wombatkv-daemon

Daemon-mode transports for WombatKV. Spawn one wombatkv-daemon process; serve many engines over SHM (same host) + TCP (cross host)

HTTP/1.1 (cross host, load-balancer friendly).

Modules

module	what
`arena`	shared memory-mapped arena for the future zero-copy data plane
`lifecycle`	SHM-prefix server + heartbeat monitor + reopen-on-restart
`client`	`RemoteKvStoreClient` (SHM client)
`tcp_transport`	compio TPC server (SO_REUSEPORT + dispatch bridge) + `TcpKvClient`
`http_transport`	compio TPC server (SO_REUSEPORT + dispatch bridge) + `HttpKvClient`
`envelope`	RFC 0018 universal wire envelope: magic + version + CRC32C + len
`runtime_tpc`	per-shard compio runtime spawn + CPU pinning

CLI

wombatkv-daemon \
    --prefix <name>      # SHM prefix (repeatable for multiple engines)
    --tcp <addr>         # TCP listener (repeatable)
    --http <addr>        # HTTP listener (repeatable)
    --tpc                # opt-in: per-shard compio runtime

Or via env: WMBT_KV_TCP=<a,b,c> / WMBT_KV_HTTP=<a,b,c> / WMBT_KV_TCP_TPC_THREADS=N (default 2) / WMBT_KV_HTTP_TPC_THREADS=N (default 2) / WMBT_KV_TCP_DISPATCH_WORKERS=M (default 8) / WMBT_KV_HTTP_DISPATCH_WORKERS=M (default 8).

TPC architecture

The compio-bridge variant (serve_tcp_compio_bridge / serve_http_compio_bridge) shards the accept path with SO_REUSEPORT across N OS threads each running a compio runtime, and ferries decoded WireRequest frames to a separate sync worker pool via DispatchHandle (flume). The dispatch closure is shared with the SHM path so all transports land in one foyer + S3 backend.

Built on the compio per-shard TCP server + dispatch-bridge pattern.

Wire format (RFC 0018 universal envelope)

+---------+---------+---------+---------+--------------------+
| magic 4 | ver 4LE | crc 4LE | len 4LE | rkyv body[len] ... |
| 'WMBT'  | u32     | u32     | u32     |                    |
+---------+---------+---------+---------+--------------------+

CRC32C is Castagnoli (polynomial 0x82F63B78), same algorithm as ds4's v4 sidecar + v2 block envelopes. Single CRC32C across the stack.

Test

# Lib tests (envelope + 10 wire corruption tests + transport
# concurrent-client correctness + TPC keep-alive pipelined):
cargo test -p wombatkv-daemon --release

# DST chaos build:
cargo build -p wombatkv-daemon --release --features dst

RFC pointers

RFC 0014, cabi TCP extension (TCP transport + ds4 env gate)
RFC 0018, wire envelope discipline (universal 16-byte envelope)