Add logic to populate initial node identity from stake table (#2099)

It was noticed that the initial list of node identities does not consider the public
keys listed in the stake table.  This can easily be demonstrated by launching the
`node-metrics` binary with `ESPRESSO_NODE_VALIDATOR_STAKE_TABLE_SOURCE_BASE_URL`
and `ESPRESSO_NODE_VALIDATOR_LEAF_STREAM_SOURCE_BASE_URL` populated, but missing
`ESPRESSO_NODE_VALIDATOR_INITIAL_NODE_PUBLIC_BASE_URLS`.

In this case the list of node identities will be empty, and the information coming down
to consuming clients will be missing all node identities.

The fix is to modify the `DataState` structure so that it is initially populated with
information from the passed in stake table.

node-metrics/src/api/node_validator/v0/create_node_validator_api.rs

@@ -294,12 +294,7 @@ pub async fn create_node_validator_processing(
         .await
         .map_err(CreateNodeValidatorProcessingError::FailedToGetStakeTable)?;
 
-    let data_state = DataState::new(
-        Default::default(),
-        Default::default(),
-        stake_table,
-        Default::default(),
-    );
+    let data_state = DataState::new(Default::default(), Default::default(), stake_table);
 
     let data_state = Arc::new(RwLock::new(data_state));
     let client_thread_state = Arc::new(RwLock::new(client_thread_state));

node-metrics/src/service/data_state/mod.rs

@@ -46,8 +46,17 @@ impl DataState {
         latest_blocks: CircularBuffer<MAX_HISTORY, BlockDetail<SeqTypes>>,
         latest_voters: CircularBuffer<MAX_HISTORY, BitVec<u16>>,
         stake_table: StakeTable<BLSPubKey, StateVerKey, CircuitField>,
-        node_identity: Vec<NodeIdentity>,
     ) -> Self {
+        let node_identity = {
+            let stake_table_iter_result = stake_table.try_iter(SnapshotVersion::Head);
+            match stake_table_iter_result {
+                Ok(into_iter) => into_iter
+                    .map(|(key, _, _)| NodeIdentity::from_public_key(key))
+                    .collect(),
+                Err(_) => vec![],
+            }
+        };
+
         Self {
             latest_blocks,
             latest_voters,