chapter describes the general use of plugins in SeisComP.
+
+
+Overview
+========
+
+Plugins expand the functionality of :ref:`applications <concepts_modules>`.
+They are C++ shared object libraries which are dynamically loaded at runtime
+into an application.
+
+Typical plugins provide access to:
+
+* :ref:`Databases <concepts_database>`
+* :ref:`Recordstream implementations <global_recordstream>`
+* :ref:`Locator routines <sec_index_extensions>`
+* :ref:`Amplitude and magnitude types <sec_index_extensions>`
+* :ref:`Waveform quality <scqc>`.
+
+The plugin files themselves are located in :file:`share/plugins`.
+
+By just loading a plugin an application does not change
+it's way to function magically. Common plugins just implement a certain
+interface (see e.g. messaging or RecordStream) and exhibit that functionality
+by adding a new entry to the internal interface factory. As an example an
+application makes use of interface ``DatabaseInterface``. Technically it
+creates a new object implementing a certain interface by calling the C++
+method:
+
+.. code-block:: sh
+
+   db = DatabaseInterface::Create("mysql");
+
+Without having a plugin loaded the returned object will be NULL or to put it
+in other words, there is not implementation for mysql available.
+
+Once the plugin ``dbmysql`` is loaded into the application, an implementation
+for type mysql is added and will be available to the application. It is
+still required for the application to explicitly ask for a particular
+interface. That is most likely left to the user by adding a corresponding
+configuration option to the configuration file.
+
+That means, if an application loads two plugins, e.g. ``dbmysql`` and
+``dbpostgresql`` that does not mean that it will not read from two database
+at a time. It means the user has now the option to either use a MySQL database
+or a PostgreSQL database. He still needs to make his choice in the
+configuration file.
+
+Trunk plugins are only supported as shared object libraries and therefore are
+required to be written in C++. Implementations for all available interfaces
+can be added. An incomplete list of SeisComP C++ interfaces:
+
+* :ref:`Messaging <concepts_messaging>`
+* :ref:`Database <concepts_database>`
+* :ref:`RecordStream <concepts_recordstream>`
+* Record formats
+* Map projections
+* :ref:`Time domain filters <filter-grammar>`
+* Importer
+* Exporter
+* **Amplitude processors**
+* **Magnitude processors**
+
+This is just a subset of available extensible interface factories. The
+emphasized entries refer to the factories which are most commonly extended.
+
+
+Location and Configuration
+==========================
+
+Plugins are located in :file:`$SEISCOMP_ROOT/share/pugins`. In order to make a
+plugins available for a module it must be added to the configuration of
+:confval:`plugins` of the global parameters of a module or in
+:ref:`global_configuration`.
+
+Configuring :confval:`plugins` with the name of a plugin will let the exclusively
+use this plugin and no other ones, e.g. default plugins. Example: ::
+
+   plugins = evrc
+
+In order to add a plugin to the default plugins or plugins loaded by before, e.g.
+by the global configuration, load these