Plugin option for shell (#517)

* calling plugin without shell

* spelling error

* option on register to select a shell

crates/nu-command/src/core_commands/register.rs

@@ -32,6 +32,12 @@ impl Command for Register {
                 SyntaxShape::Any,
                 "Block with signature description as json object",
             )
+            .named(
+                "shell",
+                SyntaxShape::Filepath,
+                "path of shell used to run plugin (cmd, sh, python, etc)",
+                Some('s'),
+            )
             .category(Category::Core)
     }
 

crates/nu-parser/src/parse_keywords.rs

@@ -1195,7 +1195,7 @@ pub fn parse_register(
         .map(|expr| {
             let name_expr = working_set.get_span_contents(expr.span);
             String::from_utf8(name_expr.to_vec())
-                .map_err(|_| ParseError::NonUtf8(spans[1]))
+                .map_err(|_| ParseError::NonUtf8(expr.span))
                 .and_then(|name| {
                     canonicalize(&name).map_err(|_| ParseError::FileNotFound(name, expr.span))
                 })
@@ -1224,7 +1224,7 @@ pub fn parse_register(
                 .map(|encoding| (path, encoding))
         });
 
-    // Signature is the only optional value from the call and will be used to decide if
+    // Signature is an optional value from the call and will be used to decide if
     // the plugin is called to get the signatures or to use the given signature
     let signature = call.positional.get(1).map(|expr| {
         let signature = working_set.get_span_contents(expr.span);
@@ -1237,16 +1237,52 @@ pub fn parse_register(
         })
     });
 
+    // Shell is another optional value used as base to call shell to plugins
+    let shell = call.get_flag_expr("shell").map(|expr| {
+        let shell_expr = working_set.get_span_contents(expr.span);
+
+        String::from_utf8(shell_expr.to_vec())
+            .map_err(|_| ParseError::NonUtf8(expr.span))
+            .and_then(|name| {
+                canonicalize(&name).map_err(|_| ParseError::FileNotFound(name, expr.span))
+            })
+            .and_then(|path| {
+                if path.exists() & path.is_file() {
+                    Ok(path)
+                } else {
+                    Err(ParseError::FileNotFound(format!("{:?}", path), expr.span))
+                }
+            })
+    });
+
+    let shell = match shell {
+        None => None,
+        Some(path) => match path {
+            Ok(path) => Some(path),
+            Err(err) => {
+                return (
+                    Statement::Pipeline(Pipeline::from_vec(vec![Expression {
+                        expr: Expr::Call(call),
+                        span: call_span,
+                        ty: Type::Unknown,
+                        custom_completion: None,
+                    }])),
+                    Some(err),
+                );
+            }
+        },
+    };
+
     let error = match signature {
         Some(signature) => arguments.and_then(|(path, encoding)| {
             signature.map(|signature| {
-                let plugin_decl = PluginDeclaration::new(path, signature, encoding);
+                let plugin_decl = PluginDeclaration::new(path, signature, encoding, shell);
                 working_set.add_decl(Box::new(plugin_decl));
                 working_set.mark_plugins_file_dirty();
             })
         }),
         None => arguments.and_then(|(path, encoding)| {
-            get_signature(path.as_path(), &encoding)
+            get_signature(path.as_path(), &encoding, &shell)
                 .map_err(|err| {
                     ParseError::LabeledError(
                         "Error getting signatures".into(),
@@ -1258,8 +1294,12 @@ pub fn parse_register(
                     for signature in signatures {
                         // create plugin command declaration (need struct impl Command)
                         // store declaration in working set
-                        let plugin_decl =
-                            PluginDeclaration::new(path.clone(), signature, encoding.clone());
+                        let plugin_decl = PluginDeclaration::new(
+                            path.clone(),
+                            signature,
+                            encoding.clone(),
+                            shell.clone(),
+                        );
 
                         working_set.add_decl(Box::new(plugin_decl));
                     }

crates/nu-plugin/src/plugin/declaration.rs

@@ -14,16 +14,23 @@ pub struct PluginDeclaration {
     name: String,
     signature: Signature,
     filename: PathBuf,
+    shell: Option<PathBuf>,
     encoding: EncodingType,
 }
 
 impl PluginDeclaration {
-    pub fn new(filename: PathBuf, signature: Signature, encoding: EncodingType) -> Self {
+    pub fn new(
+        filename: PathBuf,
+        signature: Signature,
+        encoding: EncodingType,
+        shell: Option<PathBuf>,
+    ) -> Self {
         Self {
             name: signature.name.clone(),
             signature,
             filename,
             encoding,
+            shell,
         }
     }
 }
@@ -52,7 +59,7 @@ impl Command for PluginDeclaration {
         // Decode information from plugin
         // Create PipelineData
         let source_file = Path::new(&self.filename);
-        let mut plugin_cmd = create_command(source_file);
+        let mut plugin_cmd = create_command(source_file, &self.shell);
 
         let mut child = plugin_cmd.spawn().map_err(|err| {
             let decl = engine_state.get_decl(call.decl_id);
@@ -131,7 +138,7 @@ impl Command for PluginDeclaration {
         Ok(pipeline_data)
     }
 
-    fn is_plugin(&self) -> Option<(&PathBuf, &str)> {
-        Some((&self.filename, self.encoding.to_str()))
+    fn is_plugin(&self) -> Option<(&PathBuf, &str, &Option<PathBuf>)> {
+        Some((&self.filename, self.encoding.to_str(), &self.shell))
     }
 }

crates/nu-plugin/src/plugin/mod.rs

@@ -4,7 +4,7 @@ pub use declaration::PluginDeclaration;
 use crate::protocol::{LabeledError, PluginCall, PluginResponse};
 use crate::EncodingType;
 use std::io::BufReader;
-use std::path::Path;
+use std::path::{Path, PathBuf};
 use std::process::{Command as CommandSys, Stdio};
 
 use nu_protocol::ShellError;
@@ -35,10 +35,15 @@ pub trait PluginEncoder: Clone {
     ) -> Result<PluginResponse, ShellError>;
 }
 
-fn create_command(path: &Path) -> CommandSys {
-    let mut process = match path.extension() {
-        None => std::process::Command::new(path),
-        Some(extension) => {
+fn create_command(path: &Path, shell: &Option<PathBuf>) -> CommandSys {
+    let mut process = match (path.extension(), shell) {
+        (_, Some(shell)) => {
+            let mut process = std::process::Command::new(shell);
+            process.arg(path);
+
+            process
+        }
+        (Some(extension), None) => {
             let (shell, separator) = match extension.to_str() {
                 Some("cmd") | Some("bat") => (Some("cmd"), Some("/c")),
                 Some("sh") => (Some("sh"), Some("-c")),
@@ -63,6 +68,7 @@ fn create_command(path: &Path) -> CommandSys {
                 _ => std::process::Command::new(path),
             }
         }
+        (None, None) => std::process::Command::new(path),
     };
 
     // Both stdout and stdin are piped so we can receive information from the plugin
@@ -71,8 +77,12 @@ fn create_command(path: &Path) -> CommandSys {
     process
 }
 
-pub fn get_signature(path: &Path, encoding: &EncodingType) -> Result<Vec<Signature>, ShellError> {
-    let mut plugin_cmd = create_command(path);
+pub fn get_signature(
+    path: &Path,
+    encoding: &EncodingType,
+    shell: &Option<PathBuf>,
+) -> Result<Vec<Signature>, ShellError> {
+    let mut plugin_cmd = create_command(path, shell);
 
     let mut child = plugin_cmd.spawn().map_err(|err| {
         ShellError::PluginFailedToLoad(format!("Error spawning child process: {}", err))

crates/nu-protocol/src/engine/command.rs

@@ -48,8 +48,9 @@ pub trait Command: Send + Sync + CommandClone {
         self.name().contains(' ')
     }
 
-    // Is a plugin command (returns plugin's path and encoding if yes)
-    fn is_plugin(&self) -> Option<(&PathBuf, &str)> {
+    // Is a plugin command (returns plugin's path, encoding and type of shell
+    // if the declaration is a plugin)
+    fn is_plugin(&self) -> Option<(&PathBuf, &str, &Option<PathBuf>)> {
         None
     }
 

crates/nu-protocol/src/engine/engine_state.rs

@@ -230,12 +230,33 @@ impl EngineState {
                 self.plugin_decls().try_for_each(|decl| {
                     // A successful plugin registration already includes the plugin filename
                     // No need to check the None option
-                    let (path, encoding) = decl.is_plugin().expect("plugin should have file name");
-                    let file_name = path.to_str().expect("path should be a str");
+                    let (path, encoding, shell) =
+                        decl.is_plugin().expect("plugin should have file name");
+                    let file_name = path
+                        .to_str()
+                        .expect("path was checked during registration as a str");
 
                     serde_json::to_string_pretty(&decl.signature())
                         .map(|signature| {
-                            format!("register {} -e {} {}\n\n", file_name, encoding, signature)
+                            // Extracting the possible path to the shell used to load the plugin
+                            let shell_str = match shell {
+                                Some(path) => format!(
+                                    "-s {}",
+                                    path.to_str().expect(
+                                        "shell path was checked during registration as a str"
+                                    )
+                                ),
+                                None => "".into(),
+                            };
+
+                            // Each signature is stored in the plugin file with the required
+                            // encoding, shell and signature
+                            // This information will be used when loading the plugin
+                            // information when nushell starts
+                            format!(
+                                "register {} -e {} {} {}\n\n",
+                                file_name, encoding, shell_str, signature
+                            )
                         })
                         .map_err(|err| ShellError::PluginFailedToLoad(err.to_string()))
                         .and_then(|line| {

crates/nu_plugin_python/plugin.py

@@ -21,6 +21,7 @@
 #   native python dictionaries. The encoding and decoding process could be improved
 #   by using libraries like pydantic and marshmallow
 #
+# This plugin uses python3
 # Note: To debug plugins write to stderr using sys.stderr.write
 import sys
 import json