以太坊etherenum入门教程

入门安装go-etherenum

1 搭建私有链

1.1 安装

官方文档提供两种方式，本文使用源码编译

下载源码

git clone https://github.com/ethereum/go-ethereum

安装golang

yum install golang

编译

cd go-ethereum
make geth

1.2 config配置文件

{
  "coinbase"   : "0x0000000000000000000000000000000000000000",
  "difficulty" : "0x400",
  "extraData"  : "0x0",
  "gasLimit"   : "0x2fefd8",
  "nonce"      : "0xdeadbeefdeadbeef",
  "mixhash"    : "0x0000000000000000000000000000000000000000000000000000000000000000",
  "parentHash" : "0x0000000000000000000000000000000000000000000000000000000000000000",
  "timestamp"  : "0x00",
  "alloc"      : {}
}

异常

go-ethereum/build/bin/geth init go-ethereum/eth/piccgenesis.json Fatal: invalid genesis file: json: cannot unmarshal hex string without 0x prefix into Go struct field Genesis.extraData of type hexutil.Bytes

执行成功的config.json

[root@iz2ze20vl8jnph0si0n7jsz watt]# go-ethereum/build/bin/geth init go-ethereum/eth/piccgenesis.json 
INFO [01-29|21:20:19] Allocated cache and file handles         database=/root/.ethereum/geth/chaindata cache=16 handles=16
Fatal: Failed to write genesis block: database already contains an incompatible genesis block (have d4e56740f876aef8, new a0e580c6769ac3dd)

原因由于上次执行命令初始化

启动私有链节点

启动Geth即可以启动以太坊的区块链，为了构建私有链 ，需要在Geth启动时加入一些参数，Geth参数含义如下：

build/bin/geth --datadir /home/watt/ethereumdata init eth/piccgenesis.json

config.json文件

{
  "config": {
        "chainId": 15,
        "homesteadBlock": 0,
        "eip155Block": 0,
        "eip158Block": 0
    },
    "coinbase" : "0x0000000000000000000000000000000000000000",
    "difficulty" : "0x40000",
    "extraData" : "",
    "gasLimit" : "0xffffffff",
    "nonce" : "0x0000000000000042",
    "mixhash" : "0x0000000000000000000000000000000000000000000000000000000000000000",
    "parentHash" : "0x0000000000000000000000000000000000000000000000000000000000000000",
    "timestamp" : "0x00",
    "alloc": { }
}

有个疑问那初始化的数据存储路径在哪呢？ 通过指定的路径生成数据文件名称，使用find命令查找如下

查看初始化数据文件大小如下

重新配置参数

获取当前的目录

/home/watt/go-ethereum/build/bin/geth  --datadir "/home/watt/ethereumchain" init /home/watt/go-ethereum/eth/piccgenesis.json 

创建数据存放地址并初始化创世块

/home/watt/go-ethereum/build/bin/geth --identity "PICCetherum"  --rpc  --rpccorsdomain "*" --datadir "/home/watt/ethereumchain" --port "30303"  --rpcapi "db,eth,net,web3"--networkid 95518 console

启动日志

INFO [01-29|22:08:58] Allocated cache and file handles         database=/home/watt/ethereumchain/geth/chaindata cache=16 handles=16
INFO [01-29|22:08:58] Writing custom genesis block 
INFO [01-29|22:08:58] Successfully wrote genesis state         database=chaindata                               hash=a0e580…a5e82e
INFO [01-29|22:08:58] Allocated cache and file handles         database=/home/watt/ethereumchain/geth/lightchaindata cache=16 handles=16
INFO [01-29|22:08:58] Writing custom genesis block 
INFO [01-29|22:08:58] Successfully wrote genesis state         database=lightchaindata                               hash=a0e580…a5e82e
[root@iz2ze20vl8jnph0si0n7jsz go-ethereum]# /home/watt/go-ethereum/build/bin/geth --identity "PICCetherum"  --rpc  --rpccorsdomain "*" --datadir "/home/watt/ethereumchain" --port "30303"  --rpcapi "db,eth,net,web3"--networkid 95518 console
INFO [01-29|22:09:20] Starting peer-to-peer node               instance=Geth/PICCetherum/v1.8.0-unstable-722bac84/linux-amd64/go1.8.3
INFO [01-29|22:09:20] Allocated cache and file handles         database=/home/watt/ethereumchain/geth/chaindata cache=128 handles=1024
WARN [01-29|22:09:20] Upgrading database to use lookup entries 
INFO [01-29|22:09:20] Initialised chain configuration          config="{ChainID: 15 Homestead: 0 DAO:  DAOSupport: false EIP150:  EIP155: 0 EIP158: 0 Byzantium:  Engine: unknown}"
INFO [01-29|22:09:20] Disk storage enabled for ethash caches   dir=/home/watt/ethereumchain/geth/ethash count=3
INFO [01-29|22:09:20] Disk storage enabled for ethash DAGs     dir=/root/.ethash                        count=2
INFO [01-29|22:09:20] Initialising Ethereum protocol           versions="[63 62]" network=1
INFO [01-29|22:09:20] Database deduplication successful        deduped=0
INFO [01-29|22:09:20] Loaded most recent local header          number=0 hash=a0e580…a5e82e td=262144
INFO [01-29|22:09:20] Loaded most recent local full block      number=0 hash=a0e580…a5e82e td=262144
INFO [01-29|22:09:20] Loaded most recent local fast block      number=0 hash=a0e580…a5e82e td=262144
INFO [01-29|22:09:20] Regenerated local transaction journal    transactions=0 accounts=0
INFO [01-29|22:09:20] Starting P2P networking 
INFO [01-29|22:09:22] UDP listener up                          self=enode://4fadb2bd1b9e7efca20c99c067930c7bb5cd9c27ea38aef11fd514bed4abb1b2697651194fd1b765a51c3648e001542fbf57ef2c4912469e384139bb61c57f60@[::]:30303
INFO [01-29|22:09:22] HTTP endpoint opened: http://127.0.0.1:8545 
INFO [01-29|22:09:22] IPC endpoint opened: /home/watt/ethereumchain/geth.ipc 
INFO [01-29|22:09:22] RLPx listener up                         self=enode://4fadb2bd1b9e7efca20c99c067930c7bb5cd9c27ea38aef11fd514bed4abb1b2697651194fd1b765a51c3648e001542fbf57ef2c4912469e384139bb61c57f60@[::]:30303

卡住了，需要把root下的

rm -rf ethereumchain/ 
rm -rf .ethereum/

清除后重现执行执行输出如下：

INFO [01-29|22:47:57] HTTP endpoint opened: http://127.0.0.1:8545 
INFO [01-29|22:47:57] RLPx listener up                         self=enode://fc07f632a636c713a2621902d5eac3b1969afd54d255812ac767484d926fd1d5113d243467e59e8c0864e63b60240dbd7d55d3b34058fa388f1002f6b20bcfec@[::]:30303
INFO [01-29|22:47:57] IPC endpoint opened: /home/watt/ethereumchain/geth.ipc 
INFO [01-29|22:48:17] Block synchronisation started 
INFO [01-29|22:48:24] Imported new block headers               count=192 elapsed=1.250s number=192 hash=723899…123390 ignored=0
INFO [01-29|22:48:24] Imported new block headers               count=384 elapsed=53.824ms number=576 hash=41a746…6a8b38 ignored=0
INFO [01-29|22:48:24] Imported new block receipts              count=2   elapsed=17.637ms bytes=8 number=2   hash=b495a1…4698c9 ignored=0
INFO [01-29|22:48:24] Imported new block headers               count=384 elapsed=55.720ms number=960 hash=916910…1d0e2a ignored=0
INFO [01-29|22:48:24] Imported new block receipts      

但是未能调用javasript console页面 通过查询发现需要增加 --dev 参数 另开窗口

输入命令

/home/watt/go-ethereum/build/bin/geth  --dev console 2>> file_to_log_output

2

2、 使用私有链

查看账户

eth.accounts

创建用户：

personal.newAccount("111111")

其中参数为此账户的密码。

也可以先创建账户，然后输入密码：

personal.newAccount()

查看区块数据

eth.blockNumber

启动挖矿

miner.start()

返回结果为true则启动成功，具体执行情况可查看日志。

停止挖矿

miner.stop()

当在执行挖矿时日志会不停刷屏，不用管，只要命令输入全，执行即可停止挖矿。

查看账户余额

其中参数为区块链地址

eth.getBalance("0x7d1f7be4112ce63b9de04a0bf95c1e87e430bd1b")

转账

从账户0x7d1f7be4112ce63b9de04a0bf95c1e87e430bd1b转账3个以太币到0x587e57a516730381958f86703b1f8e970ff445d9。

eth.sendTransaction({from:"0x7d1f7be4112ce63b9de04a0bf95c1e87e430bd1b",to:"0x587e57a516730381958f86703b1f8e970ff445d9",value:web3.toWei(3,"ether")})

当直接执行此方法时会抛出异常：

account is locked
    at web3.js:3119:20
    at web3.js:6023:15
    at web3.js:4995:36
    at :1:1

很明显，账户被锁。

解锁转出账户

其中第一个参数为转出账户，第二个参数为密码。也可以直填写第一个参数，然后通过命令行提示再输入密码。

personal.unlockAccount("0x7d1f7be4112ce63b9de04a0bf95c1e87e430bd1b","111111")

解锁完成之后，即可执行转账操作。但此时查看时会发现接收账户依旧为原来数值。此时需要执行挖矿命令，才会把转账真正完成。

看似美好，执行命令后

> eth.accounts
["0x709447961e479f696a496243cbeff83b851908b2"]
> personal.newAccount("111111")
"0x489835dff4d2270ae2c6a148ca313858bf1e4994"
> eth.blockNumber
0
> miner.start()
null
> 

发现miner.start() 为null

Pre-allocating ether to your account
A difficulty of “0x400” allows you to mine Ether very quickly on your private testnet chain. If you create your chain and start mining, you should have hundreds of ether in a matter of minutes which is way more than enough to test transactions on your network. If you would still like to pre-allocate Ether to your account, you will need to:

Create a new Ethereum account after you create your private chain
Copy your new account address
Add the following command to your Custom_Genesis.json file:
"alloc":
{
        "0x709447961e479f696a496243cbeff83b851908b2":
        { "balance": "20000000000000000000" }
}
Note

Replace 0x1fb891f92eb557f4d688463d0d7c560552263b5a with your account address.

Save your genesis file and rerun your private chain command. Once geth is fully loaded, close it by .

We want to assign an address to the variable primary and check its balance.

Run the command geth account list in your terminal to see what account # your new address was assigned.

需要执行命令

miner.setEtherbase(personal.listAccounts[0])

查看日志

INFO [01-29|23:14:53] Starting mining operation 
INFO [01-29|23:14:53] Commit new mining work                   number=1 txs=0 uncles=0 elapsed=65.571µs
WARN [01-29|23:14:53] Block sealing failed                     err="waiting for transactions

继续努力

#返回钱包管理的账户地址列表  
#返回示例：["0x3138e3722fb4280cb67f6e858108136bfa1c9160"]
eth.accounts

#创建账户地址，参数为账户锁定密码，在转账前需要先解锁账户
#我们把这个命令运行两次，创建两个地址，加上默认的，一共有了三个账户地址
personal.newAccount('111111')
personal.newAccount('111111')

#为账户设置别名，方便命令输入
user1=eth.accounts[0]
user2=eth.accounts[1]
user3=eth.accounts[2]

#查看地址user1余额,这个地址是测试链默认开通的一个地址，里面初始化有很多币
#我们创建的另外两个地址余额未0
eth.getBalance(user1)

#查看区块高度，现在为0
eth.blockNumber

#转账测试，首先解锁账号user1
#命令运行后要求输入解锁密码，直接回车，默认账号锁定密码为空，返回true成功
personal.unlockAccount(user1)

#从user1向user2转账3个以太币
#命令运行后，提交交易立马回出发挖矿
eth.sendTransaction({from:user1,to:user2,value:web3.toWei(3,"ether")})

#查看区块高度，这时高度为1
eth.blockNumber

还是null

挖矿测试
geth启动后，自动启动挖矿，这时运行miner.start()，返回为null 无交易的时候不挖矿，当有交易时自动会触发挖矿流程

#我们可以先停止挖矿
miner.stop()

#提交交易，这时候只提交，查看账户余额，但是未确认
eth.sendTransaction({from:user1,to:user2,value:web3.toWei(3,"ether")})

#启动挖矿，确认交易，再次查看账户余额
miner.start()

#那么挖矿奖励去哪儿了？查看矿工地址
eth.coinbase

#设置矿工地址
miner.setEtherbase(eth.coinbase)

3、参考资料

区块链开发（一）搭建基于以太坊的私有链环境

私有链搭建文档

以太坊学习笔记：私有链搭建操作指南

区块链开发（二）以太坊客户端基本操作命令

以太坊执行miner.start返回null

10分钟完成阿里云环境搭建以太坊私有链