feat: add subscriptions

Signed-off-by: kjuulh <contact@kjuulh.io>

Cargo.lock

@@ -297,6 +297,8 @@ dependencies = [
  "anyhow",
  "async-trait",
  "crunch-envelope",
+ "crunch-in-memory",
+ "crunch-traits",
  "futures",
  "thiserror",
  "tokio",
@@ -323,6 +325,29 @@ dependencies = [
  "thiserror",
 ]
 
+[[package]]
+name = "crunch-in-memory"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "async-trait",
+ "crunch-traits",
+ "thiserror",
+ "tokio",
+ "tracing",
+]
+
+[[package]]
+name = "crunch-traits"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "async-trait",
+ "thiserror",
+ "tokio",
+ "uuid",
+]
+
 [[package]]
 name = "either"
 version = "1.9.0"

Cargo.toml

@@ -4,7 +4,9 @@ resolver = "2"
 
 [workspace.dependencies]
 crunch = { path = "crates/crunch" }
+crunch-traits = { path = "crates/crunch-traits" }
 crunch-envelope = { path = "crates/crunch-envelope" }
+crunch-in-memory = { path = "crates/crunch-in-memory" }
 
 anyhow = { version = "1.0.71" }
 tokio = { version = "1", features = ["full"] }

crates/crunch-envelope/build.rs

@@ -8,5 +8,11 @@ fn main() {
         .run()
         .unwrap();
 
-    prost_build::compile_protos(&["src/envelope.proto"], &["src/"]).unwrap();
+    std::fs::create_dir_all("src/generated").unwrap();
+    let mut config = prost_build::Config::default();
+    config.out_dir("src/generated/");
+
+    config
+        .compile_protos(&["src/envelope.proto"], &["src/"])
+        .unwrap();
 }

crates/crunch-envelope/src/generated/crunch.envelope.rs

@@ -0,0 +1,18 @@
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct Envelope {
+    #[prost(message, optional, tag="1")]
+    pub metadata: ::std::option::Option<Metadata>,
+    #[prost(bytes, tag="2")]
+    pub content: std::vec::Vec<u8>,
+}
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct Metadata {
+    #[prost(string, tag="1")]
+    pub domain: std::string::String,
+    #[prost(string, tag="2")]
+    pub entity: std::string::String,
+    #[prost(uint64, tag="3")]
+    pub timestamp: u64,
+    #[prost(uint64, tag="4")]
+    pub sequence: u64,
+}

crates/crunch-envelope/src/generated/mod.rs

@@ -0,0 +1,3 @@
+pub mod crunch {
+    include!("crunch.envelope.rs");
+}

crates/crunch-envelope/src/lib.rs

@@ -3,6 +3,7 @@ mod envelope_capnp;
 #[cfg(feature = "json")]
 mod json_envelope;
 
+mod generated;
 #[cfg(feature = "proto")]
 mod proto_envelope;
 

crates/crunch-envelope/src/proto_envelope.rs

@@ -1,14 +1,11 @@
-pub mod envelope {
-    include!(concat!(env!("OUT_DIR"), "/crunch.envelope.rs"));
-}
-
 use prost::Message;
 
+use crate::generated::crunch::*;
 use crate::EnvelopeError;
 
 pub fn wrap<'a>(domain: &'a str, entity: &'a str, content: &'a [u8]) -> Vec<u8> {
-    let out = envelope::Envelope {
-        metadata: Some(envelope::Metadata {
+    let out = Envelope {
+        metadata: Some(Metadata {
             domain: domain.to_string(),
             entity: entity.to_string(),
             timestamp: 0,
@@ -20,8 +17,8 @@ pub fn wrap<'a>(domain: &'a str, entity: &'a str, content: &'a [u8]) -> Vec<u8>
     out.encode_to_vec()
 }
 
-pub fn unwrap<'a>(message: &'a [u8]) -> Result<(Vec<u8>, envelope::Metadata), EnvelopeError> {
-    let out = envelope::Envelope::decode(message).map_err(EnvelopeError::ProtoError)?;
+pub fn unwrap<'a>(message: &'a [u8]) -> Result<(Vec<u8>, Metadata), EnvelopeError> {
+    let out = Envelope::decode(message).map_err(EnvelopeError::ProtoError)?;
 
     Ok((
         out.content,

crates/crunch-in-memory/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "crunch-in-memory"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+crunch-traits.workspace = true
+
+anyhow.workspace = true
+tracing.workspace = true
+tokio.workspace = true
+thiserror.workspace = true
+async-trait.workspace = true

crates/crunch-in-memory/src/lib.rs

@@ -0,0 +1,81 @@
+use std::collections::BTreeMap;
+
+use async_trait::async_trait;
+use crunch_traits::{errors::TransportError, EventInfo, Transport};
+use tokio::sync::broadcast::{Receiver, Sender};
+
+#[derive(Clone)]
+struct TransportEnvelope {
+    info: EventInfo,
+    content: Vec<u8>,
+}
+
+pub struct InMemoryTransport {
+    events: tokio::sync::RwLock<BTreeMap<String, Sender<TransportEnvelope>>>,
+}
+
+impl InMemoryTransport {
+    pub fn new() -> Self {
+        Self {
+            events: tokio::sync::RwLock::default(),
+        }
+    }
+}
+
+impl Default for InMemoryTransport {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[async_trait]
+impl Transport for InMemoryTransport {
+    async fn publish(
+        &self,
+        event_info: &EventInfo,
+        content: Vec<u8>,
+    ) -> Result<(), TransportError> {
+        let transport_key = event_info.transport_name();
+
+        // Possibly create a register handle instead, as this requires a write and then read. It may not matter for in memory though
+        {
+            let mut events = self.events.write().await;
+            if let None = events.get(&transport_key) {
+                let (sender, mut receiver) = tokio::sync::broadcast::channel(100);
+                events.insert(transport_key.clone(), sender);
+                tokio::spawn(async move {
+                    while let Ok(item) = receiver.recv().await {
+                        tracing::info!("default receiver: {}", item.info.transport_name());
+                    }
+                });
+            }
+        }
+
+        let events = self.events.read().await;
+        let sender = events
+            .get(&transport_key)
+            .expect("transport to be available, as we just created it");
+        sender
+            .send(TransportEnvelope {
+                info: event_info.clone(),
+                content,
+            })
+            .map_err(|e| anyhow::anyhow!(e.to_string()))
+            .map_err(TransportError::Err)?;
+
+        Ok(())
+    }
+}
+
+trait EventInfoExt {
+    fn transport_name(&self) -> String;
+}
+
+impl EventInfoExt for EventInfo {
+    fn transport_name(&self) -> String {
+        format!(
+            "crunch.{}.{}.{}",
+            self.domain, self.entity_type, self.event_name
+        )
+    }
+}

crates/crunch-traits/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "crunch-traits"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+anyhow.workspace = true
+tokio.workspace = true
+thiserror.workspace = true
+async-trait.workspace = true
+uuid.workspace = true

crates/crunch-traits/src/errors.rs

@@ -0,0 +1,43 @@
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum SerializeError {
+    #[error("failed to serialize {0}")]
+    FailedToSerialize(anyhow::Error),
+}
+
+#[derive(Error, Debug)]
+pub enum DeserializeError {
+    #[error("failed to serialize {0}")]
+    FailedToDeserialize(anyhow::Error),
+}
+
+#[derive(Error, Debug)]
+pub enum PublishError {
+    #[error("failed to serialize {0}")]
+    SerializeError(#[source] SerializeError),
+
+    #[error("failed to commit to database {0}")]
+    DbError(#[source] anyhow::Error),
+
+    #[error("transaction failed {0}")]
+    DbTxError(#[source] anyhow::Error),
+
+    #[error("failed to connect to database {0}")]
+    ConnectionError(#[source] anyhow::Error),
+}
+
+#[derive(Error, Debug)]
+pub enum TransportError {
+    #[error("to publish to transport {0}")]
+    Err(anyhow::Error),
+}
+
+#[derive(Error, Debug)]
+pub enum PersistenceError {
+    #[error("failed to get item {0}")]
+    GetErr(anyhow::Error),
+
+    #[error("failed to publish item {0}")]
+    UpdatePublished(anyhow::Error),
+}

crates/crunch-traits/src/lib.rs

@@ -1,13 +1,14 @@
-use std::fmt::Display;
+use std::{fmt::Display, sync::Arc};
 
 use async_trait::async_trait;
-
-use crate::{DeserializeError, SerializeError};
+use errors::{DeserializeError, PersistenceError, SerializeError, TransportError};
 
 #[async_trait]
 pub trait Persistence {
     async fn insert(&self, event_info: &EventInfo, content: Vec<u8>) -> anyhow::Result<()>;
     async fn next(&self) -> Option<String>;
+    async fn get(&self, event_id: &str) -> Result<Option<(EventInfo, Vec<u8>)>, PersistenceError>;
+    async fn update_published(&self, event_id: &str) -> Result<(), PersistenceError>;
 }
 
 pub trait Serializer {
@@ -24,6 +25,7 @@ pub trait Deserializer {
 pub struct EventInfo {
     pub domain: &'static str,
     pub entity_type: &'static str,
+    pub event_name: &'static str,
 }
 
 impl Display for EventInfo {
@@ -38,3 +40,7 @@ impl Display for EventInfo {
 pub trait Event: Serializer + Deserializer {
     fn event_info(&self) -> EventInfo;
 }
+
+pub mod errors;
+mod transport;
+pub use transport::*;

crates/crunch-traits/src/transport.rs

@@ -0,0 +1,12 @@
+use std::sync::Arc;
+
+use async_trait::async_trait;
+
+use crate::{errors::TransportError, EventInfo};
+
+#[async_trait]
+pub trait Transport {
+    async fn publish(&self, event_info: &EventInfo, content: Vec<u8>)
+        -> Result<(), TransportError>;
+}
+pub type DynTransport = Arc<dyn Transport + Send + Sync + 'static>;

crates/crunch/Cargo.toml

@@ -5,6 +5,8 @@ edition = "2021"
 
 [dependencies]
 crunch-envelope.workspace = true
+crunch-in-memory = { workspace = true, optional = true }
+crunch-traits.workspace = true
 
 anyhow.workspace = true
 tracing.workspace = true
@@ -17,3 +19,8 @@ futures.workspace = true
 
 [dev-dependencies]
 tracing-subscriber.workspace = true
+
+[features]
+default = ["in-memory", "traits"]
+traits = []
+in-memory = ["dep:crunch-in-memory"]

crates/crunch/examples/basic.rs

@@ -1,17 +1,17 @@
-use crunch::{Deserializer, Event, EventInfo, OutboxHandler, Persistence, Publisher, Serializer};
+use crunch::errors::*;
 
 struct SomeEvent {
     name: String,
 }
 
-impl Serializer for SomeEvent {
-    fn serialize(&self) -> Result<Vec<u8>, crunch::SerializeError> {
+impl crunch::traits::Serializer for SomeEvent {
+    fn serialize(&self) -> Result<Vec<u8>, SerializeError> {
         Ok(b"field=name".to_vec())
     }
 }
 
-impl Deserializer for SomeEvent {
-    fn deserialize(_raw: Vec<u8>) -> Result<Self, crunch::DeserializeError>
+impl crunch::traits::Deserializer for SomeEvent {
+    fn deserialize(_raw: Vec<u8>) -> Result<Self, DeserializeError>
     where
         Self: Sized,
     {
@@ -21,11 +21,12 @@ impl Deserializer for SomeEvent {
     }
 }
 
-impl Event for SomeEvent {
-    fn event_info(&self) -> EventInfo {
-        EventInfo {
+impl crunch::traits::Event for SomeEvent {
+    fn event_info(&self) -> crunch::traits::EventInfo {
+        crunch::traits::EventInfo {
             domain: "some-domain",
             entity_type: "some-entity",
+            event_name: "some-event",
         }
     }
 }
@@ -34,9 +35,10 @@ impl Event for SomeEvent {
 async fn main() -> anyhow::Result<()> {
     tracing_subscriber::fmt::init();
 
-    let in_memory = Persistence::in_memory();
-    OutboxHandler::new(in_memory.clone()).spawn();
-    let publisher = Publisher::new(in_memory);
+    let in_memory = crunch::Persistence::in_memory();
+    let transport = crunch::Transport::in_memory();
+    crunch::OutboxHandler::new(in_memory.clone(), transport.clone()).spawn();
+    let publisher = crunch::Publisher::new(in_memory);
 
     publisher
         .publish(SomeEvent {

crates/crunch/src/errors.rs

@@ -1,28 +0,0 @@
-use thiserror::Error;
-
-#[derive(Error, Debug)]
-pub enum SerializeError {
-    #[error("failed to serialize")]
-    FailedToSerialize(anyhow::Error),
-}
-
-#[derive(Error, Debug)]
-pub enum DeserializeError {
-    #[error("failed to serialize")]
-    FailedToDeserialize(anyhow::Error),
-}
-
-#[derive(Error, Debug)]
-pub enum PublishError {
-    #[error("failed to serialize")]
-    SerializeError(#[source] SerializeError),
-
-    #[error("failed to commit to database")]
-    DbError(#[source] anyhow::Error),
-
-    #[error("transaction failed")]
-    DbTxError(#[source] anyhow::Error),
-
-    #[error("failed to connect to database")]
-    ConnectionError(#[source] anyhow::Error),
-}

crates/crunch/src/impls.rs

@@ -1,10 +1,13 @@
-use std::{collections::VecDeque, ops::Deref, sync::Arc};
+use std::{
+    collections::{BTreeMap, VecDeque},
+    ops::Deref,
+    sync::Arc,
+};
 
 use async_trait::async_trait;
+use crunch_traits::{errors::PersistenceError, EventInfo};
 use tokio::sync::RwLock;
 
-use crate::{traits, EventInfo};
-
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
 enum MsgState {
     Pending,
@@ -21,20 +24,22 @@ struct Msg {
 
 pub struct InMemoryPersistence {
     outbox: Arc<RwLock<VecDeque<Msg>>>,
+    store: Arc<RwLock<BTreeMap<String, Msg>>>,
 }
 
 #[async_trait]
-impl traits::Persistence for InMemoryPersistence {
+impl crunch_traits::Persistence for InMemoryPersistence {
     async fn insert(&self, event_info: &EventInfo, content: Vec<u8>) -> anyhow::Result<()> {
         let msg = crunch_envelope::proto::wrap(event_info.domain, event_info.entity_type, &content);
-
-        let mut outbox = self.outbox.write().await;
-        outbox.push_back(Msg {
+        let msg = Msg {
             id: uuid::Uuid::new_v4().to_string(),
             info: event_info.clone(),
             msg,
             state: MsgState::Pending,
-        });
+        };
+        let mut outbox = self.outbox.write().await;
+        outbox.push_back(msg.clone());
+        self.store.write().await.insert(msg.id.clone(), msg);
 
         tracing::info!(
             event_info = event_info.to_string(),
@@ -49,25 +54,52 @@ impl traits::Persistence for InMemoryPersistence {
         let mut outbox = self.outbox.write().await;
         outbox.pop_front().map(|i| i.id)
     }
+
+    async fn get(&self, event_id: &str) -> Result<Option<(EventInfo, Vec<u8>)>, PersistenceError> {
+        Ok(self
+            .store
+            .read()
+            .await
+            .get(event_id)
+            .filter(|m| m.state == MsgState::Pending)
+            .map(|m| m.clone())
+            .map(|m| (m.info, m.msg)))
+    }
+
+    async fn update_published(&self, event_id: &str) -> Result<(), PersistenceError> {
+        match self.store.write().await.get_mut(event_id) {
+            Some(msg) => msg.state = MsgState::Published,
+            None => {
+                return Err(PersistenceError::UpdatePublished(anyhow::anyhow!(
+                    "event was not found on id: {}",
+                    event_id
+                )))
+            }
+        }
+
+        Ok(())
+    }
 }
 
 #[derive(Clone)]
 pub struct Persistence {
-    inner: Arc<dyn traits::Persistence + Send + Sync + 'static>,
+    inner: Arc<dyn crunch_traits::Persistence + Send + Sync + 'static>,
 }
 
 impl Persistence {
+    #[cfg(feature = "in-memory")]
     pub fn in_memory() -> Self {
         Self {
-            inner: Arc::new(InMemoryPersistence {
-                outbox: Arc::default(),
+            inner: std::sync::Arc::new(InMemoryPersistence {
+                outbox: std::sync::Arc::default(),
+                store: std::sync::Arc::default(),
             }),
         }
     }
 }
 
 impl Deref for Persistence {
-    type Target = Arc<dyn traits::Persistence + Send + Sync + 'static>;
+    type Target = Arc<dyn crunch_traits::Persistence + Send + Sync + 'static>;
 
     fn deref(&self) -> &Self::Target {
         &self.inner

crates/crunch/src/lib.rs

@@ -1,70 +1,18 @@
-mod errors;
 mod impls;
-mod traits;
+mod outbox;
+mod publisher;
+mod transport;
+
+#[cfg(feature = "traits")]
+pub mod traits {
+    pub use crunch_traits::{Deserializer, Event, EventInfo, Persistence, Serializer, Transport};
+}
+
+pub mod errors {
+    pub use crunch_traits::errors::*;
+}
 
-pub use errors::*;
 pub use impls::Persistence;
 pub use outbox::OutboxHandler;
-pub use traits::{Deserializer, Event, EventInfo, Serializer};
-
-mod outbox {
-    use crate::Persistence;
-
-    pub struct OutboxHandler {
-        persistence: Persistence,
-    }
-
-    impl OutboxHandler {
-        pub fn new(persistence: Persistence) -> Self {
-            Self { persistence }
-        }
-
-        pub fn spawn(&mut self) {
-            let p = self.persistence.clone();
-            tokio::spawn(async move {
-                loop {
-                    match p.next().await {
-                        Some(item) => {
-                            tracing::info!("got item: {}", item);
-                        }
-                        None => {
-                            tokio::time::sleep(std::time::Duration::from_millis(50)).await;
-                        }
-                    }
-                }
-            });
-        }
-    }
-}
-
-pub struct Publisher {
-    persistence: Persistence,
-}
-
-#[allow(dead_code)]
-impl Publisher {
-    pub fn new(persistence: Persistence) -> Self {
-        Self { persistence }
-    }
-
-    pub async fn publish<T>(&self, event: T) -> Result<(), PublishError>
-    where
-        T: Event,
-    {
-        let content = event.serialize().map_err(PublishError::SerializeError)?;
-
-        self.persistence
-            .insert(&event.event_info(), content)
-            .await
-            .map_err(PublishError::DbError)?;
-
-        Ok(())
-    }
-    pub async fn publish_tx<T>(&self, event: T) -> Result<(), PublishError>
-    where
-        T: Event,
-    {
-        // TODO: add transaction support later
-        self.publish(event).await
-    }
-}
+pub use publisher::Publisher;
+pub use transport::Transport;

crates/crunch/src/outbox.rs

@@ -0,0 +1,52 @@
+use crate::{Persistence, Transport};
+
+pub struct OutboxHandler {
+    persistence: Persistence,
+    transport: Transport,
+}
+
+impl OutboxHandler {
+    pub fn new(persistence: Persistence, transport: Transport) -> Self {
+        Self {
+            persistence,
+            transport,
+        }
+    }
+
+    pub fn spawn(&mut self) {
+        let p = self.persistence.clone();
+        let t = self.transport.clone();
+        tokio::spawn(async move {
+            loop {
+                match handle_messages(&p, &t).await {
+                    Err(e) => {
+                        tracing::error!("failed to handle message: {}", e);
+                        tokio::time::sleep(std::time::Duration::from_millis(50)).await;
+                    }
+                    Ok(None) => {
+                        tokio::time::sleep(std::time::Duration::from_millis(50)).await;
+                    }
+                    _ => (),
+                }
+            }
+        });
+    }
+}
+
+async fn handle_messages(p: &Persistence, t: &Transport) -> anyhow::Result<Option<()>> {
+    match p.next().await {
+        Some(item) => match p.get(&item).await? {
+            Some((info, content)) => {
+                t.publish(&info, content).await?;
+                p.update_published(&item).await?;
+                tracing::info!("published item: {}", item);
+            }
+            None => {
+                tracing::info!("did not find any events for item: {}", item);
+            }
+        },
+        None => return Ok(None),
+    }
+
+    Ok(Some(()))
+}

crates/crunch/src/publisher.rs

@@ -0,0 +1,35 @@
+use crunch_traits::{errors::PublishError, Event};
+
+use crate::Persistence;
+
+pub struct Publisher {
+    persistence: Persistence,
+}
+
+#[allow(dead_code)]
+impl Publisher {
+    pub fn new(persistence: Persistence) -> Self {
+        Self { persistence }
+    }
+
+    pub async fn publish<T>(&self, event: T) -> Result<(), PublishError>
+    where
+        T: Event,
+    {
+        let content = event.serialize().map_err(PublishError::SerializeError)?;
+
+        self.persistence
+            .insert(&event.event_info(), content)
+            .await
+            .map_err(PublishError::DbError)?;
+
+        Ok(())
+    }
+    pub async fn publish_tx<T>(&self, event: T) -> Result<(), PublishError>
+    where
+        T: Event,
+    {
+        // TODO: add transaction support later
+        self.publish(event).await
+    }
+}

crates/crunch/src/transport.rs

@@ -0,0 +1,31 @@
+use crunch_traits::DynTransport;
+
+#[derive(Clone)]
+pub struct Transport(DynTransport);
+
+impl Transport {
+    pub fn new(transport: DynTransport) -> Self {
+        Self(transport)
+    }
+
+    #[cfg(feature = "in-memory")]
+    pub fn in_memory() -> Self {
+        Self(std::sync::Arc::new(
+            crunch_in_memory::InMemoryTransport::default(),
+        ))
+    }
+}
+
+impl From<DynTransport> for Transport {
+    fn from(value: DynTransport) -> Self {
+        Self::new(value)
+    }
+}
+
+impl std::ops::Deref for Transport {
+    type Target = DynTransport;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}