Add nasctl: Go NAS control plane with React frontend

internal/modules/samba/samba.go

@@ -0,0 +1,158 @@
+package samba
+
+import (
+	"bytes"
+	"context"
+	"embed"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"text/template"
+
+	"github.com/darroyo/nasctl/internal/db"
+	"github.com/darroyo/nasctl/internal/system"
+)
+
+const ModuleName = "samba"
+
+//go:embed smb.conf.tmpl
+var smbConfTemplate embed.FS
+
+type Config struct {
+	SMBConfPath string
+	Reload      bool
+}
+
+type Module struct {
+	cfg Config
+}
+
+type templateShare struct {
+	Name         string
+	Path         string
+	Comment      string
+	ReadOnly     bool
+	GuestOK      bool
+	ValidUsers   []string
+	ValidGroups  []string
+}
+
+type templateData struct {
+	Shares []templateShare
+}
+
+func New(cfg Config) *Module {
+	if cfg.SMBConfPath == "" {
+		cfg.SMBConfPath = "/etc/samba/smb.conf"
+	}
+	return &Module{cfg: cfg}
+}
+
+func (m *Module) Name() string {
+	return ModuleName
+}
+
+func (m *Module) IsDirty(ctx context.Context, database *db.DB) (bool, error) {
+	return database.IsDirty(ModuleName)
+}
+
+func (m *Module) Apply(ctx context.Context, database *db.DB) error {
+	shares, err := database.ListSambaShares()
+	if err != nil {
+		return err
+	}
+
+	content, err := m.renderConfig(shares)
+	if err != nil {
+		return err
+	}
+
+	if err := writeAtomic(m.cfg.SMBConfPath, content); err != nil {
+		return err
+	}
+
+	if m.cfg.Reload {
+		stdout, stderr, err := system.Run(ctx, "systemctl", "reload", "smbd")
+		if err != nil {
+			return fmt.Errorf("reload smbd: %w (stdout=%q stderr=%q)", err, stdout, stderr)
+		}
+	}
+
+	message := fmt.Sprintf("applied %d samba share(s) to %s", len(shares), m.cfg.SMBConfPath)
+	if err := database.AppendApplyLog(ModuleName, message, true); err != nil {
+		return err
+	}
+	return database.ClearDirty(ModuleName)
+}
+
+func (m *Module) renderConfig(shares []db.SambaShare) ([]byte, error) {
+	tmplContent, err := smbConfTemplate.ReadFile("smb.conf.tmpl")
+	if err != nil {
+		return nil, fmt.Errorf("read smb.conf template: %w", err)
+	}
+
+	funcMap := template.FuncMap{
+		"join": strings.Join,
+	}
+
+	tmpl, err := template.New("smb.conf").Funcs(funcMap).Parse(string(tmplContent))
+	if err != nil {
+		return nil, fmt.Errorf("parse smb.conf template: %w", err)
+	}
+
+	data := templateData{Shares: make([]templateShare, 0, len(shares))}
+	for _, share := range shares {
+		data.Shares = append(data.Shares, templateShare{
+			Name:        share.Name,
+			Path:        share.Path,
+			Comment:     share.Comment,
+			ReadOnly:    share.ReadOnly,
+			GuestOK:     share.GuestOK,
+			ValidUsers:  share.ValidUsers,
+			ValidGroups: share.ValidGroups,
+		})
+	}
+
+	var buf bytes.Buffer
+	if err := tmpl.Execute(&buf, data); err != nil {
+		return nil, fmt.Errorf("execute smb.conf template: %w", err)
+	}
+	return buf.Bytes(), nil
+}
+
+func writeAtomic(path string, content []byte) error {
+	dir := filepath.Dir(path)
+	if err := os.MkdirAll(dir, 0o755); err != nil {
+		return fmt.Errorf("create config dir: %w", err)
+	}
+
+	tmp, err := os.CreateTemp(dir, ".smb.conf.*")
+	if err != nil {
+		return fmt.Errorf("create temp file: %w", err)
+	}
+	tmpPath := tmp.Name()
+
+	cleanup := func() {
+		_ = tmp.Close()
+		_ = os.Remove(tmpPath)
+	}
+
+	if _, err := tmp.Write(content); err != nil {
+		cleanup()
+		return fmt.Errorf("write temp config: %w", err)
+	}
+	if err := tmp.Chmod(0o644); err != nil {
+		cleanup()
+		return fmt.Errorf("chmod temp config: %w", err)
+	}
+	if err := tmp.Close(); err != nil {
+		cleanup()
+		return fmt.Errorf("close temp config: %w", err)
+	}
+	if err := os.Rename(tmpPath, path); err != nil {
+		cleanup()
+		return fmt.Errorf("rename temp config: %w", err)
+	}
+	return nil
+}