Add RESP protocol detection to the sniffing framework so plaintext
Redis traffic on a port-reuse listener can be identified and routed by
protocol. Sniff() now peeks 1 byte first to match RESP type bytes
(*+-:$) without blocking, then falls through to the existing 5-byte
TLS/HTTP/SSH detection.
ParseRedisMetadata consumes exactly one RESP message via io.TeeReader
and records command/key in HandlerRecorderObject.Redis. HandleRedis in
both the sniffing (injected-dial) and forwarder (hop-selected) packages
replays the captured first message and pipes the rest, so pipelined
commands beyond the first are forwarded transparently.
Wired into all 5 dispatch sites: sni, forward/local, forward/remote,
http CONNECT, and relay tunnel handlers. forwarder paths route via
resolveRedisNode using ProtocolSelectOption(ProtoRedis), enabling
`protocol: redis` hop selection.
Part of two-phase plan (2026-07-29-sniffing-redis-postgres.md);
PostgreSQL deferred to phase 2.
Supports three modes via Gost-Record request header:
- (absent)/full: full recording with body (existing behavior)
- headers: metadata only, skip body/payload capture
- off: no recording at all
Header is stripped before forwarding. Per-request granularity
via HandlerRecorderObject.RecordMode field propagating through
the ro clone chain to all sub-paths (WS frames, H2, sniffing).
Capture client-sent Host/URI/headers/body before node HTTP rewrites are applied, so the recorder sees both the original and forwarded values. Adds a borrowBodyPrefix helper that inspects a body prefix without consuming the stream. Also serializes file recorder writes unconditionally (the underlying io.WriteCloser is not safe for concurrent Write) and drops a debug log from the bodyRegexp matcher.
User-configured metadata on recorder objects (recorders[].metadata in YAML)
was silently discarded — MetadataRecordOption existed but was never called
anywhere in the codebase, causing plugin (HTTP/gRPC) recorders to always
receive null metadata.
Fix: wrap recorders that carry config metadata in MetadataRecorder, which
auto-appends the metadata to every Record() call. This covers all paths
(handler, router, sniffer, service) with zero call-site changes.
- httpRecorder: use http.NewRequestWithContext instead of http.NewRequest
- tcpRecorder: loop Write to avoid short-write data loss
- fileRecorder: guard against nil out in Record and Close
- plugin/grpc, plugin/http: handle json.Marshal errors instead of ignoring
- fileRecorder, redis*Recorder: idempotent Close via sync.Once
- All exported symbols: add doc comments
ginuerzh