Tool to dump graphviz data for block tree (#4108)

tools/blocktree/main.go

@@ -0,0 +1,84 @@
+/**
+ * Block tree graph viz
+ *
+ * Given a DB, start slot and end slot. This tool computes the graphviz data
+ * needed to construct the block tree in graphviz data format. Then one can paste
+ * the data in a Graph rendering engine (ie. http://www.webgraphviz.com/) to see the visual format.
+
+ */
+package main
+
+import (
+	"context"
+	"encoding/hex"
+	"flag"
+	"fmt"
+	"strconv"
+
+	"github.com/emicklei/dot"
+	"github.com/prysmaticlabs/go-ssz"
+	"github.com/prysmaticlabs/prysm/beacon-chain/db"
+	"github.com/prysmaticlabs/prysm/beacon-chain/db/filters"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+)
+
+var (
+	// Required fields
+	datadir   = flag.String("datadir", "", "Path to data directory.")
+	startSlot = flag.Uint("startSlot", 0, "Start slot of the block tree")
+	endSlot   = flag.Uint("endSlot", 0, "Start slot of the block tree")
+)
+
+// Used for tree, each node is a representation of a node in the graph
+type node struct {
+	parentRoot [32]byte
+	dothNode   *dot.Node
+}
+
+func main() {
+	flag.Parse()
+	db, err := db.NewDB(*datadir)
+	if err != nil {
+		panic(err)
+	}
+
+	graph := dot.NewGraph(dot.Directed)
+	graph.Attr("rankdir", "RL")
+	graph.Attr("labeljust", "l")
+
+	startSlot := uint64(*startSlot)
+	endSlot := uint64(*endSlot)
+	filter := filters.NewFilter().SetStartSlot(startSlot).SetEndSlot(endSlot)
+	blks, err := db.Blocks(context.Background(), filter)
+	if err != nil {
+		panic(err)
+	}
+
+	// Construct nodes
+	m := make(map[[32]byte]*node)
+	for i := 0; i < len(blks); i++ {
+		b := blks[i]
+		r, err := ssz.SigningRoot(b)
+		if err != nil {
+			panic(err)
+		}
+		// Construct label of each node.
+		rStr := hex.EncodeToString(r[:2])
+		label := "slot: " + strconv.Itoa(int(b.Slot)) + "\n root: " + rStr
+		dotN := graph.Node(rStr).Box().Attr("label", label)
+		n := &node{
+			parentRoot: bytesutil.ToBytes32(b.ParentRoot),
+			dothNode:   &dotN,
+		}
+		m[r] = n
+	}
+
+	// Construct an edge only if block's parent exist in the tree.
+	for _, n := range m {
+		if _, ok := m[n.parentRoot]; ok {
+			graph.Edge(*n.dothNode, *m[n.parentRoot].dothNode)
+		}
+	}
+
+	fmt.Println(graph.String())
+}