cmd/geth: add db commands stats, compact, put, get, delete (#22014)

This PR introduces:

- db.put to put a value into the database
- db.get to read a value from the database
- db.delete to delete a value from the database
- db.stats to check compaction info from the database
- db.compact to trigger a db compaction

It also moves inspectdb to db.inspect.

ethdb/leveldb/leveldb.go

@@ -84,24 +84,36 @@ type Database struct {
 // New returns a wrapped LevelDB object. The namespace is the prefix that the
 // metrics reporting should use for surfacing internal stats.
 func New(file string, cache int, handles int, namespace string) (*Database, error) {
-	// Ensure we have some minimal caching and file guarantees
-	if cache < minCache {
-		cache = minCache
-	}
-	if handles < minHandles {
-		handles = minHandles
-	}
+	return NewCustom(file, namespace, func(options *opt.Options) {
+		// Ensure we have some minimal caching and file guarantees
+		if cache < minCache {
+			cache = minCache
+		}
+		if handles < minHandles {
+			handles = minHandles
+		}
+		// Set default options
+		options.OpenFilesCacheCapacity = handles
+		options.BlockCacheCapacity = cache / 2 * opt.MiB
+		options.WriteBuffer = cache / 4 * opt.MiB // Two of these are used internally
+	})
+}
+
+// NewCustom returns a wrapped LevelDB object. The namespace is the prefix that the
+// metrics reporting should use for surfacing internal stats.
+// The customize function allows the caller to modify the leveldb options.
+func NewCustom(file string, namespace string, customize func(options *opt.Options)) (*Database, error) {
+	options := configureOptions(customize)
 	logger := log.New("database", file)
-	logger.Info("Allocated cache and file handles", "cache", common.StorageSize(cache*1024*1024), "handles", handles)
+	usedCache := options.GetBlockCacheCapacity() + options.GetWriteBuffer()*2
+	logCtx := []interface{}{"cache", common.StorageSize(usedCache), "handles", options.GetOpenFilesCacheCapacity()}
+	if options.ReadOnly {
+		logCtx = append(logCtx, "readonly", "true")
+	}
+	logger.Info("Allocated cache and file handles", logCtx...)
 
 	// Open the db and recover any potential corruptions
-	db, err := leveldb.OpenFile(file, &opt.Options{
-		OpenFilesCacheCapacity: handles,
-		BlockCacheCapacity:     cache / 2 * opt.MiB,
-		WriteBuffer:            cache / 4 * opt.MiB, // Two of these are used internally
-		Filter:                 filter.NewBloomFilter(10),
-		DisableSeeksCompaction: true,
-	})
+	db, err := leveldb.OpenFile(file, options)
 	if _, corrupted := err.(*errors.ErrCorrupted); corrupted {
 		db, err = leveldb.RecoverFile(file, nil)
 	}
@@ -133,6 +145,20 @@ func New(file string, cache int, handles int, namespace string) (*Database, erro
 	return ldb, nil
 }
 
+// configureOptions sets some default options, then runs the provided setter.
+func configureOptions(customizeFn func(*opt.Options)) *opt.Options {
+	// Set default options
+	options := &opt.Options{
+		Filter:                 filter.NewBloomFilter(10),
+		DisableSeeksCompaction: true,
+	}
+	// Allow caller to make custom modifications to the options
+	if customizeFn != nil {
+		customizeFn(options)
+	}
+	return options
+}
+
 // Close stops the metrics collection, flushes any pending data to disk and closes
 // all io accesses to the underlying key-value store.
 func (db *Database) Close() error {