Self review.

cmd/gossamer/config.go

@@ -443,7 +443,9 @@ func setDotGlobalConfigFromToml(tomlCfg *ctoml.Config, cfg *dot.GlobalConfig) {
 		}
 
 		cfg.MetricsPort = tomlCfg.Global.MetricsPort
+
 		cfg.RetainBlocks = tomlCfg.Global.RetainBlocks
+		cfg.GCMode = tomlCfg.Global.GCMode
 	}
 }
 
@@ -473,9 +475,8 @@ func setDotGlobalConfigFromFlags(ctx *cli.Context, cfg *dot.GlobalConfig) {
 		cfg.MetricsPort = uint32(metricsPort)
 	}
 
-	// check --retain-blocks flag
 	cfg.RetainBlocks = ctx.GlobalInt64(RetainBlockNumberFlag.Name)
-
+	cfg.GCMode = ctx.GlobalString(GCModeFlag.Name)
 	cfg.NoTelemetry = ctx.Bool("no-telemetry")
 }
 

cmd/gossamer/export.go

@@ -85,6 +85,7 @@ func dotConfigToToml(dcfg *dot.Config) *ctoml.Config {
 		LogLvl:       dcfg.Global.LogLvl.String(),
 		MetricsPort:  dcfg.Global.MetricsPort,
 		RetainBlocks: dcfg.Global.RetainBlocks,
+		GCMode:       dcfg.Global.GCMode,
 	}
 
 	cfg.Log = ctoml.LogConfig{

cmd/gossamer/flags.go

@@ -285,6 +285,13 @@ var (
 		Usage: "Retain number of block from latest block while pruning",
 		Value: 256,
 	}
+
+	// GCModeFlag sets the blockchain GC mode. It's either full or archive.
+	GCModeFlag = cli.StringFlag{
+		Name:  "gcmode",
+		Usage: `Blockchain garbage collection mode ("full", "archive")`,
+		Value: "full",
+	}
 )
 
 // flag sets that are shared by multiple commands
@@ -302,6 +309,7 @@ var (
 		DBPathFlag,
 		BloomFilterSizeFlag,
 		RetainBlockNumberFlag,
+		GCModeFlag,
 	}
 
 	// StartupFlags are flags that are valid for use with the root command and the export subcommand

cmd/gossamer/main.go

@@ -235,7 +235,11 @@ func gossamerAction(ctx *cli.Context) error {
 	}
 
 	if cfg.Global.RetainBlocks < 256 {
-		return fmt.Errorf("retain blocks cannot be less than 256")
+		return fmt.Errorf("--%s cannot be less than 256", RetainBlockNumberFlag.Name)
+	}
+
+	if cfg.Global.GCMode != "full" && cfg.Global.GCMode != "archive" {
+		return fmt.Errorf("--%s must be either 'full' or 'archive'", GCModeFlag.Name)
 	}
 
 	cfg.Global.LogLvl = lvl

dot/config.go

@@ -53,6 +53,7 @@ type GlobalConfig struct {
 	MetricsPort    uint32
 	NoTelemetry    bool
 	RetainBlocks   int64
+	GCMode         string
 }
 
 // LogConfig represents the log levels for individual packages

dot/config/toml/config.go

@@ -35,6 +35,7 @@ type GlobalConfig struct {
 	LogLvl       string `toml:"log,omitempty"`
 	MetricsPort  uint32 `toml:"metrics-port,omitempty"`
 	RetainBlocks int64  `toml:"retain-blocks,omitempty"`
+	GCMode       string `toml:"gc-mode,omitempty"`
 }
 
 // LogConfig represents the log levels for individual packages

dot/node.go

@@ -237,9 +237,14 @@ func NewNode(cfg *Config, ks *keystore.GlobalKeystore, stopFunc func()) (*Node,
 	// Network Service
 	var networkSrvc *network.Service
 
-	pruner, err := state.CreatePruner(stateSrvc.DB(), cfg.Global.RetainBlocks)
-	if err != nil {
-		logger.Error("failed to create pruner:", err)
+	var pruner state.Pruner
+	if cfg.Global.GCMode == "full" {
+		pruner, err = state.CreatePruner(stateSrvc.DB(), cfg.Global.RetainBlocks)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		pruner = &state.ArchivalNodePruner{}
 	}
 
 	// check if network service is enabled

dot/services.go

@@ -165,7 +165,7 @@ func createRuntime(cfg *Config, st *state.Service, ks *keystore.GlobalKeystore,
 	return rt, nil
 }
 
-func createBABEService(cfg *Config, rt runtime.Instance, st *state.Service, ks keystore.Keystore, pruner *state.Pruner) (*babe.Service, error) {
+func createBABEService(cfg *Config, rt runtime.Instance, st *state.Service, ks keystore.Keystore, pruner state.Pruner) (*babe.Service, error) {
 	logger.Info(
 		"creating BABE service...",
 		"authority", cfg.Core.BabeAuthority,
@@ -377,7 +377,7 @@ func createBlockVerifier(st *state.Service) (*babe.VerificationManager, error) {
 	return ver, nil
 }
 
-func createSyncService(cfg *Config, st *state.Service, bp sync.BlockProducer, fg sync.FinalityGadget, dh *core.DigestHandler, verifier *babe.VerificationManager, rt runtime.Instance, pruner *state.Pruner) (*sync.Service, error) {
+func createSyncService(cfg *Config, st *state.Service, bp sync.BlockProducer, fg sync.FinalityGadget, dh *core.DigestHandler, verifier *babe.VerificationManager, rt runtime.Instance, pruner state.Pruner) (*sync.Service, error) {
 	syncCfg := &sync.Config{
 		LogLvl:           cfg.Log.SyncLvl,
 		BlockState:       st.Block,

dot/services_test.go

@@ -23,6 +23,7 @@ import (
 	"time"
 
 	"github.com/ChainSafe/gossamer/dot/network"
+	"github.com/ChainSafe/gossamer/dot/state"
 	"github.com/ChainSafe/gossamer/dot/types"
 	"github.com/ChainSafe/gossamer/lib/keystore"
 	"github.com/ChainSafe/gossamer/lib/utils"
@@ -136,7 +137,7 @@ func TestCreateSyncService(t *testing.T) {
 	ver, err := createBlockVerifier(stateSrvc)
 	require.NoError(t, err)
 
-	_, err = createSyncService(cfg, stateSrvc, nil, nil, nil, ver, rt, nil)
+	_, err = createSyncService(cfg, stateSrvc, nil, nil, nil, ver, rt, &state.ArchivalNodePruner{})
 	require.NoError(t, err)
 }
 
@@ -233,7 +234,7 @@ func TestCreateBABEService(t *testing.T) {
 	rt, err := createRuntime(cfg, stateSrvc, ks, &network.Service{})
 	require.NoError(t, err)
 
-	bs, err := createBABEService(cfg, rt, stateSrvc, ks.Babe, nil)
+	bs, err := createBABEService(cfg, rt, stateSrvc, ks.Babe, &state.ArchivalNodePruner{})
 	require.NoError(t, err)
 	require.NotNil(t, bs)
 }

dot/state/pruner.go

@@ -13,24 +13,24 @@ import (
 
 const (
 	journalPrefix = "journal"
-	lastPruned    = "last_pruned"
+	lastPrunedKey = "last_pruned"
 )
 
-type journalRecord struct {
-	blockHash *common.Hash
-	// Hash of keys that are inserted into state trie of the block
-	insertedKeys []*common.Hash
-	// Hash of keys that are deleted from state trie of the block
-	deletedKeys []*common.Hash
+// Pruner is implemented by FullNodePruner and ArchivalNodePruner.
+type Pruner interface {
+	StoreJournalRecord(deleted, inserted []*common.Hash, blockHash *common.Hash, blockNum *big.Int) error
 }
 
-type deathRow struct {
-	blockHash   *common.Hash
-	deletedKeys map[*common.Hash]int64 // keys hash that will be deleted from DB
+// ArchivalNodePruner is a no-op since we don't prune nodes in archive mode.
+type ArchivalNodePruner struct{}
+
+// StoreJournalRecord for archive node doesn't do anything.
+func (a *ArchivalNodePruner) StoreJournalRecord(deleted, inserted []*common.Hash, blockHash *common.Hash, blockNum *big.Int) error {
+	return nil
 }
 
-// Pruner stores state trie diff and allows online state trie pruning
-type Pruner struct {
+// FullNodePruner stores state trie diff and allows online state trie pruning
+type FullNodePruner struct {
 	deathList     []*deathRow
 	storageDB     chaindb.Database
 	journalDB     chaindb.Database
@@ -40,6 +40,15 @@ type Pruner struct {
 	sync.RWMutex
 }
 
+type journalRecord struct {
+	// blockHash of the block corresponding to journal record
+	blockHash *common.Hash
+	// Hash of keys that are inserted into state trie of the block
+	insertedKeys []*common.Hash
+	// Hash of keys that are deleted from state trie of the block
+	deletedKeys []*common.Hash
+}
+
 func newJournalRecord(hash *common.Hash, insertedKeys, deletedKeys []*common.Hash) *journalRecord {
 	return &journalRecord{
 		blockHash:    hash,
@@ -48,9 +57,14 @@ func newJournalRecord(hash *common.Hash, insertedKeys, deletedKeys []*common.Has
 	}
 }
 
+type deathRow struct {
+	blockHash   *common.Hash
+	deletedKeys map[*common.Hash]int64 // keys hash that will be deleted from DB
+}
+
 // CreatePruner creates a pruner
-func CreatePruner(db chaindb.Database, retainBlocks int64) (*Pruner, error) {
-	p := &Pruner{
+func CreatePruner(db chaindb.Database, retainBlocks int64) (Pruner, error) {
+	p := &FullNodePruner{
 		deathList:    make([]*deathRow, 0),
 		deathIndex:   make(map[*common.Hash]int64),
 		storageDB:    chaindb.NewTable(db, storagePrefix),
@@ -60,12 +74,7 @@ func CreatePruner(db chaindb.Database, retainBlocks int64) (*Pruner, error) {
 
 	blockNum, err := p.getLastPrunedIndex()
 	if err != nil {
-		if err == chaindb.ErrKeyNotFound {
-			blockNum = 0
-		} else {
-			logger.Error("pruner", "failed to get last pruned key", err)
-			return nil, err
-		}
+		return nil, err
 	}
 
 	logger.Info("pruner", "last pruned block", blockNum)
@@ -76,10 +85,11 @@ func CreatePruner(db chaindb.Database, retainBlocks int64) (*Pruner, error) {
 	// load deathList and deathIndex from journalRecord
 	for {
 		record, err := p.getJournalRecord(blockNum)
+		if err == chaindb.ErrKeyNotFound {
+			break
+		}
+
 		if err != nil {
-			if err == chaindb.ErrKeyNotFound {
-				break
-			}
 			return nil, err
 		}
 
@@ -97,11 +107,13 @@ func CreatePruner(db chaindb.Database, retainBlocks int64) (*Pruner, error) {
 		blockNum++
 	}
 
+	go p.start()
+
 	return p, nil
 }
 
 // StoreJournalRecord stores journal record into DB and add deathRow into deathList
-func (p *Pruner) StoreJournalRecord(deleted, inserted []*common.Hash, blockHash *common.Hash, blockNum *big.Int) error {
+func (p *FullNodePruner) StoreJournalRecord(deleted, inserted []*common.Hash, blockHash *common.Hash, blockNum *big.Int) error {
 	jr := newJournalRecord(blockHash, inserted, deleted)
 	encRecord, err := scale.Encode(jr)
 	if err != nil {
@@ -122,15 +134,15 @@ func (p *Pruner) StoreJournalRecord(deleted, inserted []*common.Hash, blockHash
 	return nil
 }
 
-func (p *Pruner) addDeathRow(jr *journalRecord, blockNum int64) error {
+func (p *FullNodePruner) addDeathRow(jr *journalRecord, blockNum int64) error {
 	p.Lock()
 	defer p.Unlock()
 
 	// remove re-inserted keys
 	for _, k := range jr.insertedKeys {
 		if num, ok := p.deathIndex[k]; ok {
-			delete(p.deathIndex, k)
 			delete(p.deathList[num-p.pendingNumber].deletedKeys, k)
+			delete(p.deathIndex, k)
 		}
 	}
 
@@ -154,8 +166,7 @@ func (p *Pruner) addDeathRow(jr *journalRecord, blockNum int64) error {
 	return nil
 }
 
-// PruneOne starts online pruning process
-func (p *Pruner) PruneOne() {
+func (p *FullNodePruner) start() {
 	logger.Info("pruning started")
 
 	for {
@@ -168,14 +179,14 @@ func (p *Pruner) PruneOne() {
 		p.Lock()
 
 		// pop first element from death list
-		dr := p.deathList[0]
-		err := p.deleteKeys(dr.deletedKeys)
+		row := p.deathList[0]
+		err := p.deleteKeys(row.deletedKeys)
 		if err != nil {
 			logger.Error("pruner", "failed to delete keys for block", p.pendingNumber)
 			continue
 		}
 
-		for k := range dr.deletedKeys {
+		for k := range row.deletedKeys {
 			delete(p.deathIndex, k)
 		}
 
@@ -190,7 +201,7 @@ func (p *Pruner) PruneOne() {
 	}
 }
 
-func (p *Pruner) storeJournal(num int64, record []byte) error {
+func (p *FullNodePruner) storeJournal(num int64, record []byte) error {
 	encNum, err := scale.Encode(num)
 	if err != nil {
 		return err
@@ -204,7 +215,7 @@ func (p *Pruner) storeJournal(num int64, record []byte) error {
 	return nil
 }
 
-func (p *Pruner) getJournalRecord(num int64) ([]byte, error) {
+func (p *FullNodePruner) getJournalRecord(num int64) ([]byte, error) {
 	encNum, err := scale.Encode(num)
 	if err != nil {
 		return nil, err
@@ -218,22 +229,26 @@ func (p *Pruner) getJournalRecord(num int64) ([]byte, error) {
 	return val, nil
 }
 
-func (p *Pruner) storeLastPrunedIndex(blockNum int64) error {
+func (p *FullNodePruner) storeLastPrunedIndex(blockNum int64) error {
 	encNum, err := scale.Encode(blockNum)
 	if err != nil {
 		return err
 	}
 
-	err = p.journalDB.Put([]byte(lastPruned), encNum)
+	err = p.journalDB.Put([]byte(lastPrunedKey), encNum)
 	if err != nil {
 		return err
 	}
 
 	return nil
 }
 
-func (p *Pruner) getLastPrunedIndex() (int64, error) {
-	val, err := p.journalDB.Get([]byte(lastPruned))
+func (p *FullNodePruner) getLastPrunedIndex() (int64, error) {
+	val, err := p.journalDB.Get([]byte(lastPrunedKey))
+	if err != chaindb.ErrKeyNotFound {
+		return 0, nil
+	}
+
 	if err != nil {
 		return 0, err
 	}
@@ -246,7 +261,7 @@ func (p *Pruner) getLastPrunedIndex() (int64, error) {
 	return blockNum.(int64), err
 }
 
-func (p *Pruner) deleteKeys(nodesHash map[*common.Hash]int64) error {
+func (p *FullNodePruner) deleteKeys(nodesHash map[*common.Hash]int64) error {
 	for k := range nodesHash {
 		err := p.storageDB.Del(k.ToBytes())
 		if err != nil {

dot/state/service.go

@@ -51,8 +51,6 @@ type Service struct {
 	// Below are for testing only.
 	BabeThresholdNumerator   uint64
 	BabeThresholdDenominator uint64
-
-	pruner *Pruner
 }
 
 // NewService create a new instance of Service
@@ -69,7 +67,6 @@ func NewService(path string, lvl log.Lvl) *Service {
 		Storage: nil,
 		Block:   nil,
 		closeCh: make(chan interface{}),
-		pruner:  nil,
 	}
 }
 
@@ -180,7 +177,6 @@ func (s *Service) Start() error {
 	logger.Info("created state service", "head", s.Block.BestBlockHash(), "highest number", num)
 	// Start background goroutine to GC pruned keys.
 	go s.Storage.pruneStorage(s.closeCh)
-
 	return nil
 }