lbcd/cmd/addblock/addblock.go
Dave Collins 491acd4ca6 blockchain: Rework to use new db interface.
This commit is the first stage of several that are planned to convert
the blockchain package into a concurrent safe package that will
ultimately allow support for multi-peer download and concurrent chain
processing.  The goal is to update btcd proper after each step so it can
take advantage of the enhancements as they are developed.

In addition to the aforementioned benefit, this staged approach has been
chosen since it is absolutely critical to maintain consensus.
Separating the changes into several stages makes it easier for reviewers
to logically follow what is happening and therefore helps prevent
consensus bugs.  Naturally there are significant automated tests to help
prevent consensus issues as well.

The main focus of this stage is to convert the blockchain package to use
the new database interface and implement the chain-related functionality
which it no longer handles.  It also aims to improve efficiency in
various areas by making use of the new database and chain capabilities.

The following is an overview of the chain changes:

- Update to use the new database interface
- Add chain-related functionality that the old database used to handle
  - Main chain structure and state
  - Transaction spend tracking
- Implement a new pruned unspent transaction output (utxo) set
  - Provides efficient direct access to the unspent transaction outputs
  - Uses a domain specific compression algorithm that understands the
    standard transaction scripts in order to significantly compress them
  - Removes reliance on the transaction index and paves the way toward
    eventually enabling block pruning
- Modify the New function to accept a Config struct instead of
  inidividual parameters
- Replace the old TxStore type with a new UtxoViewpoint type that makes
  use of the new pruned utxo set
- Convert code to treat the new UtxoViewpoint as a rolling view that is
  used between connects and disconnects to improve efficiency
- Make best chain state always set when the chain instance is created
  - Remove now unnecessary logic for dealing with unset best state
- Make all exported functions concurrent safe
  - Currently using a single chain state lock as it provides a straight
    forward and easy to review path forward however this can be improved
    with more fine grained locking
- Optimize various cases where full blocks were being loaded when only
  the header is needed to help reduce the I/O load
- Add the ability for callers to get a snapshot of the current best
  chain stats in a concurrent safe fashion
  - Does not block callers while new blocks are being processed
- Make error messages that reference transaction outputs consistently
  use <transaction hash>:<output index>
- Introduce a new AssertError type an convert internal consistency
  checks to use it
- Update tests and examples to reflect the changes
- Add a full suite of tests to ensure correct functionality of the new
  code

The following is an overview of the btcd changes:

- Update to use the new database and chain interfaces
- Temporarily remove all code related to the transaction index
- Temporarily remove all code related to the address index
- Convert all code that uses transaction stores to use the new utxo
  view
- Rework several calls that required the block manager for safe
  concurrency to use the chain package directly now that it is
  concurrent safe
- Change all calls to obtain the best hash to use the new best state
  snapshot capability from the chain package
- Remove workaround for limits on fetching height ranges since the new
  database interface no longer imposes them
- Correct the gettxout RPC handler to return the best chain hash as
  opposed the hash the txout was found in
- Optimize various RPC handlers:
  - Change several of the RPC handlers to use the new chain snapshot
    capability to avoid needlessly loading data
  - Update several handlers to use new functionality to avoid accessing
    the block manager so they are able to return the data without
    blocking when the server is busy processing blocks
  - Update non-verbose getblock to avoid deserialization and
    serialization overhead
  - Update getblockheader to request the block height directly from
    chain and only load the header
  - Update getdifficulty to use the new cached data from chain
  - Update getmininginfo to use the new cached data from chain
  - Update non-verbose getrawtransaction to avoid deserialization and
    serialization overhead
  - Update gettxout to use the new utxo store versus loading
    full transactions using the transaction index

The following is an overview of the utility changes:
- Update addblock to use the new database and chain interfaces
- Update findcheckpoint to use the new database and chain interfaces
- Remove the dropafter utility which is no longer supported

NOTE: The transaction index and address index will be reimplemented in
another commit.
2016-04-11 16:47:27 -05:00

130 lines
3.4 KiB
Go

// Copyright (c) 2013-2016 The btcsuite developers
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package main
import (
"os"
"path/filepath"
"runtime"
"github.com/btcsuite/btcd/blockchain"
database "github.com/btcsuite/btcd/database2"
"github.com/btcsuite/btcd/limits"
"github.com/btcsuite/btclog"
)
const (
// blockDbNamePrefix is the prefix for the btcd block database.
blockDbNamePrefix = "blocks"
)
var (
cfg *config
log btclog.Logger
)
// loadBlockDB opens the block database and returns a handle to it.
func loadBlockDB() (database.DB, error) {
// The database name is based on the database type.
dbName := blockDbNamePrefix + "_" + cfg.DbType
dbPath := filepath.Join(cfg.DataDir, dbName)
log.Infof("Loading block database from '%s'", dbPath)
db, err := database.Open(cfg.DbType, dbPath, activeNetParams.Net)
if err != nil {
// Return the error if it's not because the database doesn't
// exist.
if dbErr, ok := err.(database.Error); !ok || dbErr.ErrorCode !=
database.ErrDbDoesNotExist {
return nil, err
}
// Create the db if it does not exist.
err = os.MkdirAll(cfg.DataDir, 0700)
if err != nil {
return nil, err
}
db, err = database.Create(cfg.DbType, dbPath, activeNetParams.Net)
if err != nil {
return nil, err
}
}
log.Info("Block database loaded")
return db, nil
}
// realMain is the real main function for the utility. It is necessary to work
// around the fact that deferred functions do not run when os.Exit() is called.
func realMain() error {
// Load configuration and parse command line.
tcfg, _, err := loadConfig()
if err != nil {
return err
}
cfg = tcfg
// Setup logging.
backendLogger := btclog.NewDefaultBackendLogger()
defer backendLogger.Flush()
log = btclog.NewSubsystemLogger(backendLogger, "")
database.UseLogger(btclog.NewSubsystemLogger(backendLogger, "BCDB: "))
blockchain.UseLogger(btclog.NewSubsystemLogger(backendLogger, "CHAN: "))
// Load the block database.
db, err := loadBlockDB()
if err != nil {
log.Errorf("Failed to load database: %v", err)
return err
}
defer db.Close()
fi, err := os.Open(cfg.InFile)
if err != nil {
log.Errorf("Failed to open file %v: %v", cfg.InFile, err)
return err
}
defer fi.Close()
// Create a block importer for the database and input file and start it.
// The done channel returned from start will contain an error if
// anything went wrong.
importer, err := newBlockImporter(db, fi)
if err != nil {
log.Errorf("Failed create block importer: %v", err)
return err
}
// Perform the import asynchronously. This allows blocks to be
// processed and read in parallel. The results channel returned from
// Import contains the statistics about the import including an error
// if something went wrong.
log.Info("Starting import")
resultsChan := importer.Import()
results := <-resultsChan
if results.err != nil {
log.Errorf("%v", results.err)
return results.err
}
log.Infof("Processed a total of %d blocks (%d imported, %d already "+
"known)", results.blocksProcessed, results.blocksImported,
results.blocksProcessed-results.blocksImported)
return nil
}
func main() {
// Use all processor cores and up some limits.
runtime.GOMAXPROCS(runtime.NumCPU())
if err := limits.SetLimits(); err != nil {
os.Exit(1)
}
// Work around defer not working after os.Exit()
if err := realMain(); err != nil {
os.Exit(1)
}
}