feat: add discovery

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

crates/churn/src/agent/agent_state.rs

@@ -1,5 +1,9 @@
 use std::{ops::Deref, sync::Arc};
 
+use crate::api::Discovery;
+
+use super::{config::AgentConfig, discovery_client::DiscoveryClient, grpc_client::GrpcClient};
+
 #[derive(Clone)]
 pub struct AgentState(Arc<State>);
 
@@ -23,10 +27,24 @@ impl Deref for AgentState {
     }
 }
 
-pub struct State {}
+pub struct State {
+    pub grpc: GrpcClient,
+    pub config: AgentConfig,
+    pub discovery: Discovery,
+}
 
 impl State {
     pub async fn new() -> anyhow::Result<Self> {
-        Ok(Self {})
+        let config = AgentConfig::new().await?;
+        let discovery = DiscoveryClient::new(&config.discovery);
+        let discovery = discovery.discover().await?;
+
+        let grpc = GrpcClient::new(&discovery.process_host);
+
+        Ok(Self {
+            grpc,
+            config,
+            discovery,
+        })
     }
 }

crates/churn/src/agent/config.rs

@@ -0,0 +1,80 @@
+use anyhow::Context;
+use serde::{Deserialize, Serialize};
+use uuid::Uuid;
+
+#[derive(Clone)]
+pub struct AgentConfig {
+    pub agent_id: String,
+    pub discovery: String,
+}
+
+impl AgentConfig {
+    pub async fn new() -> anyhow::Result<Self> {
+        let config = ConfigFile::load().await?;
+
+        Ok(Self {
+            agent_id: config.agent_id,
+            discovery: config.discovery,
+        })
+    }
+}
+
+#[derive(Serialize, Deserialize)]
+struct ConfigFile {
+    agent_id: String,
+    discovery: String,
+}
+
+impl ConfigFile {
+    pub async fn load() -> anyhow::Result<Self> {
+        let directory = dirs::data_dir()
+            .ok_or(anyhow::anyhow!("failed to get data dir"))?
+            .join("io.kjuulh.churn-agent")
+            .join("churn-agent.toml");
+
+        if !directory.exists() {
+            anyhow::bail!(
+                "No churn agent file was setup, run `churn agent setup` to setup the defaults"
+            )
+        }
+
+        let contents = tokio::fs::read_to_string(&directory).await?;
+
+        toml::from_str(&contents).context("failed to parse the contents of the churn agent config")
+    }
+
+    pub async fn write_default(discovery: impl Into<String>, force: bool) -> anyhow::Result<Self> {
+        let s = Self {
+            agent_id: Uuid::new_v4().to_string(),
+            discovery: discovery.into(),
+        };
+
+        let directory = dirs::data_dir()
+            .ok_or(anyhow::anyhow!("failed to get data dir"))?
+            .join("io.kjuulh.churn-agent")
+            .join("churn-agent.toml");
+
+        if let Some(parent) = directory.parent() {
+            tokio::fs::create_dir_all(&parent).await?;
+        }
+
+        if !force && directory.exists() {
+            anyhow::bail!("config file already exists, consider moving it to a backup before trying again: {}", directory.display());
+        }
+
+        let contents = toml::to_string_pretty(&s)
+            .context("failed to convert default implementation to string")?;
+
+        tokio::fs::write(directory, contents.as_bytes())
+            .await
+            .context("failed to write to agent file")?;
+
+        Ok(s)
+    }
+}
+
+pub async fn setup_config(discovery: impl Into<String>, force: bool) -> anyhow::Result<()> {
+    ConfigFile::write_default(discovery, force).await?;
+
+    Ok(())
+}

crates/churn/src/agent/discovery_client.rs

@@ -0,0 +1,21 @@
+use crate::api::Discovery;
+
+pub struct DiscoveryClient {
+    host: String,
+}
+
+impl DiscoveryClient {
+    pub fn new(discovery_host: impl Into<String>) -> Self {
+        Self {
+            host: discovery_host.into(),
+        }
+    }
+
+    pub async fn discover(&self) -> anyhow::Result<Discovery> {
+        tracing::info!(
+            "getting details from discovery endpoint: {}/discovery",
+            self.host.trim_end_matches('/')
+        );
+        crate::api::Discovery::get_from_host(&self.host).await
+    }
+}

crates/churn/src/agent/event_handler.rs

@@ -0,0 +1,53 @@
+use notmad::{Component, MadError};
+
+use super::{agent_state::AgentState, config::AgentConfig, grpc_client::GrpcClient};
+
+#[derive(Clone)]
+pub struct EventHandler {
+    config: AgentConfig,
+    grpc: GrpcClient,
+}
+
+impl EventHandler {
+    pub fn new(state: impl Into<AgentState>) -> Self {
+        let state: AgentState = state.into();
+
+        Self {
+            config: state.config.clone(),
+            grpc: state.grpc.clone(),
+        }
+    }
+}
+
+#[async_trait::async_trait]
+impl Component for EventHandler {
+    fn name(&self) -> Option<String> {
+        Some("event_handler".into())
+    }
+
+    async fn run(
+        &self,
+        cancellation_token: tokio_util::sync::CancellationToken,
+    ) -> Result<(), notmad::MadError> {
+        tokio::select! {
+            _ = cancellation_token.cancelled() => {},
+            res = self.grpc.listen_events("agents", None::<String>, self.clone()) => {
+                res.map_err(MadError::Inner)?;
+            },
+            res = self.grpc.listen_events("agents", Some(&self.config.agent_id), self.clone()) => {
+                res.map_err(MadError::Inner)?;
+            }
+        }
+
+        Ok(())
+    }
+}
+
+#[async_trait::async_trait]
+impl super::grpc_client::ListenEventsExecutor for EventHandler {
+    async fn execute(&self, event: crate::grpc::ListenEventsResponse) -> anyhow::Result<()> {
+        tracing::info!(value = event.value, "received event");
+
+        Ok(())
+    }
+}

crates/churn/src/agent/grpc_client.rs

@@ -0,0 +1,100 @@
+use tonic::transport::{Channel, ClientTlsConfig};
+
+use crate::grpc::{churn_client::ChurnClient, *};
+
+#[derive(Clone)]
+pub struct GrpcClient {
+    host: String,
+}
+
+impl GrpcClient {
+    pub fn new(host: impl Into<String>) -> Self {
+        Self { host: host.into() }
+    }
+
+    pub async fn get_key(
+        &self,
+        namespace: &str,
+        id: Option<impl Into<String>>,
+        key: &str,
+    ) -> anyhow::Result<Option<String>> {
+        let mut client = self.client().await?;
+
+        let resp = client
+            .get_key(GetKeyRequest {
+                key: key.into(),
+                namespace: namespace.into(),
+                id: id.map(|i| i.into()),
+            })
+            .await?;
+        let resp = resp.into_inner();
+
+        Ok(resp.value)
+    }
+
+    pub async fn set_key(
+        &self,
+        namespace: &str,
+        id: Option<impl Into<String>>,
+        key: &str,
+        value: &str,
+    ) -> anyhow::Result<()> {
+        let mut client = self.client().await?;
+
+        client
+            .set_key(SetKeyRequest {
+                key: key.into(),
+                value: value.into(),
+                namespace: namespace.into(),
+                id: id.map(|i| i.into()),
+            })
+            .await?;
+
+        Ok(())
+    }
+
+    pub async fn listen_events(
+        &self,
+        namespace: &str,
+        id: Option<impl Into<String>>,
+        exec: impl ListenEventsExecutor,
+    ) -> anyhow::Result<()> {
+        let mut client = self.client().await?;
+
+        let resp = client
+            .listen_events(ListenEventsRequest {
+                namespace: namespace.into(),
+                id: id.map(|i| i.into()),
+            })
+            .await?;
+
+        let mut inner = resp.into_inner();
+        while let Ok(Some(message)) = inner.message().await {
+            exec.execute(message).await?;
+        }
+
+        Ok(())
+    }
+
+    async fn client(&self) -> anyhow::Result<ChurnClient<tonic::transport::Channel>> {
+        let channel = if self.host.starts_with("https") {
+            Channel::from_shared(self.host.to_owned())?
+                .tls_config(ClientTlsConfig::new().with_native_roots())?
+                .connect()
+                .await?
+        } else {
+            Channel::from_shared(self.host.to_owned())?
+                .connect()
+                .await?
+        };
+
+        let client = ChurnClient::new(channel);
+
+        Ok(client)
+    }
+}
+
+#[async_trait::async_trait]
+pub trait ListenEventsExecutor {
+    async fn execute(&self, event: ListenEventsResponse) -> anyhow::Result<()>;
+}

crates/churn/src/agent/refresh.rs

@@ -4,21 +4,24 @@ use super::agent_state::AgentState;
 
 #[derive(Clone)]
 pub struct AgentRefresh {
-    _state: AgentState,
-    host: String,
+    process_host: String,
 }
 
 impl AgentRefresh {
-    pub fn new(state: impl Into<AgentState>, host: impl Into<String>) -> Self {
+    pub fn new(state: impl Into<AgentState>) -> Self {
+        let state: AgentState = state.into();
         Self {
-            _state: state.into(),
-            host: host.into(),
+            process_host: state.discovery.process_host.clone(),
         }
     }
 }
 
 #[async_trait::async_trait]
 impl notmad::Component for AgentRefresh {
+    fn name(&self) -> Option<String> {
+        Some("agent_refresh".into())
+    }
+
     async fn run(
         &self,
         cancellation_token: tokio_util::sync::CancellationToken,
@@ -39,7 +42,7 @@ impl notmad::Component for AgentRefresh {
 #[async_trait::async_trait]
 impl nodrift::Drifter for AgentRefresh {
     async fn execute(&self, _token: tokio_util::sync::CancellationToken) -> anyhow::Result<()> {
-        tracing::info!(host = self.host, "refreshing agent");
+        tracing::info!(process_host = self.process_host, "refreshing agent");
 
         // Get plan
         let plan = Plan::new();