Files
thoughts/crates/adapters/nats/src/lib.rs

111 lines
3.4 KiB
Rust

use async_trait::async_trait;
use domain::{
errors::DomainError,
events::{DomainEvent, EventEnvelope},
ports::EventConsumer,
};
use event_payload::EventPayload;
use event_publisher::Transport;
use futures::stream::BoxStream;
// ── NatsTransport — raw NATS publish backend ────────────────────────────────
pub struct NatsTransport {
client: async_nats::Client,
}
impl NatsTransport {
pub fn new(client: async_nats::Client) -> Self { Self { client } }
}
#[async_trait]
impl Transport for NatsTransport {
async fn publish_bytes(&self, subject: &str, bytes: &[u8]) -> Result<(), DomainError> {
self.client
.publish(subject.to_string(), bytes.to_vec().into())
.await
.map_err(|e| DomainError::Internal(e.to_string()))
}
}
// ── NatsEventConsumer — subscribes and yields EventEnvelopes ────────────────
pub struct NatsEventConsumer {
client: async_nats::Client,
}
impl NatsEventConsumer {
pub fn new(client: async_nats::Client) -> Self { Self { client } }
}
impl EventConsumer for NatsEventConsumer {
fn consume(&self) -> BoxStream<'_, Result<EventEnvelope, DomainError>> {
let client = self.client.clone();
Box::pin(async_stream::try_stream! {
let mut sub = client
.subscribe(">")
.await
.map_err(|e| DomainError::Internal(e.to_string()))?;
use futures::StreamExt;
while let Some(msg) = sub.next().await {
let payload = match serde_json::from_slice::<EventPayload>(&msg.payload) {
Ok(p) => p,
Err(e) => {
tracing::warn!("failed to deserialize event payload: {e}");
continue;
}
};
let event = match DomainEvent::try_from(payload) {
Ok(e) => e,
Err(e) => {
tracing::warn!("failed to convert payload to domain event: {e}");
continue;
}
};
yield EventEnvelope {
event,
ack: Box::new(|| {}),
nack: Box::new(|| {}),
};
}
})
}
}
#[cfg(test)]
mod tests {
use super::*;
use domain::value_objects::{LikeId, ThoughtId, UserId};
#[test]
fn payload_from_domain_event_has_correct_subject() {
let event = DomainEvent::ThoughtCreated {
thought_id: ThoughtId::new(),
user_id: UserId::new(),
in_reply_to_id: None,
};
let payload = EventPayload::from(&event);
assert_eq!(payload.subject(), "thoughts.created");
}
#[test]
fn domain_event_roundtrip_via_payload() {
let uid = UserId::new();
let tid = ThoughtId::new();
let event = DomainEvent::LikeAdded {
like_id: LikeId::new(),
user_id: uid.clone(),
thought_id: tid.clone(),
};
let payload = EventPayload::from(&event);
let back = DomainEvent::try_from(payload).unwrap();
if let DomainEvent::LikeAdded { user_id, thought_id, .. } = back {
assert_eq!(user_id, uid);
assert_eq!(thought_id, tid);
} else {
panic!("wrong variant");
}
}
}