fix: ensure fd monitor file is closed at end of the script run

When running gptscript with providers and --events-stream-to flag, the
file passed to --events-stream-to would be closed after the provider was
setup. This is an error because the file should remain open for the
duration of the script run.

This change will ensure that the file is only closed when the script is
complete.

Additionally, this change introduces 0644 permissions when creating a
file passed to --events-stream-to.

Signed-off-by: Donnie Adams <donnie@acorn.io>

Author: thedadams

pkg/monitor/fd.go

@@ -7,6 +7,7 @@ import (
 	"strconv"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/gptscript-ai/gptscript/pkg/runner"
@@ -22,7 +23,8 @@ type Event struct {
 }
 
 type fileFactory struct {
-	file *os.File
+	file         *os.File
+	runningCount atomic.Int32
 }
 
 // NewFileFactory creates a new monitor factory that writes events to the location specified.
@@ -44,23 +46,26 @@ func NewFileFactory(loc string) (runner.MonitorFactory, error) {
 
 		file = os.NewFile(uintptr(fd), "events")
 	} else {
-		file, err = os.OpenFile(loc, os.O_WRONLY|os.O_CREATE, 0)
+		file, err = os.OpenFile(loc, os.O_WRONLY|os.O_CREATE, 0644)
 		if err != nil {
 			return nil, err
 		}
 	}
 
 	return &fileFactory{
-		file: file,
+		file:         file,
+		runningCount: atomic.Int32{},
 	}, nil
 }
 
-func (s fileFactory) Start(_ context.Context, prg *types.Program, env []string, input string) (runner.Monitor, error) {
+func (s *fileFactory) Start(_ context.Context, prg *types.Program, env []string, input string) (runner.Monitor, error) {
+	s.runningCount.Add(1)
 	fd := &fd{
-		prj:   prg,
-		env:   env,
-		input: input,
-		file:  s.file,
+		prj:     prg,
+		env:     env,
+		input:   input,
+		file:    s.file,
+		factory: s,
 	}
 
 	fd.event(Event{
@@ -74,12 +79,21 @@ func (s fileFactory) Start(_ context.Context, prg *types.Program, env []string,
 	return fd, nil
 }
 
+func (s *fileFactory) close() {
+	if count := s.runningCount.Add(-1); count == 0 {
+		if err := s.file.Close(); err != nil {
+			log.Errorf("error closing monitor file: %v", err)
+		}
+	}
+}
+
 type fd struct {
 	prj     *types.Program
 	env     []string
 	input   string
 	file    *os.File
 	runLock sync.Mutex
+	factory *fileFactory
 }
 
 func (f *fd) Event(event runner.Event) {
@@ -117,9 +131,7 @@ func (f *fd) Stop(output string, err error) {
 	}
 
 	f.event(e)
-	if err = f.file.Close(); err != nil {
-		log.Errorf("Failed to close file: %v", err)
-	}
+	f.factory.close()
 }
 
 func (f *fd) Pause() func() {