nssh: ntfy read deadlines + one-shot remote prep #3
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| Original file line number | Diff line number | Diff line change |
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@@ -24,11 +24,11 @@ import ( | |
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| var localhostRe = regexp.MustCompile(`(?:localhost|127\.0\.0\.1):(\d+)`) | ||
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| // prepareRemote probes the remote's nssh version and writes the session file + | ||
| // seeds the JSONL log in a single SSH login-shell invocation. Returns the | ||
| // remote nssh version, or "" if not installed / unreadable. Non-fatal on | ||
| // errors — shim may still work with a pinned config.toml or no log at all. | ||
| func prepareRemote(sshTarget string, cfg nsshConfig) string { | ||
| event := map[string]any{ | ||
| "ts": time.Now().UTC().Format(time.RFC3339Nano), | ||
| "event": "session-open", | ||
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@@ -40,9 +40,15 @@ func writeRemoteSession(sshTarget string, cfg nsshConfig) { | |
| } | ||
| eventJSON, _ := json.Marshal(event) | ||
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| // bash -l so PATH includes ~/.local/bin even for non-interactive sessions. | ||
| // Heredocs with quoted delimiters ('EOF') prevent shell expansion inside, | ||
| // so TOML and JSON pass through verbatim regardless of contents. | ||
| script := fmt.Sprintf(`set -e | ||
| if command -v nssh >/dev/null 2>&1; then | ||
| echo "NSSH_VERSION: $(nssh --version 2>/dev/null | head -1 | awk '{print $2}')" | ||
| else | ||
| echo "NSSH_VERSION: none" | ||
| fi | ||
| dir="${XDG_STATE_HOME:-$HOME/.local/state}/nssh" | ||
| mkdir -p "$dir" | ||
| cat > "$dir/session" <<'NSSH_SESSION_EOF' | ||
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@@ -54,12 +60,26 @@ cat >> "$dir/nssh.%s.jsonl" <<'NSSH_LOG_EOF' | |
| NSSH_LOG_EOF | ||
| `, cfg.Server, cfg.Topic, cfg.Topic, string(eventJSON)) | ||
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| cmd := exec.Command("ssh", "-o", "BatchMode=yes", sshTarget, "bash", "-l", "-s") | ||
| cmd.Stdin = strings.NewReader(script) | ||
| cmd.Stderr = os.Stderr | ||
| out, err := cmd.Output() | ||
| if err != nil { | ||
| fmt.Fprintf(os.Stderr, "nssh: remote prepare: %v\n", err) | ||
| return "" | ||
| } | ||
| for _, line := range strings.Split(string(out), "\n") { | ||
| v, ok := strings.CutPrefix(line, "NSSH_VERSION: ") | ||
| if !ok { | ||
| continue | ||
| } | ||
| v = strings.TrimSpace(v) | ||
| if v == "" || v == "none" { | ||
| return "" | ||
| } | ||
| return v | ||
| } | ||
| return "" | ||
| } | ||
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| func resolveShortHost(sshArgs []string) string { | ||
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@@ -177,10 +197,38 @@ func handleOpen(rawURL, sshTarget string) { | |
| } | ||
| } | ||
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| // deadlineConn wraps net.Conn to push the read deadline forward on every Read. | ||
| // The ntfy server sends keepalive events every ~55s, so if no bytes arrive | ||
| // for well past that window the connection is silently dead (laptop sleep, NAT | ||
| // rebind, proxy drop) — the next Read returns i/o timeout and the subscriber | ||
| // reconnects. Without this, Read can block forever on a zombie TCP socket. | ||
| type deadlineConn struct { | ||
| net.Conn | ||
| period time.Duration | ||
| } | ||
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| func (c *deadlineConn) Read(p []byte) (int, error) { | ||
| _ = c.Conn.SetReadDeadline(time.Now().Add(c.period)) | ||
| return c.Conn.Read(p) | ||
| } | ||
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| func subscribeNtfy(ctx context.Context, cfg nsshConfig, sshTarget string) { | ||
| topicURL := cfg.topicURL() | ||
| endpoint := topicURL + "/json" | ||
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| dialer := &net.Dialer{KeepAlive: 15 * time.Second} | ||
| client := &http.Client{ | ||
| Transport: &http.Transport{ | ||
| DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) { | ||
| conn, err := dialer.DialContext(ctx, network, addr) | ||
|
Comment on lines
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Replacing the default client transport with a custom Useful? React with 👍 / 👎. |
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| if err != nil { | ||
| return nil, err | ||
| } | ||
| return &deadlineConn{Conn: conn, period: 90 * time.Second}, nil | ||
| }, | ||
| ResponseHeaderTimeout: 30 * time.Second, | ||
| }, | ||
| } | ||
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There was a problem hiding this comment. Custom transport loses DefaultTransport's 30s dial timeoutMedium Severity The   Reviewed by Cursor Bugbot for commit 9af7c7e. Configure here. |
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| for { | ||
| if ctx.Err() != nil { | ||
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@@ -214,6 +262,9 @@ func subscribeNtfy(ctx context.Context, cfg nsshConfig, sshTarget string) { | |
| go handleMessage(msg, topicURL, sshTarget) | ||
| } | ||
| } | ||
| if err := scanner.Err(); err != nil && ctx.Err() == nil { | ||
| fmt.Fprintf(os.Stderr, "nssh: ntfy stream ended (%v) — reconnecting\n", err) | ||
| } | ||
| resp.Body.Close() | ||
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| select { | ||
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@@ -385,10 +436,6 @@ func nsshMain() { | |
| return | ||
| } | ||
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| cfg := loadConfig() | ||
| if cfg.Topic == "" { | ||
| cfg.Topic = generateTopic() | ||
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@@ -401,7 +448,23 @@ func nsshMain() { | |
| "server": cfg.Server, | ||
| }) | ||
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| // One SSH login-shell to probe version, write the session file, and seed | ||
| // the remote JSONL log before the interactive session starts. | ||
| remoteVer := prepareRemote(sshTarget, cfg) | ||
| if localVer := version(); looksLikeSemver(localVer) { | ||
| switch { | ||
| case remoteVer == "": | ||
| fmt.Fprintln(os.Stderr, "nssh: not installed on remote — clipboard bridge will not work") | ||
| if promptYes(" install it now?") { | ||
| infectRemote(sshTarget, false) | ||
| } | ||
| case remoteVer != localVer: | ||
| fmt.Fprintf(os.Stderr, "nssh: remote version %s, local %s\n", remoteVer, localVer) | ||
| if promptYes(" update remote to " + localVer + "?") { | ||
| infectRemote(sshTarget, false) | ||
| } | ||
| } | ||
| } | ||
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| ctx, cancel := context.WithCancel(context.Background()) | ||
| defer cancel() | ||
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Version output discarded when session write fails
Low Severity
The script uses
set -eand echoesNSSH_VERSION:beforemkdir/cat. If the version probe succeeds but session-file writing fails (permissions, disk full), the script exits non-zero. Go'scmd.Output()still returns the captured stdout, but theerr != nilcheck discards it and returns"". This causes a misleading "not installed on remote" prompt when nssh IS installed but the session directory is unwritable.Additional Locations (1)
cmd/nssh/main.go#L65-L69Reviewed by Cursor Bugbot for commit 9af7c7e. Configure here.