Ubuntu Manpage: g.extension - Maintains GRASS Addons extensions in local GRASS installation.

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.

KEYWORDS

       general, installation, extensions, addons, download

SYNOPSIS

       g.extension
       g.extension --help
       g.extension  [-lcgasdift]  extension=name  operation=string    [url=url]     [prefix=path]
       [proxy=proxy[,proxy,...]]   [--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)

       --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: add

       url=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_BASE

       proxy=proxy[,proxy,...]
           Set the proxy with: "http=<value>,ftp=<value>"

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.

Managing installed extensions
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.

Where the extensions are installed
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/.grass7/addons, on MS-Windows it is $APPDATA\GRASS7\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.

Source code sources and repositories
GRASS GIS Addons SVN repository
By default, g.extension installs extensions from the official GRASS GIS Addons SVN
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 OSGeo
Trac. This, however, works only for certain directories where the download of ZIP files
was enabled by project administrators of the trac server.

Local source code directory
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.

Local source code ZIP file
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 web (specified by an URL).

Online repositories: GitHub, GitLab and Bitbucket
For well known general hosting services, namely GitHub, GitLab and Bitbucket, g.extension
supports the download of a repository as a ZIP file. Here the user only needs to provide
a base URL to the repository web page (with or without the https:// part). For GitLab and
Bitbucket, the latest source code in the default branch is downloaded, for GitHub, the
latest source code in the master branch is downloaded. Of course, a user can still
specify the full URL of a ZIP file and install a specific branch or release 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.

Needed directory layout
When none of the above sources is identified, g.extension assumes that the source is a
Subversion repository and uses the svn 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.

Compilation and installation
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

   Download and install of an extension
       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

   Download and install of an extension when behind a proxy
       Example for an open http proxy:
       # syntax: http://proxyurl:proxyport
       g.extension extension=r.stream.distance proxy="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://username:password@proxy.example.com:8080"

   Managing the extensions
       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

   Installing from various online repositories: GitHub, GitLab, Bitbucket
       Simple URL to GitHub, GitLab, Bitbucket repositories:
       g.extension r.example url=github.com/johnsmith/r.example
       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.

   Installing when writing a module locally
       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/

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).

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: Please install GRASS development package
       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.

AUTHORS

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

       Last changed: $Date: 2017-01-05 08:56:15 +0100 (Thu, 05 Jan 2017) $

SOURCE CODE

       Available at: g.extension source code (history)

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       © 2003-2018 GRASS Development Team, GRASS GIS 7.4.0 Reference Manual