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use crate::actor::Actor;
use crate::actor::ActorHandle;
use crate::message::ActorError;
use crate::message::Message;
use crate::message::MessageEnvelope;
use crate::state_actor;
use async_trait::async_trait;
use std::collections::HashMap;
use tokio::sync::mpsc;
// TODO:
// use rust std Path to update and persist petgraph graph Edges and
// lookup/upsert actor for each input record msg send
/// actor graph director creates a graph and instantiates all the actors that
/// it is forwarding commands to. director also accepts metadata to create
/// and store graph edges to support arbitrary paths
pub struct Director {
pub receiver: mpsc::Receiver<MessageEnvelope>,
pub store_actor: Option<ActorHandle>,
pub output: Option<ActorHandle>,
pub actors: HashMap<String, ActorHandle>,
namespace: String,
}
#[async_trait]
impl Actor for Director {
async fn stop(&self) {}
// TODO: I've spent a lot of time trying to refactor this into 3 functions
// but I'm stuck on them all dragging mut self along... Learning....
async fn handle_envelope(&mut self, envelope: MessageEnvelope) {
log::trace!(
"director namespace {} handling_envelope {envelope:?}",
self.namespace
);
let MessageEnvelope {
message,
respond_to,
..
} = envelope;
match &message {
Message::Update { path, .. } | Message::Query { path } => {
// resurrect and forward if this is either Update or Query
let mut actor_is_in_init = false;
let actor = self.actors.entry(path.clone()).or_insert_with(|| {
actor_is_in_init = true;
state_actor::new(path.clone(), 8, None)
});
let loaded: bool = match &self.store_actor {
Some(store_actor) if actor_is_in_init => {
match actor.integrate(String::from(path), store_actor).await {
Ok(_) => {
// actor has read its journal
true
}
Err(e) => {
log::error!("can not load actor: {e}");
false
}
}
}
_ => true,
};
if loaded {
let journaled: bool = match message.clone() {
Message::Update { path: _, .. } => {
if let Some(store_actor) = &self.store_actor {
// jrnl the new msg
let jrnl_msg = store_actor.ask(message.clone()).await;
match jrnl_msg {
Ok(r) => match r {
Message::EndOfStream {} => {
// successfully jrnled the msg, it is now safe to
// send it to the actor to process
true
}
m => {
log::warn!("Unexpected store message: {m:?}");
false
}
},
Err(e) => {
log::warn!("error {e}");
false
}
}
} else {
// jrnl is disabled, jsut process the message
true
}
}
Message::Query { path: _, .. } => true,
m => {
log::warn!("unexpected message: {:?}", m);
false
}
};
if journaled {
//send message to the actor and support ask results
let r = actor.ask(message.clone()).await;
if let Some(respond_to) = respond_to {
respond_to.send(r.clone()).expect("can not reply to ask");
}
// forward response if output is configured
if let Some(o) = &self.output {
if let Ok(message) = r {
let senv = MessageEnvelope {
message,
respond_to: None,
..Default::default()
};
o.send(senv).await.expect("receiver not ready");
}
}
} else {
log::error!("cannot journal input to actor {path} - see logs");
if let Some(respond_to) = respond_to {
respond_to
.send(Err(ActorError {
reason: String::from(format!(
"cannot journal input to actor {path}"
)),
}))
.expect("can not reply to ask");
}
}
} else {
log::error!("cannot load actor {path} - see logs");
if let Some(respond_to) = respond_to {
respond_to
.send(Err(ActorError {
reason: String::from(format!("cannot load actor {path}")),
}))
.expect("can not reply to ask");
}
}
}
Message::EndOfStream {} => {
log::debug!("complete");
if let Some(a) = &self.output {
let senv = MessageEnvelope {
message,
respond_to,
..Default::default()
};
a.send(senv).await.expect("cannot send");
} else if let Some(respond_to) = respond_to {
// else we're the end of the line so reply if this is an ask
respond_to.send(Ok(message)).expect("can not reply to ask");
}
}
m => log::warn!("unexpected message: {:?}", m),
}
}
}
/// actor private constructor
impl Director {
fn new(
namespace: String,
receiver: mpsc::Receiver<MessageEnvelope>,
output: Option<ActorHandle>,
store_actor: Option<ActorHandle>,
) -> Self {
Director {
namespace,
actors: HashMap::new(),
receiver,
output,
store_actor,
}
}
}
/// actor handle public constructor
pub fn new(
namespace: String,
bufsz: usize,
output: Option<ActorHandle>,
store_actor: Option<ActorHandle>,
) -> ActorHandle {
async fn start(mut actor: Director) {
while let Some(envelope) = actor.receiver.recv().await {
actor.handle_envelope(envelope).await;
}
}
let (sender, receiver) = mpsc::channel(bufsz);
let actor = Director::new(namespace.clone(), receiver, output, store_actor);
let actor_handle = ActorHandle::new(sender);
tokio::spawn(start(actor));
log::debug!("{} started", namespace);
actor_handle
}