g.extension - Maintains GRASS Addons extensions in local GRASS installation.

Authors

       Markus Neteler (original shell script)
       Martin Landa, Czech Technical University in Prague, Czech Republic (Python rewrite)
       Vaclav Petras, NCSU GeoForAll Lab (support for general sources, partial refactoring)

Description

g.extension downloads and installs, removes or updates extensions (addons) from the official GRASS GIS
Addons repository or from user-specified source code repositories into the local GRASS GIS installation.

Two types of extensions are supported:

• Python scripts: they are installed without the need of compilation or (usually) the need of
special dependencies.

• Source code (mostly written in C programming language; may also be written in C++, Fortran or
other languages): while on MS-Windows systems the requested GRASS GIS extension is downloaded
pre-compiled from the GRASS GIS site, on Unix based systems the installation is preceded by the
automated download of the extension’s source code along with subsequent compilation and
installation. This requires a compiler environment to be present on the user’s computer.

Managinginstalledextensions
Re-running g.extension on an installed GRASS GIS Addon extension re-installs the requested extension
which may include updates.

To bulk-update all locally installed GRASS GIS extensions, g.extension.all module is available.

Wheretheextensionsareinstalled
GRASS GIS extensions are installed by g.extension into a dedicated directory. The default is a directory
for application data and settings inside the user’s home directory. On GNU/Linux it is
$HOME/.grass8/addons, on MS-Windows it is %APPDATA%\Roaming\GRASS8\addons. The name of the directory is
stored in the GRASS_ADDON_BASE environmental variable.

The flag -s changes this install target directory to the GRASS GIS installation directory (determined by
GISBASE environmental variable, e.g. /usr/) rather than the default directory defined as per
GRASS_ADDON_BASE (see also documentation for variables). g.extension checks if the user has permission
to write to GISBASE or GRASS_ADDON_BASE.

The place where the extensions are installed can be customized by the option prefix. Ensuring that these
extensions will be accessible in GRASS GIS is in this case in the responsibility of the user.

SourcecodesourcesandrepositoriesGRASSGISAddonsrepositoryonGitHub
By default, g.extension installs extensions from the official GRASS GIS Addons GitHub repository.
However, different sources can be specified using the url option.

Individual extensions can also be installed by providing a URL to the source code on GitHub or OSGeo
Trac. The latter, however, works only for certain directories where the download of ZIP files was enabled
by project administrators of the trac server.

Localsourcecodedirectory
Optionally, new extension can be also installed from a source code placed in a local directory on disk.
This is advantageous when developing a new module. To keep the directory clean, the directory content is
copied to a temporary directory and the compilation happens there.

SourcecodeinaZIPorTARarchive
In addition, new extension can be also installed from a ZIP file or an archive file from the TAR family
(e.g., .tar.gz or .bz2). The file can be on disk (specified with a path), or on the web (specified by an
URL).

Onlinerepositories:GitHub,GitLabandBitbucket
For well known general hosting services, namely GitHub, GitLab and Bitbucket, g.extension supports the
download of a repository. Here the user only needs to provide a base URL to the repository web page
(with or without the https:// part). For GitHub, GitLab and Bitbucket, the latest source code in the
default branch is downloaded, unless a specific branch is requested in the branch option. Of course, a
user can still specify the full URL of a ZIP file e.g. for a specific release and install the archived
code in this way (ZIP file mechanism will be applied).

For the official repository, g.extension supports listing available extensions (addons) and few other
metadata-related operations which depend on a specific infrastructure. For other sources and
repositories, this is not supported because it is assumed that other sources contain only one extension,
typically a module or group of modules with a Makefile at the root of the repository.

Neededdirectorylayout
When none of the above sources is identified, g.extension assumes that the source is in a GitHub
repository and uses the git command line tool to obtain the source code. The expected structure of the
repository should be the same as the one of the official repository.

Non-official sources are supported on all operating systems except for MS-Windows.

Compilationandinstallation
On MS-Windows systems, where compilation tools are typically not readily locally installed, g.extension
downloads a precompiled executable from the GRASS GIS project server. On all other operating systems
where it is not difficult to install compilation tools, g.extension downloads the source code of the
requested extension (addon) and compiles it locally. This applies for both C and Python modules as well
as any other extensions. The reason is that more things such as manual page are compiled, not only the
source code (which is really necessary to compile just in case of C).

Examples

Downloadandinstallofanextension
       Download and install r.stream.distance into current GRASS installation
       g.extension extension=r.stream.distance
       This installs the extension from the official repository.  For convenience, a shorter syntax can be used:
       g.extension r.stream.distance

   Downloadandinstallofanextensionwhenbehindaproxy
       Example for an open http proxy:
       # syntax: http://proxyurl:proxyport
       g.extension extension=r.stream.distance proxy="http=http://proxy.example.com:8080"

       Example for a proxy with proxy authentication:
       # syntax: http://username:password@proxyurl:proxyport
       g.extension extension=r.stream.distance proxy="http=http://username:password@proxy.example.com:8080"

   Managingtheextensions
       List all available extensions in the official GRASS GIS Addons repository:
       g.extension -l
       List all locally installed extensions:
       g.extension -a
       Removal of a locally installed extension:
       g.extension extension=r.stream.distance operation=remove

   Installingfromvariousonlinerepositories:GitHub,GitLab,Bitbucket
       Simple URL to GitHub, GitLab, Bitbucket repositories:
       g.extension r.example.plus url="https://github.com/wenzeslaus/r.example.plus"
       Simple URL to GitHub, GitLab, Bitbucket repositories from a specific (e.g. development) branch:
       g.extension r.example.plus url="https://github.com/wenzeslaus/r.example.plus" branch=master
       Simple URL to OSGeo Trac (downloads a ZIP file, requires download to be enabled in Trac):
       g.extension r.example url=trac.osgeo.org/.../r.example
       In general, when a ZIP file or other archive is provided, the full URL can be used:
       g.extension r.example url=http://example.com/.../r.example?format=zip
       Note that because of MS-Windows operating system architecture, only official repository is  supported  on
       this platform.

   InstallaspecificversionfromAddons
       To  install  a specific version from GRASS GIS Addons, specify the full URL pointing to Trac code browser
       and include Subversion  revision  number.  For  example,  this  installs  the  version  number  57854  of
       r.local.relief module:
       g.extension r.local.relief url="https://trac.osgeo.org/grass/browser/grass-addons/grass7/raster/r.local.relief?rev=57854&format=zip"

   Installingwhenwritingamodulelocally
       Having source code of a GRASS module in a directory on disk one can install it using:
       g.extension r.example url=/local/directory/r.example/

Keywords

       general, installation, extensions, addons, download

Known Issues

       Toolboxes in the official repository cannot be downloaded.

       On  MS-Windows,  only the official repository is working because there is no way of compiling the modules
       (a Python replacement for Python scripts should be implemented).

Name

g.extension  - Maintains GRASS Addons extensions in local GRASS installation.
       Downloads  and  installs  extensions  from  GRASS  Addons repository or other source into the local GRASS
       installation or removes installed extensions.

Requirements

       In  order  to  clone source code repositories, the git command line tool is required. The installation of
       single AddOns is most efficient with versions of git that support so called sparsecheckout,  which  was
       introduced  with  version  2.25.  With  older  versions  of  git,  the  entire  AddOns repository will be
       downloaded.  On UNIX like systems, installation is done with the  make  command  line  tool.  For  AddOns
       written in C / C++, a respective build environment is needed.

Source Code

       Available at: g.extension source code (history)

       Accessed: Friday Apr 04 01:21:11 2025

       Main index | General index | Topics index | Keywords index | Graphical index | Full index

       © 2003-2025 GRASS Development Team, GRASS GIS 8.4.1 Reference Manual

GRASS 8.4.1                                                                                  g.extension(1grass)

Synopsis

g.extensiong.extension--helpg.extension     [-lcgasdifto]     extension=nameoperation=string      [url=url]        [prefix=path]
       [proxy=proxy[,proxy,...]]   [branch=branch]   [--help]  [--verbose]  [--quiet]  [--ui]

   Flags:-l
           List available extensions in the official GRASS GIS Addons repository

       -c
           List available extensions in the official GRASS GIS Addons repository including module description

       -g
           List available extensions in the official GRASS GIS Addons repository (shell script style)

       -a
           List locally installed extensions

       -s
           Install system-wide (may need system administrator rights)

       -d
           Download source code and exit

       -i
           Do not install new extension, just compile it

       -f
           Force removal when uninstalling extension (operation=remove)

       -t
           Operate on toolboxes instead of single modules (experimental)

       -o
           url refers to a fork of the official extension repository

       --help
           Print usage summary

       --verbose
           Verbose module output

       --quiet
           Quiet module output

       --ui
           Force launching GUI dialog

   Parameters:extension=name[required]
           Name of extension to install or remove
           Name of toolbox (set of extensions) when -t flag is given

       operation=string[required]
           Operation to be performed
           Options: add,remove
           Default: addurl=url
           URL or directory to get the extension from (supported only on Linux and Mac)
           The official repository is used by default. User can specify a ZIP file, directory or a repository on
           common  hosting  services.  If  not  identified, Subversion repository is assumed. See manual for all
           options.

       prefix=path
           Prefix where to install extension (ignored when flag -s is given)
           Default: $GRASS_ADDON_BASEproxy=proxy[,proxy,...]
           Set the proxy with: "http=<value>,ftp=<value>"

       branch=branch
           Specific branch to fetch addon from (only used when fetching from git)

Troubleshooting

       Since extensions have to be compiled on Unix based  systems  (Linux,  Mac  OSX  etc.)   unless  a  Python
       extension is installed, a full compiler environment must be present on the user’s computer.

   ERROR:PleaseinstallGRASSdevelopmentpackage
       While  GRASS  GIS  is available on the user’s computer, the respective development package is lacking. If
       GRASS was installed from a (Linux) repository, also the grass-dev* package (commonly named "grass-dev" or
       "grass-devel", sometimes along with the version number) must be installed.