From d4a2be8a9e0bd8b59ad911b4d4bb75fba1a1a5b2 Mon Sep 17 00:00:00 2001
From: Simon Wicky <simon@nymtech.net>
Date: Tue, 30 Jan 2024 09:48:32 +0100
Subject: [PATCH] augment topology with described nodes

---
 .../topology_control/nym_api_provider.rs      | 12 ++++++++-
 common/topology/src/lib.rs                    | 25 ++++++++++++++++---
 2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/common/client-core/src/client/topology_control/nym_api_provider.rs b/common/client-core/src/client/topology_control/nym_api_provider.rs
index 824294793b..90fc23cc8c 100644
--- a/common/client-core/src/client/topology_control/nym_api_provider.rs
+++ b/common/client-core/src/client/topology_control/nym_api_provider.rs
@@ -77,13 +77,23 @@ impl NymApiTopologyProvider {
             Ok(gateways) => gateways,
         };
 
+        let nodes_described = match self.validator_client.get_cached_described_nodes().await {
+            Err(err) => {
+                error!("failed to get described nodes - {err}");
+                return None;
+            }
+            Ok(epoch) => epoch,
+        };
+
         let topology = nym_topology_from_detailed(mixnodes, gateways)
+            .with_described_nodes(nodes_described.clone())
             .filter_system_version(&self.client_version);
 
         if let Err(err) = self.check_layer_distribution(&topology) {
             warn!("The current filtered active topology has extremely skewed layer distribution. It cannot be used: {err}");
             self.use_next_nym_api();
-            None
+            let empty_topology = NymTopology::empty().with_described_nodes(nodes_described);
+            Some(empty_topology)
         } else {
             Some(topology)
         }
diff --git a/common/topology/src/lib.rs b/common/topology/src/lib.rs
index 039e30eb94..36543b7243 100644
--- a/common/topology/src/lib.rs
+++ b/common/topology/src/lib.rs
@@ -19,7 +19,7 @@ use std::str::FromStr;
 
 #[cfg(feature = "serializable")]
 use ::serde::{Deserialize, Deserializer, Serialize, Serializer};
-use nym_api_requests::models::DescribedGateway;
+use nym_api_requests::models::{DescribedGateway, DescribedNymNode};
 
 pub mod error;
 pub mod filter;
@@ -115,11 +115,29 @@ pub type MixLayer = u8;
 pub struct NymTopology {
     mixes: BTreeMap<MixLayer, Vec<mix::Node>>,
     gateways: Vec<gateway::Node>,
+    described_nodes: Vec<DescribedNymNode>,
 }
 
 impl NymTopology {
     pub fn new(mixes: BTreeMap<MixLayer, Vec<mix::Node>>, gateways: Vec<gateway::Node>) -> Self {
-        NymTopology { mixes, gateways }
+        NymTopology {
+            mixes: mixes.clone(),
+            gateways: gateways.clone(),
+            described_nodes: Vec::new(),
+        }
+    }
+
+    pub fn empty() -> Self {
+        NymTopology {
+            mixes: BTreeMap::new(),
+            gateways: Vec::new(),
+            described_nodes: Vec::new(),
+        }
+    }
+
+    pub fn with_described_nodes(mut self, described_nodes: Vec<DescribedNymNode>) -> Self {
+        self.described_nodes = described_nodes;
+        self
     }
 
     pub fn new_unordered(unordered_mixes: Vec<mix::Node>, gateways: Vec<gateway::Node>) -> Self {
@@ -130,7 +148,7 @@ impl NymTopology {
             layer_entry.push(node)
         }
 
-        NymTopology { mixes, gateways }
+        NymTopology::new(mixes, gateways)
     }
 
     #[cfg(feature = "serializable")]
@@ -379,6 +397,7 @@ impl NymTopology {
         NymTopology {
             mixes: self.mixes.filter_by_version(expected_mix_version),
             gateways: self.gateways.clone(),
+            described_nodes: self.described_nodes.clone(),
         }
     }
 }