Add ptCid command (#733)

Signed-off-by: Jakub Sztandera <[email protected]>

cmd/f3/main.go

@@ -25,6 +25,7 @@ func main() {
 			&runCmd,
 			&manifestCmd,
 			&observerCmd,
+			&toolsCmd,
 		},
 	}
 

cmd/f3/tools.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+
+	"github.com/filecoin-project/go-f3/certs"
+	"github.com/filecoin-project/go-f3/gpbft"
+	"github.com/urfave/cli/v2"
+)
+
+var toolsCmd = cli.Command{
+	Name:  "tools",
+	Usage: "various tools for f3",
+	Subcommands: []*cli.Command{
+		&ptCidCmd,
+	},
+}
+
+var ptCidCmd = cli.Command{
+	Name:  "ptCid",
+	Usage: "compute the CID of a json power table",
+	Action: func(c *cli.Context) error {
+		var entries gpbft.PowerEntries
+		err := json.NewDecoder(os.Stdin).Decode(&entries)
+		if err != nil {
+			return fmt.Errorf("error while decoding: %w", err)
+		}
+
+		cid, err := certs.MakePowerTableCID(entries)
+		if err != nil {
+			return fmt.Errorf("error while computing CID: %w", err)
+		}
+
+		fmt.Printf("%s\n", cid)
+		return nil
+	},
+}