navidrome/plugins/host_kvstore.go
Deluan 2b2bc5dcb2 feat(plugins): implement KVStore service for persistent key-value storage
Signed-off-by: Deluan <deluan@navidrome.org>
2025-12-31 17:06:31 -05:00

251 lines
7.4 KiB
Go

package plugins
import (
"context"
"database/sql"
"errors"
"fmt"
"os"
"path/filepath"
"strings"
"sync/atomic"
"github.com/dustin/go-humanize"
_ "github.com/mattn/go-sqlite3"
"github.com/navidrome/navidrome/conf"
"github.com/navidrome/navidrome/log"
"github.com/navidrome/navidrome/plugins/host"
)
const (
defaultMaxKVStoreSize = 1 * 1024 * 1024 // 1MB default
maxKeyLength = 256 // Max key length in bytes
)
// kvstoreServiceImpl implements the host.KVStoreService interface.
// Each plugin gets its own SQLite database for isolation.
type kvstoreServiceImpl struct {
pluginName string
db *sql.DB
maxSize int64
currentSize atomic.Int64 // cached total size, updated on Set/Delete
}
// newKVStoreService creates a new kvstoreServiceImpl instance with its own SQLite database.
func newKVStoreService(pluginName string, perm *KVStorePermission) (*kvstoreServiceImpl, error) {
// Parse max size from permission, default to 1MB
maxSize := int64(defaultMaxKVStoreSize)
if perm != nil && perm.MaxSize != nil && *perm.MaxSize != "" {
parsed, err := humanize.ParseBytes(*perm.MaxSize)
if err != nil {
return nil, fmt.Errorf("invalid maxSize %q: %w", *perm.MaxSize, err)
}
maxSize = int64(parsed)
}
// Create plugin data directory
dataDir := filepath.Join(conf.Server.DataFolder, "plugins", pluginName)
if err := os.MkdirAll(dataDir, 0700); err != nil {
return nil, fmt.Errorf("creating plugin data directory: %w", err)
}
// Open SQLite database
dbPath := filepath.Join(dataDir, "kvstore.db")
db, err := sql.Open("sqlite3", dbPath+"?_busy_timeout=5000&_journal_mode=WAL&_foreign_keys=off")
if err != nil {
return nil, fmt.Errorf("opening kvstore database: %w", err)
}
db.SetMaxOpenConns(3)
db.SetMaxIdleConns(1)
// Create schema
if err := createKVStoreSchema(db); err != nil {
db.Close()
return nil, fmt.Errorf("creating kvstore schema: %w", err)
}
// Load current storage size from database
var currentSize int64
if err := db.QueryRow(`SELECT COALESCE(SUM(size), 0) FROM kvstore`).Scan(&currentSize); err != nil {
db.Close()
return nil, fmt.Errorf("loading storage size: %w", err)
}
log.Debug("Initialized plugin kvstore", "plugin", pluginName, "path", dbPath, "maxSize", humanize.Bytes(uint64(maxSize)), "currentSize", humanize.Bytes(uint64(currentSize)))
svc := &kvstoreServiceImpl{
pluginName: pluginName,
db: db,
maxSize: maxSize,
}
svc.currentSize.Store(currentSize)
return svc, nil
}
func createKVStoreSchema(db *sql.DB) error {
_, err := db.Exec(`
CREATE TABLE IF NOT EXISTS kvstore (
key TEXT PRIMARY KEY NOT NULL,
value BLOB NOT NULL,
size INTEGER NOT NULL,
created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
)
`)
return err
}
// Set stores a byte value with the given key.
func (s *kvstoreServiceImpl) Set(ctx context.Context, key string, value []byte) error {
// Validate key
if len(key) == 0 {
return fmt.Errorf("key cannot be empty")
}
if len(key) > maxKeyLength {
return fmt.Errorf("key exceeds maximum length of %d bytes", maxKeyLength)
}
newValueSize := int64(len(value))
// Get current size of this key (if it exists) to calculate delta
var oldSize int64
err := s.db.QueryRowContext(ctx, `SELECT COALESCE(size, 0) FROM kvstore WHERE key = ?`, key).Scan(&oldSize)
if err != nil && !errors.Is(err, sql.ErrNoRows) {
return fmt.Errorf("checking existing key: %w", err)
}
// Check size limits using cached total
delta := newValueSize - oldSize
newTotal := s.currentSize.Load() + delta
if newTotal > s.maxSize {
return fmt.Errorf("storage limit exceeded: would use %s of %s allowed",
humanize.Bytes(uint64(newTotal)), humanize.Bytes(uint64(s.maxSize)))
}
// Upsert the value
_, err = s.db.ExecContext(ctx, `
INSERT INTO kvstore (key, value, size, created_at, updated_at)
VALUES (?, ?, ?, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP)
ON CONFLICT(key) DO UPDATE SET
value = excluded.value,
size = excluded.size,
updated_at = CURRENT_TIMESTAMP
`, key, value, newValueSize)
if err != nil {
return fmt.Errorf("storing value: %w", err)
}
// Update cached size
s.currentSize.Add(delta)
log.Trace(ctx, "KVStore.Set", "plugin", s.pluginName, "key", key, "size", newValueSize)
return nil
}
// Get retrieves a byte value from storage.
func (s *kvstoreServiceImpl) Get(ctx context.Context, key string) ([]byte, bool, error) {
var value []byte
err := s.db.QueryRowContext(ctx, `SELECT value FROM kvstore WHERE key = ?`, key).Scan(&value)
if err == sql.ErrNoRows {
return nil, false, nil
}
if err != nil {
return nil, false, fmt.Errorf("reading value: %w", err)
}
log.Trace(ctx, "KVStore.Get", "plugin", s.pluginName, "key", key, "found", true)
return value, true, nil
}
// Delete removes a value from storage.
func (s *kvstoreServiceImpl) Delete(ctx context.Context, key string) error {
// Get size of the key being deleted to update cache
var oldSize int64
err := s.db.QueryRowContext(ctx, `SELECT size FROM kvstore WHERE key = ?`, key).Scan(&oldSize)
if errors.Is(err, sql.ErrNoRows) {
// Key doesn't exist, nothing to delete
return nil
}
if err != nil {
return fmt.Errorf("checking key size: %w", err)
}
_, err = s.db.ExecContext(ctx, `DELETE FROM kvstore WHERE key = ?`, key)
if err != nil {
return fmt.Errorf("deleting value: %w", err)
}
// Update cached size
s.currentSize.Add(-oldSize)
log.Trace(ctx, "KVStore.Delete", "plugin", s.pluginName, "key", key)
return nil
}
// Has checks if a key exists in storage.
func (s *kvstoreServiceImpl) Has(ctx context.Context, key string) (bool, error) {
var count int
err := s.db.QueryRowContext(ctx, `SELECT COUNT(*) FROM kvstore WHERE key = ?`, key).Scan(&count)
if err != nil {
return false, fmt.Errorf("checking key: %w", err)
}
return count > 0, nil
}
// List returns all keys matching the given prefix.
func (s *kvstoreServiceImpl) List(ctx context.Context, prefix string) ([]string, error) {
var rows *sql.Rows
var err error
if prefix == "" {
rows, err = s.db.QueryContext(ctx, `SELECT key FROM kvstore ORDER BY key`)
} else {
// Escape special LIKE characters in prefix
escapedPrefix := strings.ReplaceAll(prefix, "%", "\\%")
escapedPrefix = strings.ReplaceAll(escapedPrefix, "_", "\\_")
rows, err = s.db.QueryContext(ctx, `SELECT key FROM kvstore WHERE key LIKE ? ESCAPE '\' ORDER BY key`, escapedPrefix+"%")
}
if err != nil {
return nil, fmt.Errorf("listing keys: %w", err)
}
defer rows.Close()
var keys []string
for rows.Next() {
var key string
if err := rows.Scan(&key); err != nil {
return nil, fmt.Errorf("scanning key: %w", err)
}
keys = append(keys, key)
}
if err := rows.Err(); err != nil {
return nil, fmt.Errorf("iterating keys: %w", err)
}
log.Trace(ctx, "KVStore.List", "plugin", s.pluginName, "prefix", prefix, "count", len(keys))
return keys, nil
}
// GetStorageUsed returns the total storage used by this plugin in bytes.
func (s *kvstoreServiceImpl) GetStorageUsed(ctx context.Context) (int64, error) {
used := s.currentSize.Load()
log.Trace(ctx, "KVStore.GetStorageUsed", "plugin", s.pluginName, "bytes", used)
return used, nil
}
// Close closes the SQLite database connection.
// This is called when the plugin is unloaded.
func (s *kvstoreServiceImpl) Close() error {
if s.db != nil {
log.Debug("Closing plugin kvstore", "plugin", s.pluginName)
return s.db.Close()
}
return nil
}
// Compile-time verification
var _ host.KVStoreService = (*kvstoreServiceImpl)(nil)