snapshot of https://github.com/golang-migrate/migrate.git (master, 2026-09-15; blobs > 131072B omitted)

source/httpfs/partial_driver.go

@@ -0,0 +1,156 @@
+package httpfs
+
+import (
+	"errors"
+	"io"
+	"net/http"
+	"os"
+	"path"
+	"strconv"
+
+	"github.com/golang-migrate/migrate/v4/source"
+)
+
+// PartialDriver is a helper service for creating new source drivers working with
+// http.FileSystem instances. It implements all source.Driver interface methods
+// except for Open(). New driver could embed this struct and add missing Open()
+// method.
+//
+// To prepare PartialDriver for use Init() function.
+type PartialDriver struct {
+	migrations *source.Migrations
+	fs         http.FileSystem
+	path       string
+}
+
+// Init prepares not initialized PartialDriver instance to read migrations from a
+// http.FileSystem instance and a relative path.
+func (p *PartialDriver) Init(fs http.FileSystem, path string) error {
+	root, err := fs.Open(path)
+	if err != nil {
+		return err
+	}
+
+	files, err := root.Readdir(0)
+	if err != nil {
+		_ = root.Close()
+		return err
+	}
+	if err = root.Close(); err != nil {
+		return err
+	}
+
+	ms := source.NewMigrations()
+	for _, file := range files {
+		if file.IsDir() {
+			continue
+		}
+
+		m, err := source.DefaultParse(file.Name())
+		if err != nil {
+			continue // ignore files that we can't parse
+		}
+
+		if !ms.Append(m) {
+			return source.ErrDuplicateMigration{
+				Migration: *m,
+				FileInfo:  file,
+			}
+		}
+	}
+
+	p.fs = fs
+	p.path = path
+	p.migrations = ms
+	return nil
+}
+
+// Close is part of source.Driver interface implementation. This is a no-op.
+func (p *PartialDriver) Close() error {
+	return nil
+}
+
+// First is part of source.Driver interface implementation.
+func (p *PartialDriver) First() (version uint, err error) {
+	if version, ok := p.migrations.First(); ok {
+		return version, nil
+	}
+	return 0, &os.PathError{
+		Op:   "first",
+		Path: p.path,
+		Err:  os.ErrNotExist,
+	}
+}
+
+// Prev is part of source.Driver interface implementation.
+func (p *PartialDriver) Prev(version uint) (prevVersion uint, err error) {
+	if version, ok := p.migrations.Prev(version); ok {
+		return version, nil
+	}
+	return 0, &os.PathError{
+		Op:   "prev for version " + strconv.FormatUint(uint64(version), 10),
+		Path: p.path,
+		Err:  os.ErrNotExist,
+	}
+}
+
+// Next is part of source.Driver interface implementation.
+func (p *PartialDriver) Next(version uint) (nextVersion uint, err error) {
+	if version, ok := p.migrations.Next(version); ok {
+		return version, nil
+	}
+	return 0, &os.PathError{
+		Op:   "next for version " + strconv.FormatUint(uint64(version), 10),
+		Path: p.path,
+		Err:  os.ErrNotExist,
+	}
+}
+
+// ReadUp is part of source.Driver interface implementation.
+func (p *PartialDriver) ReadUp(version uint) (r io.ReadCloser, identifier string, err error) {
+	if m, ok := p.migrations.Up(version); ok {
+		body, err := p.open(path.Join(p.path, m.Raw))
+		if err != nil {
+			return nil, "", err
+		}
+		return body, m.Identifier, nil
+	}
+	return nil, "", &os.PathError{
+		Op:   "read up for version " + strconv.FormatUint(uint64(version), 10),
+		Path: p.path,
+		Err:  os.ErrNotExist,
+	}
+}
+
+// ReadDown is part of source.Driver interface implementation.
+func (p *PartialDriver) ReadDown(version uint) (r io.ReadCloser, identifier string, err error) {
+	if m, ok := p.migrations.Down(version); ok {
+		body, err := p.open(path.Join(p.path, m.Raw))
+		if err != nil {
+			return nil, "", err
+		}
+		return body, m.Identifier, nil
+	}
+	return nil, "", &os.PathError{
+		Op:   "read down for version " + strconv.FormatUint(uint64(version), 10),
+		Path: p.path,
+		Err:  os.ErrNotExist,
+	}
+}
+
+func (p *PartialDriver) open(path string) (http.File, error) {
+	f, err := p.fs.Open(path)
+	if err == nil {
+		return f, nil
+	}
+	// Some non-standard file systems may return errors that don't include the path, that
+	// makes debugging harder.
+	if !errors.As(err, new(*os.PathError)) {
+		err = &os.PathError{
+			Op:   "open",
+			Path: path,
+			Err:  err,
+		}
+	}
+	return nil, err
+}