From 18d95b9a1fcedaed3d3227054425c44ec77364ef Mon Sep 17 00:00:00 2001
From: Graham McIntire <graham@mcintire.me>
Date: Fri, 24 Oct 2025 15:00:43 -0500
Subject: [PATCH] fix: add timeout for cluster formation to ensure APRS-IS
 connection
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Previously, when clustering was enabled, the leader election process
would wait indefinitely for the cluster to form. If cluster formation
failed or took too long, no leader would be elected and the APRS-IS
connection would never start, leaving the system disconnected.

Changes:
- Add 30-second timeout for cluster formation
- Force leader election after timeout, even in single-node mode
- Add election_forced flag to prevent duplicate election attempts
- Improve logging to distinguish between cluster and single-node modes

This ensures that at least one node will always connect to APRS-IS,
even if clustering fails completely.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
---
 lib/aprsme/cluster/leader_election.ex | 55 +++++++++++++++++++++------
 1 file changed, 44 insertions(+), 11 deletions(-)

diff --git a/lib/aprsme/cluster/leader_election.ex b/lib/aprsme/cluster/leader_election.ex
index 06c8855..b7fb58c 100644
--- a/lib/aprsme/cluster/leader_election.ex
+++ b/lib/aprsme/cluster/leader_election.ex
@@ -9,6 +9,8 @@ defmodule Aprsme.Cluster.LeaderElection do
 
   @election_key {:aprs_is_leader, __MODULE__}
   @check_interval 5_000
+  # Maximum time to wait for cluster formation before proceeding with election (30 seconds)
+  @max_cluster_wait 30_000
 
   def start_link(opts) do
     GenServer.start_link(__MODULE__, opts, name: __MODULE__)
@@ -45,8 +47,10 @@ defmodule Aprsme.Cluster.LeaderElection do
 
     if cluster_enabled do
       Logger.info("Clustering enabled - waiting for cluster formation before leader election")
-      # Wait longer for cluster to form, then check periodically
+      # Wait for cluster to form, then check periodically
       Process.send_after(self(), :check_cluster_and_elect, 2_000)
+      # Set a timeout to force election if cluster doesn't form
+      Process.send_after(self(), :force_election_timeout, @max_cluster_wait)
     else
       Logger.info("Clustering disabled - proceeding with immediate leader election")
       # Non-clustered mode - elect immediately
@@ -56,22 +60,51 @@ defmodule Aprsme.Cluster.LeaderElection do
     # Schedule periodic checks
     Process.send_after(self(), :check_leadership, @check_interval)
 
-    {:ok, %{is_leader: false, leader_node: nil, cluster_enabled: cluster_enabled}}
+    {:ok, %{is_leader: false, leader_node: nil, cluster_enabled: cluster_enabled, election_forced: false}}
   end
 
   @impl true
   def handle_info(:check_cluster_and_elect, state) do
-    connected_nodes = Node.list()
-
-    if length(connected_nodes) > 0 do
-      Logger.info("Cluster formed with #{length(connected_nodes)} other nodes: #{inspect(connected_nodes)}")
-      Logger.info("Proceeding with leader election")
-      Process.send_after(self(), :attempt_election, 100)
+    # Don't keep checking if election was already forced
+    if state.election_forced do
       {:noreply, state}
     else
-      Logger.info("Cluster not yet formed - waiting...")
-      # Check again in 2 seconds
-      Process.send_after(self(), :check_cluster_and_elect, 2_000)
+      connected_nodes = Node.list()
+
+      if length(connected_nodes) > 0 do
+        Logger.info("Cluster formed with #{length(connected_nodes)} other nodes: #{inspect(connected_nodes)}")
+        Logger.info("Proceeding with leader election")
+        Process.send_after(self(), :attempt_election, 100)
+        {:noreply, %{state | election_forced: true}}
+      else
+        Logger.debug("Cluster not yet formed - waiting...")
+        # Check again in 2 seconds
+        Process.send_after(self(), :check_cluster_and_elect, 2_000)
+        {:noreply, state}
+      end
+    end
+  end
+
+  @impl true
+  def handle_info(:force_election_timeout, state) do
+    # Only force election if we haven't already started one
+    if not state.election_forced and not state.is_leader do
+      connected_nodes = Node.list()
+
+      if length(connected_nodes) == 0 do
+        Logger.warning(
+          "Cluster formation timeout reached after #{@max_cluster_wait}ms with no connected nodes. " <>
+            "Proceeding with leader election in single-node mode to ensure APRS-IS connection."
+        )
+      else
+        Logger.info(
+          "Forcing leader election after #{@max_cluster_wait}ms wait with #{length(connected_nodes)} connected nodes"
+        )
+      end
+
+      Process.send_after(self(), :attempt_election, 100)
+      {:noreply, %{state | election_forced: true}}
+    else
       {:noreply, state}
     end
   end