Add chain info command

cmd/chain.go

@@ -0,0 +1,32 @@
+// Copyright © 2020 Weald Technology Trading
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cmd
+
+import (
+	"github.com/spf13/cobra"
+)
+
+// chainCmd represents the chain command
+var chainCmd = &cobra.Command{
+	Use:   "chain",
+	Short: "Obtain information about an Ethereum 2 chain",
+	Long:  "Obtain information about an Ethereum 2 chain",
+}
+
+func init() {
+	RootCmd.AddCommand(chainCmd)
+}
+
+func chainFlags(cmd *cobra.Command) {
+}

cmd/chaininfo.go

@@ -0,0 +1,68 @@
+// Copyright © 2020 Weald Technology Trading
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/spf13/cobra"
+	"github.com/wealdtech/ethdo/grpc"
+)
+
+var chainInfoCmd = &cobra.Command{
+	Use:   "info",
+	Short: "Obtain information about a chain",
+	Long: `Obtain information about a chain.  For example:
+
+    ethdo chain info
+
+In quiet mode this will return 0 if the chain information can be obtained, otherwise 1.`,
+	Run: func(cmd *cobra.Command, args []string) {
+		err := connect()
+		errCheck(err, "Failed to obtain connection to Ethereum 2 beacon chain node")
+		config, err := grpc.FetchChainConfig(eth2GRPCConn)
+		errCheck(err, "Failed to obtain beacon chain configuration")
+
+		genesisTime, err := grpc.FetchGenesis(eth2GRPCConn)
+		errCheck(err, "Failed to obtain genesis time")
+
+		if quiet {
+			os.Exit(_exit_success)
+		}
+
+		fmt.Printf("Genesis time:\t\t%s\n", genesisTime.Format(time.UnixDate))
+		slot := timestampToSlot(genesisTime.Unix(), time.Now().Unix(), config["SecondsPerSlot"].(uint64))
+		fmt.Printf("Current slot:\t\t%d\n", slot)
+		fmt.Printf("Current epoch:\t\t%d\n", slot/int64(config["SlotsPerEpoch"].(uint64)))
+		outputIf(verbose, fmt.Sprintf("Genesis timestamp:\t%v", genesisTime.Unix()))
+		outputIf(verbose, fmt.Sprintf("Seconds per slot:\t%v", config["SecondsPerSlot"].(uint64)))
+		outputIf(verbose, fmt.Sprintf("Slots per epoch:\t%v", config["SlotsPerEpoch"].(uint64)))
+
+		os.Exit(_exit_success)
+	},
+}
+
+func init() {
+	chainCmd.AddCommand(chainInfoCmd)
+	chainFlags(chainInfoCmd)
+}
+
+func timestampToSlot(genesis int64, timestamp int64, secondsPerSlot uint64) int64 {
+	if timestamp < genesis {
+		return 0
+	}
+	return (timestamp - genesis) / int64(secondsPerSlot)
+}