refactor: Socket Unification — a fixed 2-WebSocket budget per tab (state socket + relay mux)#378
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…e WebSocket (#375) * refactor: Mux session-state + host-metrics SSE into one WebSocket Replace the per-server EventSource pool and host-metrics EventSource with a single /ws/state connection (hello/subscribe/ack protocol), eliminating steady-state h1 pool usage that was blocking WebSocket handshakes on Firefox/WebKit once 6 SSE connections saturated the pool. Retires GET /api/sessions/stream; SSE event names/payloads move verbatim into the new envelope, and attachServer/subscribe* consumer seams are unchanged. * Update ship status and record PR URL * fix: address review feedback from @Copilot * Update review-pr status --------- Co-authored-by: Sahil Ahuja <sahilahuja@gmail.com>
# Conflicts: # app/frontend/tests/e2e/chat-view.spec.ts # docs/memory/run-kit/index.md # docs/memory/run-kit/ui-patterns.md
Co-authored-by: Sahil Ahuja <sahilahuja@gmail.com>
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July 17, 2026 18:57
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Summary
Session-state SSE streams saturate the browser's 6-per-origin HTTP/1.1 pool on plaintext origins — and on Firefox/WebKit a full pool blocks new WebSocket handshakes entirely, so a multi-server host could never connect a terminal. This branch collapses the per-tab connection budget from
panes + servers + 1long-lived streams to exactly two WebSockets:/ws/state(all session-state + host-metrics) and/ws/terminals(all pane relays, muxed). Evidence:docs/findings/socket-pool-accounting.md,docs/findings/relay-mux-hol.md; design:fab/plans/sahil/socket-unification.md.Changes
260716-qf3j-state-socket): new/ws/statehandler with an in-band hello/subscribe/ack protocol;sseHubclient edge generalized to per-connection subscription sets (producers frozen, payloads byte-identical);GET /api/sessions/stream+handleSSEretired;session-context.tsxswapped onto aStateSocketclient preserving everyattachServer/subscribe*seam; connection dots keyed on subscription acks; 12 e2e specs migrated to a shared/ws/statemock; structurally fixes the long-standingattachServer→SSE race (multi-server-sidebarflake).260717-803u-relay-mux): new/ws/terminalshandler — binary[u32 streamId][payload]frames + JSON control ops, per-stream bounded queues + fair scheduler (spike-proven v1 requirement: 1.66s → 32ms echo p50 under co-stream flood);handleRelay+/relay/{windowId}retired; frontendRelayMuxsingleton +TerminalClientport preserving the four delicate seams (confirmation-gate receipt, connect-select epoch, pane suspension as stream close/open, per-stream deferred reset); connection-budget e2e guard tightened to 2 WS + 0 SSE.ecd5eeeb): deadBoardEntriesFetcherchain and deadsetPreviewScopeclient fn removed; dead/relayVite dev-proxy block dropped;relay.gofolded into the socket files (sharedupgrader→state_ws.go,forceTERM→terminals_ws.go); test-onlyoutFrame.payload()relocated to the test file; unused e2e mock control surface collapsed; stale SSE/EventSource transport comments reworded across backend + frontend.Chat still rides its own SSE by design — it joins the state socket in change 3 (
chat-on-state-socket), not in this branch.