Crate nu_plugin

Nu Plugin: Plugin library for Nushell

This crate contains the interface necessary to build Nushell plugins in Rust. Additionally, it contains public, but undocumented, items used by Nushell itself to interface with Nushell plugins. This documentation focuses on the interface needed to write an independent plugin.

Nushell plugins are stand-alone applications that communicate with Nushell over stdin and stdout using a standardizes serialization framework to exchange the typed data that Nushell commands utilize natively.

A typical plugin application will define a struct that implements the Plugin trait and then, in it’s main method, pass that Plugin to the serve_plugin function, which will handle all of the input and output serialization when invoked by Nushell.

use nu_plugin::{EvaluatedCall, LabeledError, MsgPackSerializer, Plugin, serve_plugin};
use nu_protocol::{PluginSignature, Value};

struct MyPlugin;

impl Plugin for MyPlugin {
    fn signature(&self) -> Vec<PluginSignature> {
        todo!();
    }
    fn run(
        &mut self,
        name: &str,
        call: &EvaluatedCall,
        input: &Value
    ) -> Result<Value, LabeledError> {
        todo!();
    }
}

fn main() {
   serve_plugin(&mut MyPlugin{}, MsgPackSerializer)
}

Nushell’s source tree contains a Plugin Example that demonstrates the full range of plugin capabilities.

Re-exports

• pub use plugin::get_signature;
• pub use plugin::PluginDeclaration;
• pub use protocol::PluginResponse;
• pub use serializers::EncodingType;

Structs

• EvaluatedCall
  A representation of the plugin’s invocation command including command line args
• JsonSerializer
  A PluginEncoder that enables the plugin to communicate with Nushel with JSON serialized data.
• LabeledError
  An error message with debugging information that can be passed to Nushell from the plugin
• MsgPackSerializer
  A PluginEncoder that enables the plugin to communicate with Nushel with MsgPack serialized data.

Traits

• Plugin
  The basic API for a Nushell plugin

Functions

• serve_plugin
  Function used to implement the communication protocol between nushell and an external plugin.