Update b2_nodes.md

[panditdhamdhere]

corrected a small typo.
in the B² Nodes docs page there is small spelling error.
update this from "availablity" to "availability"

[hailuu01041990-lab]

// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see http://www.gnu.org/licenses/.

// p2psim provides a command-line client for a simulation HTTP API.
//
// Here is an example of creating a 2 node network with the first node
// connected to the second:
//
// $ p2psim node create
// Created node01
//
// $ p2psim node start node01
// Started node01
//
// $ p2psim node create
// Created node02
//
// $ p2psim node start node02
// Started node02
//
// $ p2psim node connect node01 node02
// Connected node01 to node02
//
package main

import (
"context"
"encoding/json"
"fmt"
"io"
"os"
"strings"
"text/tabwriter"

"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/p2p/discover"
"github.com/ethereum/go-ethereum/p2p/simulations"
"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
"github.com/ethereum/go-ethereum/rpc"
"gopkg.in/urfave/cli.v1"

)

var client *simulations.Client

func main() {
app := cli.NewApp()
app.Usage = "devp2p simulation command-line client"
app.Flags = []cli.Flag{
cli.StringFlag{
Name: "api",
Value: "http://localhost:8888",
Usage: "simulation API URL",
EnvVar: "P2PSIM_API_URL",
},
}
app.Before = func(ctx *cli.Context) error {
client = simulations.NewClient(ctx.GlobalString("api"))
return nil
}
app.Commands = []cli.Command{
{
Name: "show",
Usage: "show network information",
Action: showNetwork,
},
{
Name: "events",
Usage: "stream network events",
Action: streamNetwork,
Flags: []cli.Flag{
cli.BoolFlag{
Name: "current",
Usage: "get existing nodes and conns first",
},
cli.StringFlag{
Name: "filter",
Value: "",
Usage: "message filter",
},
},
},
{
Name: "snapshot",
Usage: "create a network snapshot to stdout",
Action: createSnapshot,
},
{
Name: "load",
Usage: "load a network snapshot from stdin",
Action: loadSnapshot,
},
{
Name: "node",
Usage: "manage simulation nodes",
Action: listNodes,
Subcommands: []cli.Command{
{
Name: "list",
Usage: "list nodes",
Action: listNodes,
},
{
Name: "create",
Usage: "create a node",
Action: createNode,
Flags: []cli.Flag{
cli.StringFlag{
Name: "name",
Value: "",
Usage: "node name",
},
cli.StringFlag{
Name: "services",
Value: "",
Usage: "node services (comma separated)",
},
cli.StringFlag{
Name: "key",
Value: "",
Usage: "node private key (hex encoded)",
},
},
},
{
Name: "show",
ArgsUsage: "",
Usage: "show node information",
Action: showNode,
},
{
Name: "start",
ArgsUsage: "",
Usage: "start a node",
Action: startNode,
},
{
Name: "stop",
ArgsUsage: "",
Usage: "stop a node",
Action: stopNode,
},
{
Name: "connect",
ArgsUsage: " ",
Usage: "connect a node to a peer node",
Action: connectNode,
},
{
Name: "disconnect",
ArgsUsage: " ",
Usage: "disconnect a node from a peer node",
Action: disconnectNode,
},
{
Name: "rpc",
ArgsUsage: " []",
Usage: "call a node RPC method",
Action: rpcNode,
Flags: []cli.Flag{
cli.BoolFlag{
Name: "subscribe",
Usage: "method is a subscription",
},
},
},
},
},
}
if err := app.Run(os.Args); err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
}

func showNetwork(ctx *cli.Context) error {
if len(ctx.Args()) != 0 {
return cli.ShowCommandHelp(ctx, ctx.Command.Name)
}
network, err := client.GetNetwork()
if err != nil {
return err
}
w := tabwriter.NewWriter(ctx.App.Writer, 1, 2, 2, ' ', 0)
defer w.Flush()
fmt.Fprintf(w, "NODES\t%d\n", len(network.Nodes))
fmt.Fprintf(w, "CONNS\t%d\n", len(network.Conns))
return nil
}

func streamNetwork(ctx *cli.Context) error {
if len(ctx.Args()) != 0 {
return cli.ShowCommandHelp(ctx, ctx.Command.Name)
}
events := make(chan *simulations.Event)
sub, err := client.SubscribeNetwork(events, simulations.SubscribeOpts{
Current: ctx.Bool("current"),
Filter: ctx.String("filter"),
})
if err != nil {
return err
}
defer sub.Unsubscribe()
enc := json.NewEncoder(ctx.App.Writer)
for {
select {
case event := <-events:
if err := enc.Encode(event); err != nil {
return err
}
case err := <-sub.Err():
return err
}
}
}

func createSnapshot(ctx *cli.Context) error {
if len(ctx.Args()) != 0 {
return cli.ShowCommandHelp(ctx, ctx.Command.Name)
}
snap, err := client.CreateSnapshot()
if err != nil {
return err
}
return json.NewEncoder(os.Stdout).Encode(snap)
}

func loadSnapshot(ctx *cli.Context) error {
if len(ctx.Args()) != 0 {
return cli.ShowCommandHelp(ctx, ctx.Command.Name)
}
snap := &simulations.Snapshot{}
if err := json.NewDecoder(os.Stdin).Decode(snap); err != nil {
return err
}
return client.LoadSnapshot(snap)
}

func listNodes(ctx *cli.Context) error {
if len(ctx.Args()) != 0 {
return cli.ShowCommandHelp(ctx, ctx.Command.Name)
}
nodes, err := client.GetNodes()
if err != nil {
return err
}
w := tabwriter.NewWriter(ctx.App.Writer, 1, 2, 2, ' ', 0)
defer w.Flush()
fmt.Fprintf(w, "NAME\tPROTOCOLS\tID\n")
for _, node := range nodes {
fmt.Fprintf(w, "%s\t%s\t%s\n", node.Name, strings.Join(protocolList(node), ","), node.ID)
}
return nil
}

func protocolList(node *p2p.NodeInfo) []string {
protos := make([]string, 0, len(node.Protocols))
for name := range node.Protocols {
protos = append(protos, name)
}
return protos
}

func createNode(ctx *cli.Context) error {
if len(ctx.Args()) != 0 {
return cli.ShowCommandHelp(ctx, ctx.Command.Name)
}
config := adapters.RandomNodeConfig()
config.Name = ctx.String("name")
if key := ctx.String("key"); key != "" {
privKey, err := crypto.HexToECDSA(key)
if err != nil {
return err
}
config.ID = discover.PubkeyID(&privKey.PublicKey)
config.PrivateKey = privKey
}
if services := ctx.String("services"); services != "" {
config.Services = strings.Split(services, ",")
}
node, err := client.CreateNode(config)
if err != nil {
return err
}
fmt.Fprintln(ctx.App.Writer, "Created", node.Name)
return nil
}

func showNode(ctx *cli.Context) error {
args := ctx.Args()
if len(args) != 1 {
return cli.ShowCommandHelp(ctx, ctx.Command.Name)
}
nodeName := args[0]
node, err := client.GetNode(nodeName)
if err != nil {
return err
}
w := tabwriter.NewWriter(ctx.App.Writer, 1, 2, 2, ' ', 0)
defer w.Flush()
fmt.Fprintf(w, "NAME\t%s\n", node.Name)
fmt.Fprintf(w, "PROTOCOLS\t%s\n", strings.Join(protocolList(node), ","))
fmt.Fprintf(w, "ID\t%s\n", node.ID)
fmt.Fprintf(w, "ENODE\t%s\n", node.Enode)
for name, proto := range node.Protocols {
fmt.Fprintln(w)
fmt.Fprintf(w, "--- PROTOCOL INFO: %s\n", name)
fmt.Fprintf(w, "%v\n", proto)
fmt.Fprintf(w, "---\n")
}
return nil
}

func startNode(ctx *cli.Context) error {
args := ctx.Args()
if len(args) != 1 {
return cli.ShowCommandHelp(ctx, ctx.Command.Name)
}
nodeName := args[0]
if err := client.StartNode(nodeName); err != nil {
return err
}
fmt.Fprintln(ctx.App.Writer, "Started", nodeName)
return nil
}

func stopNode(ctx *cli.Context) error {
args := ctx.Args()
if len(args) != 1 {
return cli.ShowCommandHelp(ctx, ctx.Command.Name)
}
nodeName := args[0]
if err := client.StopNode(nodeName); err != nil {
return err
}
fmt.Fprintln(ctx.App.Writer, "Stopped", nodeName)
return nil
}

func connectNode(ctx *cli.Context) error {
args := ctx.Args()
if len(args) != 2 {
return cli.ShowCommandHelp(ctx, ctx.Command.Name)
}
nodeName := args[0]
peerName := args[1]
if err := client.ConnectNode(nodeName, peerName); err != nil {
return err
}
fmt.Fprintln(ctx.App.Writer, "Connected", nodeName, "to", peerName)
return nil
}

func disconnectNode(ctx *cli.Context) error {
args := ctx.Args()
if len(args) != 2 {
return cli.ShowCommandHelp(ctx, ctx.Command.Name)
}
nodeName := args[0]
peerName := args[1]
if err := client.DisconnectNode(nodeName, peerName); err != nil {
return err
}
fmt.Fprintln(ctx.App.Writer, "Disconnected", nodeName, "from", peerName)
return nil
}

func rpcNode(ctx *cli.Context) error {
args := ctx.Args()
if len(args) < 2 {
return cli.ShowCommandHelp(ctx, ctx.Command.Name)
}
nodeName := args[0]
method := args[1]
rpcClient, err := client.RPCClient(context.Background(), nodeName)
if err != nil {
return err
}
if ctx.Bool("subscribe") {
return rpcSubscribe(rpcClient, ctx.App.Writer, method, args[3:]...)
}
var result interface{}
params := make([]interface{}, len(args[3:]))
for i, v := range args[3:] {
params[i] = v
}
if err := rpcClient.Call(&result, method, params...); err != nil {
return err
}
return json.NewEncoder(ctx.App.Writer).Encode(result)
}

func rpcSubscribe(client *rpc.Client, out io.Writer, method string, args ...string) error {
parts := strings.SplitN(method, "_", 2)
namespace := parts[0]
method = parts[1]
ch := make(chan interface{})
subArgs := make([]interface{}, len(args)+1)
subArgs[0] = method
for i, v := range args {
subArgs[i+1] = v
}
sub, err := client.Subscribe(context.Background(), namespace, ch, subArgs...)
if err != nil {
return err
}
defer sub.Unsubscribe()
enc := json.NewEncoder(out)
for {
select {
case v := <-ch:
if err := enc.Encode(v); err != nil {
return err
}
case err := <-sub.Err():
return err
}
}
}

[hailuu01041990-lab]

activeAccounts":[{"address":"0x21158cA054C7107cF5669fbF4671f64138081a9d","coin":20000714,"derivationPath":"m/44'/60'/0'/0/0","publicKey":"046270231e3c2085c747c9658e57ad449ef4583b9f144ea5ca5e5ca42f58a4c31c73210f189c2fa0b688e1451a70eb006cddf7952ceaa0096abaca51a4915cbe2a"}],"crypto":{"cipher":"aes-128-ctr","cipherparams":{"iv":"d128c3d42131696104c9bc635a4a8197"},"ciphertext":"d4ee6c68494e24730ef1abf16bd318fa5aa67b09b321a46b77a9c249b9ab9c00","kdf":"scrypt","kdfparams":{"dklen":32,"n":16384,"p":4,"r":8,"salt":"cb15ee6b65c689b9d5dc461259a16d8714c0f8794bce33ff85fd16621c053916"},"mac":"330e666349bbc6bcfbbdf8c129bed4123d24633290a22880c5893562fe89f18e"},"id":"6b1a80f2-2e18-4dad-ac2f-95d8c69c4ecf","name":"","type":"private-key","version":3}