The single-node bypass in hop.Select() was preventing FailFilter from
being applied when retry excludes reduced available nodes to one.
This caused failed forwarder nodes to keep being selected instead of
failing over to healthy alternatives.
FailFilter's built-in safety guard (len <= 1 returns as-is) ensures
the last remaining node is never permanently blocked.
Address reviewer feedback from PR #14 fix:
1. Single-node case: Bypass selector/FailFilter to ensure availability.
This matches upstream go-gost/x behavior - single nodes should always
be attempted regardless of recent failures.
2. Multi-node case: Preserve FailFilter's backoff contract. When all nodes
are marked as failed, return nil to signal 'no healthy nodes' rather
than falling back to a known-bad node. This prevents hammering unhealthy
nodes and respects the failTimeout window.
The handler's retry loop with ExcludeNodes context handles the multi-node
failover properly - this change ensures hop.Select() provides correct
information about node health status.
Fixes intermittent forwarding failures introduced by #14.
When a forwarding rule has multiple backend nodes configured, the first
node failure would cause the entire forward to fail instead of trying
the next available node.
Root causes fixed:
- FailFilter skipped filtering when only 1 node remained
- hop.Select() bypassed selector for single-node hops
- Handlers only attempted one node before giving up
Changes:
- selector/filter.go: Remove len<=1 early return, always filter failed nodes
- hop/hop.go: Remove single-node bypass, add ExcludeNodes context support
- ctx/value.go: Add ContextWithExcludeNodes/ExcludeNodesFromContext helpers
- handler/forward/local: Add maxRetries config, implement retry loop
- handler/forward/remote: Add maxRetries config, implement retry loop
- forwarder/sniffer.go: Add retry logic to dial() and dialTLS()
Closes#12
root