feat(caddystorage): implement the machine-local CaddyStorage gRPC service

internal/machine/caddystorage/server.go

@@ -0,0 +1,191 @@
+// Package caddystorage implements the machine-local Caddy storage API.
+// See internal/machine/api/pb/caddy_storage.proto for the gRPC service definition.
+package caddystorage
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"maps"
+	"path"
+	"slices"
+	"strings"
+
+	"github.com/psviderski/uncloud/internal/machine/api/pb"
+	"github.com/psviderski/uncloud/internal/machine/store"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+	"google.golang.org/protobuf/types/known/emptypb"
+	"google.golang.org/protobuf/types/known/timestamppb"
+)
+
+// Namespace identifies Caddy storage records in the cluster key-value store.
+const Namespace = "caddy_storage"
+
+// Server implements the machine-local CaddyStorage gRPC service.
+type Server struct {
+	pb.UnimplementedCaddyStorageServer
+	store *store.Keyspace
+}
+
+func NewServer(store *store.Keyspace) *Server {
+	return &Server{store: store}
+}
+
+func (s *Server) Store(ctx context.Context, req *pb.StoreCaddyStorageRequest) (*emptypb.Empty, error) {
+	if err := validateKey(req.Key); err != nil {
+		return nil, status.Error(codes.InvalidArgument, err.Error())
+	}
+	if err := s.store.Put(ctx, req.Key, req.Value); err != nil {
+		return nil, status.Errorf(codes.Internal, "put value: %v", err)
+	}
+
+	return &emptypb.Empty{}, nil
+}
+
+func (s *Server) Load(ctx context.Context, req *pb.LoadCaddyStorageRequest) (*pb.LoadCaddyStorageResponse, error) {
+	if err := validateKey(req.Key); err != nil {
+		return nil, status.Error(codes.InvalidArgument, err.Error())
+	}
+
+	record, err := s.store.Get(ctx, req.Key)
+	if errors.Is(err, store.ErrKeyNotFound) {
+		return nil, status.Errorf(codes.NotFound, "Caddy storage key %q not found", req.Key)
+	}
+	if err != nil {
+		return nil, status.Errorf(codes.Internal, "get value: %v", err)
+	}
+
+	return &pb.LoadCaddyStorageResponse{
+		Messages: []*pb.MachineCaddyStorageValue{{
+			Value:     record.Value,
+			UpdatedAt: timestamppb.New(record.UpdatedAt),
+		}},
+	}, nil
+}
+
+func (s *Server) Delete(ctx context.Context, req *pb.DeleteCaddyStorageRequest) (*pb.EmptyResponse, error) {
+	if err := validateKey(req.Key); err != nil {
+		return nil, status.Error(codes.InvalidArgument, err.Error())
+	}
+
+	// Delete the key and all keys prefixed by it in case it's a directory.
+	if err := errors.Join(
+		s.store.Delete(ctx, req.Key, store.KeyspaceDeleteOptions{}),
+		s.store.Delete(ctx, req.Key+"/", store.KeyspaceDeleteOptions{Prefix: true}),
+	); err != nil {
+		return nil, status.Errorf(codes.Internal, "delete key: %v", err)
+	}
+
+	return &pb.EmptyResponse{
+		Messages: []*pb.Empty{{}},
+	}, nil
+}
+
+func (s *Server) List(ctx context.Context, req *pb.ListCaddyStorageRequest) (*pb.ListCaddyStorageResponse, error) {
+	if req.Prefix != "" {
+		if err := validateKey(req.Prefix); err != nil {
+			return nil, status.Error(codes.InvalidArgument, err.Error())
+		}
+	}
+
+	storagePrefix := req.Prefix
+	if storagePrefix != "" {
+		storagePrefix += "/"
+	}
+	records, err := s.store.List(ctx, storagePrefix, store.KeyspaceListOptions{KeysOnly: true})
+	if err != nil {
+		return nil, status.Errorf(codes.Internal, "list keys: %v", err)
+	}
+	// No descendants can mean an existing terminal key or a missing path.
+	// Check the exact key for non-root prefixes. An empty prefix lists the storage root.
+	if len(records) == 0 && req.Prefix != "" {
+		if _, err = s.store.Get(ctx, req.Prefix); errors.Is(err, store.ErrKeyNotFound) {
+			return nil, status.Errorf(codes.NotFound, "Caddy storage prefix %q not found", req.Prefix)
+		} else if err != nil {
+			return nil, status.Errorf(codes.Internal, "get prefix value: %v", err)
+		}
+	}
+
+	return &pb.ListCaddyStorageResponse{
+		Messages: []*pb.MachineCaddyStorageKeys{{
+			Keys: listKeys(records, req.Prefix, req.Recursive),
+		}},
+	}, nil
+}
+
+func listKeys(records []store.Record, prefix string, recursive bool) []string {
+	keys := make(map[string]struct{})
+	for _, record := range records {
+		relative := record.Key
+		if prefix != "" {
+			relative = strings.TrimPrefix(record.Key, prefix+"/")
+		}
+		components := strings.Split(relative, "/")
+		if !recursive {
+			keys[path.Join(prefix, components[0])] = struct{}{}
+			continue
+		}
+
+		for i := range components {
+			keys[path.Join(prefix, path.Join(components[:i+1]...))] = struct{}{}
+		}
+	}
+
+	return slices.Sorted(maps.Keys(keys))
+}
+
+func (s *Server) Stat(ctx context.Context, req *pb.StatCaddyStorageRequest) (*pb.StatCaddyStorageResponse, error) {
+	if err := validateKey(req.Key); err != nil {
+		return nil, status.Error(codes.InvalidArgument, err.Error())
+	}
+
+	record, err := s.store.Get(ctx, req.Key)
+	if err == nil {
+		return &pb.StatCaddyStorageResponse{
+			Messages: []*pb.MachineCaddyStorageKeyInfo{{
+				Key:        req.Key,
+				UpdatedAt:  timestamppb.New(record.UpdatedAt),
+				Size:       int64(len(record.Value)),
+				IsTerminal: true,
+			}},
+		}, nil
+	}
+	if !errors.Is(err, store.ErrKeyNotFound) {
+		return nil, status.Errorf(codes.Internal, "get value: %v", err)
+	}
+
+	// A terminal key is not found. Check if there are any keys prefixed by the key to determine if it's a directory.
+	records, err := s.store.List(ctx, req.Key+"/", store.KeyspaceListOptions{KeysOnly: true})
+	if err != nil {
+		return nil, status.Errorf(codes.Internal, "list keys: %v", err)
+	}
+	if len(records) == 0 {
+		return nil, status.Errorf(codes.NotFound, "Caddy storage key %q not found", req.Key)
+	}
+
+	return &pb.StatCaddyStorageResponse{
+		Messages: []*pb.MachineCaddyStorageKeyInfo{{
+			Key:        req.Key,
+			IsTerminal: false,
+		}},
+	}, nil
+}
+
+func validateKey(key string) error {
+	if key == "" {
+		return fmt.Errorf("key is empty")
+	}
+	if strings.HasPrefix(key, "/") || strings.HasSuffix(key, "/") {
+		return fmt.Errorf("key %q must not have a leading or trailing slash", key)
+	}
+	if strings.Contains(key, "\\") {
+		return fmt.Errorf("key %q must use forward slashes", key)
+	}
+	for component := range strings.SplitSeq(key, "/") {
+		if component == "" || component == "." || component == ".." {
+			return fmt.Errorf("key %q contains an invalid path component", key)
+		}
+	}
+	return nil
+}