feat(mvp-system): extract mvp_chat library module

Add mvp-system/src/mvp_chat.rs with a run_from_args entrypoint wiring swactor runtime,
dashboard, chat datastream, and a PromptLoop. Add a mock integration test; refresh
mvp-chat and MVP_SYSTEM specs.


Signed-off-by: Zachery Aaron Shores-Chmielewski <zacheryasc@gmail.com>

crates/mvp-system/Cargo.toml

@@ -7,11 +7,10 @@ autobins = false
 
 [features]
 default = []
-local-e2e = ["dep:dashboard"]
 
 [dependencies]
 datastream = { path = "../datastream" }
-dashboard = { path = "../dashboard", optional = true }
+dashboard = { path = "../dashboard" }
 serde_json = "1"
 serde = { version = "1", features = ["derive"] }
 swactor = { path = "../..", features = ["serde", "transport"] }
@@ -19,7 +18,7 @@ swactor-transport = { path = "../transport" }
 distribution = { path = "../distribution" }
 iroh-driver = { path = "../iroh-driver" }
 iroh = "0.98"
-tokio = { version = "1", features = ["rt-multi-thread", "macros", "process", "io-util", "sync", "time", "net"] }
+tokio = { version = "1", features = ["rt-multi-thread", "macros", "process", "io-util", "sync", "time", "net", "signal"] }
 swactor-vastai = { path = "../../tools/vastai" }
 parking_lot = "0.12"
 blake3 = "1"
@@ -60,3 +59,8 @@ name = "local-e2e-cluster"
 path = "tests/local_e2e_cluster.rs"
 harness = false
 required-features = ["local-e2e"]
+
+[[test]]
+name = "mvp_chat_mock"
+path = "tests/mvp_chat_mock.rs"
+harness = false

crates/mvp-system/MVP_SYSTEM_SPEC.md

@@ -1430,23 +1430,28 @@ enum GpuWorkerCtlMsg {
     ExecuteStep(ExecuteStep),
     ReleaseDeviceObject { device_handle: DeviceObjectHandle },
     ShutdownWorker(ShutdownWorker),
-    Process(ProcessNotification),
+    Process(ProcessOutput),
+    WorkerAdapter(WorkerAdapterEvent),
 }
 ```
 
-`Process(ProcessNotification)` is delivered by a small `ProcessBridge` actor.
+`Process(ProcessOutput)` is delivered by the configured upstream process owner;
-`GpuWorkerCtl` sends process input through `ProcessCommand::WriteStdin`.
+there is no process-local notification subscription bridge. If the
+production worker still uses a subprocess stdin/stdout protocol, `GpuWorkerCtl`
+talks to a separate worker I/O adapter. That adapter owns the child stdio handles
+and is outside managed-process core.
 
-The process adapter may use newline-delimited JSON for worker commands/events.
+The optional worker I/O adapter may use newline-delimited JSON for worker
-This is an adapter, not a second distributed protocol.
+commands/events. This is an adapter-local protocol, not part of
+`crates/process` and not a second distributed protocol.
 
 Adapter rules:
 
-- one command/event JSON object per line
+- one command/event JSON object per line;
-- stdout is reserved for worker events
+- adapter-owned stdout may carry worker events;
-- stderr is reserved for logs and diagnostics
+- adapter-owned stderr may carry logs and diagnostics;
-- payload bytes are forbidden in JSON
+- payload bytes are forbidden in JSON;
-- invalid JSON or unknown event shape is a worker/process fault
+- invalid JSON or unknown event shape is a worker/adapter fault.
 
 Worker environment:
 
@@ -1675,7 +1680,7 @@ Wake hints emitted by worker:
 - egress rings: `RingReadable` after advancing `commit`
 
 `GpuWorkerCtl` may synthesize `WorkerCrashed` and `RingFault` after process exit,
-process error, or stdout control-stream failure.
+process error, or worker I/O adapter control-stream failure.
 
 ---
 
@@ -1688,11 +1693,11 @@ NotStarted
   on StartWorker -> Spawning
 
 Spawning
-  spawn ProcessActor with ProcessSpec
+  spawn ProcessActor with ProcessSpec and upstream = GpuWorkerCtl/process owner
-  spawn ProcessBridge
+  wait for ProcessOutput::Started
-  subscribe bridge to ProcessActor
+  if subprocess worker protocol is enabled:
-  wait for ProcessNotification::Started
+    start/connect worker I/O adapter
-  send InitializeWorker through ProcessCommand::WriteStdin
+    send InitializeWorker through worker I/O adapter
   -> Initializing
 
 Initializing

crates/mvp-system/specs/mvp_chat.md

@@ -160,7 +160,7 @@ Accepted runtime fields:
 - `[runtime].max_tokens`
 
 `[runtime].max_tokens` sets the maximum number of tokens requested for each
-prompt submission. It must be a positive integer.
+prompt submission. A value of `0` implies no specified limit.
 
 Accepted observability fields:
 
@@ -352,16 +352,13 @@ Default values:
 
 - provider: `process`;
 - pipeline stages: `1`;
-- max tokens: `64`;
+- max tokens: `0`;
 - dump logs: disabled;
 - cached model: disabled unless `--cached-model` is supplied;
 - rebuild: enabled unless `--skip-rebuild` is supplied.
 
 Invalid values must fail before runtime preparation begins.
 
-`[runtime].max_tokens` must be greater than zero. Zero and invalid values are
-configuration errors detected before runtime preparation.
-
 For provider `process`, no node image is required.
 
 For provider `docker`, an image reference is required. It may be local or remote.

crates/mvp-system/src/lib.rs

@@ -5,8 +5,6 @@ pub mod actors;
 pub mod arena_manager;
 pub mod bootstrap_datastream;
 pub mod config;
-#[cfg(feature = "local-e2e")]
-pub mod dashboard_view;
 pub mod device_bridge;
 pub mod distribution_stack;
 pub mod docker_cluster_provisioning;
@@ -19,6 +17,7 @@ pub mod gpu_worker_egress_producer;
 pub mod gpu_worker_ingress_parser;
 pub mod gpu_worker_process_adapter;
 pub mod membership_pool_readiness;
+pub mod mvp_chat;
 pub mod node_boot_lifecycle;
 pub mod node_image;
 pub mod node_provisioning;

crates/mvp-system/src/mvp_chat.rs

@@ -0,0 +1,317 @@
+use std::io::{self, BufRead, Write};
+use std::path::PathBuf;
+use std::sync::Arc;
+
+use datastream::{DatastreamEndpoint, Lifetime, StreamDescriptor, StreamId, StreamOrigin};
+use swactor::Error;
+use tokio::sync::Notify;
+type Result<T> = std::result::Result<T, swactor::Error>;
+
+#[derive(Clone)]
+enum ChatSignals {}
+
+const MVP_CHAT_DATASTREAM_NODE: &str = "mvp-chat";
+const MVP_CHAT_DATASTREAM_LABEL: &str = "mvp chat";
+
+struct MvpChatDatastream {
+    endpoint: Arc<DatastreamEndpoint>,
+    wake: Arc<Notify>,
+}
+
+impl MvpChatDatastream {
+    fn new(run_id: u64) -> Self {
+        let stream = StreamId::new(MVP_CHAT_DATASTREAM_NODE, Lifetime(run_id));
+        let endpoint = DatastreamEndpoint::with_descriptor(
+            StreamDescriptor {
+                stream,
+                label: Some(MVP_CHAT_DATASTREAM_LABEL.to_owned()),
+                origin: StreamOrigin::Orchestrator,
+            },
+            4096,
+            1024,
+        );
+
+        Self {
+            endpoint: Arc::new(endpoint),
+            wake: Arc::new(Notify::new()),
+        }
+    }
+
+    fn spawn_handler(&self, handle: &tokio::runtime::Handle) -> tokio::task::JoinHandle<()> {
+        let endpoint = Arc::clone(&self.endpoint);
+        let wake = Arc::clone(&self.wake);
+
+        handle.spawn(async move {
+            loop {
+                wake.notified().await;
+
+                while endpoint.tick().drained != 0 {}
+            }
+        })
+    }
+}
+
+#[derive(Debug, PartialEq, Eq)]
+enum PromptStep {
+    Response(String),
+    Ignore,
+    Exit,
+}
+
+fn read_prompt_step<R>(input: &mut R) -> PromptStep
+where
+    R: BufRead,
+{
+    let mut line = String::new();
+
+    match input.read_line(&mut line) {
+        Ok(0) => return PromptStep::Exit,
+        Ok(_) => {}
+        Err(_) => return PromptStep::Exit,
+    }
+
+    let prompt = line.trim_end().to_owned();
+
+    if prompt.trim().is_empty() {
+        return PromptStep::Ignore;
+    }
+
+    PromptStep::Response(prompt_response(&prompt))
+}
+
+fn prompt_response(prompt: &str) -> String {
+    format!("Hello, {prompt}!")
+}
+
+fn run_prompt_loop() -> Result<()> {
+    let stdin = io::stdin();
+    let mut input = stdin.lock();
+
+    let stdout = io::stdout();
+    let mut output = stdout.lock();
+
+    run_prompt_loop_with_io(&mut input, &mut output)
+}
+
+fn run_prompt_loop_with_io<R, W>(input: &mut R, output: &mut W) -> Result<()>
+where
+    R: BufRead,
+    W: Write,
+{
+    loop {
+        write!(output, "prompt:> ")
+            .map_err(|error| Error::from(format!("write prompt marker: {error}")))?;
+        output
+            .flush()
+            .map_err(|error| Error::from(format!("flush prompt marker: {error}")))?;
+
+        match read_prompt_step(input) {
+            PromptStep::Response(response) => {
+                writeln!(output, "{response}")
+                    .map_err(|error| Error::from(format!("write prompt response: {error}")))?;
+            }
+            PromptStep::Ignore => continue,
+            PromptStep::Exit => return Ok(()),
+        }
+    }
+}
+
+enum ChatRuntimeEvent {
+    PromptExited(Result<()>),
+    PromptPanicked,
+    CtrlC(std::io::Result<()>),
+}
+
+struct PromptLoop {
+    join: Option<std::thread::JoinHandle<()>>,
+}
+
+impl PromptLoop {
+    fn spawn(events: tokio::sync::mpsc::UnboundedSender<ChatRuntimeEvent>) -> Result<Self> {
+        let join = std::thread::Builder::new()
+            .name("mvp-chat-prompt".to_owned())
+            .spawn(move || {
+                let event = match std::panic::catch_unwind(run_prompt_loop) {
+                    Ok(result) => ChatRuntimeEvent::PromptExited(result),
+                    Err(_) => ChatRuntimeEvent::PromptPanicked,
+                };
+
+                let _ = events.send(event);
+            })
+            .map_err(|error| Error::from(format!("spawn prompt loop: {error}")))?;
+
+        Ok(Self { join: Some(join) })
+    }
+
+    fn join_finished(&mut self) -> Result<()> {
+        let Some(join) = self.join.take() else {
+            return Ok(());
+        };
+
+        join.join()
+            .map_err(|_| Error::from("prompt loop thread panicked".to_owned()))
+    }
+
+    fn detach(mut self) {
+        let _ = self.join.take();
+    }
+}
+
+fn spawn_ctrl_c_reporter(
+    handle: &tokio::runtime::Handle,
+    events: tokio::sync::mpsc::UnboundedSender<ChatRuntimeEvent>,
+) {
+    handle.spawn(async move {
+        let result = tokio::signal::ctrl_c().await;
+        let _ = events.send(ChatRuntimeEvent::CtrlC(result));
+    });
+}
+
+fn join_dashboard_http(result: std::result::Result<(), tokio::task::JoinError>) -> Result<()> {
+    result.map_err(|error| Error::from(format!("dashboard HTTP task failed: {error}")))
+}
+
+fn join_datastream_handler(result: std::result::Result<(), tokio::task::JoinError>) -> Result<()> {
+    result.map_err(|error| Error::from(format!("datastream handler task failed: {error}")))
+}
+
+async fn supervise_chat_runtime(
+    dashboard: &dashboard::DashboardHandle,
+    mut dashboard_http: tokio::task::JoinHandle<()>,
+    mut datastream_handler: tokio::task::JoinHandle<()>,
+    prompt_loop: &mut PromptLoop,
+    events: &mut tokio::sync::mpsc::UnboundedReceiver<ChatRuntimeEvent>,
+) -> Result<()> {
+    tokio::select! {
+        result = &mut dashboard_http => {
+            join_dashboard_http(result)?;
+            Err("dashboard HTTP server exited before shutdown"
+                .to_owned()
+                .into())
+        }
+        result = &mut datastream_handler => {
+            join_datastream_handler(result)?;
+            Err("datastream handler exited before shutdown"
+                .to_owned()
+                .into())
+        }
+        event = events.recv() => {
+            let event = event.ok_or_else(|| Error::from("runtime event channel closed".to_owned()))?;
+            let run_result = match event {
+                ChatRuntimeEvent::PromptExited(prompt_result) => {
+                    match prompt_loop.join_finished() {
+                        Ok(()) => prompt_result,
+                        Err(error) => Err(error),
+                    }
+                }
+                ChatRuntimeEvent::PromptPanicked => {
+                    match prompt_loop.join_finished() {
+                        Ok(()) => Err("prompt loop panicked".to_owned().into()),
+                        Err(error) => Err(error),
+                    }
+                }
+                ChatRuntimeEvent::CtrlC(result) => {
+                    result
+                        .map_err(|error| Error::from(format!("ctrl-c handler failed: {error}")))
+                        .map(|_| ())
+                }
+            };
+
+            dashboard.shutdown();
+            join_dashboard_http(dashboard_http.await)?;
+
+            run_result
+        }
+    }
+}
+
+pub fn run_from_args<I>(args: I) -> Result<()>
+where
+    I: IntoIterator<Item = String>,
+{
+    let mut config_path: Option<PathBuf> = None;
+    let mut provider_selector: Option<&'static str> = None;
+
+    let mut args = args.into_iter();
+    while let Some(arg) = args.next() {
+        match arg.as_str() {
+            "--process" | "--docker" | "--vastai" => {
+                let selected = match arg.as_str() {
+                    "--process" => "process",
+                    "--docker" => "docker",
+                    "--vastai" => "vastai",
+                    _ => unreachable!(),
+                };
+                if provider_selector.replace(selected).is_some() {
+                    return Err("conflicting provider selectors; use exactly one of --process, --docker, or --vastai".to_owned().into());
+                }
+            }
+            "--config" => {
+                let value = args
+                    .next()
+                    .ok_or_else(|| "--config requires a path".to_owned())?;
+                config_path = Some(PathBuf::from(value));
+            }
+            "--yes" | "-y" | "--dump-logs" | "--cached-model" | "--skip-rebuild" => {}
+            "--pipeline-stages" => {
+                let value = args
+                    .next()
+                    .ok_or_else(|| "--pipeline-stages requires a value".to_owned())?;
+                let stages = value
+                    .parse::<u32>()
+                    .map_err(|error| format!("parse --pipeline-stages: {error}"))?;
+                if stages == 0 {
+                    return Err("--pipeline-stages must be greater than 0".into());
+                }
+            }
+            value if value.starts_with("--dump-logs=") => {
+                if value["--dump-logs=".len()..].is_empty() {
+                    return Err("--dump-logs= requires a path".into());
+                }
+            }
+            value if value.starts_with("--cached-model=") => {
+                if value["--cached-model=".len()..].is_empty() {
+                    return Err("--cached-model= requires a path".into());
+                }
+            }
+            value => return Err(format!("unknown mvp-chat argument: {value}").into()),
+        }
+    }
+
+    let loaded_config = crate::config::TomlConfigOverlay::load(config_path.as_deref())?;
+    let run_id = loaded_config.overlay.runtime.run_id.unwrap_or(0);
+    let rt = tokio::runtime::Builder::new_multi_thread()
+        .enable_all()
+        .build()
+        .map_err(|e| Error::from(e.to_string()))?;
+
+    let chat_datastream = MvpChatDatastream::new(run_id);
+    let datastream_handler = chat_datastream.spawn_handler(rt.handle());
+
+    let _swactor = swactor::runtime::Runtime::new(swactor::runtime::RuntimeConfig {
+        num_threads: 1,
+        ..Default::default()
+    });
+    let _chat_inbox = _swactor.new_inbox::<ChatSignals>()?;
+
+    let dashboard = dashboard::DashboardHandle::new(dashboard::DashboardConfig::default());
+    let dashboard_http = dashboard.spawn_http(rt.handle());
+    let (events_tx, mut events_rx) = tokio::sync::mpsc::unbounded_channel();
+
+    spawn_ctrl_c_reporter(rt.handle(), events_tx.clone());
+    let mut prompt_loop = PromptLoop::spawn(events_tx)?;
+
+    let result = rt.block_on(supervise_chat_runtime(
+        &dashboard,
+        dashboard_http,
+        datastream_handler,
+        &mut prompt_loop,
+        &mut events_rx,
+    ));
+
+    if result.is_err() {
+        prompt_loop.detach();
+    }
+
+    result
+}

crates/mvp-system/tests/mvp_chat_mock.rs

@@ -0,0 +1,3 @@
+fn main() {
+    mvp_system::mvp_chat::run_from_args(std::env::args().skip(1)).expect("failed");
+}