[fs] Migrate filesystem abstraction to afero

Author: infogulch

build.go

@@ -8,7 +8,6 @@ import (
 	"encoding/base64"
 	"fmt"
 	"io"
-	"io/fs"
 	"log/slog"
 	"net/http"
 	"path"
@@ -21,6 +20,7 @@ import (
 
 	"github.com/andybalholm/brotli"
 	"github.com/klauspost/compress/zstd"
+	"github.com/spf13/afero"
 	"github.com/tdewolff/minify/v2"
 )
 
@@ -171,7 +171,7 @@ func catch(description string, fn func()) (err error) {
 var routeMatcher *regexp.Regexp = regexp.MustCompile("^(GET|POST|PUT|PATCH|DELETE|SSE) (.*)$")
 
 func (b *builder) addTemplateHandler(path_ string) error {
-	content, err := fs.ReadFile(b.config.TemplatesFS, path_)
+	content, err := afero.ReadFile(b.config.TemplatesFS, path_)
 	if err != nil {
 		return fmt.Errorf("could not read template file '%s': %v", path_, err)
 	}

config.go

@@ -6,8 +6,9 @@ import (
 	"context"
 	"fmt"
 	"html/template"
-	"io/fs"
 	"log/slog"
+
+	"github.com/spf13/afero"
 )
 
 func New() (c *Config) {
@@ -17,11 +18,11 @@ func New() (c *Config) {
 }
 
 type Config struct {
-	// The path to the templates directory. Default `templates`.
+	// The path to the templates directory within the filesystem. Default `templates`.
 	TemplatesDir string `json:"templates_dir,omitempty" arg:"-t,--template-dir" default:"templates"`
 
-	// The FS to load templates from. Overrides TemplatesDir if not nil.
-	TemplatesFS fs.FS `json:"-" arg:"-"`
+	// The FS to load templates from. Default: a FS made from the current working directory.
+	TemplatesFS afero.Fs `json:"-" arg:"-"`
 
 	// File extension to search for to find template files. Default `.html`.
 	TemplateExtension string `json:"template_extension,omitempty" arg:"--template-ext" default:".html"`
@@ -92,7 +93,7 @@ func (c *Config) Options(options ...Option) (*Config, error) {
 
 type Option func(*Config) error
 
-func WithTemplateFS(fs fs.FS) Option {
+func WithTemplateFS(fs afero.Fs) Option {
 	return func(c *Config) error {
 		if fs == nil {
 			return fmt.Errorf("nil fs")

dot_fs.go

@@ -6,77 +6,68 @@ import (
 	"io"
 	"io/fs"
 	"log/slog"
-	"path"
-)
 
-type dotFS struct {
-	fs     fs.FS
-	log    *slog.Logger
-	opened map[fs.File]struct{}
-}
+	"github.com/spf13/afero"
+)
 
 // Dir
 type Dir struct {
-	dot  *dotFS
-	path string
+	fs     afero.Fs
+	log    *slog.Logger
+	opened map[afero.File]struct{}
 }
 
-// Dir returns a
-func (d Dir) Dir(name string) (Dir, error) {
-	name = path.Clean(name)
-	if st, err := d.Stat(name); err != nil {
-		return Dir{}, err
-	} else if !st.IsDir() {
-		return Dir{}, fmt.Errorf("not a directory: %s", name)
+// Chroot returns a copy of the filesystem with root changed to path.
+func (d Dir) Chroot(path string) (Dir, error) {
+	if _, err := d.fs.Stat(path); err != nil {
+		return Dir{}, fmt.Errorf("failed to chroot to %#v: %w", path, err)
 	}
-	return Dir{dot: d.dot, path: path.Join(d.path, name)}, nil
+	fs := afero.NewBasePathFs(d.fs, path)
+	return Dir{
+		fs:     fs,
+		log:    d.log,
+		opened: d.opened,
+	}, nil
 }
 
-// List reads and returns a slice of names from the given directory relative to
-// the FS root.
-func (d Dir) List(name string) ([]fs.DirEntry, error) {
-	return fs.ReadDir(d.dot.fs, path.Join(d.path, path.Clean(name)))
+// ReadDir reads the directory named by dirname and returns a list of directory entries sorted by filename.
+func (d Dir) ReadDir(path string) ([]fs.FileInfo, error) {
+	return afero.ReadDir(d.fs, path)
 }
 
 // Exists returns true if filename can be opened successfully.
-func (d Dir) Exists(name string) bool {
-	name = path.Join(d.path, path.Clean(name))
-	file, err := d.Open(name)
-	if err == nil {
-		file.Close()
-		return true
-	}
-	return false
+func (d Dir) Exists(filename string) bool {
+	_, err := d.fs.Stat(filename)
+	return err == nil
 }
 
 // Stat returns Stat of a filename.
 //
 // Note: if you intend to read the file, afterwards, calling .Open instead may
 // be more efficient.
-func (d Dir) Stat(name string) (fs.FileInfo, error) {
-	name = path.Join(d.path, path.Clean(name))
-	file, err := d.dot.fs.Open(name)
-	if err != nil {
-		return nil, err
-	}
-	defer file.Close()
-	return file.Stat()
+func (d Dir) Stat(filename string) (fs.FileInfo, error) {
+	return d.fs.Stat(filename)
 }
 
 // Read returns the contents of a filename relative to the FS root as a string.
 func (d Dir) Read(name string) (string, error) {
-	name = path.Join(d.path, path.Clean(name))
-
 	buf := bufPool.Get().(*bytes.Buffer)
 	buf.Reset()
 	defer bufPool.Put(buf)
+	defer buf.Reset()
 
-	file, err := d.dot.fs.Open(name)
+	file, err := d.fs.Open(name)
 	if err != nil {
 		return "", err
 	}
 	defer file.Close()
 
+	stat, err := file.Stat()
+	if err != nil {
+		return "", err
+	}
+	buf.Grow(int(stat.Size()))
+
 	_, err = io.Copy(buf, file)
 	if err != nil {
 		return "", err
@@ -86,16 +77,14 @@ func (d Dir) Read(name string) (string, error) {
 }
 
 // Open opens the file
-func (d Dir) Open(name string) (fs.File, error) {
-	name = path.Join(d.path, path.Clean(name))
-
-	file, err := d.dot.fs.Open(name)
+func (d Dir) Open(filename string) (afero.File, error) {
+	file, err := d.fs.Open(filename)
 	if err != nil {
-		return nil, fmt.Errorf("failed to open file at path '%s': %w", name, err)
+		return nil, fmt.Errorf("failed to open file at path %#v: %w", filename, err)
 	}
 
-	d.dot.log.Debug("opened file", slog.String("path", name))
-	d.dot.opened[file] = struct{}{}
+	d.log.Debug("opened file", slog.String("filename", filename))
+	d.opened[file] = struct{}{}
 
-	return d.dot.fs.Open(name)
+	return file, nil
 }

dot_fs_config.go

@@ -6,13 +6,14 @@ import (
 	"fmt"
 	"io/fs"
 	"log/slog"
-	"os"
+
+	"github.com/spf13/afero"
 )
 
 // WithDir creates an [xtemplate.Option] that can be used with
 // [xtemplate.Config.Server], [xtemplate.Config.Instance], or [xtemplate.Main]
 // to add an fs dot provider to the config.
-func WithDir(name string, fs fs.FS) Option {
+func WithDir(name string, fs afero.Fs) Option {
 	return func(c *Config) error {
 		if fs == nil {
 			return fmt.Errorf("cannot create DotFSProvider with null FS with name %s", name)
@@ -27,9 +28,10 @@ func WithDir(name string, fs fs.FS) Option {
 //
 // By setting a cli flag: “
 type DotDirConfig struct {
-	Name  string `json:"name"`
-	fs.FS `json:"-"`
-	Path  string `json:"path"`
+	Name string   `json:"name"`
+	Path string   `json:"path"`
+	Type string   `json:"type"`
+	FS   afero.Fs `json:"-"`
 }
 
 var _ CleanupDotProvider = &DotDirConfig{}
@@ -39,7 +41,7 @@ func (p *DotDirConfig) Init(ctx context.Context) error {
 	if p.FS != nil {
 		return nil
 	}
-	newfs := os.DirFS(p.Path)
+	newfs := afero.NewBasePathFs(afero.NewOsFs(), p.Path)
 	if _, err := newfs.(interface {
 		Stat(string) (fs.FileInfo, error)
 	}).Stat("."); err != nil {
@@ -49,10 +51,10 @@ func (p *DotDirConfig) Init(ctx context.Context) error {
 	return nil
 }
 func (p *DotDirConfig) Value(r Request) (any, error) {
-	return Dir{dot: &dotFS{p.FS, GetLogger(r.R.Context()), make(map[fs.File]struct{})}, path: "."}, nil
+	return Dir{p.FS, GetLogger(r.R.Context()), make(map[afero.File]struct{})}, nil
 }
 func (p *DotDirConfig) Cleanup(a any, err error) error {
-	v := a.(Dir).dot
+	v := a.(Dir)
 	errs := []error{}
 	for file := range v.opened {
 		if err := file.Close(); err != nil {

go.mod

@@ -20,6 +20,7 @@ require (
 	github.com/microcosm-cc/bluemonday v1.0.27
 	github.com/nats-io/nats-server/v2 v2.10.24
 	github.com/nats-io/nats.go v1.38.0
+	github.com/spf13/afero v1.14.0
 	github.com/tdewolff/minify/v2 v2.21.2
 	github.com/yuin/goldmark v1.7.8
 	github.com/yuin/goldmark-highlighting/v2 v2.0.0-20230729083705-37449abec8cc
@@ -115,7 +116,6 @@ require (
 	github.com/spf13/cobra v1.9.1 // indirect
 	github.com/spf13/pflag v1.0.6 // indirect
 	github.com/stoewer/go-strcase v1.2.0 // indirect
-	github.com/stretchr/testify v1.10.0 // indirect
 	github.com/tailscale/tscert v0.0.0-20240608151842-d3f834017e53 // indirect
 	github.com/tdewolff/parse/v2 v2.7.19 // indirect
 	github.com/urfave/cli v1.22.14 // indirect
@@ -134,7 +134,7 @@ require (
 	golang.org/x/mod v0.24.0 // indirect
 	golang.org/x/net v0.38.0 // indirect
 	golang.org/x/sync v0.12.0 // indirect
-	golang.org/x/sys v0.31.0 // indirect
+	golang.org/x/sys v0.34.0 // indirect
 	golang.org/x/term v0.30.0 // indirect
 	golang.org/x/text v0.23.0 // indirect
 	golang.org/x/time v0.11.0 // indirect
@@ -143,6 +143,5 @@ require (
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20241007155032-5fefd90f89a9 // indirect
 	google.golang.org/grpc v1.67.1 // indirect
 	google.golang.org/protobuf v1.35.1 // indirect
-	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
 	howett.net/plist v1.0.0 // indirect
 )