Child process manager api (#64)

* child process api

* added hook to js

* process API + restructured process state storage

* formatting

* added path-pid check and fixed probs

* prettier

* added profile checking function

---------

Co-authored-by: Wyatt <wyatt@modrinth.com>

theseus/src/api/mod.rs

@@ -1,9 +1,10 @@
 //! API for interacting with Theseus
 pub mod auth;
+pub mod process;
 pub mod profile;
 pub mod profile_create;
-pub mod tags;
 pub mod settings;
+pub mod tags;
 
 pub mod data {
     pub use crate::state::{
@@ -16,6 +17,7 @@ pub mod prelude {
     pub use crate::{
         auth::{self, Credentials},
         data::*,
+        process,
         profile::{self, Profile},
         profile_create, settings, State,
     };

theseus/src/api/process.rs

@@ -0,0 +1,161 @@
+//! Theseus process management interface
+use std::path::{Path, PathBuf};
+
+use crate::state::MinecraftChild;
+pub use crate::{
+    state::{
+        Hooks, JavaSettings, MemorySettings, Profile, Settings, WindowSize,
+    },
+    State,
+};
+
+// Gets whether a child process stored in the state by PID has finished
+#[tracing::instrument]
+pub async fn has_finished_by_pid(pid: u32) -> crate::Result<bool> {
+    Ok(get_exit_status_by_pid(pid).await?.is_some())
+}
+
+// Gets the exit status of a child process stored in the state by PID
+#[tracing::instrument]
+pub async fn get_exit_status_by_pid(pid: u32) -> crate::Result<Option<i32>> {
+    let state = State::get().await?;
+    let children = state.children.read().await;
+    Ok(children.exit_status(&pid).await?.and_then(|f| f.code()))
+}
+
+// Gets the PID of each stored process in the state
+#[tracing::instrument]
+pub async fn get_all_pids() -> crate::Result<Vec<u32>> {
+    let state = State::get().await?;
+    let children = state.children.read().await;
+    Ok(children.keys())
+}
+
+// Gets the PID of each *running* stored process in the state
+#[tracing::instrument]
+pub async fn get_all_running_pids() -> crate::Result<Vec<u32>> {
+    let state = State::get().await?;
+    let children = state.children.read().await;
+    children.running_keys().await
+}
+
+// Gets the Profile paths of each *running* stored process in the state
+#[tracing::instrument]
+pub async fn get_all_running_profile_paths() -> crate::Result<Vec<PathBuf>> {
+    let state = State::get().await?;
+    let children = state.children.read().await;
+    children.running_profile_paths().await
+}
+
+// Gets the Profiles (cloned) of each *running* stored process in the state
+#[tracing::instrument]
+pub async fn get_all_running_profiles() -> crate::Result<Vec<Profile>> {
+    let state = State::get().await?;
+    let children = state.children.read().await;
+    children.running_profiles().await
+}
+
+// Gets the PID of each stored process in the state by profile path
+#[tracing::instrument]
+pub async fn get_pids_by_profile_path(
+    profile_path: &Path,
+) -> crate::Result<Vec<u32>> {
+    let state = State::get().await?;
+    let children = state.children.read().await;
+    children.running_keys_with_profile(profile_path).await
+}
+
+// Gets stdout of a child process stored in the state by PID, as a string
+#[tracing::instrument]
+pub async fn get_stdout_by_pid(pid: u32) -> crate::Result<String> {
+    let state = State::get().await?;
+    // Get stdout from child
+    let children = state.children.read().await;
+
+    // Extract child or return crate::Error
+    if let Some(child) = children.get(&pid) {
+        let child = child.read().await;
+        Ok(child.stdout.get_output().await?)
+    } else {
+        Err(crate::ErrorKind::LauncherError(format!(
+            "No child process with PID {}",
+            pid
+        ))
+        .as_error())
+    }
+}
+
+// Gets stderr of a child process stored in the state by PID, as a string
+#[tracing::instrument]
+pub async fn get_stderr_by_pid(pid: u32) -> crate::Result<String> {
+    let state = State::get().await?;
+    // Get stdout from child
+    let children = state.children.read().await;
+
+    // Extract child or return crate::Error
+    if let Some(child) = children.get(&pid) {
+        let child = child.read().await;
+        Ok(child.stderr.get_output().await?)
+    } else {
+        Err(crate::ErrorKind::LauncherError(format!(
+            "No child process with PID {}",
+            pid
+        ))
+        .as_error())
+    }
+}
+
+// Kill a child process stored in the state by PID, as a string
+#[tracing::instrument]
+pub async fn kill_by_pid(pid: u32) -> crate::Result<()> {
+    let state = State::get().await?;
+    let children = state.children.read().await;
+    if let Some(mchild) = children.get(&pid) {
+        let mut mchild = mchild.write().await;
+        kill(&mut mchild).await
+    } else {
+        // No error returned for already finished process
+        Ok(())
+    }
+}
+
+// Wait for a child process stored in the state by PID
+#[tracing::instrument]
+pub async fn wait_for_by_pid(pid: u32) -> crate::Result<()> {
+    let state = State::get().await?;
+    let children = state.children.read().await;
+    // No error returned for already killed process
+    if let Some(mchild) = children.get(&pid) {
+        let mut mchild = mchild.write().await;
+        wait_for(&mut mchild).await
+    } else {
+        // No error returned for already finished process
+        Ok(())
+    }
+}
+
+// Kill a running child process directly, and wait for it to be killed
+#[tracing::instrument]
+pub async fn kill(running: &mut MinecraftChild) -> crate::Result<()> {
+    running.child.kill().await?;
+    wait_for(running).await
+}
+
+// Await on the completion of a child process directly
+#[tracing::instrument]
+pub async fn wait_for(running: &mut MinecraftChild) -> crate::Result<()> {
+    let result = running.child.wait().await.map_err(|err| {
+        crate::ErrorKind::LauncherError(format!(
+            "Error running minecraft: {err}"
+        ))
+    })?;
+
+    match result.success() {
+        false => Err(crate::ErrorKind::LauncherError(format!(
+            "Minecraft exited with non-zero code {}",
+            result.code().unwrap_or(-1)
+        ))
+        .as_error()),
+        true => Ok(()),
+    }
+}

theseus/src/api/profile.rs

@@ -1,4 +1,5 @@
 //! Theseus profile management interface
+use crate::state::MinecraftChild;
 pub use crate::{
     state::{JavaSettings, Profile},
     State,
@@ -9,10 +10,7 @@ use std::{
     path::{Path, PathBuf},
     sync::Arc,
 };
-use tokio::{
-    process::{Child, Command},
-    sync::RwLock,
-};
+use tokio::{process::Command, sync::RwLock};
 
 /// Add a profile to the in-memory state
 #[tracing::instrument]
@@ -114,7 +112,7 @@ pub async fn list(
 pub async fn run(
     path: &Path,
     credentials: &crate::auth::Credentials,
-) -> crate::Result<Arc<RwLock<Child>>> {
+) -> crate::Result<Arc<RwLock<MinecraftChild>>> {
     let state = State::get().await.unwrap();
     let settings = state.settings.read().await;
     let profile = get(path).await?.ok_or_else(|| {
@@ -227,31 +225,8 @@ pub async fn run(
             "Process failed to stay open.".to_string(),
         )
     })?;
-    let child_arc = state_children.insert(pid, mc_process);
+    let mchild_arc =
+        state_children.insert_process(pid, path.to_path_buf(), mc_process);
 
-    Ok(child_arc)
-}
-
-#[tracing::instrument]
-pub async fn kill(running: &mut Child) -> crate::Result<()> {
-    running.kill().await?;
-    wait_for(running).await
-}
-
-#[tracing::instrument]
-pub async fn wait_for(running: &mut Child) -> crate::Result<()> {
-    let result = running.wait().await.map_err(|err| {
-        crate::ErrorKind::LauncherError(format!(
-            "Error running minecraft: {err}"
-        ))
-    })?;
-
-    match result.success() {
-        false => Err(crate::ErrorKind::LauncherError(format!(
-            "Minecraft exited with non-zero code {}",
-            result.code().unwrap_or(-1)
-        ))
-        .as_error()),
-        true => Ok(()),
-    }
+    Ok(mchild_arc)
 }

theseus/src/api/settings.rs

@@ -21,4 +21,4 @@ pub async fn set(settings: Settings) -> crate::Result<()> {
     // Replaces the settings struct in the RwLock with the passed argument
     *state.settings.write().await = settings;
     Ok(())
-}
+}

theseus/src/launcher/mod.rs

@@ -1,5 +1,5 @@
 //! Logic for launching Minecraft
-use crate::state as st;
+use crate::{process, state as st};
 use daedalus as d;
 use dunce::canonicalize;
 use std::{path::Path, process::Stdio};
@@ -176,6 +176,18 @@ pub async fn launch_minecraft(
 
     let env_args = Vec::from(env_args);
 
+    // Check if profile has a running profile, and reject running the command if it does
+    // Done late so a quick double call doesn't launch two instances
+    let existing_processes =
+        process::get_pids_by_profile_path(instance_path).await?;
+    if let Some(pid) = existing_processes.first() {
+        return Err(crate::ErrorKind::LauncherError(format!(
+            "Profile {} is already running at PID: {pid}",
+            instance_path.display()
+        ))
+        .as_error());
+    }
+
     command
         .args(
             args::get_jvm_arguments(
@@ -217,8 +229,8 @@ pub async fn launch_minecraft(
         .current_dir(instance_path.clone())
         .env_clear()
         .envs(env_args)
-        .stdout(Stdio::inherit())
-        .stderr(Stdio::inherit());
+        .stdout(Stdio::piped())
+        .stderr(Stdio::piped());
 
     command.spawn().map_err(|err| {
         crate::ErrorKind::LauncherError(format!(

theseus/src/state/children.rs

@@ -1,33 +1,166 @@
+use std::path::{Path, PathBuf};
 use std::{collections::HashMap, sync::Arc};
-use tokio::process::Child;
+use tokio::io::{AsyncBufReadExt, BufReader};
+use tokio::process::{ChildStderr, ChildStdout};
 use tokio::sync::RwLock;
 
+use super::Profile;
+
 // Child processes (instances of Minecraft)
-// A wrapper over a Hashmap connecting PID -> Child
-// Left open for future functionality re: polling children
-pub struct Children(HashMap<u32, Arc<RwLock<Child>>>);
+// A wrapper over a Hashmap connecting PID -> MinecraftChild
+pub struct Children(HashMap<u32, Arc<RwLock<MinecraftChild>>>);
+
+// Minecraft Child, bundles together the PID, the actual Child, and the easily queryable stdout and stderr streams
+#[derive(Debug)]
+pub struct MinecraftChild {
+    pub pid: u32,
+    pub profile_path: PathBuf, //todo: make UUID when profiles are recognized by UUID
+    pub child: tokio::process::Child,
+    pub stdout: SharedOutput,
+    pub stderr: SharedOutput,
+}
 
 impl Children {
     pub fn new() -> Children {
         Children(HashMap::new())
     }
 
-    // Inserts and returns a ref to the child
-    // Unlike a Hashmap, this directly returns the reference to the Child rather than any previously stored Child that may exist
-    pub fn insert(
+    // Inserts a child process to keep track of, and returns a reference to the container struct MinecraftChild
+    // The threads for stdout and stderr are spawned here
+    // Unlike a Hashmap's 'insert', this directly returns the reference to the Child rather than any previously stored Child that may exist
+    pub fn insert_process(
         &mut self,
         pid: u32,
-        child: tokio::process::Child,
-    ) -> Arc<RwLock<Child>> {
-        let child = Arc::new(RwLock::new(child));
-        self.0.insert(pid, child.clone());
-        child
+        profile_path: PathBuf,
+        mut child: tokio::process::Child,
+    ) -> Arc<RwLock<MinecraftChild>> {
+        // Create std watcher threads for stdout and stderr
+        let stdout = SharedOutput::new();
+        if let Some(child_stdout) = child.stdout.take() {
+            let stdout_clone = stdout.clone();
+            tokio::spawn(async move {
+                if let Err(e) = stdout_clone.read_stdout(child_stdout).await {
+                    eprintln!("Stdout process died with error: {}", e);
+                }
+            });
+        }
+        let stderr = SharedOutput::new();
+        if let Some(child_stderr) = child.stderr.take() {
+            let stderr_clone = stderr.clone();
+            tokio::spawn(async move {
+                if let Err(e) = stderr_clone.read_stderr(child_stderr).await {
+                    eprintln!("Stderr thread died with error: {}", e);
+                }
+            });
+        }
+
+        // Create MinecraftChild
+        let mchild = MinecraftChild {
+            pid,
+            profile_path,
+            child,
+            stdout,
+            stderr,
+        };
+        let mchild = Arc::new(RwLock::new(mchild));
+        self.0.insert(pid, mchild.clone());
+        mchild
     }
 
     // Returns a ref to the child
-    pub fn get(&self, pid: &u32) -> Option<Arc<RwLock<Child>>> {
+    pub fn get(&self, pid: &u32) -> Option<Arc<RwLock<MinecraftChild>>> {
         self.0.get(pid).cloned()
     }
+
+    // Gets all PID keys
+    pub fn keys(&self) -> Vec<u32> {
+        self.0.keys().cloned().collect()
+    }
+
+    // Get exit status of a child by PID
+    // Returns None if the child is still running
+    pub async fn exit_status(
+        &self,
+        pid: &u32,
+    ) -> crate::Result<Option<std::process::ExitStatus>> {
+        if let Some(child) = self.get(pid) {
+            let child = child.clone();
+            let mut child = child.write().await;
+            Ok(child.child.try_wait()?)
+        } else {
+            Ok(None)
+        }
+    }
+
+    // Gets all PID keys of running children
+    pub async fn running_keys(&self) -> crate::Result<Vec<u32>> {
+        let mut keys = Vec::new();
+        for key in self.keys() {
+            if let Some(child) = self.get(&key) {
+                let child = child.clone();
+                let mut child = child.write().await;
+                if child.child.try_wait()?.is_none() {
+                    keys.push(key);
+                }
+            }
+        }
+        Ok(keys)
+    }
+
+    // Gets all PID keys of running children with a given profile path
+    pub async fn running_keys_with_profile(
+        &self,
+        profile_path: &Path,
+    ) -> crate::Result<Vec<u32>> {
+        let running_keys = self.running_keys().await?;
+        let mut keys = Vec::new();
+        for key in running_keys {
+            if let Some(child) = self.get(&key) {
+                let child = child.clone();
+                let child = child.read().await;
+                if child.profile_path == profile_path {
+                    keys.push(key);
+                }
+            }
+        }
+        Ok(keys)
+    }
+
+    // Gets all profiles of running children
+    pub async fn running_profile_paths(&self) -> crate::Result<Vec<PathBuf>> {
+        let mut profiles = Vec::new();
+        for key in self.keys() {
+            if let Some(child) = self.get(&key) {
+                let child = child.clone();
+                let mut child = child.write().await;
+                if child.child.try_wait()?.is_none() {
+                    profiles.push(child.profile_path.clone());
+                }
+            }
+        }
+        Ok(profiles)
+    }
+
+    // Gets all profiles of running children
+    // Returns clones because it would be serialized anyway
+    pub async fn running_profiles(&self) -> crate::Result<Vec<Profile>> {
+        let mut profiles = Vec::new();
+        for key in self.keys() {
+            if let Some(child) = self.get(&key) {
+                let child = child.clone();
+                let mut child = child.write().await;
+                if child.child.try_wait()?.is_none() {
+                    if let Some(prof) =
+                        crate::api::profile::get(&child.profile_path.clone())
+                            .await?
+                    {
+                        profiles.push(prof);
+                    }
+                }
+            }
+        }
+        Ok(profiles)
+    }
 }
 
 impl Default for Children {
@@ -35,3 +168,58 @@ impl Default for Children {
         Self::new()
     }
 }
+
+// SharedOutput, a wrapper around a String that can be read from and written to concurrently
+// Designed to be used with ChildStdout and ChildStderr in a tokio thread to have a simple String storage for the output of a child process
+#[derive(Clone, Debug)]
+pub struct SharedOutput {
+    output: Arc<RwLock<String>>,
+}
+
+impl SharedOutput {
+    fn new() -> Self {
+        SharedOutput {
+            output: Arc::new(RwLock::new(String::new())),
+        }
+    }
+
+    // Main entry function to a created SharedOutput, returns the log as a String
+    pub async fn get_output(&self) -> crate::Result<String> {
+        let output = self.output.read().await;
+        Ok(output.clone())
+    }
+
+    async fn read_stdout(
+        &self,
+        child_stdout: ChildStdout,
+    ) -> crate::Result<()> {
+        let mut buf_reader = BufReader::new(child_stdout);
+        let mut line = String::new();
+
+        while buf_reader.read_line(&mut line).await? > 0 {
+            {
+                let mut output = self.output.write().await;
+                output.push_str(&line);
+            }
+            line.clear();
+        }
+        Ok(())
+    }
+
+    async fn read_stderr(
+        &self,
+        child_stderr: ChildStderr,
+    ) -> crate::Result<()> {
+        let mut buf_reader = BufReader::new(child_stderr);
+        let mut line = String::new();
+
+        while buf_reader.read_line(&mut line).await? > 0 {
+            {
+                let mut output = self.output.write().await;
+                output.push_str(&line);
+            }
+            line.clear();
+        }
+        Ok(())
+    }
+}