ethdb/remotedb, cmd: add support for remote (readonly) databases

cmd/utils/flags.go

@@ -50,6 +50,7 @@ import (
  "github.com/ethereum/go-ethereum/eth/gasprice"
  "github.com/ethereum/go-ethereum/eth/tracers"
  "github.com/ethereum/go-ethereum/ethdb"
+ "github.com/ethereum/go-ethereum/ethdb/remotedb"
  "github.com/ethereum/go-ethereum/ethstats"
  "github.com/ethereum/go-ethereum/graphql"
  "github.com/ethereum/go-ethereum/internal/ethapi"
@@ -114,6 +115,10 @@ var (
  Usage: "Data directory for the databases and keystore",
  Value: DirectoryString(node.DefaultDataDir()),
  }
+ RemoteDBFlag = cli.StringFlag{
+ Name: "remotedb",
+ Usage: "URL for remote database",
+ }
  AncientFlag = DirectoryFlag{
  Name: "datadir.ancient",
  Usage: "Data directory for ancient chain segments (default = inside chaindata)",
@@ -841,6 +846,7 @@ var (
  DatabasePathFlags = []cli.Flag{
  DataDirFlag,
  AncientFlag,
+ RemoteDBFlag,
  }
 )
 
@@ -1953,12 +1959,14 @@ func MakeChainDatabase(ctx *cli.Context, stack *node.Node, readonly bool) ethdb.
  err error
  chainDb ethdb.Database
  )
- if ctx.GlobalString(SyncModeFlag.Name) == "light" {
- name := "lightchaindata"
- chainDb, err = stack.OpenDatabase(name, cache, handles, "", readonly)
- } else {
- name := "chaindata"
- chainDb, err = stack.OpenDatabaseWithFreezer(name, cache, handles, ctx.GlobalString(AncientFlag.Name), "", readonly)
+ switch {
+ case ctx.GlobalIsSet(RemoteDBFlag.Name):
+ log.Info("Using remote db", "url", ctx.GlobalString(RemoteDBFlag.Name))
+ chainDb, err = remotedb.New(ctx.GlobalString(RemoteDBFlag.Name))
+ case ctx.GlobalString(SyncModeFlag.Name) == "light":
+ chainDb, err = stack.OpenDatabase("lightchaindata", cache, handles, "", readonly)
+ default:
+ chainDb, err = stack.OpenDatabaseWithFreezer("chaindata", cache, handles, ctx.GlobalString(AncientFlag.Name), "", readonly)
  }
  if err != nil {
  Fatalf("Could not open database: %v", err)

ethdb/remotedb/remotedb.go

@@ -0,0 +1,173 @@
+// Copyright 2022 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Package remotedb implements the key-value database layer based on a remote geth
+// node. Under the hood, it utilises the `debug_dbGet` method to implement a
+// read-only database.
+// There really are no guarantees in this database, since the local geth does not
+// exclusive access, but it can be used for basic diagnostics of a remote node.
+package remotedb
+
+import (
+ "errors"
+ "strings"
+
+ "github.com/ethereum/go-ethereum/common/hexutil"
+ "github.com/ethereum/go-ethereum/ethdb"
+ "github.com/ethereum/go-ethereum/rpc"
+)
+
+// Database is a key-value lookup for a remote database via debug_dbGet.
+type Database struct {
+ remote *rpc.Client
+}
+
+func (db *Database) Has(key []byte) (bool, error) {
+ if _, err := db.Get(key); err != nil {
+ return true, nil
+ }
+ return false, nil
+}
+
+func (db *Database) Get(key []byte) ([]byte, error) {
+ var resp hexutil.Bytes
+ err := db.remote.Call(&resp, "debug_dbGet", hexutil.Bytes(key))
+ if err != nil {
+ return nil, err
+ }
+ return resp, nil
+}
+
+func (db *Database) HasAncient(kind string, number uint64) (bool, error) {
+ if _, err := db.Ancient(kind, number); err != nil {
+ return true, nil
+ }
+ return false, nil
+}
+
+func (db *Database) Ancient(kind string, number uint64) ([]byte, error) {
+ var resp hexutil.Bytes
+ err := db.remote.Call(&resp, "debug_dbAncient", kind, number)
+ if err != nil {
+ return nil, err
+ }
+ return resp, nil
+}
+
+func (db *Database) AncientRange(kind string, start, count, maxBytes uint64) ([][]byte, error) {
+ panic("not supported")
+}
+
+func (db *Database) Ancients() (uint64, error) {
+ var resp uint64
+ err := db.remote.Call(&resp, "debug_dbAncients")
+ return resp, err
+}
+
+func (db *Database) Tail() (uint64, error) {
+ panic("not supported")
+}
+
+func (db *Database) AncientSize(kind string) (uint64, error) {
+ panic("not supported")
+}
+
+func (db *Database) ReadAncients(fn func(op ethdb.AncientReaderOp) error) (err error) {
+ return fn(db)
+}
+
+func (db *Database) Put(key []byte, value []byte) error {
+ panic("not supported")
+}
+
+func (db *Database) Delete(key []byte) error {
+ panic("not supported")
+}
+
+func (db *Database) ModifyAncients(f func(ethdb.AncientWriteOp) error) (int64, error) {
+ panic("not supported")
+}
+
+func (db *Database) TruncateHead(n uint64) error {
+ panic("not supported")
+}
+
+func (db *Database) TruncateTail(n uint64) error {
+ panic("not supported")
+}
+
+func (db *Database) Sync() error {
+ return nil
+}
+
+func (db *Database) MigrateTable(s string, f func([]byte) ([]byte, error)) error {
+ panic("not supported")
+}
+
+func (db *Database) NewBatch() ethdb.Batch {
+ panic("not supported")
+}
+
+func (db *Database) NewBatchWithSize(size int) ethdb.Batch {
+ panic("not supported")
+}
+
+func (db *Database) NewIterator(prefix []byte, start []byte) ethdb.Iterator {
+ panic("not supported")
+}
+
+func (db *Database) Stat(property string) (string, error) {
+ panic("not supported")
+}
+
+func (db *Database) AncientDatadir() (string, error) {
+ panic("not supported")
+}
+
+func (db *Database) Compact(start []byte, limit []byte) error {
+ return nil
+}
+
+func (db *Database) NewSnapshot() (ethdb.Snapshot, error) {
+ panic("not supported")
+}
+
+func (db *Database) Close() error {
+ db.remote.Close()
+ return nil
+}
+
+func dialRPC(endpoint string) (*rpc.Client, error) {
+ if endpoint == "" {
+ return nil, errors.New("endpoint must be specified")
+ }
+ if strings.HasPrefix(endpoint, "rpc:") || strings.HasPrefix(endpoint, "ipc:") {
+ // Backwards compatibility with geth < 1.5 which required
+ // these prefixes.
+ endpoint = endpoint[4:]
+ }
+ return rpc.Dial(endpoint)
+}
+
+func New(endpoint string) (ethdb.Database, error) {
+ client, err := dialRPC(endpoint)
+ if err != nil {
+ return nil, err
+ }
+ return &Database{
+ remote: client,
+ }, nil
+}

internal/ethapi/api.go

@@ -1972,15 +1972,6 @@ func (api *PrivateDebugAPI) SetHead(number hexutil.Uint64) {
  api.b.SetHead(uint64(number))
 }
 
-// DbGet returns the raw value of a key stored in the database.
-func (api *PrivateDebugAPI) DbGet(key string) (hexutil.Bytes, error) {
- blob, err := common.ParseHexOrString(key)
- if err != nil {
- return nil, err
- }
- return api.b.ChainDb().Get(blob)
-}
-
 // PublicNetAPI offers network related RPC methods
 type PublicNetAPI struct {
  net *p2p.Server

internal/ethapi/dbapi.go

@@ -0,0 +1,43 @@
+// Copyright 2022 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package ethapi
+
+import (
+ "github.com/ethereum/go-ethereum/common"
+ "github.com/ethereum/go-ethereum/common/hexutil"
+)
+
+// DbGet returns the raw value of a key stored in the database.
+func (api *PrivateDebugAPI) DbGet(key string) (hexutil.Bytes, error) {
+ blob, err := common.ParseHexOrString(key)
+ if err != nil {
+ return nil, err
+ }
+ return api.b.ChainDb().Get(blob)
+}
+
+// DbAncient retrieves an ancient binary blob from the append-only immutable files.
+// It is a mapping to the `AncientReaderOp.Ancient` method
+func (api *PrivateDebugAPI) DbAncient(kind string, number uint64) (hexutil.Bytes, error) {
+ return api.b.ChainDb().Ancient(kind, number)
+}
+
+// DbAncients returns the ancient item numbers in the ancient store.
+// It is a mapping to the `AncientReaderOp.Ancients` method
+func (api *PrivateDebugAPI) DbAncients() (uint64, error) {
+ return api.b.ChainDb().Ancients()
+}

internal/web3ext/web3ext.go

@@ -476,6 +476,16 @@ web3._extend({
  call: 'debug_dbGet',
  params: 1
  }),
+ new web3._extend.Method({
+ name: 'dbAncient',
+ call: 'debug_dbAncient',
+ params: 2
+ }),
+ new web3._extend.Method({
+ name: 'dbAncients',
+ call: 'debug_dbAncients',
+ params: 0
+ }),
  ],
  properties: []
 });