Add tracker package

Moved from snapshot repo

go.mod

@@ -2,7 +2,10 @@ module github.com/vulcanize/go-eth-state-node-iterator
 
 go 1.18
 
-require github.com/ethereum/go-ethereum v1.10.23
+require (
+	github.com/ethereum/go-ethereum v1.10.23
+	github.com/sirupsen/logrus v1.9.0
+)
 
 require (
 	github.com/VictoriaMetrics/fastcache v1.6.0 // indirect
@@ -24,7 +27,7 @@ require (
 	github.com/tklauser/numcpus v0.2.2 // indirect
 	github.com/yusufpapurcu/wmi v1.2.2 // indirect
 	golang.org/x/crypto v0.0.0-20220829220503-c86fa9a7ed90 // indirect
-	golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a // indirect
+	golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8 // indirect
 )
 
 replace github.com/ethereum/go-ethereum v1.10.23 => github.com/vulcanize/go-ethereum v1.10.23-statediff-4.2.0-alpha

go.sum

@@ -108,12 +108,15 @@ github.com/prometheus/tsdb v0.10.0/go.mod h1:oi49uRhEe9dPUTlS3JRZOwJuVi6tmh10QSg
 github.com/shirou/gopsutil v3.21.11+incompatible h1:+1+c1VGhc88SSonWP6foOcLhvnKlUeu/erjjvaPEYiI=
 github.com/shirou/gopsutil v3.21.11+incompatible/go.mod h1:5b4v6he4MtMOwMlS0TUMTu2PcXUg8+E1lC7eC3UO/RA=
 github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPxbbu5VWo=
+github.com/sirupsen/logrus v1.9.0 h1:trlNQbNUG3OdDrDil03MCb1H2o9nJ1x4/5LYw7byDE0=
+github.com/sirupsen/logrus v1.9.0/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=
 github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72/go.mod h1:JwIasOWyU6f++ZhiEuf87xNszmSA2myDM2Kzu9HwQUA=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.7.2 h1:4jaiDzPyXQvSd7D0EjG45355tLlV3VOECpq10pLC+8s=
 github.com/stretchr/testify v1.7.2/go.mod h1:R6va5+xMeoiuVRoj+gSkQ7d3FALtqAAGI1FQKckRals=
 github.com/syndtr/goleveldb v1.0.1-0.20220614013038-64ee5596c38a h1:1ur3QoCqvE5fl+nylMaIr9PVV1w343YRDtsy+Rwu7XI=
@@ -169,8 +172,9 @@ golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20211216021012-1d35b9e2eb4e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220412211240-33da011f77ad/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a h1:dGzPydgVsqGcTRVwiLJ1jVbufYwmzD3LfVPLKsKg+0k=
 golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8 h1:0A+M6Uqn+Eje4kHMK80dtF3JCXC4ykBgQG4Fe06QRhQ=
+golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
@@ -205,5 +209,6 @@ gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

tracker/tracker.go

@@ -0,0 +1,243 @@
+package tracker
+
+import (
+	"bytes"
+	"context"
+	"encoding/csv"
+	"fmt"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"github.com/ethereum/go-ethereum/core/state"
+	"github.com/ethereum/go-ethereum/trie"
+	log "github.com/sirupsen/logrus"
+
+	iter "github.com/vulcanize/go-eth-state-node-iterator"
+)
+
+type Tracker struct {
+	recoveryFile string
+
+	startChan chan *Iterator
+	stopChan  chan *Iterator
+	started   map[*Iterator]struct{}
+	stopped   []*Iterator
+	running   bool
+}
+
+type Iterator struct {
+	trie.NodeIterator
+	tracker *Tracker
+
+	SeekedPath []byte // latest path seeked from the tracked iterator
+	EndPath    []byte // endPath for the tracked iterator
+}
+
+func New(file string, buf uint) Tracker {
+	return Tracker{
+		recoveryFile: file,
+		startChan:    make(chan *Iterator, buf),
+		stopChan:     make(chan *Iterator, buf),
+		started:      map[*Iterator]struct{}{},
+		running:      true,
+	}
+}
+
+func (tr *Tracker) CaptureSignal(cancelCtx context.CancelFunc) {
+	sigChan := make(chan os.Signal, 1)
+
+	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
+	go func() {
+		sig := <-sigChan
+		log.Errorf("Signal received (%v), stopping", sig)
+		// cancel context on receiving a signal
+		// on ctx cancellation, all the iterators complete processing of their current node before stopping
+		cancelCtx()
+	}()
+}
+
+// Wraps an iterator in a Iterator. This should not be called once halts are possible.
+func (tr *Tracker) Tracked(it trie.NodeIterator, recoveredPath []byte) (ret *Iterator) {
+	// create seeked path of max capacity (65)
+	iterSeekedPath := make([]byte, 0, 65)
+	// intially populate seeked path with the recovered path
+	// to be used in trie traversal
+	if recoveredPath != nil {
+		iterSeekedPath = append(iterSeekedPath, recoveredPath...)
+	}
+
+	// if the iterator being tracked is a PrefixBoundIterator, capture it's end path
+	// to be used in trie traversal
+	var endPath []byte
+	if boundedIter, ok := it.(*iter.PrefixBoundIterator); ok {
+		endPath = boundedIter.EndPath
+	}
+
+	ret = &Iterator{it, tr, iterSeekedPath, endPath}
+	tr.startChan <- ret
+	return
+}
+
+// explicitly stops an iterator
+func (tr *Tracker) StopIterator(it *Iterator) {
+	tr.stopChan <- it
+}
+
+// dumps iterator path and bounds to a text file so it can be restored later
+func (tr *Tracker) dump() error {
+	log.Debugf("Dumping recovery state to: %s", tr.recoveryFile)
+	var rows [][]string
+	for it := range tr.started {
+		var startPath []byte
+		var endPath []byte
+		if impl, ok := it.NodeIterator.(*iter.PrefixBoundIterator); ok {
+			// if the iterator being tracked is a PrefixBoundIterator,
+			// initialize start and end paths with its bounds
+			startPath = impl.StartPath
+			endPath = impl.EndPath
+		}
+
+		// if seeked path and iterator path are non-empty, use iterator's path as startpath
+		if !bytes.Equal(it.SeekedPath, []byte{}) && !bytes.Equal(it.Path(), []byte{}) {
+			startPath = it.Path()
+		}
+
+		rows = append(rows, []string{
+			fmt.Sprintf("%x", startPath),
+			fmt.Sprintf("%x", endPath),
+			fmt.Sprintf("%x", it.SeekedPath),
+		})
+	}
+
+	file, err := os.Create(tr.recoveryFile)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+	out := csv.NewWriter(file)
+
+	return out.WriteAll(rows)
+}
+
+// attempts to read iterator state from file
+// if file doesn't exist, returns an empty slice with no error
+func (tr *Tracker) Restore(tree state.Trie) ([]trie.NodeIterator, error) {
+	file, err := os.Open(tr.recoveryFile)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, nil
+		}
+		return nil, err
+	}
+	log.Debugf("Restoring recovery state from: %s", tr.recoveryFile)
+
+	defer file.Close()
+	in := csv.NewReader(file)
+	in.FieldsPerRecord = 3
+	rows, err := in.ReadAll()
+	if err != nil {
+		return nil, err
+	}
+
+	var ret []trie.NodeIterator
+	for _, row := range rows {
+		// pick up where each interval left off
+		var startPath []byte
+		var endPath []byte
+		var recoveredPath []byte
+
+		if len(row[0]) != 0 {
+			if _, err = fmt.Sscanf(row[0], "%x", &startPath); err != nil {
+				return nil, err
+			}
+		}
+		if len(row[1]) != 0 {
+			if _, err = fmt.Sscanf(row[1], "%x", &endPath); err != nil {
+				return nil, err
+			}
+		}
+		if len(row[2]) != 0 {
+			if _, err = fmt.Sscanf(row[2], "%x", &recoveredPath); err != nil {
+				return nil, err
+			}
+		}
+
+		// force the lower bound path to an even length (required by geth API/HexToKeyBytes)
+		if len(startPath)&0b1 == 1 {
+			// decrement first to avoid skipped nodes
+			decrementPath(startPath)
+			startPath = append(startPath, 0)
+		}
+		it := iter.NewPrefixBoundIterator(tree.NodeIterator(iter.HexToKeyBytes(startPath)), startPath, endPath)
+		ret = append(ret, tr.Tracked(it, recoveredPath))
+	}
+
+	log.Debugf("Restored %d iterators", len(ret))
+	return ret, nil
+}
+
+func (tr *Tracker) HaltAndDump() error {
+	tr.running = false
+
+	// drain any pending iterators
+	close(tr.startChan)
+	for start := range tr.startChan {
+		tr.started[start] = struct{}{}
+	}
+	close(tr.stopChan)
+	for stop := range tr.stopChan {
+		tr.stopped = append(tr.stopped, stop)
+	}
+
+	for _, stop := range tr.stopped {
+		delete(tr.started, stop)
+	}
+
+	if len(tr.started) == 0 {
+		// if the tracker state is empty, erase any existing recovery file
+		err := os.Remove(tr.recoveryFile)
+		if os.IsNotExist(err) {
+			err = nil
+		}
+		return err
+	}
+
+	return tr.dump()
+}
+
+func (it *Iterator) Next(descend bool) bool {
+	ret := it.NodeIterator.Next(descend)
+
+	if !ret {
+		if it.tracker.running {
+			it.tracker.stopChan <- it
+		} else {
+			log.Errorf("iterator stopped after tracker halted: path=%x", it.Path())
+		}
+	}
+	return ret
+}
+
+// Subtracts 1 from the last byte in a path slice, carrying if needed.
+// Does nothing, returning false, for all-zero inputs.
+func decrementPath(path []byte) bool {
+	// check for all zeros
+	allzero := true
+	for i := 0; i < len(path); i++ {
+		allzero = allzero && path[i] == 0
+	}
+	if allzero {
+		return false
+	}
+	for i := len(path) - 1; i >= 0; i-- {
+		val := path[i]
+		path[i]--
+		if val == 0 {
+			path[i] = 0xf
+		} else {
+			return true
+		}
+	}
+	return true
+}