feat: idle-timeout keepalive model with auto-resume - #3
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Replace absolute ExpiresAt field with computed property derived from LastActiveAt + Timeout. Data-plane requests (any traffic routed through the proxy) now implicitly reset the idle timer via Manager.MarkActivity, eliminating the need for SDK clients to explicitly call /timeout to keep sandboxes alive. Key changes: - Sandbox.ExpiresAt field → ExpiresAt() computed method - Add Sandbox.Timeout and Sandbox.LastActiveAt as sources of truth - Add LabelTimeout Docker label for Rehydrate to recover original TTL - EnforceTimeouts uses idle check (now - LastActiveAt >= Timeout) instead of absolute deadline (now > ExpiresAt) - dispatch.go NewRouter accepts onActivity callback, wired to Manager.MarkActivity in main.go - MarkActivity coalesces writes (default 1s) to avoid lock contention - Config: EDVABE_KEEPALIVE_ENABLED (default on), EDVABE_KEEPALIVE_COALESCE - API responses and dashboard include lastActiveAt field Design inspired by CubeSandbox's traffic-driven keepalive model.
KeepaliveEnabled was a bool with broken default handling — both branches of the if set true, making it impossible to disable keepalive. Changed to *bool: nil = default on, &true = explicit on, &false = off.
Drop *bool three-state approach. main.go is the only Options constructor and always passes a concrete bool. The original bug was just redundant if-branches — a direct assignment fixes it.
Pre-flight ContainerInspect before pause/unpause: Pause returns early if already paused, Unpause returns early if already running. Robust against Docker API message changes across versions. Fixes the Manager TOCTOU race (Resume/Connect check State==Paused under lock, release, then call unpause - a concurrent resume wins the race) and enables recovery from external docker commands.
Data-plane traffic (any request routed through the proxy) now auto-resumes a paused sandbox before forwarding. This mirrors CubeSandbox sandbox_state.lua gate: a browser refresh or SDK request to a paused sandbox transparently unpauses it instead of hanging or erroring. NewProxy gains a third AutoResumer interface param (satisfied by Manager.Connect, which unpauses + resets the idle clock). Running sandboxes skip the check entirely. Paused sandboxes get Connect(id, sb.Timeout) — preserving the original TTL while granting a fresh idle lease. Two new tests: TestAutoResumePausedSandbox verifies the resume+forward path; TestProxyNoResumeForRunningSandbox verifies no spurious Connect for running sandboxes.
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Summary
Replaces the absolute
ExpiresAtdeadline model with a computedLastActiveAt + Timeoutidle model, adds data-plane auto-keepalive, idempotent docker pause/unpause, and proxy-level auto-resume for paused sandboxes.Changes
1. Idle-timeout model with data-plane auto-keepalive
Sandbox.ExpiresAtfield → computedExpiresAt()method (LastActiveAt + Timeout)LastActiveAt+Timeoutfields as sources of truthManager.MarkActivity(id)called by dispatch on every data-plane request (coalesced to 1s/sandbox)EnforceTimeoutsuses idle check (now - LastActiveAt >= Timeout) instead of absolute deadlineLabelTimeoutDocker label for Rehydrate to recover original TTLEDVABE_KEEPALIVE_ENABLED(default on),EDVABE_KEEPALIVE_COALESCE(default 1s)lastActiveAtfield2. Idempotent docker pause/unpause
ContainerInspectbefore pause/unpause: return nil if already in desired state3. Auto-resume paused sandboxes on data-plane requests
Manager.Connect(id, sb.Timeout)to resume + reset idle clockInspired by CubeSandbox's traffic-driven keepalive model and sandbox_state.lua auto-resume gate.
Test plan
go vet ./...passesgo test ./...passesTestAutoResumePausedSandbox— verifies resume+forward pathTestProxyNoResumeForRunningSandbox— verifies no spurious Connect for running sandboxesExpiresAt()method