Brotherhood Block Chain Course: In-depth Analysis of CMD in Taifang Source Code Analysis (I)

Keywords: Go network snapshot Blockchain Database

Brothers Link Block Chain Course Etaifang Source Code Analysis CMD in-depth analysis.

cmd packet analysis

There are 13 subpackages under cmd. In addition to util packages, each subpackage has a main function. The init method of each main function defines the commands supported by the main function, such as

Under the get package:
func init() {
    // Initialize the CLI app and start Geth
    app.Action = geth
    app.HideVersion = true // we have a command to print the version
    app.Copyright = "Copyright 2013-2017 The go-ethereum Authors"
    app.Commands = []cli.Command{
        // See chaincmd.go:
        initCommand,
        importCommand,
        exportCommand,
        copydbCommand,
        removedbCommand,
        dumpCommand,
        // See monitorcmd.go:
        monitorCommand,
        // See accountcmd.go:
        accountCommand,
        walletCommand,
        // See consolecmd.go:
        consoleCommand,
        attachCommand,
        javascriptCommand,
        // See misccmd.go:
        makecacheCommand,
        makedagCommand,
        versionCommand,
        bugCommand,
        licenseCommand,
        // See config.go
        dumpConfigCommand,
    }
    sort.Sort(cli.CommandsByName(app.Commands))
}
Then initCommand is analyzed separately:
initCommand = cli.Command{
Action: utils.MigrateFlags(initGenesis),
Name: "init",
Usage: "Bootstrap and initialize a new genesis block",
ArgsUsage: "<genesisPath>",
Flags: []cli.Flag{
utils.DataDirFlag,
utils.LightModeFlag,
},
Category: "BLOCKCHAIN COMMANDS",
Description: `
The init command initializes a new genesis block and definition for the network.
This is a destructive action and changes the network in which you will be
participating.
Name is the command corresponding to the command, action is the action that calls the command to complete, usage represents the purpose, arguUsage shows the number of parameters followed by the command and the meaning of each parameter.
The init method is actually to initialize the creation block. flags represent the additional commands that can be executed by this subcommand. If you change the init command, you can take two parameters and click in utils.DataDirFlag to see that:
// General settings
DataDirFlag = DirectoryFlag{
Name: "datadir",
Usage: "Data directory for the databases and keystore",
Value: DirectoryString{node.DefaultDataDir()},
}
  • You can use -- datadir [dir] to specify the path to the database, and if you don't specify the default path because the parameter has value, it's also. ethereum under the home directory.
  • /cmd/wnode/main.go starts by connecting to other nodes
  • / cmd/geth /cmd/swarm defines many commands

The rlpdump subpackage of cmd under eth, whose main function is to dump RLP data from a given file in readable form. If the file name is omitted, the data will be read from stdin

　 /rlpdump

Decoding rlp data
help of command of rlpdump
Usage: /tmp/___cmd_rlpdump_test [-noascii] [-hex <data>] [filename]
-hex string
  dump given hex data
-noascii
  don't print ASCII strings readably
-single
  print only the first element, discard the rest

Dumps RLP data from the given file in readable form.
If the filename is omitted, data is read from stdin.
example1:
demo command: --hex f872f870845609a1ba64c0b8660480136e573eb81ac4a664f8f76e4887ba927f791a053ec5ff580b1037a8633320ca70f8ec0cdea59167acaa1debc07bc0a0b3a5b41bdf0cb4346c18ddbbd2cf222f54fed795dde94417d2e57f85a580d87238efc75394ca4a92cfe6eb9debcc3583c26fee8580
success_result_demo:
[
[
5609a1ba,
"d",
[],
0480136e573eb81ac4a664f8f76e4887ba927f791a053ec5ff580b1037a8633320ca70f8ec0cdea59167acaa1debc07bc0a0b3a5b41bdf0cb4346c18ddbbd2cf222f54fed795dde94417d2e57f85a580d87238efc75394ca4a92cfe6eb9debcc3583c26fee85,
"",
],
]
example2:
demo command: --noascii --hex CE0183FFFFFFC4C304050583616263
success_result_demo:
[
01,
ffffff,
[
[
04,
05,
05,
],
],
616263,
]

Analysis of p2psim subpackage under cmd package, p2psim is a command line client for the HTTP API

First, we start the corresponding main function, and the corresponding startup parameter is -- help, to see the use of all commands under the package, the results are as follows:
NAME:
___go_build_main_go__1_ - devp2p simulation command-line client

USAGE:
___go_build_main_go__1_ [global options] command [command options] [arguments...]

VERSION:
0.0.0

COMMANDS:
show show network information
events stream network events
snapshot create a network snapshot to stdout
load load a network snapshot from stdin
node manage simulation nodes
help, h Shows a list of commands or help for one command

GLOBAL OPTIONS:
--api value simulation API URL (default: "http://localhost:8888") [$P2PSIM_API_URL]
--help, -h show help
--version, -v print the version
This subpackage provides commands on how to issue:
p2psim show
p2psim events [--current] [--filter=FILTER]
p2psim snapshot
p2psim load
p2psim node create [--name=NAME] [--services=SERVICES] [--key=KEY]
p2psim node list
p2psim node show <node>
p2psim node start <node>
p2psim node stop <node>
p2psim node connect <node> <peer>
p2psim node disconnect <node> <peer>
p2psim node rpc <node> <method> [<args>] [--subscribe]
To use the commands under this subpackage properly, we need to run the main function of / p2p/simulations/examples/ping-pong.go to start a simulation network with simple running nodes.

After normal start-up, you will see:

INFO [01-23|11:17:10] using sim adapter
INFO [01-23|11:17:10] starting simulation server on 0.0.0.0:8888...
After the service starts, it provides the following API, which is equivalent to the above command. The implementation of command invocation is actually to invoke API, and the path prefix of access is 0.0.0:8888:
GET / Get network information
POST /start Start all nodes in the network
POST /stop Stop all nodes in the network
GET /events Stream network events
GET /snapshot Take a network snapshot
POST /snapshot Load a network snapshot
POST /nodes Create a node
GET /nodes Get all nodes in the network
GET /nodes/:nodeid Get node information
POST /nodes/:nodeid/start Start a node
POST /nodes/:nodeid/stop Stop a node
POST /nodes/:nodeid/conn/:peerid Connect two nodes
DELETE /nodes/:nodeid/conn/:peerid Disconnect two nodes
GET /nodes/:nodeid/rpc Make RPC requests to a node via WebSocket
Without going into API, the service of emulation network is up. Now we begin to use the command under p2psim package:

/p2psim

  • show
function: Displays the status of the current simulation network
args:""
demo: show
notice:
success_result_demo:
NODES 0
CONNS 0
  • snapshot
function:Export node information of current simulation network
args:""
demo: shapshot
notice:
success_result_demo:
{"nodes":[{"node":{"config":{"id":"085416957c3a0afef6aabe6c0d6b27b7cf8a61f28a3a5439010fcc9e49945a1818ea38946dda8c82004b231ab771450ee0d87886163b65eaa48ecfbcb85e871d","private_key":"3480d230f453e7c207bbd3b770bf774dc8a17e599394f9283147a35c3ead561c","name":"node1","services":["ping-pong"]},"up":true}},{"node":{"config":{"id":"cedbaecccfe42d04b742d1be6e924e0654a7eb1aa584d497f98d24951b156ada84bcfc6455ff37ba1fc81179d0a7c3da1ba34945be19d1fe5cd4c8a32a659a7b","private_key":"b7592cdeee6195c4486fcdd8007e1aedfd3a49e6c9f53e0845bf977d4ad043cc","name":"node2","services":["ping-pong"]},"up":false}}],"conns":[{"one":"cedbaecccfe42d04b742d1be6e924e0654a7eb1aa584d497f98d24951b156ada84bcfc6455ff37ba1fc81179d0a7c3da1ba34945be19d1fe5cd4c8a32a659a7b","other":"085416957c3a0afef6aabe6c0d6b27b7cf8a61f28a3a5439010fcc9e49945a1818ea38946dda8c82004b231ab771450ee0d87886163b65eaa48ecfbcb85e871d","up":false}]}
  • node

  • create

function:Create a node
args:[--name=NAME] [--services=SERVICES] [--key=KEY]
demo: node create --name node1
notice:
success_result_demo:
Created node1

  • list

function:List the node information of the current simulation network
args:""
demo: node list
notice:
success_result_demo:
NAME PROTOCOLS ID
node1 085416957c3a0afef6aabe6c0d6b27b7cf8a61f28a3a5439010fcc9e49945a1818ea38946dda8c82004b231ab771450ee0d87886163b65eaa48ecfbcb85e871d
node2 cedbaecccfe42d04b742d1be6e924e0654a7eb1aa584d497f98d24951b156ada84bcfc6455ff37ba1fc81179d0a7c3da1ba34945be19d1fe5cd4c8a32a659a7b

  • show

function:View the specific information of a node in the simulation network
args:<node>
demo: node show node1
notice:
success_result_demo:
NAME node1
PROTOCOLS
ID 085416957c3a0afef6aabe6c0d6b27b7cf8a61f28a3a5439010fcc9e49945a1818ea38946dda8c82004b231ab771450ee0d87886163b65eaa48ecfbcb85e871d
ENODE enode://085416957c3a0afef6aabe6c0d6b27b7cf8a61f28a3a5439010fcc9e49945a1818ea38946dda8c82004b231ab771450ee0d87886163b65eaa48ecfbcb85e871d@127.0.0.1:30303

  • start

function:Start a node
args:<node>
demo: node start node1
notice:
success_result_demo:
Started node1

  • connect

function: Connect one node to another
args:<node> <peer>
demo: node connect node2 node1
notice:
success_result_demo:
Connected node2 to node1

  • disconnect

function:Node disconnection
args:<node> <peer>
demo: node disconnect node2 node1
notice:
success_result_demo:
Disconnected node2 from node1

  • stop

function:Stop a node
args:<node>
demo: node stop node2
notice:
success_result_demo:
Stopped node2

  • rpc

function:call rpc Interface
args:<node> <method> [<args>] [--subscribe]
demo: node rpc node1 admin
notice:
success_result_demo:
　// TODO

Posted by Tory on Wed, 30 Jan 2019 16:24:14 -0800

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