forked from molecule-ai/molecule-core
## Symptom
Canvas detail-panel "config + filesystem load" took ~20s. Reported on
production hongming tenant, workspace c7c28c0b-... (Claude Code Agent T2).
## Two stacked latency sources
### 1. Server-side: per-call EIC tunnel setup (~80% of the win)
`workspace-server/internal/handlers/template_files_eic.go::realWithEICTunnel`
performed ssh-keygen + SendSSHPublicKey + open-tunnel + waitForPort PER call.
4 callers (read/write/list/delete) each paid the full ~3-5s setup cost even
when fired back-to-back on the same workspace EC2.
Fix: refcounted pool keyed on instanceID with TTL ≤ 50s (under the 60s
SendSSHPublicKey grant). One tunnel serves N file ops; concurrent acquires
for the same instance share the slot via a pendingSetups gate; LRU eviction
caps simultaneous tracked instances at 32. Poisons entries on tunnel-fatal
errors (connection refused, broken pipe, auth failed) so the next acquire
builds fresh. Cleanup on panic via defer-release pattern (added after
self-review caught a refcount-leak hazard).
Public API unchanged — `var withEICTunnel` rebinds to `pooledWithEICTunnel`
at package init, so all 4 callers inherit pooling for free.
10 unit tests pin: 4-ops-amortise (1 setup), different-instances-do-not-share,
TTL eviction, poison invalidates, concurrent-acquire-single-setup,
TTL=0 escape hatch, LRU eviction at cap, error classification heuristic,
refcount blocks expired eviction, panic poisons entry. All green.
### 2. Canvas-side: serial fan-out + duplicate fetch (~20% of the win)
`canvas/src/components/tabs/ConfigTab.tsx::loadConfig` awaited 3 independent
metadata GETs (`/workspaces/{id}`, `/model`, `/provider`) serially.
`AgentCardSection` fired a SECOND `/workspaces/{id}` from its own useEffect.
Fix: Promise.all over the 3 metadata GETs (each leg keeps its existing
.catch fallback semantics). AgentCardSection now reads `agentCard` from
the canvas store (`useCanvasStore`) instead of refetching — the canvas
already hydrates `node.data.agentCard` from the platform event stream.
Defensive selector handles test mocks without a `nodes` array.
## Verification
- `go test ./internal/handlers/` 5.07s green (full handlers package, including
10 new pool tests)
- `go vet ./internal/handlers/` clean
- `npx vitest run` — 1380/1380 canvas unit tests pass (2 test FILES fail on
a pre-existing xyflow CSS-load issue in vitest config, unrelated to this
change)
- `npx tsc --noEmit` clean
Live wall-time verification deferred to Phase 4 / E2E (canvas browser session
required; external probe blocked by 403 since the canvas auth chain is
session-cookie + Origin header, not a bearer token I can fabricate).
## Backwards compatibility
API surface unchanged. All 4 EIC handler callers use the rebound var; no
caller migration. Pool defaults to enabled (TTL=50s); tests can disable by
setting poolTTL=0 or by overwriting withEICTunnel directly (existing stub
pattern in template_files_eic_dispatch_test.go preserved).
## Hostile self-review (3 weakest spots)
1. `fnErrIndicatesTunnelFault` is a substring grep on err.Error() — the
marker list is hand-curated and ssh client error formats vary across
OpenSSH versions. A future ssh that reports a tunnel failure via a
phrasing not in the list would NOT poison the entry → next callers reuse
a dead tunnel until TTL evicts. Acceptable: TTL bounds the impact (≤50s
of bad reuse), and the heuristic covers every tunnel-error shape that
appears in the existing test fixtures and known incidents.
2. `acquire`'s for-loop has unbounded retry potential under pathological
churn (signal closed → new acquirer → setup fails → repeat). No bounded
retry counter. Today there is no test exercise for "flaky setup that
succeeds-then-fails-then-succeeds"; if observability ever shows this
shape, add a max-retry guard. Filed as a known limitation, not blocking.
3. The substring assertion `strings.Contains` style I used for tunnel-fault
classification could false-positive on app-level error messages that
happen to contain "permission denied" or "broken pipe" verbatim. The
classification test covers the discriminator but only against the
error shapes we know today. Acceptable: poisoning errs on the side of
building fresh, which is correct-but-slightly-slow rather than incorrect.
## Phase 4 / E2E plan
- Live timing of the canvas detail-panel open against a real workspace
(browser session, not external probe).
- Target: perceived latency under 2s on warm pool. Cold open still pays
one tunnel setup (~3-5s) — the pool buys you the SECOND through Nth
panel-open within the TTL window.
- Memory `feedback_chase_verification_to_staging` applies — will not
declare done at PR-merge; will follow through to user-visible behavior
on staging.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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