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|
// pty-prompt is a PTY broker for LLM-driven interactive prompts.
//
// An LLM (or any caller that cannot hold a persistent connection) drives an
// interactive program — e.g. `git add -p`, `git rebase -i`, an installer
// wizard — across many separate process invocations. The tricky part is that
// *something* has to keep the pseudo-terminal and the spawned process alive
// between those invocations. pty-prompt does that by splitting itself into:
//
// - a background daemon that owns the PTY, the spawned child process and a
// rolling buffer of everything the child has written, and
// - a thin CLI client that the LLM calls once per request, talking to the
// daemon over a unix-domain socket.
//
// The surface is intentionally tiny — five verbs:
//
// start spawn a command under a PTY held by a background daemon
// step [TEXT] write TEXT + Enter (or just re-poll if TEXT is omitted),
// wait for output to settle, return everything new since
// the input. With no TEXT it only re-polls.
// wait block until the child exits, then return everything since
// the call plus the exit status (no quiescence heuristic)
// stop graceful shutdown (SIGTERM, then SIGKILL after a grace)
// kill-session force shutdown (SIGKILL immediately)
//
// Because a prompt-based program never tells us "I am done", step uses a
// quiescence heuristic: after sending input we wait until the child has
// produced no new bytes for --timeout milliseconds, then return what
// accumulated. When you instead want to wait for real completion (e.g. a
// non-interactive build), the wait verb blocks until the child actually exits.
// Output is ANSI-stripped by default (pass --raw to keep escape codes, e.g. for
// full-screen TUIs).
package main
import (
"bufio"
"context"
"encoding/json"
"errors"
"fmt"
"io"
"net"
"os"
"os/exec"
"os/signal"
"path/filepath"
"regexp"
"strconv"
"strings"
"sync"
"syscall"
"time"
"github.com/creack/pty"
)
const (
defaultSession = "default"
defaultTimeout = 500 * time.Millisecond // quiet period that counts as "settled"
defaultMaxWait = 30 * time.Second // hard cap on how long a step read may block
defaultWaitCap = 60 * time.Minute // default hard cap for the wait verb
defaultCols = 120
defaultRows = 40
bufferCap = 1 << 20 // keep at most the last 1 MiB of output
pollInterval = 20 * time.Millisecond
daemonReadyByte = 'K'
)
// request is the wire format the client sends to the daemon (one JSON object
// per connection, newline-terminated).
type request struct {
Op string `json:"op"` // step | wait | status | stop | kill
Text string `json:"text,omitempty"` // payload for step (Enter is always appended)
TimeoutMs int `json:"timeout_ms,omitempty"` // step: quiescence window
MaxWaitMs int `json:"max_wait_ms,omitempty"` // wait: hard cap on how long to block for exit
Raw bool `json:"raw,omitempty"` // return raw bytes instead of ANSI-stripped
}
// response is what the daemon writes back (JSON, newline-terminated).
type response struct {
Data string `json:"data"` // output bytes since the input (ANSI-stripped unless raw)
Exited bool `json:"exited"` // has the child exited?
ExitErr string `json:"exit_err,omitempty"` // child's exit error, if any
Err string `json:"err,omitempty"` // protocol/handler error
RunningMs int `json:"running_ms,omitempty"` // ms since the session (daemon) started
QuietMs int `json:"quiet_ms,omitempty"` // ms since the child last produced output
}
func main() {
if len(os.Args) < 2 {
usage(os.Stderr)
os.Exit(2)
}
cmd := os.Args[1]
args := os.Args[2:]
var err error
switch cmd {
case "__daemon":
err = runDaemon(args)
case "start":
err = cmdStart(args)
case "step":
err = cmdStep(args)
case "wait":
err = cmdWait(args)
case "stop":
err = cmdStop(args)
case "kill-session":
err = cmdKill(args)
case "-h", "--help", "help":
usage(os.Stdout)
return
default:
fmt.Fprintf(os.Stderr, "[pty-prompt: %s | unknown command %q]\n\n", nowStamp(), cmd)
usage(os.Stderr)
os.Exit(2)
}
if err != nil {
fmt.Fprintf(os.Stderr, "[pty-prompt: %s | %v]\n", nowStamp(), err)
os.Exit(1)
}
}
func usage(w io.Writer) {
fmt.Fprint(w, `pty-prompt — PTY broker for LLM-driven interactive prompts
USAGE:
pty-prompt start [--session NAME] [--timeout MS] [--raw] -- CMD [ARGS...]
Spawn CMD under a PTY held by a background daemon, then print the
program's initial output (after it goes quiet for --timeout ms).
pty-prompt step [--session NAME] [--timeout MS] [--raw] [TEXT]
Write TEXT followed by Enter, wait for the output to settle, and print
everything produced since the input. With no TEXT, only re-poll (useful
when a program is still working). This is the one verb you iterate with:
e.g. "pty-prompt step y" answers a prompt and shows the next one.
pty-prompt wait [--session NAME] [--max-wait MS] [--raw]
Block until the child exits, then print everything produced since the
call plus the exit status. Unlike step, there is no quiet-window
heuristic — the only stopping condition is real completion. Use this for
non-interactive commands (e.g. a build) where you just want the result.
--max-wait caps the block (default 60m) so a wedged child can't hang you.
pty-prompt stop [--session NAME]
Gracefully terminate the child (SIGTERM, then SIGKILL after a grace
period) and shut the daemon down.
pty-prompt kill-session [--session NAME]
Force-terminate the child (SIGKILL immediately) and shut the daemon
down. Use when a child is wedged and ignores SIGTERM.
NOTES:
- --session defaults to "default", so simple use needs no name.
- --timeout is the "quiet" window (ms) that counts as settled (default 500).
- --max-wait (wait verb) caps how long to block for exit (default 60m).
- Output is ANSI-stripped by default; pass --raw to keep escape codes (e.g.
for full-screen TUIs).
- There is no reliable "done" signal for prompt-based programs; step simply
waits until no new bytes arrive for --timeout. When the child exits, step
reports it. For a real "wait for completion", use the wait verb.
- Every invocation prints a one-line status to stderr (program output stays
on stdout), e.g.:
[pty-prompt: 13:58:42 | running for 16s, quiet for 1.5s, still running]
[pty-prompt: 14:00:56 | running for 2m14s, quiet for 0.3s, exited: exit status 1]
[pty-prompt: 14:00:56 | ran for 2m14s, exited, session "build" stopped]
The leading HH:MM:SS is the wall-clock time (an absolute reference across
polls); "running for" is time since the session started; "quiet for" is time
since the child last produced output (useful to tell progress from a hang).
`)
}
// ───────────────────────────── client side ─────────────────────────────
func cmdStart(args []string) error {
session := defaultSession
timeout := defaultTimeout
raw := false
var cmdArgs []string
i := 0
for i < len(args) {
a := args[i]
switch {
case a == "--":
cmdArgs = args[i+1:]
i = len(args)
case a == "--session":
session, i = needVal(args, i)
case strings.HasPrefix(a, "--session="):
session = strings.TrimPrefix(a, "--session=")
i++
case a == "--timeout":
var v string
v, i = needVal(args, i)
timeout = msOr(v, timeout)
case a == "--raw":
raw = true
i++
default:
return fmt.Errorf("start: unexpected argument %q (did you forget -- before the command?)", a)
}
}
if len(cmdArgs) == 0 {
return errors.New("start: missing command; usage: pty-prompt start [opts] -- CMD [ARGS...]")
}
sock := socketPath(session)
if isAlive(sock) {
// Report how long the existing session has been running, if reachable.
if resp, err := call(session, request{Op: "status"}); err == nil {
return fmt.Errorf("session %q already running for %s (stop it first)",
session, humanDuration(resp.RunningMs))
}
return fmt.Errorf("session %q already running (stop it first)", session)
}
_ = os.Remove(sock)
if err := os.MkdirAll(filepath.Dir(sock), 0o700); err != nil {
return err
}
// Re-exec ourselves as the detached daemon.
self, err := os.Executable()
if err != nil {
return err
}
dArgs := []string{"__daemon",
"--session", session,
"--cols", strconv.Itoa(defaultCols),
"--rows", strconv.Itoa(defaultRows),
"--",
}
dArgs = append(dArgs, cmdArgs...)
// Pipe so we can block until the daemon signals readiness.
pr, pw, err := os.Pipe()
if err != nil {
return err
}
daemon := exec.Command(self, dArgs...)
daemon.Stdin = nil
daemon.Stdout = pw
// Send the detached daemon's stderr to a per-session log file rather than
// inheriting ours. The daemon outlives this `start` invocation; if it held
// our stderr open, a caller that pipes `start` (e.g. `| tail`) would hang
// waiting for EOF that never comes until the daemon dies.
if logf, err := os.Create(socketPath(session) + ".log"); err == nil {
daemon.Stderr = logf
defer logf.Close()
} else {
daemon.Stderr = nil
}
daemon.SysProcAttr = &syscall.SysProcAttr{Setsid: true} // detach into its own session
if err := daemon.Start(); err != nil {
pr.Close()
pw.Close()
return err
}
pw.Close()
// Wait for the readiness byte (or EOF on early failure).
buf := make([]byte, 1)
if _, err := io.ReadFull(pr, buf); err != nil {
pr.Close()
return fmt.Errorf("start: daemon failed to come up: %w", err)
}
pr.Close()
_ = daemon.Process.Release()
// Now grab the initial output.
resp, err := call(session, request{Op: "step", TimeoutMs: int(timeout / time.Millisecond), Raw: raw})
if err != nil {
return err
}
return emit(resp)
}
// cmdStep is the one verb you iterate with: write TEXT + Enter (or just
// re-poll if TEXT is omitted), wait for the output to settle, and print
// everything produced since the input.
func cmdStep(args []string) error {
session := defaultSession
timeout := defaultTimeout
raw := false
var rest []string
i := 0
for i < len(args) {
a := args[i]
switch {
case a == "--session":
session, i = needVal(args, i)
case strings.HasPrefix(a, "--session="):
session = strings.TrimPrefix(a, "--session=")
i++
case a == "--timeout":
var v string
v, i = needVal(args, i)
timeout = msOr(v, timeout)
case a == "--raw":
raw = true
i++
case a == "--":
rest = append(rest, args[i+1:]...)
i = len(args)
default:
rest = append(rest, a)
i++
}
}
// TEXT is optional: with no TEXT, step only re-polls (no input written).
text := strings.Join(rest, " ")
resp, err := call(session, request{
Op: "step",
Text: text,
TimeoutMs: int(timeout / time.Millisecond),
Raw: raw,
})
if err != nil {
return err
}
return emit(resp)
}
// cmdWait blocks until the child exits, then prints everything produced since
// the call plus the exit status. Unlike step, it has no quiet-window heuristic:
// the only stopping condition is real completion (bounded by --max-wait).
func cmdWait(args []string) error {
session := defaultSession
maxWait := defaultWaitCap
raw := false
i := 0
for i < len(args) {
a := args[i]
switch {
case a == "--session":
session, i = needVal(args, i)
case strings.HasPrefix(a, "--session="):
session = strings.TrimPrefix(a, "--session=")
i++
case a == "--max-wait":
var v string
v, i = needVal(args, i)
maxWait = msOr(v, maxWait)
case strings.HasPrefix(a, "--max-wait="):
maxWait = msOr(strings.TrimPrefix(a, "--max-wait="), maxWait)
i++
case a == "--raw":
raw = true
i++
default:
return fmt.Errorf("wait: unexpected argument %q", a)
}
}
resp, err := call(session, request{
Op: "wait",
MaxWaitMs: int(maxWait / time.Millisecond),
Raw: raw,
})
if err != nil {
return err
}
return emit(resp)
}
func cmdStop(args []string) error {
return shutdown(sessionOnly(args), "stop")
}
func cmdKill(args []string) error {
return shutdown(sessionOnly(args), "kill")
}
// shutdown sends a stop/kill request and waits for the daemon to tear down its
// socket so a subsequent start sees a clean slate.
func shutdown(session, op string) error {
resp, err := call(session, request{Op: op})
if err != nil && !errors.Is(err, io.EOF) {
// The daemon closes the connection as it exits, so EOF is expected.
if !isConnReset(err) {
return err
}
}
sock := socketPath(session)
deadline := time.Now().Add(3 * time.Second)
for time.Now().Before(deadline) {
if !isAlive(sock) {
break
}
time.Sleep(20 * time.Millisecond)
}
_ = os.Remove(sock)
_ = os.Remove(sock + ".log")
// At-stop child state, folded into the status line alongside the run time.
state := "still running at stop"
if resp.Exited {
if resp.ExitErr != "" {
state = "exited: " + resp.ExitErr
} else {
state = "exited"
}
}
fmt.Fprintf(os.Stderr, "[pty-prompt: %s | ran for %s, %s, session %q stopped]\n",
nowStamp(), humanDuration(resp.RunningMs), state, session)
return nil
}
// call connects to a session daemon, sends one request and reads one response.
func call(session string, req request) (response, error) {
sock := socketPath(session)
conn, err := net.DialTimeout("unix", sock, 2*time.Second)
if err != nil {
return response{}, fmt.Errorf("no running session %q (start one with: pty-prompt start --session %s -- CMD)", session, session)
}
defer conn.Close()
enc := json.NewEncoder(conn)
if err := enc.Encode(req); err != nil {
return response{}, err
}
var resp response
dec := json.NewDecoder(bufio.NewReader(conn))
if err := dec.Decode(&resp); err != nil {
return response{}, err
}
if resp.Err != "" {
return resp, fmt.Errorf("%s", resp.Err)
}
return resp, nil
}
// emit prints the raw program output to stdout and a one-line status to stderr.
// The status line is always printed — including when there is no new output
// (the common "still running, nothing new" poll) — since that is exactly when
// the running/quiet timing is most useful.
func emit(resp response) error {
io.WriteString(os.Stdout, resp.Data)
state := "still running"
if resp.Exited {
if resp.ExitErr != "" {
state = "exited: " + resp.ExitErr
} else {
state = "exited"
}
}
fmt.Fprintf(os.Stderr, "[pty-prompt: %s | running for %s, quiet for %s, %s]\n",
nowStamp(), humanDuration(resp.RunningMs), humanDuration(resp.QuietMs), state)
return nil
}
// ───────────────────────────── daemon side ─────────────────────────────
type broker struct {
mu sync.Mutex
buf []byte // rolling output buffer (capped at bufferCap)
lastData time.Time // when the last byte arrived
startedAt time.Time // when the session (daemon) started
exited bool
exitErr error
ptmx *os.File
cmd *exec.Cmd
ctx context.Context // cancelled when the daemon should shut down
cancel context.CancelFunc // call to request shutdown (stop op, signal, child exit)
waitOnce sync.Once // guards the single allowed exec.Cmd.Wait()
termOnce sync.Once // guards teardown so it runs exactly once
}
// reap calls cmd.Wait() at most once and records the exit status. Both the
// read loop (on PTY EOF) and terminate() funnel through here, so Wait is never
// called twice.
func (b *broker) reap() {
b.waitOnce.Do(func() {
werr := b.cmd.Wait()
b.mu.Lock()
b.exited = true
b.exitErr = werr
b.mu.Unlock()
})
}
func runDaemon(args []string) error {
session := defaultSession
cols, rows := defaultCols, defaultRows
var cmdArgs []string
i := 0
for i < len(args) {
a := args[i]
switch {
case a == "--session":
session, i = needVal(args, i)
case a == "--cols":
var v string
v, i = needVal(args, i)
cols = atoiOr(v, cols)
case a == "--rows":
var v string
v, i = needVal(args, i)
rows = atoiOr(v, rows)
case a == "--":
cmdArgs = args[i+1:]
i = len(args)
default:
return fmt.Errorf("__daemon: unexpected arg %q", a)
}
}
if len(cmdArgs) == 0 {
return errors.New("__daemon: missing command")
}
sock := socketPath(session)
ln, err := net.Listen("unix", sock)
if err != nil {
return fmt.Errorf("__daemon: listen: %w", err)
}
defer ln.Close()
defer os.Remove(sock)
child := exec.Command(cmdArgs[0], cmdArgs[1:]...)
child.Env = append(os.Environ(), "TERM=xterm-256color")
ptmx, err := pty.StartWithSize(child, &pty.Winsize{Cols: uint16(cols), Rows: uint16(rows)})
if err != nil {
return fmt.Errorf("__daemon: start pty: %w", err)
}
defer ptmx.Close()
// The daemon's whole lifecycle hangs off this context. It is cancelled by:
// - a SIGTERM/SIGINT (via signal.NotifyContext),
// - a `stop` request from a client,
// - the child process exiting (readLoop calls cancel()).
ctx, cancel := signal.NotifyContext(context.Background(), syscall.SIGTERM, syscall.SIGINT)
defer cancel()
now := time.Now()
b := &broker{ptmx: ptmx, cmd: child, lastData: now, startedAt: now, ctx: ctx, cancel: cancel}
// Reader goroutine: drain the PTY into the rolling buffer until EOF.
go b.readLoop()
// When the context is cancelled, terminate the child and unblock Accept by
// closing the listener. This is the single, deterministic shutdown path.
go func() {
<-ctx.Done()
b.terminate()
ln.Close()
}()
// Tell the parent (start) we are ready to accept connections.
if _, err := os.Stdout.Write([]byte{daemonReadyByte}); err == nil {
os.Stdout.Close()
}
for {
conn, err := ln.Accept()
if err != nil {
return nil // listener closed → context cancelled, shutting down
}
b.handle(conn)
conn.Close()
}
}
func (b *broker) readLoop() {
rd := make([]byte, 4096)
for {
n, err := b.ptmx.Read(rd)
if n > 0 {
b.mu.Lock()
b.buf = append(b.buf, rd[:n]...)
if len(b.buf) > bufferCap {
b.buf = b.buf[len(b.buf)-bufferCap:]
}
b.lastData = time.Now()
b.mu.Unlock()
}
if err != nil {
// EOF / child closed the PTY: record exit status. We do NOT cancel
// the context here — the daemon stays up after the child exits so a
// final `read`/`status` can still retrieve the last output and the
// exit result. Shutdown happens on an explicit `stop` or a signal.
b.reap()
return
}
}
}
// handle processes a single request.
func (b *broker) handle(conn net.Conn) {
var req request
dec := json.NewDecoder(conn)
if err := dec.Decode(&req); err != nil {
writeResp(conn, response{Err: "bad request: " + err.Error()})
return
}
timeout := durMs(req.TimeoutMs, defaultTimeout)
maxWait := defaultMaxWait
switch req.Op {
case "step":
// Mark the buffer position before writing, so the snapshot returns only
// what the child produces in response (including the echo of our input).
marker := b.bufLen()
if req.Text != "" {
if _, err := b.ptmx.Write([]byte(req.Text + "\r")); err != nil {
writeResp(conn, response{Err: "write: " + err.Error()})
return
}
// Wait for the child to start responding before measuring quiescence.
// Otherwise, on a slow program (or right after start, while the shell
// is still enabling echo), the quiet window can elapse before any
// byte arrives and we return an empty reply.
b.waitForData(marker, timeout, maxWait)
}
b.waitQuiet(timeout, maxWait)
writeResp(conn, b.snapshot(marker, req.Raw))
case "wait":
// Block until the child exits (or the hard cap elapses), then return
// everything produced since this call. Unlike step, the only stopping
// condition is real completion — no quiet-window heuristic.
marker := b.bufLen()
cap := durMs(req.MaxWaitMs, defaultWaitCap)
b.waitExit(cap)
writeResp(conn, b.snapshot(marker, req.Raw))
case "status":
// Read-only probe: report timing and child state without touching input.
writeResp(conn, b.statusResp())
case "stop":
writeResp(conn, b.statusResp())
// Graceful shutdown: cancelling the context runs terminate() (SIGTERM,
// then SIGKILL after a grace) and tears down the listener.
b.cancel()
case "kill":
writeResp(conn, b.statusResp())
// Force shutdown: SIGKILL the child immediately, then cancel so the
// listener and daemon tear down.
b.forceKill()
b.cancel()
default:
writeResp(conn, response{Err: "unknown op: " + req.Op})
}
}
// waitForData blocks until the buffer has grown past `marker` (i.e. the child
// produced at least one byte in response to our input), or until `grace`
// elapses, or until the child exits / the daemon shuts down. It bounds the
// wait by maxWait as a safety net. This absorbs the startup/slow-program race
// where the quiescence window would otherwise expire before any reply arrives.
func (b *broker) waitForData(marker int, grace, maxWait time.Duration) {
bound := grace
if maxWait < bound {
bound = maxWait
}
ctx, cancel := context.WithTimeout(b.ctx, bound)
defer cancel()
ticker := time.NewTicker(pollInterval)
defer ticker.Stop()
for {
b.mu.Lock()
grown := len(b.buf) > marker
exited := b.exited
b.mu.Unlock()
if grown || exited {
return
}
select {
case <-ctx.Done():
return
case <-ticker.C:
}
}
}
// waitQuiet blocks until the child has produced no new output for `quiet`,
// or until `maxWait` elapses, or until the daemon's context is cancelled
// (shutdown). If the child has already exited and the buffer is drained, it
// returns promptly.
func (b *broker) waitQuiet(quiet, maxWait time.Duration) {
ctx, cancel := context.WithTimeout(b.ctx, maxWait)
defer cancel()
ticker := time.NewTicker(pollInterval)
defer ticker.Stop()
for {
b.mu.Lock()
idle := time.Since(b.lastData)
exited := b.exited
b.mu.Unlock()
if idle >= quiet {
return
}
if exited && idle >= quiet/2 {
// Child is gone; don't wait the full window for nothing.
return
}
select {
case <-ctx.Done():
// maxWait elapsed or the daemon is shutting down.
return
case <-ticker.C:
}
}
}
// waitExit blocks until the child process has exited, or until `cap` elapses,
// or until the daemon's context is cancelled (shutdown). This is the "wait for
// completion" primitive behind the wait verb: its only stopping condition is
// real exit, not a quiescence heuristic.
func (b *broker) waitExit(cap time.Duration) {
ctx, cancel := context.WithTimeout(b.ctx, cap)
defer cancel()
ticker := time.NewTicker(pollInterval)
defer ticker.Stop()
for {
b.mu.Lock()
exited := b.exited
b.mu.Unlock()
if exited {
return
}
select {
case <-ctx.Done():
// cap elapsed or the daemon is shutting down.
return
case <-ticker.C:
}
}
}
// snapshot returns the bytes produced since `marker`. Output is ANSI-stripped
// unless raw is set.
func (b *broker) snapshot(marker int, raw bool) response {
b.mu.Lock()
defer b.mu.Unlock()
if marker > len(b.buf) {
marker = len(b.buf)
}
data := b.buf[marker:]
out := string(data)
if !raw {
out = stripANSI(out)
}
return response{
Data: out,
Exited: b.exited,
ExitErr: errStr(b.exitErr),
RunningMs: int(time.Since(b.startedAt) / time.Millisecond),
QuietMs: int(time.Since(b.lastData) / time.Millisecond),
}
}
func (b *broker) bufLen() int {
b.mu.Lock()
defer b.mu.Unlock()
return len(b.buf)
}
func (b *broker) state() (exited bool, exitErr error) {
b.mu.Lock()
defer b.mu.Unlock()
return b.exited, b.exitErr
}
// statusResp reports the child's exit state plus timing (running/quiet), with
// no output payload. Used by the status/stop/kill ops.
func (b *broker) statusResp() response {
b.mu.Lock()
defer b.mu.Unlock()
return response{
Exited: b.exited,
ExitErr: errStr(b.exitErr),
RunningMs: int(time.Since(b.startedAt) / time.Millisecond),
QuietMs: int(time.Since(b.lastData) / time.Millisecond),
}
}
// terminate shuts the child down cleanly (SIGTERM, then SIGKILL after a grace
// period) and closes the PTY. It is idempotent.
func (b *broker) terminate() {
b.termOnce.Do(func() {
b.mu.Lock()
exited := b.exited
proc := b.cmd.Process
b.mu.Unlock()
if !exited && proc != nil {
_ = proc.Signal(syscall.SIGTERM)
done := make(chan struct{})
go func() { b.reap(); close(done) }()
select {
case <-done:
case <-time.After(2 * time.Second):
_ = proc.Kill()
b.reap()
}
}
// Closing the PTY also unblocks readLoop's Read.
_ = b.ptmx.Close()
})
}
// forceKill SIGKILLs the child immediately (no SIGTERM grace). Safe to call
// before terminate(); the subsequent context-cancel-driven terminate() is a
// no-op for the already-dead process and still closes the PTY.
func (b *broker) forceKill() {
b.mu.Lock()
exited := b.exited
proc := b.cmd.Process
b.mu.Unlock()
if !exited && proc != nil {
_ = proc.Kill()
b.reap()
}
}
func writeResp(conn net.Conn, resp response) {
enc := json.NewEncoder(conn)
_ = enc.Encode(resp)
}
// ───────────────────────────── helpers ─────────────────────────────
// ansiRe matches the terminal escape sequences we strip from returned output:
// CSI sequences (cursor moves, colours, erases: ESC [ ... final-byte), OSC
// sequences (ESC ] ... BEL or ST), and lone two-byte escapes (e.g. ESC =).
var ansiRe = regexp.MustCompile(`\x1b\[[0-9;?]*[ -/]*[@-~]` +
`|\x1b\][^\x07\x1b]*(?:\x07|\x1b\\)` +
`|\x1b[@-Z\\-_]`)
// stripANSI removes ANSI escape sequences and carriage returns so the caller
// gets clean, line-oriented text. CR is dropped (PTYs emit CRLF) but other
// printable content and newlines are preserved.
func stripANSI(s string) string {
s = ansiRe.ReplaceAllString(s, "")
s = strings.ReplaceAll(s, "\r", "")
return s
}
func socketDir() string {
base := os.Getenv("XDG_RUNTIME_DIR")
if base == "" {
base = os.TempDir()
}
return filepath.Join(base, "pty-prompt")
}
func socketPath(session string) string {
return filepath.Join(socketDir(), session+".sock")
}
// isAlive reports whether a daemon is accepting connections on sock.
func isAlive(sock string) bool {
conn, err := net.DialTimeout("unix", sock, 500*time.Millisecond)
if err != nil {
return false
}
conn.Close()
return true
}
func needVal(args []string, i int) (string, int) {
if i+1 >= len(args) {
return "", i + 1
}
return args[i+1], i + 2
}
func sessionOnly(args []string) string {
session := defaultSession
for i := 0; i < len(args); i++ {
switch {
case args[i] == "--session" && i+1 < len(args):
session = args[i+1]
i++
case strings.HasPrefix(args[i], "--session="):
session = strings.TrimPrefix(args[i], "--session=")
}
}
return session
}
func atoiOr(s string, def int) int {
if n, err := strconv.Atoi(s); err == nil {
return n
}
return def
}
func msOr(s string, def time.Duration) time.Duration {
if n, err := strconv.Atoi(s); err == nil && n >= 0 {
return time.Duration(n) * time.Millisecond
}
return def
}
func durMs(ms int, def time.Duration) time.Duration {
if ms <= 0 {
return def
}
return time.Duration(ms) * time.Millisecond
}
// humanDuration renders a millisecond count as a short, human-readable string:
// sub-second values keep one decimal ("0.4s"), whole seconds up to a minute are
// plain ("16s"), and a minute or more is "Mm Ss" ("2m14s").
func humanDuration(ms int) string {
if ms < 0 {
ms = 0
}
if ms < 1000 {
return fmt.Sprintf("%.1fs", float64(ms)/1000)
}
secs := ms / 1000
if secs < 60 {
return fmt.Sprintf("%ds", secs)
}
return fmt.Sprintf("%dm%ds", secs/60, secs%60)
}
// nowStamp is the current local wall-clock time as HH:MM:SS, prefixed to every
// status line so a caller polling across separate invocations has an absolute
// time reference (not just relative running/quiet durations).
func nowStamp() string {
return time.Now().Format("15:04:05")
}
func errStr(err error) string {
if err == nil {
return ""
}
return err.Error()
}
func isConnReset(err error) bool {
return errors.Is(err, syscall.ECONNRESET) || errors.Is(err, io.ErrUnexpectedEOF)
}
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