Provide a safer alternative to
composer global require.
Cgr has been used in real-world environments for several months with no reported problems; however, see 'Limitations', below.
global require command is a recommended installation technique for many PHP commandline tools; however, users who install tools in this way risk encountering installation failures caused by dependency conflicts between different projects. The cgr script behaves similarly to
composer global require, using
composer require to install a global-per-user copy of a commandline tool, but in an isolated location that will not experience dependency conflicts with other globally-installed tools.
The cgr script is unrelated to security; it is not any more, nor any less secure than installing via composer global require.
Composer itself recommends
composer global require as a "convenience" command for installing commandline tools. Unfortunately, this recommendation is at odds with the basic assumption of Composer, which is that every project's dependencies should be managed independently. The Composer
global command creates a single "global" project; projects installed via
composer global require will all be installed in this location, and their dependencies will all be merged. This means that conflicts can arise between two independent projects that were never designed to work together, and have no need for their dependencies to be combined into a single autoloader. When this sort of situation does arise, it is often very difficult for beginners to diagnose.
This script, called
cgr, is named after "composer global require", the Composer command that it emulates. It offers a replacement mechanism for installing PHP commandline tools globally that is functionally equivalent (nearly) to the existing command, but much safer. The Cgr script will make a separate directory for each project installed; by default, the installation location is
~/.composer/global/org/project. Any binary scripts listed in the installed project's composer.json file will be installed to the standard Composer bin directory,
Installation and Usage
Because the cgr script has no dependencies of its own, it is safe to install via the Composer
global require command:
composer global require consolidation/cgr
If you have not already done so, you will also need to add the
vendor/bin from the Composer home directory to your $PATH. Thereafter, you may subsitute
cgr for any commandline tool whose installation instructions recommends the use of Composer
To add the correct bin directory to your PATH:
PATH="$(composer config -g home)/vendor/bin:$PATH"
Unlike the composer global require command, it is possible using cgr to set the minimum stability for a project before installing it. This is done in the same way as the
composer create-project command:
cgr --stability RC pantheon-systems/terminus 1.0.0-alpha2
The behavior of the cgr script can be customized with commandline options and environment variables.
|--composer-path||CGR_COMPOSER_PATH||The path to the Composer binary.|
|--base-dir||CGR_BASE_DIR||Where to store "global" projects.|
|--bin-dir||CGR_BIN_DIR||Where to install project binaries.|
If these variables are not defined, then cgr uses the value of the
COMPOSER_HOME environment variable as the base directory to use as described in the Composer documentation on environment variables.
To configure cgr to install binaries to ~/bin, add the following to your ~/.bashrc file:
You may select any directory you like for the
CGR_BIN_DIR, as long as it is in your $PATH.
To display the information of a project, run:
cgr info drush/drush
To display the information of all projects installed via 'cgr', run:
Updating and Removing
To update a project that you installed with
cgr update drush/drush
To update everything installed by
To remove a project:
cgr remove drush/drush
To update or remove cgr itself, run
composer global update consolidation/cgr or
composer global remove cgr. Note that removing cgr has no effect on the commands you installed with cgr; they will remain installed and functional.
If you find that
cgr is still behaving like a standard Composer
global require command, double-check the settings of your $PATH variable, and use
which cgr and
alias cgr to deterime whether or not this script is being selected by your shell. It is possible that cgr may conflict with some other tool; for example, the oh-my-zsh project defines a cgr alias. If this is an issue for you, either
unalias cgr, or perhaps add
alias cgrx="$HOME/.composer/vendor/bin/cgr" to run this experimental tool as
Composer will also load Composer Plugins from the "global" Composer project. This is rare; however, if you would like to install a Composer Installer globally, then you must use the
composer global require command directly. The cgr script isolates the projects it installs from each other to avoid potential conflicts between dependencies; this isolation also makes any Composer Plugins unavailable in the global context.
Manual Use of Native Composer Features
The cgr script maintains the convenience of automatically managing the global installation location for you; however, if this is not desired, you may simply run commands similar to:
COMPOSER_BIN_DIR=$HOME/bin composer require org/project:~1.0
If you go this route, you will need to set up your install location manually using
cd as necessary prior to running
composer require. You cannot simply set COMPOSER_BIN_DIR globally, as doing this would cause the binaries from local projects to be installed into your global bin directory, which would, of course, not be desirable.
In a Continuous Integration script, the following construct is useful:
/usr/bin/env COMPOSER_BIN_DIR=$HOME/bin composer --working-dir=$HOME/project require org/project:~1.0
Change the installation directory (
$HOME/project) to match the project being installed, so that every project is installed in its own separate location.
Composer Bin Plugin
The Composer plugin bamarni/composer-bin-plugin offers a similar way to manage isolated installation of binary tools by defining separate named installation locations. This gives a convenient way to install multiple projects together (e.g. install Robo along with external projects providing additional Robo tasks in a 'robo' project).
It is hoped that this tool will be an interim solution, until changes in Composer make it unnecessary. See the Composer issue for updates.