vendor: add buildkit

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/github.com/moby/buildkit/session/secrets/secretsprovider/secretsprovider.go

@@ -0,0 +1,60 @@
+package secretsprovider
+
+import (
+	"context"
+
+	"github.com/moby/buildkit/session"
+	"github.com/moby/buildkit/session/secrets"
+	"github.com/pkg/errors"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+// MaxSecretSize is the maximum byte length allowed for a secret
+const MaxSecretSize = 500 * 1024 // 500KB
+
+func NewSecretProvider(store secrets.SecretStore) session.Attachable {
+	return &secretProvider{
+		store: store,
+	}
+}
+
+type secretProvider struct {
+	store secrets.SecretStore
+}
+
+func (sp *secretProvider) Register(server *grpc.Server) {
+	secrets.RegisterSecretsServer(server, sp)
+}
+
+func (sp *secretProvider) GetSecret(ctx context.Context, req *secrets.GetSecretRequest) (*secrets.GetSecretResponse, error) {
+	dt, err := sp.store.GetSecret(ctx, req.ID)
+	if err != nil {
+		if errors.Cause(err) == secrets.ErrNotFound {
+			return nil, status.Errorf(codes.NotFound, err.Error())
+		}
+		return nil, err
+	}
+	if l := len(dt); l > MaxSecretSize {
+		return nil, errors.Errorf("invalid secret size %d", l)
+	}
+
+	return &secrets.GetSecretResponse{
+		Data: dt,
+	}, nil
+}
+
+func FromMap(m map[string][]byte) session.Attachable {
+	return NewSecretProvider(mapStore(m))
+}
+
+type mapStore map[string][]byte
+
+func (m mapStore) GetSecret(ctx context.Context, id string) ([]byte, error) {
+	v, ok := m[id]
+	if !ok {
+		return nil, errors.WithStack(secrets.ErrNotFound)
+	}
+	return v, nil
+}