Add SandboxProxyWrapper that intercepts requests with Host headers
matching {port}-{sandbox_id}.{domain} and proxies them through the
owning host agent's /proxy endpoint.
Authentication is via X-API-Key only (no JWT). The API key's team must
own the sandbox. Export EnsureScheme from lifecycle package for reuse.
Request flow: SDK -> Caddy -> CP catch-all -> Host Agent -> sandbox VM.
This is an intermediate state — needs further work for the full code
interpreter feature.
Replaces the hardcoded CP_HOST_AGENT_ADDR single-agent setup with a
DB-driven registration system supporting multiple host agents (BYOC).
Key changes:
- Host agents register via one-time token, receive a 7-day JWT + 60-day
refresh token; heartbeat loop auto-refreshes on 401/403 and pauses all
sandboxes if refresh fails
- HostClientPool: lazy Connect RPC client cache keyed by host ID, replacing
the single static agent client throughout the API and service layers
- RoundRobinScheduler: picks an online host for each new sandbox via
ListActiveHosts; extensible for future scheduling strategies
- HostMonitor (replaces Reconciler): passive heartbeat staleness check marks
hosts unreachable and sandboxes missing after 90s; active reconciliation
per online host restores missing-but-alive sandboxes and stops orphans
- Graceful host delete: returns 409 with affected sandbox list without
?force=true; force-delete destroys sandboxes then evicts pool client
- Snapshot delete broadcasts to all online hosts (templates have no host_id)
- sandbox.Manager.PauseAll: pauses all running VMs on CP connectivity loss
- New migration: host_refresh_tokens table with token rotation (issue-then-
revoke ordering to prevent lockout on mid-rotation crash)
- New sandbox status 'missing' (reversible, unlike 'stopped') and host
status 'unreachable'; both reflected in OpenAPI spec
- Fix: refresh token auth failure now returns 401 (was 400 via generic
'invalid' substring match in serviceErrToHTTP)
- REST API (chi router): sandbox CRUD, exec, pause/resume, file write/read
- PostgreSQL persistence via pgx/v5 + sqlc (sandboxes table with goose migration)
- Connect RPC client to host agent for all VM operations
- Reconciler syncs host agent state with DB every 30s (detects TTL-reaped sandboxes)
- OpenAPI 3.1 spec served at /openapi.yaml, Swagger UI at /docs
- Added WriteFile/ReadFile RPCs to hostagent proto and implementations
- File upload via multipart form, download via JSON body POST
- sandbox_id propagated from control plane to host agent on create
