Files
codex/codex-rs/tcp-tunnel
richardopenai 8d44977aa2 Add opt-in JSON diagnostics for TCP tunnels (#50131)
## What changed

Add `codex tcp-tunnel --diagnostics-json` to emit versioned, newline-delimited JSON diagnostics on stderr. Records classify startup, CONNECT, transport, and control failures without exposing credentials, addresses, headers, or raw error messages. Rejected CONNECT records may include a validated `http_status`.

Distinguish terminal failures from recoverable stream and transport events, flush terminal records before returning a generic error, and preserve stdout readiness and credential acknowledgments. Keep human-readable diagnostics as the default and document the version 1 schema and consumer fallback rules.

## Testing

Add tests for bounded output, error-chain suppression, terminal flushing, control error classification, CONNECT status validation, legacy behavior, and flag parsing. Extend the reconnect test to exercise a rejected CONNECT followed by a successful connection in JSON mode.

GitOrigin-RevId: 350f67fe8e3f313e8a6d3bb0fd891952b77647fd
2026-10-02 00:46:14 +00:00
..

HTTP/3 TCP tunnel

The ordinary Codex binary includes the hidden codex tcp-tunnel command. It forwards a loopback TCP listener to an explicitly selected host and port through a TLS-verified HTTP/3 CONNECT proxy. The proxy URL must be an exact HTTPS origin in the supplied policy file; the target is provided separately as host:port or [IPv6]:port.

The initial bearer must be provided as a single line on standard input (--auth-token-stdin). With --auth-token-updates-stdin, later lines replace the bearer for new connections, emit AUTH_UPDATED, and closure of the controlling pipe stops the tunnel. With --connect-headers-stdin, the first line is instead a JSON list of ["x-name","value"] pairs; token lines follow. Only non-forwarding x- extension headers are accepted. No header values or credentials belong in the command arguments.

The process emits LISTENING 127.0.0.1:<port> after connecting to the proxy. A proxy handshake does not authorize the target; each local connection makes its own authenticated CONNECT. The listener survives transport reconnects, but TCP streams are never replayed.

--diagnostics-json opts into newline-delimited JSON on stderr. Version 1 contains v, phase (startup, connect, transport, or control), code (failed, timeout, rejected, closed, draining, or invalid_input), and terminal. A rejected CONNECT may also include a numeric http_status (100–599, excluding 2xx). Records contain no credentials, addresses, headers, or raw error messages and are less than 256 bytes. Stdout readiness and credential acknowledgments are unchanged. A terminal record is flushed before an unsuccessful return; closing the controlling pipe normally emits no failure. The CLI may append a generic error line after the terminal record. Nonterminal events may concern one TCP stream or a reconnecting shared transport and do not identify the cause of a later child-process failure. Consumers must ignore records with unknown versions or fields and keep a generic fallback for helpers without this flag.

Version 1 terminal combinations are startup/{failed,timeout}, control/{failed,invalid_input}, and transport/failed. Nonterminal combinations are connect/{failed,rejected} and transport/{failed,timeout,closed,draining}. Other combinations are unknown records and must use the generic fallback.