Skip to main content

proto v0.12 - Experimental WASM plugins

· 2 min read
Miles Johnson
Miles Johnson
Founder, developer

After months of hard work, we're excited to release our first iteration of WASM plugins for proto.

WASM plugins​

Three months ago, we published an RFC for supporting plugins in proto. Plugins are a must, as they allow consumers to easily extend proto with additional tools, instead of them being built into proto core (which is very time consuming).

Two months ago, we released support for TOML plugins. These are very simple plugins powered by static configuration files. They're great for simple tools like CLIs and pre-built languages, as everything is powered by static HTTP URLs and file names. However, sometimes you need dynamic control...

And after 2 months of development, and help from the Extism team, we're excited to announce initial support for WASM plugins. WASM is a portable binary format, with sandboxed access to the file system (via WASI), and the ability to execute processes and fetch URLs. This means that plugins can be written in any language that compiles to WASM, like Rust, C, C++, Go, TypeScript, and more. This removes the requirement of writing Rust and contributing to proto directly!

View WASM plugin guide

Using WASM plugins​

Once the .wasm file is publicly available for download, we can configure it as a plugin in .prototools.

[plugins]
my-plugin = "source:https://domain.com/path/to/wasm/plugin.wasm"

And execute all proto commands using the configured plugin identifier.

proto install my-plugin

Example implementation​

The official guide above walks you through creating a plugin, but to demonstrate the power of WASM plugins, here's an example function that defines parameters for downloading and installing Node.js. This is written in Rust and using Extism's official PDK.

#[plugin_fn]
pub fn download_prebuilt(
    Json(input): Json<DownloadPrebuiltInput>,
) -> FnResult<Json<DownloadPrebuiltOutput>> {
    let version = input.env.version;
    let arch = input.env.arch;

    let prefix = match input.env.os {
        HostOS::Linux => format!("node-v{version}-linux-{arch}"),
        HostOS::MacOS => format!("node-v{version}-darwin-{arch}"),
        HostOS::Windows => format!("node-v{version}-win-{arch}"),
        other => {
            return Err(PluginError::UnsupportedPlatform {
                tool: NAME.into(),
                platform: format!("{:?}", other),
            })?;
        }
    };

    let filename = if input.env.os == HostOS::Windows {
        format!("{prefix}.zip")
    } else {
        format!("{prefix}.tar.xz")
    };

    Ok(Json(DownloadPrebuiltOutput {
        archive_prefix: Some(prefix),
        download_url: format!("https://nodejs.org/dist/v{version}/{filename}"),
        download_name: Some(filename),
        checksum_url: Some(format!("https://nodejs.org/dist/v{version}/SHASUMS256.txt")),
        ..DownloadPrebuiltOutput::default()
    }))
}

Other changes​

View the official release for a full list of changes.