Make initialisation message error more straightforward

binaries/daemon/src/pending.rs

@@ -1,4 +1,7 @@
-use std::collections::{HashMap, HashSet};
+use std::{
+    collections::{HashMap, HashSet},
+    intrinsics::mir::Len,
+};
 
 use dora_core::{
     config::NodeId,
@@ -6,7 +9,7 @@ use dora_core::{
     daemon_messages::{DaemonReply, DataflowId, Timestamped},
     message::uhlc::{Timestamp, HLC},
 };
-use eyre::{bail, Context};
+use eyre::{bail, Context, ContextCompat};
 use tokio::{net::TcpStream, sync::oneshot};
 
 use crate::tcp_utils::tcp_send;
@@ -128,11 +131,20 @@ impl PendingNodes {
                 None => Ok(()),
             }
         } else {
+            let node_id_message = if self.exited_before_subscribe.len() == 1 {
+                self.exited_before_subscribe
+                    .iter()
+                    .next()
+                    .map(|node_id| node_id.to_string())
+                    .unwrap_or("<node_id>".to_string())
+            } else {
+                "<node_id>".to_string()
+            };
             Err(format!(
                 "Some nodes exited before subscribing to dora: {:?}\n\n\
                 This is typically happens when an initialization error occurs
                 in the node or operator. To check the output of the failed
-                nodes, run `dora logs {} <node_id>`.",
+                nodes, run `dora logs {} {node_id_message}`.",
                 self.exited_before_subscribe, self.dataflow_id
             ))
         };