From 2d72790c1a6d8eaec52c3583442703f83ce52131 Mon Sep 17 00:00:00 2001
From: royalcat <k.adamovich20@gmail.com>
Date: Wed, 19 Jun 2024 00:17:10 +0300
Subject: [PATCH] logfs opened files

---
 cmd/tstor/main.go           |  5 ++++-
 src/export/nfs/kvhandler.go |  3 +--
 src/vfs/fs.go               |  3 ---
 src/vfs/log.go              | 42 ++++++++++++++++++++++++++++++++-----
 4 files changed, 42 insertions(+), 11 deletions(-)

diff --git a/cmd/tstor/main.go b/cmd/tstor/main.go
index 3e7ad43..23e874e 100644
--- a/cmd/tstor/main.go
+++ b/cmd/tstor/main.go
@@ -109,7 +109,10 @@ func run(configPath string) error {
 		vfs.NewCtxBillyFs("/", ctxbilly.WrapFileSystem(sourceFs)),
 		tsrv, ytdlpsrv,
 	)
-	sfs = vfs.WrapLogFS(sfs)
+	sfs, err = vfs.WrapLogFS(sfs)
+	if err != nil {
+		return err
+	}
 
 	if conf.Mounts.Fuse.Enabled {
 		mh := fuse.NewHandler(conf.Mounts.Fuse.AllowOther, conf.Mounts.Fuse.Path)
diff --git a/src/export/nfs/kvhandler.go b/src/export/nfs/kvhandler.go
index d84c94b..729a996 100644
--- a/src/export/nfs/kvhandler.go
+++ b/src/export/nfs/kvhandler.go
@@ -154,8 +154,7 @@ func (c *CachingHandler) InvalidateHandle(ctx context.Context, fs nfs.Filesystem
 	return c.activeHandles.Delete(ctx, id)
 }
 
-// const maxInt = int(^uint(0) >> 1)
-const maxHandlers = 8129
+const maxHandlers = int(^uint(0) >> 1)
 
 // HandleLimit exports how many file handles can be safely stored by this cache.
 func (c *CachingHandler) HandleLimit() int {
diff --git a/src/vfs/fs.go b/src/vfs/fs.go
index 88cc267..79cb242 100644
--- a/src/vfs/fs.go
+++ b/src/vfs/fs.go
@@ -8,7 +8,6 @@ import (
 	"time"
 
 	"github.com/royalcat/ctxio"
-	"go.opentelemetry.io/otel"
 )
 
 type File interface {
@@ -24,8 +23,6 @@ type File interface {
 
 var ErrNotImplemented = errors.New("not implemented")
 
-var tracer = otel.Tracer("git.kmsign.ru/royalcat/tstor/src/vfs")
-
 type Filesystem interface {
 	// Open opens the named file for reading. If successful, methods on the
 	// returned file can be used for reading; the associated file descriptor has
diff --git a/src/vfs/log.go b/src/vfs/log.go
index e229c73..ece02aa 100644
--- a/src/vfs/log.go
+++ b/src/vfs/log.go
@@ -3,19 +3,32 @@ package vfs
 import (
 	"context"
 	"errors"
+	"fmt"
 	"io/fs"
 	"log/slog"
 	"reflect"
 	"time"
 
 	"git.kmsign.ru/royalcat/tstor/pkg/rlog"
+	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/metric"
 	"go.opentelemetry.io/otel/trace"
 )
 
+var (
+	meter  = otel.Meter("git.kmsign.ru/royalcat/tstor/src/vfs")
+	tracer = otel.Tracer("git.kmsign.ru/royalcat/tstor/src/vfs")
+)
+
+type fsTelemetry struct {
+	openedFiles metric.Int64UpDownCounter
+}
+
 type LogFS struct {
 	fs  Filesystem
 	log *rlog.Logger
+	tel *fsTelemetry
 
 	timeout     time.Duration
 	readTimeout time.Duration
@@ -27,13 +40,19 @@ func isLoggableError(err error) bool {
 
 var _ Filesystem = (*LogFS)(nil)
 
-func WrapLogFS(vfs Filesystem) *LogFS {
+func WrapLogFS(vfs Filesystem) (*LogFS, error) {
+	openedFiles, err := meter.Int64UpDownCounter("vfs.opened_files")
+	if err != nil {
+		return nil, fmt.Errorf("failed to create opened_files metric: %w", err)
+	}
+
 	return &LogFS{
 		fs:          vfs,
 		log:         rlog.Component("logfs"),
+		tel:         &fsTelemetry{openedFiles: openedFiles},
 		timeout:     time.Minute * 3,
 		readTimeout: time.Minute,
-	}
+	}, nil
 }
 
 // ModTime implements Filesystem.
@@ -104,7 +123,12 @@ func (fs *LogFS) Open(ctx context.Context, filename string) (file File, err erro
 	if isLoggableError(err) {
 		fs.log.Error(ctx, "Failed to open file")
 	}
-	file = WrapLogFile(file, filename, fs.log, fs.readTimeout)
+	file = wrapLogFile(file, filename, fs.log, fs.readTimeout, fs.tel)
+
+	if file != nil {
+		fs.tel.openedFiles.Add(ctx, 1)
+	}
+
 	return file, err
 }
 
@@ -178,7 +202,9 @@ type LogFile struct {
 	filename string
 	f        File
 
-	log     *rlog.Logger
+	log *rlog.Logger
+	tel *fsTelemetry
+
 	timeout time.Duration
 }
 
@@ -194,11 +220,12 @@ func (f *LogFile) Type() fs.FileMode {
 
 var _ File = (*LogFile)(nil)
 
-func WrapLogFile(f File, filename string, log *rlog.Logger, timeout time.Duration) *LogFile {
+func wrapLogFile(f File, filename string, log *rlog.Logger, timeout time.Duration, tel *fsTelemetry) *LogFile {
 	return &LogFile{
 		filename: filename,
 		f:        f,
 		log:      log.With(slog.String("filename", filename)),
+		tel:      tel,
 		timeout:  timeout,
 	}
 }
@@ -221,6 +248,11 @@ func (f *LogFile) Close(ctx context.Context) (err error) {
 	if isLoggableError(err) {
 		f.log.Error(ctx, "Failed to close", rlog.Error(err))
 	}
+
+	if err != nil {
+		f.tel.openedFiles.Add(ctx, -1)
+	}
+
 	return err
 }