Implement DAG for flow

Signed-off-by: Lee Smet <lee.smet@hotmail.com>

src/rpc.rs

@@ -9,10 +9,11 @@ use jsonrpsee::{
     server::{ServerBuilder, ServerHandle},
     types::error::ErrorObjectOwned,
 };
-use serde::{Deserialize, Serialize};
+use serde::Deserialize;
 use serde_json::{Value, json};
 
 use crate::{
+    dag::{DagError, FlowDag, build_flow_dag},
     models::{Actor, Context, Flow, Job, Message, MessageFormatType, Runner, ScriptType},
     storage::RedisDriver,
     time::current_timestamp,
@@ -45,6 +46,22 @@ fn storage_err(e: Box<dyn std::error::Error + Send + Sync>) -> ErrorObjectOwned
     }
 }
 
+fn dag_err(e: DagError) -> ErrorObjectOwned {
+    match e {
+        DagError::Storage(inner) => storage_err(inner),
+        DagError::MissingDependency { .. } => ErrorObjectOwned::owned(
+            -32020,
+            "DAG Missing Dependency",
+            Some(Value::String(e.to_string())),
+        ),
+        DagError::CycleDetected { .. } => ErrorObjectOwned::owned(
+            -32021,
+            "DAG Cycle Detected",
+            Some(Value::String(e.to_string())),
+        ),
+    }
+}
+
 // -----------------------------
 // Create DTOs and Param wrappers
 // -----------------------------
@@ -447,6 +464,21 @@ pub fn build_module(state: Arc<AppState>) -> RpcModule<()> {
             })
             .expect("register flow.load");
     }
+    {
+        let state = state.clone();
+        module
+            .register_async_method("flow.dag", move |params, _caller, _ctx| {
+                let state = state.clone();
+                async move {
+                    let p: FlowLoadParams = params.parse().map_err(invalid_params_err)?;
+                    let dag: FlowDag = build_flow_dag(&state.redis, p.context_id, p.id)
+                        .await
+                        .map_err(dag_err)?;
+                    Ok::<_, ErrorObjectOwned>(dag)
+                }
+            })
+            .expect("register flow.dag");
+    }
 
     // Job
     {