feat: shed: command for decoding block headers

cmd/lotus-shed/block.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"bytes"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"github.com/filecoin-project/lotus/chain/types"
+	lcli "github.com/filecoin-project/lotus/cli"
+	"github.com/urfave/cli/v2"
+)
+
+var blockCmd = &cli.Command{
+	Name:      "block",
+	Usage:     "Output decoded block header in readeble form",
+	ArgsUsage: "[block header hex]",
+	Action: func(cctx *cli.Context) error {
+		if cctx.NArg() != 1 {
+			return lcli.IncorrectNumArgs(cctx)
+		}
+
+		b, err := hex.DecodeString(cctx.Args().First())
+		if err != nil {
+			return err
+		}
+
+		var blk types.BlockHeader
+		if err := blk.UnmarshalCBOR(bytes.NewReader(b)); err != nil {
+			return err
+		}
+
+		jb, err := json.MarshalIndent(blk, "", "  ")
+		if err != nil {
+			return err
+		}
+
+		fmt.Println(string(jb))
+		return nil
+	},
+}

cmd/lotus-shed/main.go

@@ -89,6 +89,7 @@ func main() {
 		indexesCmd,
 		FevmAnalyticsCmd,
 		mismatchesCmd,
+		blockCmd,
 	}
 
 	app := &cli.App{