# Contributing Documentation — SeisComP Release documentation

6.9.0

# Contributing Documentation

This is the documentation for the core processing elements and utilities that make up the SeisComP system. It aims to document the configuration and command line options for SeisComP in multiple formats (HTML, man, PDF, ePub etc) in a consistent way. The functionality of SeisComP differs between versions so the documentation is versioned along with SeisComP. For more general topics and tutorials please refer to the SeisComP wiki [1].

The documentation is written in reStructuredText [2] (reST) a simple text mark up format. The documentation is generated using Sphinx [3] which is used to create the Python documentation [4]. The Sphinx website has a very good introduction to reST [5] and also covers the Sphinx specific directives [6].

If you would like to add to this documentation or you find an error, then please submit a patch to SeisComP on GitHub [7] or report to the SeisComP discussion forum [8].

Note

Please understand the documentation style guide before contributing documentation.

If you view the HTML version of the documentation in a browser, then you can use the Show Source link on each page to view the reST source. The source and the documentation files for executables (see below) are good starting points for a new patch.

## Documenting Executables

The documentation for executables is generated from two sources:

‘executable’.xml

  An XML file that contains a brief description of the command, markup describing the command line parameters, and any configuration parameters for the executable. Each parameter should have a brief description of the purpose of the parameter.

  The description should be plain text and not contain reST markup. Where parameters are common across a number of executables they should be placed in the appropriate common file and referred to using their publicID.

  All XML files live in the `doc/apps` directory of the source distribution or in `etc/descriptions` of an installation.

‘executable’.rst

  This is a text file in reST markup that gives any more-detailed description and examples for the executable. It is combined with the corresponding .xml to create the full documentation. The first entry in the file should be a paragraph giving a more detailed description of the executable.

These two files should be placed in a `descriptions` sub-directory of the respective module, e.g. `src/seedlink/apps/seedlink/descriptions/seedlink.rst`. The intention is that the documentation is close to the code to make it easier for developers to keep the documentation up to date with code changes.

For a new executable an entry should also be made in the man section of `conf.py`. The man page is a short form of the documentation that is generated from only the .xml file.

## Images

Any images should be placed in a suitable sub-directory of `descriptions/media`. Read the documentation on image styles for more details. The images can then be referred to (in .rst) like:

    .. figure::  media/scolv/scolv-overview.png
       :width: 16cm
       :align: center

       Overview of the defrobnicator switches in :ref:`scolv`.

The images will be moved to the correct location during the documentation build.

## Understanding the XML

As mentioned before XML is used to generate brief descriptions of the configuration and command line parameters. This section describes the XML format.

Any description XML uses the root element seiscomp:

    <?xml version="1.0" encoding="UTF-8"?>
    <seiscomp>
      ...
    </seiscomp>

Three elements are used inside the root element: module, plugin and binding. Modules, plugins and bindings can be described in one XML or split up into one file per description. It is better to have things as close as possible. A module and its binding should go into one module.XML whereas plugins should go into separate XML files.

### Module

A template for a description XML file can be found in `doc/templates/app.xml`.

The XML file describes the SeisComP module with the configuration and command-line parameters.

Element: module

Name | XML type | Mandatory | Description
--- | --- | --- | ---
name | attrib | yes | The name of the module. This name must be unique among all available modules.
category | attrib | no | The category of the module. It is used by the configurator to group modules and by the documentation generator to create the final document structure. The category can contain slashes to introduce hierarchies.
standalone | attrib | no | The standalone attribute is also optional and by default false. Standalone means that the module does not take the global configuration files (e.g. `etc/global.cfg`) into account.
inherit-global-bindings | attrib | no | If global bindings are inherited. The default is ‘false’. If ‘yes’, then all parameters of the global binding are also available in the module binding to allow overwriting them. Standalone modules will never inherit global bindings regardless the value of this attribute.
description | element | no | A short description of the module.
configuration | element | no | The available configuration parameters. See element configuration.
command-line | element | no | The available command-line options. See element command-line.

It follows a simple example of how a module definition looks like.

    <?xml version="1.0" encoding="UTF-8"?>
    <seiscomp>
      <module name="scevent" category="Modules/Processing">
        <description>
          Associates an Origin to an Event or forms a new Event if no match
          is found. Selects the preferred magnitude.
        </description>
        <configuration/>
        <command-line/>
      </module>
    </seiscomp>

### Plugin

A template for a description XML file can be found in `doc/templates/plugin.xml`.

The XML file describes the SeisComP plugin with the configuration and command-line parameters. This is most likely the case when an application loads dynamically shared libraries also called plugins.

Element: plugin

Name | XML type | Mandatory | Description
--- | --- | --- | ---
name | attrib | yes | The name of the plugin.
extends | element | yes | The list of names of module names that the plugin extends, separated by commas.
description | element | no | A short description of the plugin.
configuration | element | no | The available configuration parameters. See element configuration.

Below is a simple example of how a plugin definition appears in XML.

    <?xml version="1.0" encoding="UTF-8"?>
    <seiscomp>
      <plugin name="NonLinLoc">
        <extends>global</extends>
        <description>
          NonLinLoc locator wrapper plugin for SeisComP.
          NonLinLoc was written by Anthony Lomax (http://alomax.free.fr/nlloc).
        </description>
        <configuration/>
        <command-line/>
      </plugin>
    </seiscomp>

### Binding

A binding template can be found in `doc/templates/binding.xml`.

It describes the set of configuration parameters to configure a station for a module.

Element: binding

Name | XML type | Mandatory | Description
--- | --- | --- | ---
module | attrib | yes | The name of the module this binding belongs to.
description | element | no | A short description of the binding.
configuration | element | no | The available configuration parameters. See element configuration.

Below is an example of how a simple binding definition appears as XML.

    <?xml version="1.0" encoding="UTF-8"?>
    <seiscomp>
      <binding module="seedlink">
        <description>
          Configures sources and parameters of a SeedLink station.
        </description>
        <configuration/>
      </binding>
    </seiscomp>

### Configuration

This element is used to describe the configuration parameters (not command-line, just configuration file) of a module, binding and plugin.

Element: configuration

Name | XML type | Mandatory | Description
--- | --- | --- | ---

parameter

element

no

A top level parameter that does not contain dots in the configuration file.

    param = value
    group.param = "another value"

Here `param` is a top level parameter whereas `group.param` is not. See parameter.

struct | element | no | A top level structure definition. Structures are different from groups and parameters as they can be instantiated by an arbitrary name.

group

element

no

A parameter group that describes a logical grouping of parameters also called “scope” or “namespace”. If a parameter in the configuration file contains dots, then only the last part is a parameter all others are groups.

    group1.group2.param = value

Element: parameter

Name | XML type | Mandatory | Description
--- | --- | --- | ---
name | attrib | yes | The name of the parameter. This name must be unique among all parameters of the same level.
type | attrib | no | An optional description of the parameter type which can be interpreted by a configurator to provide specialized input widgets. It is also important for the user how the parameter is read by the module.
unit | attrib | no | An optional unit such as “s” or “km” or “deg”.
default | attrib | no | The default value the module uses if this parameter is not configured.
description | element | no | Gives a brief description of the parameter.

Element: struct

Name | XML type | Mandatory | Description
--- | --- | --- | ---
type | attrib | yes | The name of the struct type. This name is used in a configurator to give a selection of available types to be instantiated.

link

attrib

no

The absolute reference parameter as it would appear in the configuration file which holds all instantiated structures.

    # 'link' parameter holding all available
    # structures. "local" and "teleseismic"
    # are instances of a structure defined
    # below.
    locator.profiles = local, teleseismic

    # The structure defined in locator.profile
    # would have "locator.profiles" as link
    # attribute.
    locator.profile.local.param = value
    locator.profile.teleseismic.param = value

description | element | no | Gives a brief description of the parameter.
parameter | element | no | Describes a parameter in the struct. See parameter.
struct | element | no | Describes a struct part of this struct.
group | element | no | Describes a group part of this struct. See group.

Element: group

Name | XML type | Mandatory | Description
--- | --- | --- | ---
name | attrib | yes | The name of the group. This name must be unique among all groups of the same level.
description | element | no | Gives a brief description of the parameter.
parameter | element | no | Describes a parameter in the group. See parameter.
struct | element | no | Describes a struct part of this group. See struct.
group | element | no | Describes a group part of this group.

Below is an example of the plugin definition for the NonLinLoc plugin. It contains groups, parameters and structures.

    <?xml version="1.0" encoding="UTF-8"?>
    <seiscomp>
      <plugin name="NonLinLoc">
        <extends>global</extends>
        <description>...</description>
        <configuration>
          <group name="NonLinLoc">
            <parameter name="publicID" type="string"
                       default="NLL.@time/%Y%m%d%H%M%S.%f@.@id@">
              <description>
                PublicID creation pattern for an origin created by NonLinLoc.
              </description>
            </parameter>

            <parameter name="outputPath" type="path" default="/tmp/sc3.nll">
              <description>
                Defines the output path for all native NonLinLoc input and
                output files.
              </description>
            </parameter>

            <parameter name="profiles" type="list:string">
              <description>
                Defines a list of active profiles to be used by the plugin.
              </description>
            </parameter>

            <group name="profile">
              <struct type="NonLinLoc profile" link = "NonLinLoc.profiles">
                <description>
                  Defines a regional profile that is used if a prelocation falls
                  inside the configured region.
                </description>
                <parameter name="earthModelID" type="string">
                  <description>
                    earthModelID that is stored in the created origin.
                  </description>
                </parameter>
              </struct>
            </group>
          </group>
        </configuration>
      </plugin>
    </seiscomp>

### Command-line

This element is used to describe the command-line options of a module. The element structure is much simpler than the configuration element. The command-line only contains group elements which in turn have either option or optionReference elements. Through the optionReference element it is possible to refer to existing command-line options. This is important for all modules that are using the SeisComP libraries because they share a set of basic command-line options inherited from the Application class.

Element: command-line

Name | XML type | Mandatory | Description
--- | --- | --- | ---
synopsis | element | no | Optional description of how to start the module.
description | element | no | Optional description of the command-line and non option parameters.
group | element | no | Describes an option group. See group.

Element: group

Name | XML type | Mandatory | Description
--- | --- | --- | ---
name | attrib | yes | The name of the group. This name must be unique among all groups of the same level.
option | element | no | An option part of this group. See option.
optionReference | element | no | A reference to an existing option using its publicID.

Element: option

Name | XML type | Mandatory | Description
--- | --- | --- | ---
flag | attrib | semi | The short option flag. Either this attribute or long-flag must be set.
long-flag | attrib | semi | The long option flag. Either this attribute or flag must be set.
param-ref | attrib | no | Refers to a configuration parameter name that this parameter overrides. Name is the full path, e.g. connection.server and not just server.
argument | attrib | no | The optional argument string. If argument is not set, the option is a switch.
default | attrib | no | The option’s default value used if the option is not given though it is hard in most cases because command-line options very often redefine configuration parameters which is then used as a default value for the option.
publicID | attrib | no | The optional publicID of the option to be able to reference it from an optionReference element. The publicID must be unique among all defined options.
description | element | no | Gives a brief description of the option.

Below is an example of the module definition for scautoloc (extract).

    <?xml version="1.0" encoding="UTF-8"?>
    <seiscomp>
      <module name="scautoloc" category="Modules/Processing">
        <description>Locates seismic events.</description>
        <configuration>
          ...
        </configuration>
        <command-line>
          <group name="Generic">
            <optionReference>generic#help</optionReference>
            <optionReference>generic#version</optionReference>
            <optionReference>generic#config-file</optionReference>
            <optionReference>generic#plugins</optionReference>
            <optionReference>generic#daemon</optionReference>
            <optionReference>generic#auto-shutdown</optionReference>
            <optionReference>generic#shutdown-master-module</optionReference>
            <optionReference>generic#shutdown-master-username</optionReference>
          </group>

          <group name="Mode">
            <option flag="" long-flag="test" argument="" default="">
              <description>Do not send any object</description>
            </option>

            <option flag="" long-flag="offline" argument="" default="">
              <description>
                Do not connect to a messaging server. Instead a
                station-locations.conf file can be provided. This implies
                --test and --playback
              </description>
            </option>

            <option flag="" long-flag="playback" argument="" default="">
              <description>Flush origins immediately without delay</description>
            </option>
          </group>
        </command-line>
      </module>
    </seiscomp>

## References

[ 1 ]

https://www.seiscomp.de/

[ 2 ]

https://docutils.sourceforge.io/rst.html

[ 3 ]

https://www.sphinx-doc.org/

[ 4 ]

https://docs.python.org/

[ 5 ]

https://www.sphinx-doc.org/en/master/usage/restructuredtext/index.html

[ 6 ]

https://www.sphinx-doc.org/en/master/usage/restructuredtext/directives.html

[ 7 ]

https://github.com/SeisComP

[ 8 ]

https://forum.seiscomp.de