fix: sftp support using public key authentication

internal/api/server.go

@@ -100,8 +100,9 @@ func (s *Server) AddRepo(ctx context.Context, req *connect.Request[v1.Repo]) (*c
 	}
 
 	r := restic.NewRepo(bin, req.Msg)
+
 	// use background context such that the init op can try to complete even if the connection is closed.
-	if err := r.Init(context.Background()); err != nil {
+	if err := r.Init(context.Background(), restic.WithPropagatedEnvVars(restic.EnvToPropagate...)); err != nil {
 		return nil, fmt.Errorf("failed to init repo: %w", err)
 	}
 

internal/orchestrator/repo.go

@@ -58,7 +58,7 @@ func (r *RepoOrchestrator) Backup(ctx context.Context, plan *v1.Plan, progressCa
 	defer r.mu.Unlock()
 	if !r.initialized {
 
-		if err := r.repo.Init(ctx); err != nil {
+		if err := r.repo.Init(ctx, restic.WithPropagatedEnvVars(restic.EnvToPropagate...)); err != nil {
 			return nil, fmt.Errorf("failed to initialize repo: %w", err)
 		}
 		r.initialized = true

pkg/restic/restic.go

@@ -9,6 +9,7 @@ import (
 	"io"
 	"os"
 	"os/exec"
+	"slices"
 	"strings"
 	"sync"
 
@@ -20,7 +21,6 @@ var ErrPartialBackup = errors.New("incomplete backup")
 var ErrBackupFailed = errors.New("backup failed")
 
 type Repo struct {
-	mu          sync.Mutex
 	cmd         string
 	repo        *v1.Repo
 	initialized bool
@@ -36,6 +36,10 @@ func NewRepo(resticBin string, repo *v1.Repo, opts ...GenericOption) *Repo {
 		o(opt)
 	}
 
+	if slices.Index(opt.extraArgs, "sftp.args") == -1 {
+		opt.extraArgs = append(opt.extraArgs, "-o", "sftp.args=-oBatchMode=yes")
+	}
+
 	return &Repo{
 		cmd:         resticBin, // TODO: configurable binary path
 		repo:        repo,
@@ -56,16 +60,20 @@ func (r *Repo) buildEnv() []string {
 }
 
 // init initializes the repo, the command will be cancelled with the context.
-func (r *Repo) init(ctx context.Context) error {
+func (r *Repo) init(ctx context.Context, opts ...GenericOption) error {
 	if r.initialized {
 		return nil
 	}
 
+	opt := resolveOpts(opts)
+
 	var args = []string{"init", "--json"}
 	args = append(args, r.extraArgs...)
+	args = append(args, opt.extraArgs...)
 
 	cmd := exec.CommandContext(ctx, r.cmd, args...)
 	cmd.Env = append(cmd.Env, r.buildEnv()...)
+	cmd.Env = append(cmd.Env, opt.extraEnv...)
 
 	if output, err := cmd.CombinedOutput(); err != nil {
 		if strings.Contains(string(output), "config file already exists") || strings.Contains(string(output), "already initialized") {
@@ -78,8 +86,8 @@ func (r *Repo) init(ctx context.Context) error {
 	return nil
 }
 
-func (r *Repo) Init(ctx context.Context) error {
-	if err := r.init(ctx); err != nil && !errors.Is(err, errAlreadyInitialized) {
+func (r *Repo) Init(ctx context.Context, opts ...GenericOption) error {
+	if err := r.init(ctx, opts...); err != nil && !errors.Is(err, errAlreadyInitialized) {
 		return fmt.Errorf("init failed: %w", err)
 	}
 	return nil