feat: multi-forwarder with SRTT-based failover #77

2026-04-11T04:17:28+08:00

razvandimescu commented

2026-04-11 04:17:28 +08:00

(Migrated from github.com)

Summary

Multiple upstreams: address accepts a string or array with optional per-server port ("1.2.3.4:5353", "[::1]:5553")
Fallback pool: new fallback config field, tried only when all primaries fail
SRTT-based selection: UDP primaries sorted by smoothed round-trip time; fastest tried first
Sequential failover: on failure, records SRTT penalty and tries next candidate
Backwards compatible: address = "1.2.3.4" still works, existing configs unchanged
14 new tests (195 total): config parsing, address formats, pool labels, failover behavior, upstream re-detection

[upstream]
address = ["192.168.1.1", "192.168.1.2:5353"]
fallback = ["8.8.8.8", "1.1.1.1"]

Closes #34 (items 1, 2, 3)

Test plan

make all passes (195 tests, clippy, fmt, audit)
Single address = "..." string config still works (backwards compat)
Array config with mixed ports resolves correctly
Fallback kicks in when all primaries are unreachable
/stats shows preferred upstream via pool.label()
Network watcher re-detects upstream when auto-detected

🤖 Generated with Claude Code

## Summary - **Multiple upstreams**: `address` accepts a string or array with optional per-server port (`"1.2.3.4:5353"`, `"[::1]:5553"`) - **Fallback pool**: new `fallback` config field, tried only when all primaries fail - **SRTT-based selection**: UDP primaries sorted by smoothed round-trip time; fastest tried first - **Sequential failover**: on failure, records SRTT penalty and tries next candidate - **Backwards compatible**: `address = "1.2.3.4"` still works, existing configs unchanged - **14 new tests** (195 total): config parsing, address formats, pool labels, failover behavior, upstream re-detection ```toml [upstream] address = ["192.168.1.1", "192.168.1.2:5353"] fallback = ["8.8.8.8", "1.1.1.1"] ``` Closes #34 (items 1, 2, 3) ## Test plan - [x] `make all` passes (195 tests, clippy, fmt, audit) - [x] Single `address = "..."` string config still works (backwards compat) - [x] Array config with mixed ports resolves correctly - [x] Fallback kicks in when all primaries are unreachable - [x] `/stats` shows preferred upstream via `pool.label()` - [x] Network watcher re-detects upstream when auto-detected 🤖 Generated with [Claude Code](https://claude.com/claude-code)

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Reference: dearsky/numa#77