feat(server): broker agent for inter-actor coordination

server/crates/arbiter-server/src/actors/client/auth/mod.rs

@@ -6,7 +6,7 @@ use ed25519_dalek::VerifyingKey;
 use tracing::error;
 
 use crate::actors::client::{
-    ConnectionProps,
+    ClientConnection,
     auth::state::{AuthContext, AuthStateMachine},
     session::ClientSession,
 };
@@ -54,7 +54,7 @@ fn parse_auth_event(payload: ClientRequestPayload) -> Result<AuthEvents, Error>
     }
 }
 
-pub async fn authenticate(props: &mut ConnectionProps) -> Result<VerifyingKey, Error> {
+pub async fn authenticate(props: &mut ClientConnection) -> Result<VerifyingKey, Error> {
     let mut state = AuthStateMachine::new(AuthContext::new(props));
 
     loop {
@@ -93,7 +93,7 @@ pub async fn authenticate(props: &mut ConnectionProps) -> Result<VerifyingKey, E
 }
 
 pub async fn authenticate_and_create(
-    mut props: ConnectionProps,
+    mut props: ClientConnection,
 ) -> Result<ClientSession, Error> {
     let key = authenticate(&mut props).await?;
     let session = ClientSession::new(props, key);

server/crates/arbiter-server/src/actors/client/auth/state.rs

@@ -8,7 +8,7 @@ use ed25519_dalek::VerifyingKey;
 use tracing::error;
 
 use super::Error;
-use crate::{actors::client::ConnectionProps, db::schema};
+use crate::{actors::client::ClientConnection, db::schema};
 
 pub struct ChallengeRequest {
     pub pubkey: VerifyingKey,
@@ -68,11 +68,11 @@ async fn create_nonce(db: &crate::db::DatabasePool, pubkey_bytes: &[u8]) -> Resu
 }
 
 pub struct AuthContext<'a> {
-    pub(super) conn: &'a mut ConnectionProps,
+    pub(super) conn: &'a mut ClientConnection,
 }
 
 impl<'a> AuthContext<'a> {
-    pub fn new(conn: &'a mut ConnectionProps) -> Self {
+    pub fn new(conn: &'a mut ClientConnection) -> Self {
         Self { conn }
     }
 }

server/crates/arbiter-server/src/actors/client/mod.rs

@@ -5,7 +5,10 @@ use arbiter_proto::{
 use kameo::actor::Spawn;
 use tracing::{error, info};
 
-use crate::{actors::client::session::ClientSession, db};
+use crate::{
+    actors::{GlobalActors, client::session::ClientSession},
+    db,
+};
 
 #[derive(Debug, Clone, PartialEq, Eq, thiserror::Error)]
 pub enum ClientError {
@@ -15,27 +18,34 @@ pub enum ClientError {
     UnexpectedRequestPayload,
     #[error("State machine error")]
     StateTransitionFailed,
+    #[error("Connection registration failed")]
+    ConnectionRegistrationFailed,
     #[error(transparent)]
     Auth(#[from] auth::Error),
 }
 
 pub type Transport = Box<dyn Bi<ClientRequest, Result<ClientResponse, ClientError>> + Send>;
 
-pub struct ConnectionProps {
+pub struct ClientConnection {
     pub(crate) db: db::DatabasePool,
     pub(crate) transport: Transport,
+    pub(crate) actors: GlobalActors,
 }
 
-impl ConnectionProps {
-    pub fn new(db: db::DatabasePool, transport: Transport) -> Self {
-        Self { db, transport }
+impl ClientConnection {
+    pub fn new(db: db::DatabasePool, transport: Transport, actors: GlobalActors) -> Self {
+        Self {
+            db,
+            transport,
+            actors,
+        }
     }
 }
 
 pub mod auth;
 pub mod session;
 
-pub async fn connect_client(props: ConnectionProps) {
+pub async fn connect_client(props: ClientConnection) {
     match auth::authenticate_and_create(props).await {
         Ok(session) => {
             ClientSession::spawn(session);

server/crates/arbiter-server/src/actors/client/session.rs

@@ -4,15 +4,17 @@ use kameo::Actor;
 use tokio::select;
 use tracing::{error, info};
 
-use crate::actors::client::{ClientError, ConnectionProps};
+use crate::{actors::{
+    GlobalActors, client::{ClientError, ClientConnection}, router::RegisterClient
+}, db};
 
 pub struct ClientSession {
-    props: ConnectionProps,
+    props: ClientConnection,
     key: VerifyingKey,
 }
 
 impl ClientSession {
-    pub(crate) fn new(props: ConnectionProps, key: VerifyingKey) -> Self {
+    pub(crate) fn new(props: ClientConnection, key: VerifyingKey) -> Self {
         Self { props, key }
     }
 
@@ -33,12 +35,18 @@ type Output = Result<ClientResponse, ClientError>;
 impl Actor for ClientSession {
     type Args = Self;
 
-    type Error = ();
+    type Error = ClientError;
 
     async fn on_start(
         args: Self::Args,
-        _: kameo::prelude::ActorRef<Self>,
+        this: kameo::prelude::ActorRef<Self>,
     ) -> Result<Self, Self::Error> {
+        args.props
+            .actors
+            .router
+            .ask(RegisterClient { actor: this })
+            .await
+            .map_err(|_| ClientError::ConnectionRegistrationFailed)?;
         Ok(args)
     }
 
@@ -80,10 +88,10 @@ impl Actor for ClientSession {
 }
 
 impl ClientSession {
-    pub fn new_test(db: crate::db::DatabasePool) -> Self {
+    pub fn new_test(db: db::DatabasePool, actors: GlobalActors) -> Self {
         use arbiter_proto::transport::DummyTransport;
         let transport: super::Transport = Box::new(DummyTransport::new());
-        let props = ConnectionProps::new(db, transport);
+        let props = ClientConnection::new(db, transport, actors);
         let key = VerifyingKey::from_bytes(&[0u8; 32]).unwrap();
         Self { props, key }
     }

server/crates/arbiter-server/src/actors/mod.rs

@@ -3,14 +3,15 @@ use miette::Diagnostic;
 use thiserror::Error;
 
 use crate::{
-    actors::{bootstrap::Bootstrapper, keyholder::KeyHolder},
+    actors::{bootstrap::Bootstrapper, keyholder::KeyHolder, router::MessageRouter},
     db,
 };
 
 pub mod bootstrap;
-pub mod client;
+pub mod router;
 pub mod keyholder;
 pub mod user_agent;
+pub mod client;
 
 #[derive(Error, Debug, Diagnostic)]
 pub enum SpawnError {
@@ -28,6 +29,7 @@ pub enum SpawnError {
 pub struct GlobalActors {
     pub key_holder: ActorRef<KeyHolder>,
     pub bootstrapper: ActorRef<Bootstrapper>,
+    pub router: ActorRef<MessageRouter>,
 }
 
 impl GlobalActors {
@@ -35,6 +37,7 @@ impl GlobalActors {
         Ok(Self {
             bootstrapper: Bootstrapper::spawn(Bootstrapper::new(&db).await?),
             key_holder: KeyHolder::spawn(KeyHolder::new(db.clone()).await?),
+            router: MessageRouter::spawn(MessageRouter::default()),
         })
     }
 }

server/crates/arbiter-server/src/actors/router/mod.rs

@@ -0,0 +1,79 @@
+use std::{
+    collections::{HashMap},
+    ops::ControlFlow,
+};
+
+use kameo::{
+    Actor,
+    actor::{ActorId, ActorRef},
+    messages,
+    prelude::{ActorStopReason, Context, WeakActorRef},
+};
+use tracing::info;
+
+use crate::actors::{client::session::ClientSession, user_agent::session::UserAgentSession};
+
+#[derive(Default)]
+pub struct MessageRouter {
+    pub user_agents: HashMap<ActorId, ActorRef<UserAgentSession>>,
+    pub clients: HashMap<ActorId, ActorRef<ClientSession>>,
+}
+
+impl Actor for MessageRouter {
+    type Args = Self;
+
+    type Error = ();
+
+    async fn on_start(args: Self::Args, _: ActorRef<Self>) -> Result<Self, Self::Error> {
+        Ok(args)
+    }
+
+    async fn on_link_died(
+        &mut self,
+        _: WeakActorRef<Self>,
+        id: ActorId,
+        _: ActorStopReason,
+    ) -> Result<ControlFlow<ActorStopReason>, Self::Error> {
+        if self.user_agents.remove(&id).is_some() {
+            info!(
+                ?id,
+                actor = "MessageRouter",
+                event = "useragent.disconnected"
+            );
+        } else if self.clients.remove(&id).is_some() {
+            info!(?id, actor = "MessageRouter", event = "client.disconnected");
+        } else {
+            info!(
+                ?id,
+                actor = "MessageRouter",
+                event = "unknown.actor.disconnected"
+            );
+        }
+        Ok(ControlFlow::Continue(()))
+    }
+}
+
+#[messages]
+impl MessageRouter {
+    #[message(ctx)]
+    pub async fn register_user_agent(
+        &mut self,
+        actor: ActorRef<UserAgentSession>,
+        ctx: &mut Context<Self, ()>,
+    ) {
+        info!(id = %actor.id(), actor = "MessageRouter", event = "useragent.connected");
+        ctx.actor_ref().link(&actor).await;
+        self.user_agents.insert(actor.id(), actor);
+    }
+
+    #[message(ctx)]
+    pub async fn register_client(
+        &mut self,
+        actor: ActorRef<ClientSession>,
+        ctx: &mut Context<Self, ()>,
+    ) {
+        info!(id = %actor.id(), actor = "MessageRouter", event = "client.connected");
+        ctx.actor_ref().link(&actor).await;
+        self.clients.insert(actor.id(), actor);
+    }
+}

server/crates/arbiter-server/src/actors/user_agent/auth.rs

@@ -6,7 +6,7 @@ use ed25519_dalek::VerifyingKey;
 use tracing::error;
 
 use crate::actors::user_agent::{
-    ConnectionProps,
+    UserAgentConnection,
     auth::state::{AuthContext, AuthStateMachine}, session::UserAgentSession,
 };
 
@@ -71,7 +71,7 @@ fn parse_auth_event(payload: UserAgentRequestPayload) -> Result<AuthEvents, Erro
     }
 }
 
-pub async fn authenticate(props: &mut ConnectionProps) -> Result<VerifyingKey, Error> {
+pub async fn authenticate(props: &mut UserAgentConnection) -> Result<VerifyingKey, Error> {
     let mut state = AuthStateMachine::new(AuthContext::new(props));
 
     loop {
@@ -111,7 +111,7 @@ pub async fn authenticate(props: &mut ConnectionProps) -> Result<VerifyingKey, E
 }
 
 
-pub async fn authenticate_and_create(mut props: ConnectionProps) -> Result<UserAgentSession, Error> {
+pub async fn authenticate_and_create(mut props: UserAgentConnection) -> Result<UserAgentSession, Error> {
     let key = authenticate(&mut props).await?;
     let session = UserAgentSession::new(props, key.clone());
     Ok(session)

server/crates/arbiter-server/src/actors/user_agent/auth/state.rs

@@ -9,7 +9,7 @@ use tracing::error;
 
 use super::Error;
 use crate::{
-    actors::{bootstrap::ConsumeToken, user_agent::ConnectionProps},
+    actors::{bootstrap::ConsumeToken, user_agent::UserAgentConnection},
     db::schema,
 };
 
@@ -98,11 +98,11 @@ async fn register_key(db: &crate::db::DatabasePool, pubkey_bytes: &[u8]) -> Resu
 }
 
 pub struct AuthContext<'a> {
-    pub(super) conn: &'a mut ConnectionProps,
+    pub(super) conn: &'a mut UserAgentConnection,
 }
 
 impl<'a> AuthContext<'a> {
-    pub fn new(conn: &'a mut ConnectionProps) -> Self {
+    pub fn new(conn: &'a mut UserAgentConnection) -> Self {
         Self { conn }
     }
 }

server/crates/arbiter-server/src/actors/user_agent/mod.rs

@@ -2,10 +2,13 @@ use arbiter_proto::{
     proto::user_agent::{UserAgentRequest, UserAgentResponse},
     transport::Bi,
 };
-use kameo::actor::Spawn;
+use kameo::actor::Spawn as _;
 use tracing::{error, info};
 
-use crate::{actors::{GlobalActors, user_agent::session::UserAgentSession}, db};
+use crate::{
+    actors::{GlobalActors, user_agent::session::UserAgentSession},
+    db::{self},
+};
 
 #[derive(Debug, thiserror::Error, PartialEq)]
 pub enum UserAgentError {
@@ -23,18 +26,20 @@ pub enum UserAgentError {
     KeyHolderActorUnreachable,
     #[error(transparent)]
     Auth(#[from] auth::Error),
+    #[error("Failed registering connection")]
+    ConnectionRegistrationFailed,
 }
 
 pub type Transport =
     Box<dyn Bi<UserAgentRequest, Result<UserAgentResponse, UserAgentError>> + Send>;
 
-pub struct ConnectionProps {
+pub struct UserAgentConnection {
     db: db::DatabasePool,
     actors: GlobalActors,
     transport: Transport,
 }
 
-impl ConnectionProps {
+impl UserAgentConnection {
     pub fn new(db: db::DatabasePool, actors: GlobalActors, transport: Transport) -> Self {
         Self {
             db,
@@ -44,17 +49,17 @@ impl ConnectionProps {
     }
 }
 
-pub mod session;
 pub mod auth;
+pub mod session;
 
-pub async fn connect_user_agent(mut props: ConnectionProps) {
+pub async fn connect_user_agent(props: UserAgentConnection) {
     match auth::authenticate_and_create(props).await {
         Ok(session) => {
             UserAgentSession::spawn(session);
             info!("User authenticated, session started");
-        },
+        }
         Err(err) => {
             error!(?err, "Authentication failed, closing connection");
-        },
+        }
     }
 }

server/crates/arbiter-server/src/actors/user_agent/session.rs

@@ -15,20 +15,21 @@ use x25519_dalek::{EphemeralSecret, PublicKey};
 
 use crate::actors::{
     keyholder::{self, TryUnseal},
-    user_agent::{ConnectionProps, UserAgentError},
+    router::RegisterUserAgent,
+    user_agent::{UserAgentConnection, UserAgentError},
 };
 
 mod state;
 use state::{DummyContext, UnsealContext, UserAgentEvents, UserAgentStateMachine, UserAgentStates};
 
 pub struct UserAgentSession {
-    props: ConnectionProps,
+    props: UserAgentConnection,
     key: VerifyingKey,
     state: UserAgentStateMachine<DummyContext>,
 }
 
 impl UserAgentSession {
-    pub(crate) fn new(props: ConnectionProps, key: VerifyingKey) -> Self {
+    pub(crate) fn new(props: UserAgentConnection, key: VerifyingKey) -> Self {
         Self {
             props,
             key,
@@ -180,12 +181,23 @@ impl UserAgentSession {
 impl Actor for UserAgentSession {
     type Args = Self;
 
-    type Error = ();
+    type Error = UserAgentError;
 
     async fn on_start(
         args: Self::Args,
-        _: kameo::prelude::ActorRef<Self>,
+        this: kameo::prelude::ActorRef<Self>,
     ) -> Result<Self, Self::Error> {
+        args.props
+            .actors
+            .router
+            .ask(RegisterUserAgent {
+                actor: this.clone(),
+            })
+            .await
+            .map_err(|err| {
+                error!(?err, "Failed to register user agent connection with router");
+                UserAgentError::ConnectionRegistrationFailed
+            })?;
         Ok(args)
     }
 
@@ -230,7 +242,7 @@ impl UserAgentSession {
     pub fn new_test(db: crate::db::DatabasePool, actors: crate::actors::GlobalActors) -> Self {
         use arbiter_proto::transport::DummyTransport;
         let transport: super::Transport = Box::new(DummyTransport::new());
-        let props = ConnectionProps::new(db, actors, transport);
+        let props = UserAgentConnection::new(db, actors, transport);
         let key = VerifyingKey::from_bytes(&[0u8; 32]).unwrap();
         Self {
             props,

server/crates/arbiter-server/src/lib.rs

@@ -15,8 +15,8 @@ use tracing::info;
 
 use crate::{
     actors::{
-        client::{self, ClientError, ConnectionProps as ClientConnectionProps, connect_client},
-        user_agent::{self, ConnectionProps, UserAgentError, connect_user_agent},
+        client::{self, ClientError, ClientConnection as ClientConnectionProps, connect_client},
+        user_agent::{self, UserAgentConnection, UserAgentError, connect_user_agent},
     },
     context::ServerContext,
 };
@@ -62,6 +62,9 @@ fn client_error_status(value: ClientError) -> Status {
         }
         ClientError::StateTransitionFailed => Status::internal("State machine error"),
         ClientError::Auth(ref err) => client_auth_error_status(err),
+        ClientError::ConnectionRegistrationFailed => {
+            Status::internal("Connection registration failed")
+        }
     }
 }
 
@@ -98,6 +101,9 @@ fn user_agent_error_status(value: UserAgentError) -> Status {
         UserAgentError::StateTransitionFailed => Status::internal("State machine error"),
         UserAgentError::KeyHolderActorUnreachable => Status::internal("Vault is not available"),
         UserAgentError::Auth(ref err) => auth_error_status(err),
+        UserAgentError::ConnectionRegistrationFailed => {
+            Status::internal("Failed registering connection")
+        }
     }
 }
 
@@ -152,7 +158,11 @@ impl arbiter_proto::proto::arbiter_service_server::ArbiterService for Server {
             IdentityRecvConverter::<ClientRequest>::new(),
             ClientGrpcSender,
         );
-        let props = ClientConnectionProps::new(self.context.db.clone(), Box::new(transport));
+        let props = ClientConnectionProps::new(
+            self.context.db.clone(),
+            Box::new(transport),
+            self.context.actors.clone(),
+        );
         tokio::spawn(connect_client(props));
 
         info!(event = "connection established", "grpc.client");
@@ -174,7 +184,7 @@ impl arbiter_proto::proto::arbiter_service_server::ArbiterService for Server {
             IdentityRecvConverter::<UserAgentRequest>::new(),
             UserAgentGrpcSender,
         );
-        let props = ConnectionProps::new(
+        let props = UserAgentConnection::new(
             self.context.db.clone(),
             self.context.actors.clone(),
             Box::new(transport),

server/crates/arbiter-server/tests/client/auth.rs

@@ -1,11 +1,12 @@
-use arbiter_proto::transport::Bi;
 use arbiter_proto::proto::client::{
     AuthChallengeRequest, AuthChallengeSolution, ClientRequest,
     client_request::Payload as ClientRequestPayload,
     client_response::Payload as ClientResponsePayload,
 };
+use arbiter_proto::transport::Bi;
+use arbiter_server::actors::GlobalActors;
 use arbiter_server::{
-    actors::client::{ConnectionProps, connect_client},
+    actors::client::{ClientConnection, connect_client},
     db::{self, schema},
 };
 use diesel::{ExpressionMethods as _, insert_into};
@@ -20,7 +21,8 @@ pub async fn test_unregistered_pubkey_rejected() {
     let db = db::create_test_pool().await;
 
     let (server_transport, mut test_transport) = ChannelTransport::new();
-    let props = ConnectionProps::new(db.clone(), Box::new(server_transport));
+    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
+    let props = ClientConnection::new(db.clone(), Box::new(server_transport), actors);
     let task = tokio::spawn(connect_client(props));
 
     let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
@@ -59,7 +61,9 @@ pub async fn test_challenge_auth() {
     }
 
     let (server_transport, mut test_transport) = ChannelTransport::new();
-    let props = ConnectionProps::new(db.clone(), Box::new(server_transport));
+    let actors = GlobalActors::spawn(db.clone()).await.unwrap();
+
+    let props = ClientConnection::new(db.clone(), Box::new(server_transport), actors);
     let task = tokio::spawn(connect_client(props));
 
     // Send challenge request

server/crates/arbiter-server/tests/user_agent/auth.rs

@@ -8,7 +8,7 @@ use arbiter_server::{
     actors::{
         GlobalActors,
         bootstrap::GetToken,
-        user_agent::{ConnectionProps, connect_user_agent},
+        user_agent::{UserAgentConnection, connect_user_agent},
     },
     db::{self, schema},
 };
@@ -26,7 +26,7 @@ pub async fn test_bootstrap_token_auth() {
     let token = actors.bootstrapper.ask(GetToken).await.unwrap().unwrap();
 
     let (server_transport, mut test_transport) = ChannelTransport::new();
-    let props = ConnectionProps::new(db.clone(), actors, Box::new(server_transport));
+    let props = UserAgentConnection::new(db.clone(), actors, Box::new(server_transport));
     let task = tokio::spawn(connect_user_agent(props));
 
     let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
@@ -62,7 +62,7 @@ pub async fn test_bootstrap_invalid_token_auth() {
     let actors = GlobalActors::spawn(db.clone()).await.unwrap();
 
     let (server_transport, mut test_transport) = ChannelTransport::new();
-    let props = ConnectionProps::new(db.clone(), actors, Box::new(server_transport));
+    let props = UserAgentConnection::new(db.clone(), actors, Box::new(server_transport));
     let task = tokio::spawn(connect_user_agent(props));
 
     let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
@@ -112,7 +112,7 @@ pub async fn test_challenge_auth() {
     }
 
     let (server_transport, mut test_transport) = ChannelTransport::new();
-    let props = ConnectionProps::new(db.clone(), actors, Box::new(server_transport));
+    let props = UserAgentConnection::new(db.clone(), actors, Box::new(server_transport));
     let task = tokio::spawn(connect_user_agent(props));
 
     // Send challenge request