substrate chain spec
翟沈义
简介
链规范是一组配置信息，这些信息指示区块链节点将连接到哪个网络、它最初将与哪些节点进行通信，以及它在创世时必须具有什么样的共识关键状态。
结构
ChainSpec主要分两部分client spec和genesis state
client spec
大部分用于与网络中的其它节点进行通信，例如一组引导节点、遥测端点、可读名称连接。其中许多配置项可以被命令行标志覆盖，并且可以在区块链启动后更改这些值。
struct ClientSpec<E> {
name: String,
id: String,
#[serde(default)]
chain_type: ChainType,
boot_nodes: Vec<MultiaddrWithPeerId>,
telemetry_endpoints: Option<TelemetryEndpoints>,
protocol_id: Option<String>,
properties: Option<Properties>,
#[serde(flatten)]
extensions: E,
// Never used, left only for backward compatibility.
consensus_engine: (),
#[serde(skip_serializing)]
genesis: serde::de::IgnoredAny,
/// Mapping from `block_hash` to `wasm_code`.
///
/// The given `wasm_code` will be used to substitute the on-chain wasm code from the given
/// block hash onwards.
#[serde(default)]
code_substitutes: HashMap<String, Bytes>,
}
genesis state
链规范的第二部分是共识关键的创世配置。网络中的所有节点必须就这个初始状态达成一致，然后才能就任何后续区块达成一致。因此，这些信息必须在链开始时建立，此后如果不启动全新的区块链，则无法更改。没有命令行标志可以覆盖链规范的创世部分中的值。
链规范的创世部分包括初始代币余额、最初属于治理委员会的帐户或 sudo 密钥的持有者。Substrate 节点还将编译后的 Wasm 运行时逻辑放在链上，因此初始运行时也必须在链规范中提供。
链规范配置信息
- Rust struct 。Substrate 节点通常包括至少一个，通常是许多，硬编码到客户端的链规范。在具有“主网”概念的协议中，此规范通常在客户端中进行硬编码。
- JSON 格式。 链规范结构具有将其数据序列化为 JSON 的方法以及将 JSON 数据反序列化为链规范实例的函数。在启动测试网或私有链时，通常会随节点二进制文件一起分发 JSON 编码的链规范。
如何使用chain spec
启动链
启动一个测试网或私有网络，其行为类似于现有协议，但未连接到主网。为了实现这一点，可以通过使用命令行标志来选择替代的硬编码链规范，例如–chain local指示节点使用与字符串“local”相关联的规范。第三个选项是将链规范作为带有命令行标志的 JSON 文件提供，例如 --chain=someCustomSpec.json，在这种情况下，节点将尝试反序列化所提供的 JSON 链规范，然后使用它。
开发runtime
每个 Substrate 运行时都会有需要在创世时配置的存储项。使用FRAME开发时，任何使用该config() 选项声明的存储项都需要在创世时进行配置。配置这样的存储值是链规范的工作，特别是创世部分
自定义链规格
在为开发、测试或演示目的创建一次性网络时，可能需要真正定制的链规范。节点运营商可以将协议的默认链规范导出为 JSON 格式，然后进行编辑。substrate的子命令build-spec 可以用来导出json文件。
substrate build-spec > myCustomSpec.json
导出链规范后，操作员可以自由修改其任何字段。修改网络的名称和引导节点以及运营商希望的任何创世配置（例如代币余额）是很常见的。编辑完成后，运营商可以通过提供定制的 JSON 来启动他们的定制链。
substrate --chain=myCustomSpec.json
原始链规范(Raw chain spec)
Substrate 节点支持运行时升级，这意味着区块链的runtime可能与链开始时不同。
从 Substrate 节点的链规范.json文件中摘录：
"sudo": {
"key": "5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY"
}
在此规范可用于初始化节点的创世存储之前，人类可读的密钥必须转换为存储 trie (类似以太坊mpt)的实际存储密钥。
如果升级runtime的节点尝试从创世同步链，它将无法理解人类可读的链规范信息。出于这个原因，链规范有第二种编码方式，称为“原始”链规范。
当以 JSON 格式分发链规范时，它们应该以这种原始格式分发，以确保所有节点即使在runtime升级后也可以同步链。基于substrate的节点支持–raw标记以生成raw链规范。
substrate build-spec --chain=myCustomSpec.json --raw > customSpecRaw.json
转换后 ,上面的配置变成了这样
"0x50a63a871aced22e88ee6466fe5aa5d9": "0xd43593c715fdd31c61141abd04a99fd6822c8558854ccde39a5684e7a56da27d",
build-spec
默认可配置的flag比较少,具体实现在chain_spec.rs
- –chain 可以设置dev, local ,dev通常是一个本地节点,local通常是多个本地节点(账户也多些)
- –chain dev 和–dev等价
- –disable-default-bootnode 不生产bootnode配置,默认值
/ip4/127.0.0.1/tcp/30333/p2p/NODE_PEER_ID - –raw 将人类可读的链规范转换成原始(只有机器可读)链规范
- –node-key-type libp2p 节点id ,默认值Ed25519,目前只支持Ed25519,也可以使用其它两个flag:–node-key-file --node-key
FLAGS:
--dev
Specify the development chain
--disable-default-bootnode
Disable adding the default bootnode to the specification.
By default the `/ip4/127.0.0.1/tcp/30333/p2p/NODE_PEER_ID` bootnode is added to the specification when no
bootnode exists.
--disable-log-color
Disable log color output
--disable-log-reloading
Disable feature to dynamically update and reload the log filter.
By default this feature is enabled, however it leads to a small performance decrease. The
`system_addLogFilter` and `system_resetLogFilter` RPCs will have no effect with this option set.
-h, --help
Prints help information
--raw
Force raw genesis storage output
-V, --version
Prints version information
OPTIONS:
-d, --base-path <PATH>
Specify custom base path
--chain <CHAIN_SPEC>
Specify the chain specification.
It can be one of the predefined ones (dev, local, or staging) or it can be a path to a file with the
chainspec (such as one exported by the `build-spec` subcommand).
-l, --log <LOG_PATTERN>...
Sets a custom logging filter. Syntax is <target>=<level>, e.g. -lsync=debug.
Log levels (least to most verbose) are error, warn, info, debug, and trace. By default, all targets log
`info`. The global log level can be set with -l<level>.
--node-key <KEY>
The secret key to use for libp2p networking.
The value is a string that is parsed according to the choice of `--node-key-type` as follows:
`ed25519`: The value is parsed as a hex-encoded Ed25519 32 byte secret key, i.e. 64 hex characters.
The value of this option takes precedence over `--node-key-file`.
WARNING: Secrets provided as command-line arguments are easily exposed. Use of this option should be limited
to development and testing. To use an externally managed secret key, use `--node-key-file` instead.
--node-key-file <FILE>
The file from which to read the node's secret key to use for libp2p networking.
The contents of the file are parsed according to the choice of `--node-key-type` as follows:
`ed25519`: The file must contain an unencoded 32 byte or hex encoded Ed25519 secret key.
If the file does not exist, it is created with a newly generated secret key of the chosen type.
--node-key-type <TYPE>
The type of secret key to use for libp2p networking.
The secret key of the node is obtained as follows:
* If the `--node-key` option is given, the value is parsed as a secret key according to the type. See the
documentation for `--node-key`.
* If the `--node-key-file` option is given, the secret key is read from the specified file. See the
documentation for `--node-key-file`.
* Otherwise, the secret key is read from a file with a predetermined, type-specific name from the chain-
specific network config directory inside the base directory specified by `--base-dir`. If this file
does not exist, it is created with a newly generated secret key of the chosen type.
The node's secret key determines the corresponding public key and hence the node's peer ID in the context of
libp2p. [default: Ed25519] [possible values: Ed25519]
--tracing-receiver <RECEIVER>
Receiver to process tracing messages [default: Log] [possible values: Log]
--tracing-targets <TARGETS>
Sets a custom profiling filter. Syntax is the same as for logging: <target>=<level>
生成一个看看
./target/release/parachain-collator build-spec --chain local
2021-10-31 21:11:12 Building chain spec
{
"name": "Local Testnet",
"id": "local_testnet",
"chainType": "Local",
"bootNodes": [ "/ip4/127.0.0.1/tcp/30333/p2p/12D3KooWNirG2PZNHZh8YEdwVAurZPR42vfPS8ZAjnjPhPrWbFQv"
],
"telemetryEndpoints": null,
"protocolId": null,
"properties": null,
"relay_chain": "rococo-local",
"para_id": 2000,
"consensusEngine": null,
"codeSubstitutes": {},
"genesis": {
"runtime": {
"system": {
"changesTrieConfig": null,
"code": " <<Runtime wasm Code>>"
},
"sudo": {
"key": "5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY"
},
"parachainSystem": null,
"parachainInfo": {
"parachainId": 2000
},
"balances": {
"balances": [
[
"5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY",
1152921504606846976
],
[
"5FHneW46xGXgs5mUiveU4sbTyGBzmstUspZC92UhjJM694ty",
1152921504606846976
],
[
"5FLSigC9HGRKVhB9FiEo4Y3koPsNmBmLJbpXg2mp1hXcS59Y",
1152921504606846976
],
[
"5DAAnrj7VHTznn2AWBemMuyBwZWs6FNFjdyVXUeYum3PTXFy",
1152921504606846976
],
[
"5HGjWAeFDfFCWPsjFQdVV2Msvz2XtMktvgocEZcCj68kUMaw",
1152921504606846976
],
[
"5CiPPseXPECbkjWCa6MnjNokrgYjMqmKndv2rSnekmSK2DjL",
1152921504606846976
],
[
"5GNJqTPyNqANBkUVMN1LPPrxXnFouWXoe2wNSmmEoLctxiZY",
1152921504606846976
],
[
"5HpG9w8EBLe5XCrbczpwq5TSXvedjrBGCwqxK1iQ7qUsSWFc",
1152921504606846976
],
[
"5Ck5SLSHYac6WFt5UZRSsdJjwmpSZq85fd5TRNAdZQVzEAPT",
1152921504606846976
],
[
"5HKPmK9GYtE1PSLsS1qiYU9xQ9Si1NcEhdeCq9sw5bqu4ns8",
1152921504606846976
],
[
"5FCfAonRZgTFrTd9HREEyeJjDpT397KMzizE6T3DvebLFE7n",
1152921504606846976
],
[
"5CRmqmsiNFExV6VbdmPJViVxrWmkaXXvBrSX8oqBT8R9vmWk",
1152921504606846976
]
]
},
"aura": {
"authorities": [
"5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY",
"5FHneW46xGXgs5mUiveU4sbTyGBzmstUspZC92UhjJM694ty"
]
},
"auraExt": null
}
}
}
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