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#![warn(missing_docs)] //! Crate to easily script any rust project //! # Rscript //! The main idea is: //! - Create a new crate (my-project-api for example) //! - Add hooks to this api-crate //! - This api-crate should be used by the main-crate and by the scripts //! - Trigger Hooks in the main crate //! - Receive the hooks on the script side, and react to them with any output //! //! //! Goals: //! - Be as easy as possible to include on already established projects //! - Strive for maximum compile time guarantees //! //! This crate was extracted from [IRust](https://github.com/sigmaSd/IRust) //! //! Taking *IRust* as an example: //! - It has an API crate where hooks are defined [irust_api](https://github.com/sigmaSd/IRust/blob/master/crates/irust_api/src/lib.rs#L22) //! - It trigger hooks on the main crate [irust](https://github.com/sigmaSd/IRust/blob/master/crates/irust/src/irust.rs#L136) //! - And a script example [vim_mode](https://github.com/sigmaSd/IRust/tree/master/scripts_examples/script4/irust_vim) //! //! Check out the [examples](https://github.com/sigmaSd/Rscript/tree/master/examples) for more info. use serde::{de::DeserializeOwned, Deserialize, Serialize}; use std::{ path::Path, process::{Child, Stdio}, }; // Rexport Version, VersionReq /// *SemVer version* as defined by <https://semver.org.>\ /// The main crate must specify its version when adding scripts to [ScriptManager] pub use semver::Version; /// *SemVer version requirement* describing the intersection of some version comparators, such as >=1.2.3, <1.8.\ /// Each script must specify the required version of the main crate when responding to [Message::Greeting] pub use semver::VersionReq; /// Module that contains traits that improves writing scripts experience pub mod scripting; mod error; pub use error::Error; /// Script metadata that every script should send to the main_crate when starting up after receiving the greeting message [Message::Greeting] #[derive(Serialize, Deserialize, Debug)] pub struct ScriptInfo { /// Script name pub name: String, /// Script type: Daemon/OneShot pub script_type: ScriptType, /// The hooks that the script wants to listen to pub hooks: Box<[String]>, /// The version requirement of the program that the script will run against pub version_requirement: VersionReq, } impl ScriptInfo { /// Create a new script metadata, the new constructor tries to add more ergonomics pub fn new( name: &'static str, script_type: ScriptType, hooks: &'static [&'static str], version_requirement: VersionReq, ) -> Self { Self { name: name.into(), script_type, hooks: hooks.iter().map(|hook| String::from(*hook)).collect(), version_requirement, } } } /// ScriptType: Daemon/OneShot /// - *OneShot* scripts are expected to be spawned(process::Command::new) by the main crate ach time they are used, this should be preferred if performance and keeping state are not a concern since it has some nice advantage which is the allure of hot reloading (recompiling the script will affect the main crate while its running) /// /// - *Daemon* scripts are expected to run indefinitely, the main advantage is better performance and keeping the state #[derive(Serialize, Deserialize, Debug, Clone, Copy)] pub enum ScriptType { /// Scripts that is executed each time OneShot, /// Scripts that runs indefinitely, it will continue to receive and send hooks while its /// running Daemon, } /// ScriptManager holds all the scripts found, it can be constructed with [ScriptManager::default]\ /// Initially its empty, to populate it, we can use one of the methods to add scripts, currently only [ScriptManager::add_scripts_by_path] is provided #[derive(Default)] pub struct ScriptManager { scripts: Vec<Script>, } /// Message that is sent from the main crate to the script each time it wants to interact with it\ /// Greeting message must be sent when looking for scripts\ /// Execute message must be sent each time a hook is triggered #[derive(Serialize, Deserialize, Debug, PartialEq)] pub enum Message { /// Greet a script, the script must respond with [ScriptInfo] Greeting, /// Must be sent each time a hook is triggered Execute, } impl ScriptManager { /// Look for scripts in the specified folder\ /// It requires specifying a [VersionReq] so the script manager can check for incompatibility and if that's the case it will return an error: [Error::ScriptVersionMismatch]\ /// The script manager will send a [Message::Greeting] for every script found and the scripts must respond with [ScriptInfo] /// /// ```rust, no_run /// # use rscript::*; /// let mut sm = ScriptManager::default(); /// let scripts_path: std::path::PathBuf = todo!(); // Defined by the user /// const VERSION: &'static str = concat!("main_crate-", env!("CARGO_PKG_VERSION")); /// sm.add_scripts_by_path(scripts_path, Version::parse(VERSION).expect("version is correct")); /// ``` pub fn add_scripts_by_path<P: AsRef<Path>>( &mut self, path: P, version: Version, ) -> Result<(), Error> { fn start_script(path: &Path, version: &Version) -> Result<Script, Error> { let mut script = std::process::Command::new(path) .stdin(Stdio::piped()) .stdout(Stdio::piped()) .spawn()?; // Send Greeting Message let stdin = script.stdin.as_mut().expect("stdin is piped"); bincode::serialize_into(stdin, &Message::Greeting)?; // Receive ScriptInfo let stdout = script.stdout.as_mut().expect("stdout is piped"); let metadata: ScriptInfo = bincode::deserialize_from(stdout)?; // Check if the provided version matches the script version if !metadata.version_requirement.matches(version) { return Err(Error::ScriptVersionMismatch { program_actual_version: version.clone(), program_required_version: metadata.version_requirement, }); } // Save script depending on its type let script = if matches!(metadata.script_type, ScriptType::Daemon) { ScriptTypeInternal::Daemon(script) } else { ScriptTypeInternal::OneShot(path.to_path_buf()) }; Ok(Script { script, metadata, state: State::Active, }) } let path = path.as_ref(); for entry in std::fs::read_dir(path)? { let entry = entry?; let path = entry.path(); if path.is_file() { self.scripts.push(start_script(&path, &version)?); } } Ok(()) } /// Trigger a hook /// All scripts that are *active* and that are listening for this particular hook will receive it pub fn trigger<'a, H: 'static + Hook>( &'a mut self, hook: H, ) -> impl Iterator<Item = Result<<H as Hook>::Output, bincode::Error>> + 'a { self.scripts.iter_mut().filter_map(move |script| { if script.is_active() && script.is_listening_for::<H>() { Some(script.trigger_internal(&hook)) } else { None } }) } /// List of current scripts pub fn scripts(&self) -> &[Script] { &self.scripts } /// Mutable list of current scripts, useful for activating/deactivating a script pub fn scripts_mut(&mut self) -> &mut [Script] { &mut self.scripts } } impl Drop for ScriptManager { fn drop(&mut self) { self.scripts.iter_mut().for_each(|script| script.end()); } } /// A script abstraction // The user should not be able to construct a Script manually #[derive(Debug)] pub struct Script { metadata: ScriptInfo, script: ScriptTypeInternal, state: State, } #[derive(Debug)] enum State { Active, Inactive, } #[derive(Debug)] enum ScriptTypeInternal { Daemon(Child), OneShot(std::path::PathBuf), } impl Script { //public /// Returns the script metadata pub fn metadata(&self) -> &ScriptInfo { &self.metadata } /// Activate a script, inactive scripts will not react to hooks pub fn activate(&mut self) { self.state = State::Active; } /// Deactivate a script, inactive scripts will not react to hooks pub fn deactivate(&mut self) { self.state = State::Inactive; } /// Query the script state pub fn is_active(&self) -> bool { matches!(self.state, State::Active) } /// Check if a script is listening for a hook pub fn is_listening_for<H: Hook>(&self) -> bool { self.metadata .hooks .iter() .any(|hook| hook.as_str() == H::NAME) } /// Trigger a hook on the script, this disregards the script state as in the hook will be triggered even if the script is inactive\ /// If the script is not listening for the specified hook, an error will be returned pub fn trigger<H: Hook>(&mut self, hook: &H) -> Result<<H as Hook>::Output, Error> { if self.is_listening_for::<H>() { self.trigger_internal(hook).map_err(Error::Bincode) } else { Err(Error::ScriptIsNotListeningForHook) } } } impl Script { // private fn trigger_internal<H: Hook>( &mut self, hook: &H, ) -> Result<<H as Hook>::Output, bincode::Error> { let trigger_hook_common = |script: &mut Child| { let mut stdin = script.stdin.as_mut().expect("stdin is piped"); let stdout = script.stdout.as_mut().expect("stdout is piped"); // Send Execute message bincode::serialize_into(&mut stdin, &Message::Execute)?; // bincode write hook type bincode::serialize_into(&mut stdin, H::NAME)?; // bincode write hook bincode::serialize_into(stdin, hook)?; // bincode read result -> O bincode::deserialize_from(stdout) }; match &mut self.script { ScriptTypeInternal::Daemon(ref mut script) => trigger_hook_common(script), ScriptTypeInternal::OneShot(script_path) => trigger_hook_common( &mut std::process::Command::new(script_path) .stdin(Stdio::piped()) .stdout(Stdio::piped()) .spawn()?, ), } } fn end(&mut self) { // This errors if the script has already exited // We don't care about this error if let ScriptTypeInternal::Daemon(ref mut script) = self.script { let _ = script.kill(); } } } /// Trait to mark the hooks that will be triggered in the main crate\ /// Triggering the hook sends input to the script, and receive the output from it\ /// The output type is declared on the hook associated type\ /// The associated NAME is needed in order to differentiate the hooks received in the script\ /// The hook struct is required to implement serde::Serialize+Deserialize, so it can be used by bincode\ /// The hooks should be declared on an external crate (my-project-api for example) so they can be used both by the main crate and the script\ /// ```rust /// #[derive(serde::Serialize, serde::Deserialize)] /// struct Eval(String); /// impl rscript::Hook for Eval { /// const NAME: &'static str = "Eval"; /// type Output = Option<String>; /// } pub trait Hook: Serialize + DeserializeOwned { /// The name of the hook, required to distinguish the received hook on the script side const NAME: &'static str; /// The output type of the script type Output: Serialize + DeserializeOwned; }