把模块写到自己的包内 · Substrate Developer Hub

在这个教程中，您会在自己 crate 中编写一个 Substrate 模块，并把他引入到基于 substrate-node-template 构建的节点中。

安装 Node Template

You should already have version v3.0.0 of the Substrate Node Template compiled on your computer from when you completed the Create Your First Substrate Chain Tutorial. 如果您尚未完成该教程，请先完成它。

有经验的开发者可以跳过该教程，您可以参考 readme 里的步骤说明。

Starting with the Pallet Template

我们不会直接在节点模板中创建模块，而是创建单独的 Rust crate 。这样我们可以分离节点和模块，从而单独发布创建的模块，这样也方便其他开发者将此模块引入到他们自己的 Substrate runtime 中。 There are two ways to go about this:

Option 1: `Use This Template` from Github

On the template page you will see a big green button that invites you to Use This Template - clicking this will open up a dialog similar to a fork, but will start you with a base repository that is close with only the code from the template in your new repo.

Clone this new repo you own locally inside the node template /pallets directory

cd pallets
git clone <your new pallet repo> <pallet directory name>
# example:
# git clone [email protected]:substrate-developer-hub/substrate-pallet-template.git test-pallet

Option 2: Clone a copy of the Template

Clone the Substrate pallet template in the pallets directory of your node template:

cd pallets
git clone -b v3.0.0 --depth 1 https://github.com/substrate-developer-hub/substrate-pallet-template test-pallet

本教程中，我们把已经把模块模板放在了节点模板 目录下。这种方式不是强制性的，您也可以将模块放置在你喜欢的任何地方。比如，另一个常见的做法是把是它放在节点模板的 同级目录。

Substrate 模块模板

Let's explore the Substrate pallet template, starting with the Cargo.toml file.

Renaming Your Crate

In the Cargo.toml file, you must update the crate's name. In this tutorial, we're focusing on how to create and use the pallet rather than writing interesting pallet logic. So let's update the value of the package.name attribute in the Cargo.toml file to test-pallet.

The package section of the Cargo.toml file now looks like:

pallets/test-pallet/Cargo.toml

[package]
authors = ['Substrate DevHub <https://github.com/substrate-developer-hub>']
description = 'FRAME pallet template'
edition = '2018'
homepage = 'https://substrate.dev'
license = 'Unlicensed'
name = 'test-pallet'
repository = 'https://github.com/substrate-developer-hub/substrate-pallet-template/'
version = '3.0.0'

Compile the Template Pallet

使用以下命令，您应该能够成功检查 Substrate 模板模板：

cd test-pallet
SKIP_WASM_BUILD=1 cargo check

Your Pallet's `std` Feature

在您的 pallets/test-pallet/Cargo.toml 文件中，您会看到一些关于"std特性"的代码。在 Rust 中, 当您启用 std, 您可以让您的项目访问 Rust 标准库。在本地编译为二进制库时，这种方式没问题。

然而，Substrate 还会将 Runtime编译为 WebAssembly(Wasm)。在这种情况下，我们使用 cargo 自带的功能来禁用 Rust 标准库。因此，我们的模块以及整个 Runtime 使用的所有依赖，都必须能够用no_std 编译。如下所示，当某个模块使用 std 功能时，我们的 Cargo.toml 文件会告诉该模块只能使用他们自己的std 依赖：

pallets/test-pallet/Cargo.toml

[features]
default = ['std']
std = [
    'codec/std',
    'frame-support/std',
    'frame-system/std',
]

Consistent Substrate Dependencies

所有 Substrate 模块将依赖于一些底层的模块库，如 frame-system and frame-support。这些库是从 crates.io 中拉取的。当开发者基于模块构建自己的 Runtime 时，他们也会依赖于这些底层库。您需要确保您的模块和 Runtime之间的依赖关系是一致的。

pallets/test-pallet/Cargo.toml

# --snip--
[dependencies]
frame-support = { default-features = false, version = '3.0.0' }
# --snip--

From the above snippet, we see that this pallet template depends on version 3.0.0 of the low-level libraries. Thus it can be used in runtimes that also depend on 3.0.0.

Note that substrate adheres to the semver standards - thus each release is on the form major.minor.patch. In general it is not expected that major releases are compatible! Thus if you are developing a pallet, or integrating ones, be sure to match versions to keep things all working correctly.

Your Pallet's Dev Dependencies

Cargo.toml 文件的最后部分指定了开发环境依赖。这些是在模块测试环境中需要的依赖，但不是实际发布需要模块的依赖。

pallets/test-pallet/Cargo.toml

# --snip--
[dev-dependencies]
sp-core = { default-features = false, version = '3.0.0' }
# --snip--

您可以使用如下命令，确认 Substrate 模块模板测试通过：

SKIP_WASM_BUILD=1 cargo test

当您在此模块中自定义逻辑时，您可能会在 Cargo.toml 文件中添加依赖。

将模块添加到节点中

With our pallet now compiling and passing its tests, we're ready to add it to our node.

If you aren't familiar with including and using other crates, refer to the Cargo book for an in-depth explanation.

我们首先在节点 runtime 的 Cargo.toml 中添加我们新创建的 crate 依赖。然后指定模块只有在 Runtime 构建时才构建 std ，如下所示：

runtime/Cargo.toml

# --snip--
test-pallet = { path = '../pallets/test-pallet', default-features = false, version = '3.0.0' }

# toward the bottom
[features]
default = ['std']
std = [
    'test-pallet/std',
    # --snip--
]

You must set default-features = false so that your runtime will successfully compile to Wasm.

Next we will update runtime/src/lib.rs to actually use our new runtime pallet, by adding a trait implementation with our test_pallet and add it in our construct_runtime! macro. Add the following code blocks:

runtime/src/lib.rs

// add this line (or modify all of these to your named pallet 
// corresponding to `test-pallet` in its cargo.toml file)
pub use test_pallet;

// --snip--

// add this block
impl test_pallet::Config for Runtime {
  type Event = Event;
}

// --snip--
construct_runtime!(
  pub enum Runtime where
    Block = Block,
    NodeBlock = opaque::Block,
    UncheckedExtrinsic = UncheckedExtrinsic
  {
    // --snip--
    // add the following line
    TestPallet: test_pallet::{Module, Call, Storage, Event<T>},
  }
);

运行您的节点

At this point you have the pallet packaged up in its own crate and included in your node's runtime.

请确保您回到节点模板的根目录，然后编译节点，然后在开发模式中使用以下命令启动：

cargo build --release
./target/release/node-template --tmp --dev

现在，启动 Polkadot-JS 应用程序将其连接到本地节点以确认模块正常运行。

Note: You can also manually set the node URL in Polkadot-JS Apps by navigating to the Settings tab, and have the remote node/endpoint to connect to set to Local Node.

Congrats! You have created and integrated a new pallet inside its own crate for your node! If you want to see a solution to get to this step here is one to compare to using FRAME v1 macros.

发布您的模块

Once your pallet is no longer in test phase, you should consider publishing it to GitHub or crates.io.

Publishing on GitHub

To publish on GitHub, you need to create a GitHub repository and push your pallet's code to it.

Publishing on Crates.io

Crates.io allows permissionless publishing. Learn the procedure following their own guide about publishing on crates.io

更新 Runtime 的依赖

With your pallet now published on GitHub, crates.io, or both, we can update your runtime to use the code that is published instead of a hard-coded file system path.

Dependencies from GitHub

runtime/Cargo.toml

[dependencies.your-pallet-name]
default_features = false
git = 'https://github.com/your-username/your-pallet'
branch = 'master'

# You may choose a specific commit or tag instead of branch
# rev = '<git-commit>'
# tag = '<some tag>

Dependencies from Crates.io

runtime/Cargo.toml

[dependencies.your-pallet-name]
default_features = false
version = 'some-compatible-version'

最后一次构建

Compile one more time and notice that Cargo now grabs your pallet from GitHub or crates.io instead of using the local files.

后续步骤

恭喜你！ You've written a Substrate pallet in its own Rust crate, and published it. Other blockchain developers can now easily use your pallet in their runtime by simply including those same four lines of code in their runtime's Cargo.toml files and updating their runtime's lib.rs file.

进一步学习

我们有很多展示 Substrate 开发概念和技术的教程。
想要了解更多 Runtime 开发的技巧和模式等相关信息，请参阅我们的 Substrate Recipes。
FRAME 模块中有 FRAME 中可使用的更多功能的超详细文档注释，请查看 Substrate 中的这个示例

参考文档

Cargo 大全
更多关于 Rust 和 WebAssembly

安装 Node Template

Starting with the Pallet Template

Option 1: Use This Template from Github

Option 2: Clone a copy of the Template

Substrate 模块模板

Renaming Your Crate

Compile the Template Pallet

Your Pallet's std Feature

Consistent Substrate Dependencies

Your Pallet's Dev Dependencies

将模块添加到节点中

运行您的节点

发布您的模块

Publishing on GitHub

Publishing on Crates.io

更新 Runtime 的依赖

Dependencies from GitHub

Dependencies from Crates.io

最后一次构建

后续步骤

进一步学习

参考文档

Option 1: `Use This Template` from Github

Your Pallet's `std` Feature