feat: add protocol request dispatcher

Add a transport-neutral runa-server dispatcher that validates protocol requests, routes supported operations through runa-image-api, and converts actor snapshots, behavior revisions, events, and failures into wire DTOs. Document that event retrieval drains the in-memory queue and that network transport and authentication remain future work.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

AGENTS.md

@@ -68,6 +68,7 @@ proposed capabilities as plans, not existing behavior.
 - `crates/runa-runtime/`: single-worker scheduling and in-memory transitions.
 - `crates/runa-image-api/`: trusted in-process services for operating on an image.
 - `crates/runa-protocol/`: versioned transport-neutral request, response, and event DTOs.
+- `crates/runa-server/`: transport-neutral dispatch from protocol requests to image API services.
 - `runa-std/actors/`: default Rune actor scripts loaded by the local CLI.
 - `docs/architecture.md`: architecture, roadmap, risks, and acceptance scenario.
 - `docs/decisions/`: architectural decisions.

CHANGELOG.md

@@ -35,6 +35,8 @@ All notable changes to this project will be documented in this file.
   operations, now used by the local CLI.
 - Versioned, transport-neutral `runa-protocol` request, response, and event
   DTOs with serde support and request validation.
+- Transport-neutral `runa-server` dispatcher routing protocol commands through
+  the image API with typed replies and error codes.
 - Execution-model decision and Phase 1 runtime documentation.
 - Lifecycle tests proving failed-message retry from committed state and
   stop/restart preservation of reserved-first FIFO order.

Cargo.lock

@@ -457,6 +457,16 @@ dependencies = [
  "rune",
 ]
 
+[[package]]
+name = "runa-server"
+version = "0.0.0"
+dependencies = [
+ "runa-actor",
+ "runa-code",
+ "runa-image-api",
+ "runa-protocol",
+]
+
 [[package]]
 name = "rune"
 version = "0.14.2"

Cargo.toml

@@ -9,4 +9,5 @@ members = [
     "crates/runa-protocol",
     "crates/runa-rune",
     "crates/runa-runtime",
+    "crates/runa-server",
 ]

README.md

@@ -19,7 +19,8 @@ implemented yet. The code library now supports an in-memory versioned behavior
 registry, and the CLI exposes publishing, history, rollback, safe-boundary
 installation, pause/resume, and cancellation through a trusted in-process image
 API. A versioned transport-neutral protocol contract is now defined, but no
-network server or authentication is implemented.
+network transport or authentication is implemented. A transport-neutral
+dispatcher routes protocol requests through the same image API.
 
 The prototype uses worker-local invocation stacks and cooperative instruction
 slices, and actor snapshots report basic active-execution progress. Native
@@ -108,7 +109,8 @@ test task runs `cargo test --workspace`.
 │   ├── runa-rune/        # Phase 0 Rune experiments
 │   ├── runa-runtime/     # Single-worker actor prototype
 │   ├── runa-image-api/   # Trusted in-process image operations
-│   └── runa-protocol/    # Versioned transport-neutral wire DTOs
+│   ├── runa-protocol/    # Versioned transport-neutral wire DTOs
+│   └── runa-server/      # Transport-neutral protocol dispatcher
 ├── docs/
 │   ├── architecture.md
 │   ├── protocol.md

crates/runa-server/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "runa-server"
+version = "0.0.0"
+edition = "2024"
+
+[dependencies]
+runa-actor = { path = "../runa-actor" }
+runa-code = { path = "../runa-code" }
+runa-image-api = { path = "../runa-image-api" }
+runa-protocol = { path = "../runa-protocol" }

crates/runa-server/src/lib.rs

@@ -0,0 +1,431 @@
+//! Transport-neutral dispatch from protocol requests to image API operations.
+
+use std::num::NonZeroUsize;
+
+use runa_actor::{ActorId, Event, Message, Status};
+use runa_image_api::ImageApi;
+use runa_protocol::{
+    ActorSnapshotDto, ActorStatusDto, BehaviorDto, BehaviorVersionDto, Command, ErrorCode,
+    EventDto, ExecutionSnapshotDto, MessageDto, PROTOCOL_VERSION, ProtocolError, Reply, Request,
+    Response,
+};
+
+pub struct Server {
+    image: ImageApi,
+}
+
+impl Default for Server {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl Server {
+    pub fn new() -> Self {
+        Self {
+            image: ImageApi::new(),
+        }
+    }
+
+    pub fn with_image_api(image: ImageApi) -> Self {
+        Self { image }
+    }
+
+    pub fn dispatch(&mut self, request: Request) -> Response {
+        let request_id = request.request_id.clone();
+        let result = request
+            .validate()
+            .and_then(|()| self.dispatch_command(request.command));
+
+        Response {
+            version: PROTOCOL_VERSION,
+            request_id,
+            result,
+        }
+    }
+
+    fn dispatch_command(&mut self, command: Command) -> Result<Reply, ProtocolError> {
+        match command {
+            Command::PublishBehavior {
+                name,
+                expected_revision,
+                source,
+            } => self
+                .image
+                .publish_behavior(&name, expected_revision, &source)
+                .map(behavior_dto)
+                .map(Reply::Behavior)
+                .map_err(api_error),
+            Command::RollbackBehavior {
+                name,
+                expected_revision,
+                target_revision,
+            } => self
+                .image
+                .rollback_behavior(&name, expected_revision, target_revision)
+                .map(behavior_dto)
+                .map(Reply::Behavior)
+                .map_err(api_error),
+            Command::GetBehavior { name } => self
+                .image
+                .behavior(&name)
+                .map(behavior_dto)
+                .map(Reply::Behavior)
+                .ok_or_else(|| ProtocolError::new(ErrorCode::NotFound, "unknown behavior")),
+            Command::GetBehaviors => Ok(Reply::Behaviors(
+                self.image
+                    .behaviors()
+                    .into_iter()
+                    .map(behavior_dto)
+                    .collect(),
+            )),
+            Command::GetBehaviorSource { name, revision } => self
+                .image
+                .behavior_source(&name, revision)
+                .map(|source| Reply::BehaviorSource {
+                    source: source.to_owned(),
+                })
+                .map_err(api_error),
+            Command::Spawn {
+                behavior_name,
+                state,
+                mailbox_capacity,
+            } => {
+                let capacity = NonZeroUsize::new(mailbox_capacity)
+                    .ok_or_else(|| invalid_request("mailbox_capacity must be positive"))?;
+                self.image
+                    .spawn(&behavior_name, state, capacity)
+                    .map(|actor_id| Reply::ActorSpawned {
+                        actor_id: actor_id.0,
+                    })
+                    .map_err(api_error)
+            }
+            Command::Send { actor_id, message } => self
+                .image
+                .send(ActorId(actor_id), message_from_dto(message))
+                .map(|()| Reply::Acknowledged)
+                .map_err(api_error),
+            Command::Tick {
+                ticks,
+                instruction_budget,
+            } => {
+                let budget = NonZeroUsize::new(instruction_budget)
+                    .ok_or_else(|| invalid_request("instruction_budget must be positive"))?;
+                self.image.tick(ticks, budget);
+                Ok(Reply::TickCompleted { ticks })
+            }
+            Command::InspectActor { actor_id } => self
+                .image
+                .inspect(ActorId(actor_id))
+                .map(|snapshot| actor_snapshot_dto(&snapshot))
+                .map(Reply::Actor)
+                .map_err(api_error),
+            Command::ListActors => Ok(Reply::Actors(
+                self.image.actors().iter().map(actor_snapshot_dto).collect(),
+            )),
+            Command::GetEvents => Ok(Reply::Events(
+                self.image.events().iter().map(event_dto).collect(),
+            )),
+            Command::StopActor { actor_id } => self
+                .image
+                .stop(ActorId(actor_id))
+                .map(|()| Reply::Acknowledged)
+                .map_err(api_error),
+            Command::RestartActor { actor_id } => self
+                .image
+                .restart(ActorId(actor_id))
+                .map(|()| Reply::Acknowledged)
+                .map_err(api_error),
+            Command::PauseActor { actor_id } => self
+                .image
+                .pause(ActorId(actor_id))
+                .map(|()| Reply::Acknowledged)
+                .map_err(api_error),
+            Command::ResumeActor { actor_id } => self
+                .image
+                .resume(ActorId(actor_id))
+                .map(|()| Reply::Acknowledged)
+                .map_err(api_error),
+            Command::CancelActor { actor_id } => self
+                .image
+                .cancel(ActorId(actor_id))
+                .map(|()| Reply::Acknowledged)
+                .map_err(api_error),
+            Command::InstallBehavior {
+                actor_id,
+                behavior_name,
+            } => self
+                .image
+                .install(ActorId(actor_id), &behavior_name)
+                .map(|implementation_id| Reply::BehaviorInstalled {
+                    implementation_id: implementation_id.to_string(),
+                })
+                .map_err(api_error),
+        }
+    }
+}
+
+fn behavior_dto(behavior: runa_code::BehaviorSnapshot) -> BehaviorDto {
+    BehaviorDto {
+        name: behavior.name,
+        revision: behavior.revision,
+        current_implementation_id: behavior.current.to_string(),
+        history: behavior
+            .history
+            .into_iter()
+            .map(|version| BehaviorVersionDto {
+                revision: version.revision,
+                implementation_id: version.implementation_id.to_string(),
+            })
+            .collect(),
+    }
+}
+
+fn actor_snapshot_dto(snapshot: &runa_actor::ActorSnapshot) -> ActorSnapshotDto {
+    ActorSnapshotDto {
+        actor_id: snapshot.id.0,
+        mailbox_id: snapshot.mailbox.0,
+        implementation_id: snapshot.implementation.to_string(),
+        incarnation: snapshot.incarnation,
+        state: snapshot.state,
+        status: match &snapshot.status {
+            Status::Idle => ActorStatusDto::Idle,
+            Status::Running => ActorStatusDto::Running,
+            Status::Awaiting => ActorStatusDto::Awaiting,
+            Status::Paused => ActorStatusDto::Paused,
+            Status::Stopped => ActorStatusDto::Stopped,
+            Status::Failed(message) => ActorStatusDto::Failed(message.clone()),
+        },
+        execution: snapshot.execution.map(|execution| ExecutionSnapshotDto {
+            vm_steps: execution.vm_steps,
+            instruction_pointer: execution.instruction_pointer,
+            call_depth: execution.call_depth,
+        }),
+        queued: snapshot.queued.iter().copied().map(message_dto).collect(),
+        reserved: snapshot.reserved.map(message_dto),
+    }
+}
+
+fn message_dto(message: Message) -> MessageDto {
+    MessageDto {
+        kind: message.kind,
+        value: message.value,
+    }
+}
+
+fn message_from_dto(message: MessageDto) -> Message {
+    Message {
+        kind: message.kind,
+        value: message.value,
+    }
+}
+
+fn event_dto(event: &Event) -> EventDto {
+    match event {
+        Event::Spawned(actor_id) => EventDto::Spawned {
+            actor_id: actor_id.0,
+        },
+        Event::Committed(actor_id) => EventDto::Committed {
+            actor_id: actor_id.0,
+        },
+        Event::Failed(actor_id, message) => EventDto::Failed {
+            actor_id: actor_id.0,
+            message: message.clone(),
+        },
+        Event::Stopped(actor_id) => EventDto::Stopped {
+            actor_id: actor_id.0,
+        },
+        Event::Restarted(actor_id) => EventDto::Restarted {
+            actor_id: actor_id.0,
+        },
+        Event::Paused(actor_id) => EventDto::Paused {
+            actor_id: actor_id.0,
+        },
+        Event::Resumed(actor_id) => EventDto::Resumed {
+            actor_id: actor_id.0,
+        },
+        Event::InvocationCancelled(actor_id) => EventDto::InvocationCancelled {
+            actor_id: actor_id.0,
+        },
+        Event::BehaviorInstalled(actor_id, implementation_id) => EventDto::BehaviorInstalled {
+            actor_id: actor_id.0,
+            implementation_id: implementation_id.to_string(),
+        },
+        Event::StateMigrated(actor_id, previous_state, current_state) => EventDto::StateMigrated {
+            actor_id: actor_id.0,
+            previous_state: *previous_state,
+            current_state: *current_state,
+        },
+    }
+}
+
+fn api_error(error: impl std::fmt::Display) -> ProtocolError {
+    let message = error.to_string();
+    let code = if message.starts_with("behavior revision conflict:") {
+        ErrorCode::Conflict
+    } else if matches!(
+        message.as_str(),
+        "unknown actor"
+            | "unknown behavior"
+            | "unknown behavior revision"
+            | "unknown target behavior revision"
+            | "unknown implementation"
+    ) {
+        ErrorCode::NotFound
+    } else if matches!(
+        message.as_str(),
+        "mailbox full" | "effect exceeds mailbox capacity"
+    ) {
+        ErrorCode::CapacityExceeded
+    } else if message == "invalid behavior name" {
+        ErrorCode::InvalidRequest
+    } else {
+        ErrorCode::RuntimeFailure
+    };
+    ProtocolError::new(code, message)
+}
+
+fn invalid_request(message: impl Into<String>) -> ProtocolError {
+    ProtocolError::new(ErrorCode::InvalidRequest, message)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use runa_protocol::{Command, PROTOCOL_VERSION};
+
+    fn request(command: Command) -> Request {
+        Request {
+            version: PROTOCOL_VERSION,
+            request_id: "test-request".to_owned(),
+            command,
+        }
+    }
+
+    fn publish(server: &mut Server) -> BehaviorDto {
+        let response = server.dispatch(request(Command::PublishBehavior {
+            name: "counter".to_owned(),
+            expected_revision: None,
+            source: "pub fn handle(state, kind, value) { (state + value, []) }".to_owned(),
+        }));
+        match response.result.unwrap() {
+            Reply::Behavior(behavior) => behavior,
+            other => panic!("unexpected reply: {other:?}"),
+        }
+    }
+
+    #[test]
+    fn dispatches_behavior_actor_and_event_operations() {
+        let mut server = Server::new();
+        let behavior = publish(&mut server);
+        assert_eq!(behavior.revision, 1);
+        assert_eq!(behavior.history.len(), 1);
+
+        let spawned = server.dispatch(request(Command::Spawn {
+            behavior_name: "counter".to_owned(),
+            state: 5,
+            mailbox_capacity: 2,
+        }));
+        let actor_id = match spawned.result.unwrap() {
+            Reply::ActorSpawned { actor_id } => actor_id,
+            other => panic!("unexpected reply: {other:?}"),
+        };
+        assert_eq!(actor_id, 1);
+
+        let sent = server.dispatch(request(Command::Send {
+            actor_id,
+            message: MessageDto { kind: 0, value: 7 },
+        }));
+        assert_eq!(sent.result, Ok(Reply::Acknowledged));
+        server.dispatch(request(Command::Tick {
+            ticks: 100,
+            instruction_budget: 10,
+        }));
+
+        let inspected = server.dispatch(request(Command::InspectActor { actor_id }));
+        match inspected.result.unwrap() {
+            Reply::Actor(snapshot) => assert_eq!(snapshot.state, 12),
+            other => panic!("unexpected reply: {other:?}"),
+        }
+
+        let events = server.dispatch(request(Command::GetEvents));
+        match events.result.unwrap() {
+            Reply::Events(events) => assert!(events.iter().any(
+                |event| matches!(event, EventDto::Committed { actor_id: id } if *id == actor_id)
+            )),
+            other => panic!("unexpected reply: {other:?}"),
+        }
+        assert_eq!(
+            server.dispatch(request(Command::GetEvents)).result,
+            Ok(Reply::Events(Vec::new()))
+        );
+    }
+
+    #[test]
+    fn dispatch_preserves_request_id_and_maps_validation_and_domain_errors() {
+        let mut server = Server::new();
+        let mut invalid = request(Command::GetEvents);
+        invalid.version += 1;
+        let response = server.dispatch(invalid);
+        assert_eq!(response.request_id, "test-request");
+        assert_eq!(
+            response.result.unwrap_err().code,
+            ErrorCode::UnsupportedVersion
+        );
+
+        let missing = server.dispatch(request(Command::InspectActor { actor_id: 42 }));
+        assert_eq!(missing.result.unwrap_err().code, ErrorCode::NotFound);
+
+        publish(&mut server);
+        let conflict = server.dispatch(request(Command::PublishBehavior {
+            name: "counter".to_owned(),
+            expected_revision: Some(99),
+            source: "pub fn handle(state, kind, value) { (state, []) }".to_owned(),
+        }));
+        assert_eq!(conflict.result.unwrap_err().code, ErrorCode::Conflict);
+    }
+
+    #[test]
+    fn dispatch_supports_behavior_history_source_and_safe_install() {
+        let mut server = Server::new();
+        let first = publish(&mut server);
+        let updated = server.dispatch(request(Command::PublishBehavior {
+            name: "counter".to_owned(),
+            expected_revision: Some(first.revision),
+            source: "pub fn handle(state, kind, value) { (state * value, []) }".to_owned(),
+        }));
+        assert!(matches!(updated.result, Ok(Reply::Behavior(_))));
+
+        let source = server.dispatch(request(Command::GetBehaviorSource {
+            name: "counter".to_owned(),
+            revision: 1,
+        }));
+        assert_eq!(
+            source.result,
+            Ok(Reply::BehaviorSource {
+                source: "pub fn handle(state, kind, value) { (state + value, []) }".to_owned()
+            })
+        );
+
+        let actor_id = match server
+            .dispatch(request(Command::Spawn {
+                behavior_name: "counter".to_owned(),
+                state: 3,
+                mailbox_capacity: 1,
+            }))
+            .result
+            .unwrap()
+        {
+            Reply::ActorSpawned { actor_id } => actor_id,
+            other => panic!("unexpected reply: {other:?}"),
+        };
+        let installed = server.dispatch(request(Command::InstallBehavior {
+            actor_id,
+            behavior_name: "counter".to_owned(),
+        }));
+        assert!(matches!(
+            installed.result,
+            Ok(Reply::BehaviorInstalled { .. })
+        ));
+    }
+}

docs/architecture.md

@@ -310,7 +310,7 @@ The diagram is conceptual; Cargo dependencies should be kept minimal. A dependen
 | `runa-runtime`   | Scheduling, actor execution coordination, state commits, crash recovery, binding actor semantics to Rune execution                                 | `runa-core`, `runa-actor`, `runa-code`, `runa-rune` |
 | `runa-image-api` | Trusted in-process application services for spawning, inspecting, sending, editing, and upgrading | `runa-core`, `runa-actor`, `runa-code`, `runa-runtime` |
 | `runa-protocol`  | Versioned transport-neutral request/response/event DTOs and validation                                                                             | `serde`                                |
-| `runa-server`    | WebSocket/JSON-RPC transport, sessions, authentication, subscriptions                                                                              | `runa-protocol`, `runa-image-api`      |
+| `runa-server`    | Protocol request dispatch and, in a later increment, transport, sessions, authentication, subscriptions                                            | `runa-protocol`, `runa-image-api`      |
 | `runa-graphics`  | Native window, rendering and input mechanisms; no actor policy                                                                                     | `runa-core` if necessary               |
 | `runa-world`     | Morphic-style graphical composition and in-world development UI                                                                                    | `runa-image-api`, `runa-graphics`      |
 | `runa`           | Startup, configuration, resource wiring, shutdown                                                                                                  | Top-level crates it instantiates       |
@@ -327,7 +327,10 @@ publication, history and rollback, actor lifecycle and messaging, snapshots,
 ticks, and event retrieval. The CLI uses these application services rather
 than reaching into the code store and runtime directly. `runa-protocol` now
 defines versioned, serializable request, response, and event DTOs without
-depending on a transport or the runtime implementation.
+depending on a transport or the runtime implementation. `runa-server` now
+dispatches those commands through the image API and maps service results into
+protocol replies and typed errors. It remains an in-process dispatcher; there
+is no network transport, session model, authentication, or authorization.
 
 **Important:** `runa-core` must not contain schedulers, mailbox implementations, persistence engines, Rune VM types, service traits used by only one crate, generic helper collections, or GUI abstractions. Prefer a type defined in its owning crate until two independent consumers demonstrably need a stable shared representation.
 
@@ -432,9 +435,9 @@ inspection remain future work.
 - CLI client that can spawn, inspect, send messages, and replace behaviors.
 
 The first Phase 5 increments are a trusted in-process application API used by
-the CLI and a transport-neutral versioned protocol contract. The protocol is a
-Rust DTO crate with serde serialization; a network server and authentication
-are not yet implemented.
+the CLI, a transport-neutral versioned protocol contract, and an in-process
+dispatcher from protocol commands to application services. A network server
+and authentication are not yet implemented.
 
 ### Phase 6 — Graphical world
 

docs/protocol.md

@@ -1,9 +1,9 @@
 # Runa Protocol
 
 `runa-protocol` defines versioned request, response, and event data contracts
-for clients and a future server. It is independent of transport and runtime
-implementation; the current crate does not dispatch requests, expose a network
-endpoint, or provide authentication.
+for clients and the `runa-server` dispatcher. It is independent of transport
+and runtime implementation; the server currently dispatches requests
+in-process, with no network endpoint or authentication.
 
 ## Version 1
 
@@ -38,9 +38,14 @@ portable wire values.
 Responses echo the request ID and carry either a typed reply or a protocol
 error. Events use a separate versioned envelope. Actor and behavior snapshots
 are wire DTOs, not serialized runtime objects; implementation identities are
-represented by their stable display strings. Runtime errors and validation
-errors must be mapped by a future server to the defined error codes without
-claiming a more specific category than it can establish.
+represented by their stable display strings. The server maps known service
+failures to the defined error codes and otherwise uses `runtime_failure`
+rather than claiming a more specific category.
+
+`get_events` drains and returns the events currently accumulated by this
+single-worker image. It is not a durable subscription or replayable event log.
+Any future network transport must also impose message and request-size limits
+before dispatch; the in-process protocol crate does not impose byte limits.
 
 The current validation checks the protocol version, request ID, positive
 actor/revision identifiers where required, non-empty behavior names, mailbox

docs/runtime.md

@@ -51,6 +51,8 @@ The default per-actor slice budget is 32 instructions.
   trusted in-process service boundary.
 - `runa-protocol` defines versioned transport-neutral request, response, and
   event DTOs; it does not dispatch requests or access runtime state.
+- `runa-server` dispatches those requests through `runa-image-api` and maps
+  results to protocol replies; it currently has no network transport.
 - `runa` provides the local CLI client for that boundary.
 
 The image API is process-local and intended for trusted callers. It has no