sim-cli: exclude nodes from simulation but not from returned map

When we want to exclude nodes from random activity generation, we may
still want to include them in our map of network nodes so that the
caller can use any node in the network.

Author: carlaKC

sim-cli/src/parsing.rs

@@ -241,6 +241,16 @@ struct NodeMapping {
     alias_node_map: HashMap<String, NodeInfo>,
 }
 
+/// Creates a simulation that will run on an entirely-simulated network defined in `sim_params`,
+/// returning the simulation, a validated vector of any defined activities that were specified and
+/// a map of all the simulated nodes in the network. Note that if `sim_params::exclude` was set,
+/// the nodes will be excluded from the set of nodes actively sending/receiving random payments,
+/// but they will be included in the map so that they are available for use outside of the
+/// simulation.
+///
+/// This network can be customized by providing `interceptors` that will act on every HTLC that is
+/// forwarded by the network, and setting `custom_records` which will be set as the default TLV
+/// records set by the original sender of payments in their simulated `update_add_htlc`.
 pub async fn create_simulation_with_network(
     cfg: SimulationCfg,
     sim_params: &SimParams,
@@ -299,15 +309,18 @@ pub async fn create_simulation_with_network(
             .map_err(|e| SimulationError::SimulatedNetworkError(format!("{:?}", e)))?,
     );
 
-    let mut nodes = ln_node_from_graph(simulation_graph.clone(), routing_graph).await;
-    for pk in exclude {
-        nodes.remove(pk);
-    }
-
-    let nodes_dyn: HashMap<_, Arc<Mutex<dyn LightningNode>>> = nodes
+    // We want the full set of nodes in our graph to return to the caller so that they can take
+    // custom actions on the simulated network. For the nodes we'll pass our simulation, cast them
+    // to a dyn trait and exclude any nodes that shouldn't be included in random activity
+    // generation.
+    let nodes = ln_node_from_graph(simulation_graph.clone(), routing_graph).await;
+    let mut nodes_dyn: HashMap<_, Arc<Mutex<dyn LightningNode>>> = nodes
         .iter()
         .map(|(pk, node)| (*pk, Arc::clone(node) as Arc<Mutex<dyn LightningNode>>))
         .collect();
+    for pk in exclude {
+        nodes_dyn.remove(pk);
+    }
 
     let validated_activities =
         get_validated_activities(&nodes_dyn, nodes_info, sim_params.activity.clone()).await?;