package httpapi

import (

"context"

"errors"

"time"

"golang.org/x/xerrors"

"cdr.dev/slog"

"github.com/coder/websocket"

)

// Heartbeat loops to ping a WebSocket to keep it alive.

// Default idle connection timeouts are typically 60 seconds.

// See: https://docs.aws.amazon.com/elasticloadbalancing/latest/application/application-load-balancers.html#connection-idle-timeout

func Heartbeat(ctx context.Context, conn *websocket.Conn) {

ticker := time.NewTicker(15 * time.Second)

defer ticker.Stop()

for {

select {

case <-ctx.Done():

return

case <-ticker.C:

}

err := conn.Ping(ctx)

if err != nil {

return

}

}

}

// Heartbeat loops to ping a WebSocket to keep it alive. It calls `exit` on ping

// failure.

func HeartbeatClose(ctx context.Context, logger slog.Logger, exit func(), conn *websocket.Conn) {

interval := 15 * time.Second

ticker := time.NewTicker(interval)

defer ticker.Stop()

for {

select {

case <-ctx.Done():

return

case <-ticker.C:

}

err := pingWithTimeout(ctx, conn, interval)

if err != nil {

// context.DeadlineExceeded is expected when the client disconnects without sending a close frame

if !errors.Is(err, context.DeadlineExceeded) {

logger.Error(ctx, "failed to heartbeat ping", slog.Error(err))

}

_ = conn.Close(websocket.StatusGoingAway, "Ping failed")

exit()

return

}

}

}

func pingWithTimeout(ctx context.Context, conn *websocket.Conn, timeout time.Duration) error {

ctx, cancel := context.WithTimeout(ctx, timeout)

defer cancel()

err := conn.Ping(ctx)

if err != nil {

return xerrors.Errorf("failed to ping: %w", err)

}

return nil

}