使用Parity建立Proof-of-Authority (PoA) Ethereum Chain

5分鐘快速從無到有建立Ethereum聯盟鏈

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Taipei Ethereum Meetup

17 min readFeb 13, 2017

開發Ethereum Dapp的過程中，需要一個測試用的chain，之前是使用testrpc或直接連到Ethereum testnet (Ropsten)，不過testrpc有各種雷需要處理，而Ropsten testnet則是需要同步與等待block，相當的煩人。前幾天看到Parity 1.5版以後支援建立Proof of Authority Chains，可以直接解決上述的問題，果然一試成主顧。

若你有下列困擾，可以建立自己測試用的PoA chain

公司內網或無對外網路，無法同步區塊
降低測試時等待區塊的時間
不想碰到testrpc各種雷

PoA Chain特點有

有別於PoW (Proof-of-Work)需要解數學難題來產生block，PoA是依靠預設好的Authority nodes，負責產生block。
可依照需求設定Authority node數量。
可指定產生block的時間，例如收到交易的5秒後產生block。
一般的Ethereum node也可以連接到PoA Chain，正常發起transactions, contracts等。

這篇教學文基本上是照著Parity Demo PoA tutorial來撰寫。

Parity是一個注重效能的Ethereum Client端軟體

1. 安裝Parity (1.5.0以上版本)

請自行到Parity官網安裝，支援Ubutnu, OSX, Docker, Windows

2. 設定chain spec

PoA chain需要設定一個創世區塊

{
    "name": "DemoPoA",
    "engine": {
        "authorityRound": {
            "params": {
                "gasLimitBoundDivisor": "0x400",
                "stepDuration": "5",
                "validators" : {
                    "list": []
                }
            }
        }
    },
    "params": {
        "maximumExtraDataSize": "0x20",
        "minGasLimit": "0x1388",
        "networkID" : "0x2323"
    },
    "genesis": {
        "seal": {
            "authorityRound": {
                "step": "0x0",
                "signature": "0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"
            }
        },
        "difficulty": "0x20000",
        "gasLimit": "0x5B8D80"
    },
    "accounts": {
        "0x0000000000000000000000000000000000000001": { "balance": "1", "builtin": { "name": "ecrecover", "pricing": { "linear": { "base": 3000, "word": 0 } } } },
        "0x0000000000000000000000000000000000000002": { "balance": "1", "builtin": { "name": "sha256", "pricing": { "linear": { "base": 60, "word": 12 } } } },
        "0x0000000000000000000000000000000000000003": { "balance": "1", "builtin": { "name": "ripemd160", "pricing": { "linear": { "base": 600, "word": 120 } } } },
        "0x0000000000000000000000000000000000000004": { "balance": "1", "builtin": { "name": "identity", "pricing": { "linear": { "base": 15, "word": 3 } } } }
    }
}

stepDuration 設定成5秒產生一個區塊
validators 設定Authority的地方，目前先空著，後續產生account之後再回來填入

將上述資料存成 demo-spec.json

3. 設定兩個node

此教學會在同一台機器上跑兩個node，因此有些Parity原生的設定參數會有衝突，兩個node需要分別設定不同值。

-d 指定儲存資料與帳號的目錄
--dport 指定Parity的network port，可用來讓其他node連接
--jsonrpc-port 這是JSON RPC port，使用web3.js時會需要
ui-port Parity提供的Web-based UI port
dapps-port Parity Dapps使用的port

可以用下列指令啟動Parity node

parity --chain demo-spec.json -d /tmp/parity0 --port 30300 --jsonrpc-port 8540 --ui-port 8180 --dapps-port 8080 --jsonrpc-apis web3,eth,net,personal,parity,parity_set,traces,rpc,parity_accounts

除了打一長串的指令外，Parity也提供更為簡潔的config檔案設定方式，使用 --config 即可引用設定檔。

node0 使用如下設定檔 node0.toml

[parity]
chain = "demo-spec.json"
base_path = "/tmp/parity0"
[network]
port = 30300
[rpc]
port = 8540
apis = ["web3", "eth", "net", "personal", "parity", "parity_set", "traces", "rpc", "parity_accounts"]
[ui]
port = 8180
[dapps]
port = 8080

node1 使用如下設定檔 node1.toml

[parity]
chain = "demo-spec.json"
base_path = "/tmp/parity1"
[network]
port = 30301
[rpc]
port = 8541
apis = ["web3", "eth", "net", "personal", "parity", "parity_set", "traces", "rpc", "parity_accounts"]
[ui]
port = 8181
[dapps]
port = 8081

4. 設定帳號(Account)

我們總共要開3個帳號：2個Authority跟1個user帳號。

Step 1 首先啟動 node0 : parity --config node0.toml

接著開啟網頁 http://localhost:8180

我不知道怎麼略過WELCOME操作，所以先跟著指示隨便建立一個account，然後再刪除XD

接著新增一個user account，使用Recover account from recovery phrase功能，為了示範的一致性，使用 user 當作pass phrase

新增Authority account，一樣使用Recover account from recovery phrase功能，為了示範的一致性，使用 node0 當作pass phrase

這樣就完成 node0 的帳號設定

Authority account: 0x00Bd138aBD70e2F00903268F3Db08f2D25677C9e
User account: 0x004ec07d2329997267Ec62b4166639513386F32E

Step 2 再來設定 node1 的帳號，啟動 parity --config node1.toml ，步驟相同，連接到 http://localhost:8181 ，pass phrase使用 node1

這樣就完成 node1 的帳號設定

Authority account: 0x00Aa39d30F0D20FF03a22cCfc30B7EfbFca597C2

Step 3 將Authority account寫入 demo-spec.json 檔案

"validators" : {
    "list": [
        "0x00Bd138aBD70e2F00903268F3Db08f2D25677C9e",
        "0x00Aa39d30F0D20FF03a22cCfc30B7EfbFca597C2"
    ]
}

再將user account加入accounts，並給一些balance，後續可以使用

"0x004ec07d2329997267Ec62b4166639513386F32E": { "balance": "10000000000000000000000" }

完成後的demo-spec.json如下

{
    "name": "DemoPoA",
    "engine": {
        "authorityRound": {
            "params": {
                "gasLimitBoundDivisor": "0x400",
                "stepDuration": "5",
                "validators" : {
                    "list": [
                        "0x00Bd138aBD70e2F00903268F3Db08f2D25677C9e",
                        "0x00Aa39d30F0D20FF03a22cCfc30B7EfbFca597C2"
                    ]
                }
            }
        }
    },
    "params": {
        "maximumExtraDataSize": "0x20",
        "minGasLimit": "0x1388",
        "networkID" : "0x2323"
    },
    "genesis": {
        "seal": {
            "authorityRound": {
                "step": "0x0",
                "signature": "0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"
            }
        },
        "difficulty": "0x20000",
        "gasLimit": "0x5B8D80"
    },
    "accounts": {
        "0x0000000000000000000000000000000000000001": { "balance": "1", "builtin": { "name": "ecrecover", "pricing": { "linear": { "base": 3000, "word": 0 } } } },
        "0x0000000000000000000000000000000000000002": { "balance": "1", "builtin": { "name": "sha256", "pricing": { "linear": { "base": 60, "word": 12 } } } },
        "0x0000000000000000000000000000000000000003": { "balance": "1", "builtin": { "name": "ripemd160", "pricing": { "linear": { "base": 600, "word": 120 } } } },
        "0x0000000000000000000000000000000000000004": { "balance": "1", "builtin": { "name": "identity", "pricing": { "linear": { "base": 15, "word": 3 } } } },
        "0x004ec07d2329997267Ec62b4166639513386F32E": { "balance": "10000000000000000000000" }
    }
}

5. 啟動Authority node

為了啟動Authority node來產生區塊，我們必須設定負責產生block的signer，分別是 node0 與 node1 account

Step 1 開啟一個 node.pwds 檔案，寫入 node0 與 node1 的password，內容如下

node0
node1

Step 2 在設定檔 node0.toml 加入 [account] 及 [mining] 設定，如下

[parity]
chain = "demo-spec.json"
base_path = "/tmp/parity0"
[network]
port = 30300
[rpc]
port = 8540
apis = ["web3", "eth", "net", "personal", "parity", "parity_set", "traces", "rpc", "parity_accounts"]
[ui]
port = 8180
[dapps]
port = 8080
[account]
password = ["node.pwds"]
[mining]
engine_signer = "0x00Bd138aBD70e2F00903268F3Db08f2D25677C9e"
reseal_on_txs = "none"

Step 3 node1.toml 也一樣，如下

[parity]
chain = "demo-spec.json"
base_path = "/tmp/parity1"
[network]
port = 30301
[rpc]
port = 8541
apis = ["web3", "eth", "net", "personal", "parity", "parity_set", "traces", "rpc", "parity_accounts"]
[ui]
port = 8181
[dapps]
port = 8081
[account]
password = ["node.pwds"]
[mining]
engine_signer = "0x00Aa39d30F0D20FF03a22cCfc30B7EfbFca597C2"
reseal_on_txs = "none"

Step 4 分別啟動兩個node

parity --config node0.toml

parity --config node1.toml

6.連接兩個node

使用Postman透過JSON RPC來測試

Step 1 Post下列JSON資料至 http://localhost:8540 以取得 node0 的enode資料

{
 "jsonrpc":"2.0",
 "method":"parity_enode",
 "params":[],
 "id":0
}

Step 2 將 node0 的enode加入 node1 ，Post下列JSON資料至node1 (http://localhost:8541 )

{
 "jsonrpc":"2.0",
 "method":"parity_addReservedPeer",
 "params":["enode://6c4f53fc8536553c8f151516b7ee17f4b0719d21abe8fdd273588419cf467e3deafb414cd8efa331e4ad55fd7c2820a303a160895129e142a4306e7c3367d67c@172.20.160.80:30300"],
 "id":0
}

你的IP位址會不一樣，172.20.160.80

最後到 node1 的console畫面，會看到 0/1/25 peers，就表示已經連接上。

7. 發送transaction

透過Parity提供的web-based UI可以很容易發送transaction，這邊就不贅述了。

補充：分享給區網內其他人使用

在開發時通常會將node跑在server上，讓其他人可以透過JSON RPC port連接上去使用，此時只要在config檔裡面加入 [interface] 設定即可。

假設server ip為192.168.1.1，將 node0.toml 修改如下：

[parity]
chain = "demo-spec.json"
base_path = "/tmp/parity0"
[network]
port = 30300
[rpc]
port = 8540
apis = ["web3", "eth", "net", "personal", "parity", "parity_set", "traces", "rpc", "parity_accounts"]
interface = "192.168.1.1"
[ui]
port = 8180
[dapps]
port = 8080
[account]
password = ["node.pwds"]
[mining]
engine_signer = "0x00Bd138aBD70e2F00903268F3Db08f2D25677C9e"
reseal_on_txs = "none"

同樣 node1.toml 修改如下：

[parity]
chain = "demo-spec.json"
base_path = "/tmp/parity1"
[network]
port = 30301
[rpc]
port = 8541
apis = ["web3", "eth", "net", "personal", "parity", "parity_set", "traces", "rpc", "parity_accounts"]
interface = "192.168.1.1"
[ui]
port = 8181
[dapps]
port = 8081
[account]
password = ["node.pwds"]
[mining]
engine_signer = "0x00Aa39d30F0D20FF03a22cCfc30B7EfbFca597C2"
reseal_on_txs = "none"