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Installing Extism

The extism CLI is used to manage Extism installations and execute plugins from the command-line. In order to run Extism, your system must be able to locate the (on Linux), extism.dll (on Windows) or libextism.dylib (on macos).

Note: If you are using the Rust Host SDK, this is not the case, and can use Extism as a crate dependency in your Cargo.toml.

The following instructions will walk you through how to install the Extism CLI, and then the installation of the shared library which a Host SDK will look for automatically.

Install the Extism CLI

Using go: (recommended)

go install

There are also releases available on Github:

Note: If you have installed the old cli via python, you may need to remove it:

pip3 uninstall extism_cli --break-system-packages
which extism # shouldn't print anything, if it does, delete it

Using the Extism CLI

The most common use-case is to to install Extism from Github releases, and then install the library and header file into the installation prefix of your choice. The default prefix is /usr/local, so libraries will be installed to /usr/local/lib and the header will be installed to /usr/local/include.

sudo extism lib install

sudo may use a different path than your user. If so, you may need to tell sudo to use the PATH defined for your user with: sudo -E env "PATH=$PATH" extism lib install

Installing the latest from git

It's also possible to install the latest build from the main git branch:

sudo extism lib install --version git

Overriding install location

Pass the --prefix argument a path on disk where extism CLI will install the system files:

extism lib install --prefix ~/.local

Other CLI Features

extism [command]

Available Commands:
call Call a plugin function
completion Generate the autocompletion script for the specified shell
help Help about any command
lib Manage libextism

--github-token string Github access token, can also be set using the $GITHUB_TOKEN env variable
-h, --help help for extism
-q, --quiet Enable additional logging
-v, --verbose Enable additional logging
--version version for extism

Use "extism [command] --help" for more information about a command.

Call plug-in functions

You can use the extism CLI as a test runner to check your plug-ins outside of any Host program:

extism call --input "this is a test" test/code.wasm count_vowels
{"count": 4}

Check installed version

The CLI can also be used to get information about the installed version of libextism:

extism lib check