internet_share_tunnel

Internet share tunnel (temporary off-machine links)

Local AgentWorks servers bind loopback, so get_report_link / get_file_link URLs are same-machine previews. The internet share tunnel puts the running server on the internet through a Cloudflare quick tunnel (https://xxx.trycloudflare.com), after which those two tools return links any signed-in collaborator can open. No account, DNS, or deploy needed — cloudflared mints an ephemeral public URL on demand.

This is for temporary sharing (show a report for an hour). Durable public distribution stays on the publish flow (Vercel / Netlify / Pages / S3), which deploys static snapshots instead of exposing a live server.

Security model

• A tunnel exposes the whole server (every route), not one report. There are no anonymous links: recipients must still sign in and have workflow access, and tunnel traffic transits Cloudflare.
• Starting/stopping is admin-only, per invocation. In single-user mode the local user is an admin; in multi-user mode only directory admins.
• Default 1h expiry, max 8h. Expiry, manual stop, tunnel-process death, and server shutdown all kill the tunnel and clear the URL override, so links stop advertising a dead URL.
• Hardening that ships with this feature: /debug/pprof/* requires authentication (it used to ride the static-file exemption), and the /public/* share routes were audited — they enforce handler-level auth, workflow access, token scopes, and protected-path rules.

How it works

chat: manage_internet_share(action=start)
  → StartShareTunnel (admin check)
    → cloudflared tunnel --url http://127.0.0.1:<actualPort>
    → parse trycloudflare.com URL from stderr (45s timeout)
    → store override + arm expiry timer
  → get_report_link / get_file_link build URLs from the override
chat: manage_internet_share(action=stop|status) / expiry / shutdown
  → kill cloudflared, clear override

• agent_go/cmd/server/share_tunnel.go — supervisor, URL parsing, override, tool registration (manage_internet_share, action start|stop|status, optional duration_minutes), and GET /api/share-tunnel/status (admin-only, serves the Publish panel).
• The override lives only in effectiveShareBaseURL(), used solely by the two share-link builders. OAuth callbacks, Gmail, and bot connectors keep reading PUBLIC_URL env directly, so a temporary tunnel never rewrites their hosts.
• SetShareTunnelServerPort(actualPort) is called at startup because --port 0 (dynamic) makes the configured port wrong; StopShareTunnel() is called on server shutdown.
• CLOUDFLARED_BIN overrides the binary lookup (tests inject a stub). A missing binary errors with install instructions instead of auto-installing.
• Frontend: InternetShareSection in WorkflowPublishView shows the active URL + expiry with a whole-server warning, or a quiet inactive line. It hides entirely for non-admins (403). Start/stop stays in chat — the panel is status-only.
• Agent guidance: templates/system/secure-share-links.md points local-only link flows at the tool, with the never-start-without-explicit-request rule.

Operating notes

• One tunnel at a time; start while active returns the existing tunnel.
• A restart mints a new random URL — previously shared links break. Tell recipients links are temporary.
• If cloudflared prints no URL within 45s (slow edge assignment), start fails and the agent should retry; the supervisor kills the orphaned process.
• A fresh tunnel URL needs ~20-30s of DNS propagation before it resolves ("it may take some time to be reachable" in cloudflared's own words). If a recipient reports the link not resolving immediately after sharing, have them retry rather than re-sharing.
• Logs carry the [SHARE_TUNNEL] prefix (start/stop/expiry).