glm-5.2
2313c51f12
Phase 1 architecture for alknet-channels (multiplexing proxy on alknet/channels). Grounded in the completed de-risk POC (28 tests) and the landed ADR-070 (BidiStreamSource trait + Connection::from_source). ADRs: - 071: 9-byte chunk wire format (generalizes TTY's 5-byte) - 072: channel 0 pre-negotiated as alknet/call (no special control plane) - 073: channel lifecycle operations on the call protocol — channel/open, close, control, resources/subscribe; direction field pinned; subscribe from day one (not poll-for-v1 — StreamingHandler machinery exists) - 074: ChannelBidiStreamSource implements BidiStreamSource (ADR-070); into_sub_streams() typed accessor for TTY; accept_bi() generic path - 075: ChannelsAdapter + ChannelManager; REQ-CH-01..04 wire invariants - 076: bounded-buffer backpressure (1 MiB), 256-channel cap, monotonic IDs - 077: TTY inside channels uses sub-streams, not own wire format; amends ADR-052 scope to direct-connect TTY; channels feature on tty - 078: two-pump shutdown-on-completion contract (handler-level) - 079: hub relay translates channel 0, byte-forwards data channels - 080: ChannelClient (QUIC-only); AlknetClient core extraction deferred (OQ-55) Spec docs: overview, channels-wire, channels-connection, channels-adapter, channel-operations, channel-client. OQ-56 (full windowing) and OQ-57 (two-pump helper extraction) are genuine deferred(scope) deferrals with concrete blocking conditions; the contracts are decided, only the extensions are deferred. Hedging audit converted three research hedges into decisions: resources/subscribe (not poll), server-assigned IDs (not if-zero-RTT), bounded-buffer (not if-HOL-becomes-a-problem).
32 lines
2.0 KiB
Markdown
32 lines
2.0 KiB
Markdown
# OQ-57: Two-Pump Helper Extraction to alknet-core
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- **Origin**: `docs/research/alknet-channels/poc-summary.md` §Issues
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Surfaced #7; `docs/architecture/decisions/078-two-pump-shutdown-on-completion.md`
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- **Status**: deferred(scope)
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- **Door type**: two-way (additive — a helper function does not change any
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API surface; handlers that inline the pattern continue to work)
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- **Priority**: low
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- **Blocked on**: a second two-pump handler existing, so the shape
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convergence is observable. The tunnel handler is the first two-pump
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consumer; the SSH `direct-tcpip` channel will be the second. Extracting
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the helper from one consumer (the tunnel) would bake in a shape that the
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second consumer (SSH) might not fit — the `fn pump_bidi<R, W>(recv: R,
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send: W, ...) -> impl Future` signature is a cross-crate API surface if
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it lives in `alknet-core`. The trigger is: two real two-pump handlers
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exist and their inline implementations have converged on the same shape.
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- **Resolution**: Not yet decidable. The shutdown-on-completion *contract*
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is decided (ADR-078) — a two-pump handler MUST shut down the opposite
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sink when one pump completes, or it deadlocks. The *helper* extraction is
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an implementation convenience: ~10 lines of inline code per handler vs. a
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shared function in `alknet-core`. The contract is pinned; only the
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extraction is deferred. The helper is extracted when two real consumers
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exist and their shapes converge, so the extraction is grounded in two
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implementations rather than guessed from one.
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- **What does NOT block on this**: the two-pump pattern is documented
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(ADR-078) and the tunnel handler implements it inline. The SSH crate's
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`direct-tcpip` handler will implement it inline too. Both work without a
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shared helper. The friction is copy-paste with documentation (~10 lines),
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not a missing capability.
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- **Cross-references**: ADR-078 (the shutdown-on-completion contract),
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ADR-074 (the `accept_bi` that yields the stream pair the pumps operate
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on), `docs/research/alknet-channels/poc-summary.md` §Issues Surfaced #7 |