107 lines
3.0 KiB
Rust
107 lines
3.0 KiB
Rust
use std::{collections::BTreeMap, pin::Pin};
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use async_trait::async_trait;
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use crunch_traits::{errors::TransportError, EventInfo, Transport};
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use futures::Stream;
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use tokio::sync::broadcast::Sender;
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use tokio_stream::{wrappers::BroadcastStream, StreamExt};
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#[derive(Clone)]
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struct TransportEnvelope {
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info: EventInfo,
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content: Vec<u8>,
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}
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pub struct InMemoryTransport {
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events: tokio::sync::RwLock<BTreeMap<String, Sender<TransportEnvelope>>>,
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}
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impl InMemoryTransport {
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pub fn new() -> Self {
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Self {
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events: tokio::sync::RwLock::default(),
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}
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}
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async fn register_channel(&self, event_info: &EventInfo) {
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let transport_key = event_info.transport_name();
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// Possibly create a trait register handle instead, as this requires a write and then read. It may not matter for in memory though
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let mut events = self.events.write().await;
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if events.get(&transport_key).is_none() {
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let (sender, mut receiver) = tokio::sync::broadcast::channel(100);
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events.insert(transport_key.clone(), sender);
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tokio::spawn(async move {
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while let Ok(item) = receiver.recv().await {
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tracing::trace!("default receiver: {}", item.info.transport_name());
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}
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});
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}
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}
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}
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impl Default for InMemoryTransport {
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fn default() -> Self {
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Self::new()
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}
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}
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#[async_trait]
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impl Transport for InMemoryTransport {
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type Stream = Pin<Box<dyn Stream<Item = Vec<u8>> + Send>>;
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async fn publish(
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&self,
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event_info: &EventInfo,
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content: Vec<u8>,
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) -> Result<(), TransportError> {
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self.register_channel(event_info).await;
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let transport_key = event_info.transport_name();
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let events = self.events.read().await;
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let sender = events
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.get(&transport_key)
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.expect("transport to be available, as we just created it");
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sender
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.send(TransportEnvelope {
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info: event_info.to_owned(),
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content,
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})
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.map_err(|e| anyhow::anyhow!(e.to_string()))
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.map_err(TransportError::Err)?;
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Ok(())
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}
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async fn subscriber(
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&self,
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event_info: &EventInfo,
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) -> Result<Option<Self::Stream>, TransportError> {
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self.register_channel(event_info).await;
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let events = self.events.read().await;
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match events.get(&event_info.transport_name()) {
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Some(rx) => Ok(Some(Box::pin(
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BroadcastStream::new(rx.subscribe()).filter_map(|m| match m {
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Ok(m) => Some(m.content),
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Err(_) => None,
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}),
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))),
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None => Ok(None),
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}
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}
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}
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trait EventInfoExt {
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fn transport_name(&self) -> String;
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}
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impl EventInfoExt for EventInfo {
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fn transport_name(&self) -> String {
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format!(
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"crunch.{}.{}.{}",
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self.domain, self.entity_type, self.event_name
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)
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}
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}
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