Shed: Add a util to find the most recent null tipset

cmd/lotus-shed/chain.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"fmt"
+
+	lcli "github.com/filecoin-project/lotus/cli"
+	"github.com/urfave/cli/v2"
+)
+
+var chainCmd = &cli.Command{
+	Name:  "chain",
+	Usage: "chain-related utilities",
+	Subcommands: []*cli.Command{
+		chainNullTsCmd,
+	},
+}
+
+var chainNullTsCmd = &cli.Command{
+	Name:  "latest-null",
+	Usage: "finds the most recent null tipset",
+	Action: func(cctx *cli.Context) error {
+		api, closer, err := lcli.GetFullNodeAPI(cctx)
+		if err != nil {
+			return err
+		}
+
+		defer closer()
+		ctx := lcli.ReqContext(cctx)
+
+		ts, err := lcli.LoadTipSet(ctx, cctx, api)
+		if err != nil {
+			return err
+		}
+
+		for {
+			pts, err := api.ChainGetTipSet(ctx, ts.Parents())
+			if err != nil {
+				return err
+			}
+
+			if ts.Height() != pts.Height()+1 {
+				fmt.Println("null tipset at height ", ts.Height()-1)
+				return nil
+			}
+
+			ts = pts
+		}
+	},
+}

cmd/lotus-shed/main.go

@@ -62,6 +62,7 @@ func main() {
 		minerMultisigsCmd,
 		splitstoreCmd,
 		fr32Cmd,
+		chainCmd,
 	}
 
 	app := &cli.App{