初版功能完成

internal/siteprofile/store.go

@@ -0,0 +1,179 @@
+// Package siteprofile persists non-secret Engineer Remote CIDR preferences per Site.
+package siteprofile
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/netip"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"time"
+)
+
+const diskVersion = 1
+
+type Profile struct {
+	SiteName  string    `json:"site_name"`
+	CIDRs     []string  `json:"remote_cidrs"`
+	UpdatedAt time.Time `json:"updated_at"`
+}
+
+type diskProfiles struct {
+	Version int                `json:"version"`
+	Sites   map[string]Profile `json:"sites"`
+}
+
+type Store struct {
+	mu   sync.Mutex
+	path string
+}
+
+func NewStore(path string) (*Store, error) {
+	if strings.TrimSpace(path) == "" {
+		return nil, errors.New("Site profile path is required")
+	}
+	return &Store{path: path}, nil
+}
+
+func (s *Store) Path() string { return s.path }
+
+func (s *Store) Load() (map[string]Profile, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	profiles, err := s.loadLocked()
+	if err != nil {
+		return nil, err
+	}
+	return cloneProfiles(profiles), nil
+}
+
+func (s *Store) Save(siteID, siteName string, cidrs []string) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	siteID = strings.TrimSpace(siteID)
+	siteName = strings.TrimSpace(siteName)
+	if siteID == "" || siteName == "" {
+		return errors.New("Site ID and name are required")
+	}
+	canonical, err := canonicalCIDRs(cidrs)
+	if err != nil {
+		return err
+	}
+	profiles, err := s.loadLocked()
+	if err != nil {
+		return err
+	}
+	if len(canonical) == 0 {
+		delete(profiles, siteID)
+	} else {
+		profiles[siteID] = Profile{SiteName: siteName, CIDRs: canonical, UpdatedAt: time.Now().UTC()}
+	}
+	return s.saveLocked(profiles)
+}
+
+func (s *Store) loadLocked() (map[string]Profile, error) {
+	raw, err := os.ReadFile(s.path)
+	if errors.Is(err, os.ErrNotExist) {
+		return map[string]Profile{}, nil
+	}
+	if err != nil {
+		return nil, fmt.Errorf("read Site profiles: %w", err)
+	}
+	var stored diskProfiles
+	decoder := json.NewDecoder(strings.NewReader(string(raw)))
+	decoder.DisallowUnknownFields()
+	if err := decoder.Decode(&stored); err != nil {
+		return nil, fmt.Errorf("decode Site profiles: %w", err)
+	}
+	if err := decoder.Decode(&struct{}{}); !errors.Is(err, io.EOF) {
+		return nil, errors.New("Site profiles must contain one JSON object")
+	}
+	if stored.Version != diskVersion {
+		return nil, fmt.Errorf("unsupported Site profile version %d", stored.Version)
+	}
+	if stored.Sites == nil {
+		stored.Sites = map[string]Profile{}
+	}
+	for siteID, profile := range stored.Sites {
+		if strings.TrimSpace(siteID) == "" || strings.TrimSpace(profile.SiteName) == "" {
+			return nil, errors.New("stored Site profile has an empty Site ID or name")
+		}
+		canonical, err := canonicalCIDRs(profile.CIDRs)
+		if err != nil {
+			return nil, fmt.Errorf("validate Site profile %q: %w", siteID, err)
+		}
+		if len(canonical) == 0 {
+			return nil, fmt.Errorf("validate Site profile %q: Remote CIDRs are empty", siteID)
+		}
+		profile.CIDRs = canonical
+		stored.Sites[siteID] = profile
+	}
+	return stored.Sites, nil
+}
+
+func (s *Store) saveLocked(profiles map[string]Profile) error {
+	encoded, err := json.MarshalIndent(diskProfiles{Version: diskVersion, Sites: profiles}, "", "  ")
+	if err != nil {
+		return fmt.Errorf("encode Site profiles: %w", err)
+	}
+	encoded = append(encoded, '\n')
+	directory := filepath.Dir(s.path)
+	if err := os.MkdirAll(directory, 0o700); err != nil {
+		return fmt.Errorf("create Site profile directory: %w", err)
+	}
+	temporary, err := os.CreateTemp(directory, ".site-profiles-*.tmp")
+	if err != nil {
+		return fmt.Errorf("create temporary Site profiles: %w", err)
+	}
+	temporaryPath := temporary.Name()
+	defer os.Remove(temporaryPath)
+	if err := temporary.Chmod(0o600); err != nil {
+		temporary.Close()
+		return fmt.Errorf("restrict temporary Site profiles: %w", err)
+	}
+	if _, err := temporary.Write(encoded); err != nil {
+		temporary.Close()
+		return fmt.Errorf("write temporary Site profiles: %w", err)
+	}
+	if err := temporary.Sync(); err != nil {
+		temporary.Close()
+		return fmt.Errorf("flush temporary Site profiles: %w", err)
+	}
+	if err := temporary.Close(); err != nil {
+		return fmt.Errorf("close temporary Site profiles: %w", err)
+	}
+	if err := replaceFile(temporaryPath, s.path); err != nil {
+		return fmt.Errorf("replace Site profiles: %w", err)
+	}
+	return nil
+}
+
+func canonicalCIDRs(cidrs []string) ([]string, error) {
+	result := make([]string, 0, len(cidrs))
+	seen := make(map[netip.Prefix]struct{}, len(cidrs))
+	for _, raw := range cidrs {
+		prefix, err := netip.ParsePrefix(strings.TrimSpace(raw))
+		if err != nil || !prefix.Addr().Is4() || prefix.Bits() == 0 || prefix != prefix.Masked() {
+			return nil, fmt.Errorf("Remote CIDR must be canonical IPv4 and cannot be /0: %q", raw)
+		}
+		if _, exists := seen[prefix]; exists {
+			return nil, fmt.Errorf("duplicate Remote CIDR %q", prefix)
+		}
+		seen[prefix] = struct{}{}
+		result = append(result, prefix.String())
+	}
+	return result, nil
+}
+
+func cloneProfiles(source map[string]Profile) map[string]Profile {
+	result := make(map[string]Profile, len(source))
+	for siteID, profile := range source {
+		profile.CIDRs = append([]string(nil), profile.CIDRs...)
+		result[siteID] = profile
+	}
+	return result
+}