Process initiator working

bffhd/initiators/mod.rs

@@ -1,4 +1,5 @@
 use crate::initiators::dummy::Dummy;
+use crate::initiators::process::Process;
 use crate::resources::modules::fabaccess::Status;
 use crate::session::SessionHandle;
 use crate::{
@@ -19,6 +20,7 @@ use std::time::Duration;
 use url::Url;
 
 mod dummy;
+mod process;
 
 pub trait Initiator: Future<Output = ()> {
     fn new(params: &HashMap<String, String>, callbacks: InitiatorCallbacks) -> miette::Result<Self>
@@ -78,7 +80,7 @@ impl Future for InitiatorDriver {
 
         ready!(Pin::new(&mut self.initiator).poll(cx));
 
-        tracing::warn!(initiator=%self.name, "an initiator module ran to completion!");
+        tracing::warn!(initiator=%self.name, "initiator module ran to completion!");
 
         Poll::Ready(())
     }
@@ -139,6 +141,12 @@ fn load_single(
             resource,
             sessions.clone(),
         )),
+        "Process" => Some(InitiatorDriver::new::<Process>(
+            name.clone(),
+            params,
+            resource,
+            sessions.clone(),
+        )),
         _ => None,
     };
 

bffhd/initiators/process.rs

@@ -0,0 +1,166 @@
+use super::Initiator;
+use super::InitiatorCallbacks;
+use crate::resources::state::State;
+use crate::utils::linebuffer::LineBuffer;
+use async_process::{Child, ChildStdout, Command, Stdio};
+use futures_lite::{ready, AsyncRead};
+use miette::{miette, IntoDiagnostic};
+use serde::{Deserialize, Serialize};
+use std::collections::HashMap;
+use std::future::Future;
+use std::io;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+
+#[derive(Debug, Serialize, Deserialize)]
+pub enum InputMessage {
+    #[serde(rename = "state")]
+    SetState(State),
+}
+
+#[derive(Serialize, Deserialize)]
+pub struct OutputLine {}
+
+pub struct Process {
+    pub cmd: String,
+    pub args: Vec<String>,
+    state: Option<ProcessState>,
+    buffer: LineBuffer,
+    callbacks: InitiatorCallbacks,
+}
+
+impl Process {
+    fn spawn(&mut self) -> io::Result<()> {
+        let mut child = Command::new(&self.cmd)
+            .args(&self.args)
+            .stdin(Stdio::null())
+            .stdout(Stdio::piped())
+            .stderr(Stdio::piped())
+            .spawn()?;
+        self.state = Some(ProcessState::new(
+            child
+                .stdout
+                .take()
+                .expect("Child just spawned with piped stdout has no stdout"),
+            child,
+        ));
+        Ok(())
+    }
+}
+
+struct ProcessState {
+    pub child: Child,
+    pub stdout: ChildStdout,
+}
+
+impl ProcessState {
+    pub fn new(stdout: ChildStdout, child: Child) -> Self {
+        Self { stdout, child }
+    }
+
+    fn try_process(&mut self, buffer: &[u8], callbacks: &mut InitiatorCallbacks) -> usize {
+        tracing::trace!("trying to process current buffer");
+
+        let mut end = 0;
+
+        while let Some(idx) = buffer[end..].iter().position(|b| *b == b'\n') {
+            if idx == 0 {
+                end += 1;
+                continue;
+            }
+            let line = &buffer[end..(end + idx)];
+            self.process_line(line, callbacks);
+            end = idx;
+        }
+
+        end
+    }
+
+    fn process_line(&mut self, line: &[u8], callbacks: &mut InitiatorCallbacks) {
+        match serde_json::from_slice::<InputMessage>(line) {
+            Ok(state) => {
+                tracing::trace!(?state, "got new state for process initiator");
+            }
+            Err(error) => tracing::warn!(%error, "process initiator did not send a valid line"),
+        }
+    }
+}
+
+impl Future for Process {
+    type Output = ();
+
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        if let Process {
+            state: Some(state),
+            buffer,
+            callbacks,
+            ..
+        } = self.get_mut()
+        {
+            match state.child.try_status() {
+                Err(error) => {
+                    tracing::error!(%error, "checking child exit code returned an error");
+                    return Poll::Ready(());
+                }
+                Ok(Some(exitcode)) => {
+                    tracing::warn!(%exitcode, "child process exited");
+                    return Poll::Ready(());
+                }
+                Ok(None) => {
+                    tracing::trace!("process initiator checking on process");
+
+                    let stdout = &mut state.stdout;
+
+                    loop {
+                        let buf = buffer.get_mut_write(512);
+                        match AsyncRead::poll_read(Pin::new(stdout), cx, buf) {
+                            Poll::Pending => break,
+                            Poll::Ready(Ok(read)) => {
+                                buffer.advance_valid(read);
+                                continue;
+                            }
+                            Poll::Ready(Err(error)) => {
+                                tracing::warn!(%error, "reading from child stdout errored");
+                                return Poll::Ready(());
+                            }
+                        }
+                    }
+
+                    let processed = state.try_process(buffer, callbacks);
+                    buffer.consume(processed);
+
+                    return Poll::Pending;
+                }
+            }
+        } else {
+            tracing::warn!("process initiator has no process attached!");
+        }
+
+        Poll::Ready(())
+    }
+}
+
+impl Initiator for Process {
+    fn new(params: &HashMap<String, String>, callbacks: InitiatorCallbacks) -> miette::Result<Self>
+    where
+        Self: Sized,
+    {
+        let cmd = params
+            .get("cmd")
+            .ok_or(miette!("Process initiator requires a `cmd` parameter."))?
+            .clone();
+        let args = params
+            .get("args")
+            .map(|argv| argv.split_whitespace().map(|s| s.to_string()).collect())
+            .unwrap_or_else(Vec::new);
+        let mut this = Self {
+            cmd,
+            args,
+            state: None,
+            buffer: LineBuffer::new(),
+            callbacks,
+        };
+        this.spawn().into_diagnostic()?;
+        Ok(this)
+    }
+}