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Unify wasm-builder's README and crate docs
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@koute
koute committed Nov 27, 2023
1 parent 5f637d8 commit 0f560a8
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12 changes: 9 additions & 3 deletions substrate/utils/wasm-builder/README.md
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Expand Up @@ -13,7 +13,7 @@ A project that should be compiled as a Wasm binary needs to:

The `build.rs` file needs to contain the following code:

```rust
```rust,no_run
fn main() {
#[cfg(feature = "std")]
{
Expand All @@ -32,7 +32,7 @@ fn main() {

As the final step, you need to add the following to your project:

```rust
```rust,ignore
include!(concat!(env!("OUT_DIR"), "/wasm_binary.rs"));
```

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- `WASM_TARGET_DIRECTORY` - Will copy any build Wasm binary to the given directory. The path needs to be absolute.
- `WASM_BUILD_TOOLCHAIN` - The toolchain that should be used to build the Wasm binaries. The format needs to be the same
as used by cargo, e.g. `nightly-2020-02-20`.
- `WASM_BUILD_WORKSPACE_HINT` - Hint the workspace that is being built. This is normally not required as we walk up from
the target directory until we find a `Cargo.toml`. If the target directory is changed for
the build, this environment variable can be used to point to the actual workspace.
- `WASM_BUILD_STD` - Sets whether the Rust's standard library crates will also be built. This is necessary to make sure
the standard library crates only use the exact WASM feature set that our executor supports.
Enabled by default.
- `CARGO_NET_OFFLINE` - If `true`, `--offline` will be passed to all processes launched to prevent network access.
Useful in offline environments.

Each project can be skipped individually by using the environment variable `SKIP_PROJECT_NAME_WASM_BUILD`. Where
`PROJECT_NAME` needs to be replaced by the name of the cargo project, e.g. `node-runtime` will be `NODE_RUNTIME`.
`PROJECT_NAME` needs to be replaced by the name of the cargo project, e.g. `kitchensink-runtime` will be `NODE_RUNTIME`.

## Prerequisites

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97 changes: 1 addition & 96 deletions substrate/utils/wasm-builder/src/lib.rs
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Expand Up @@ -15,102 +15,7 @@
// See the License for the specific language governing permissions and
// limitations under the License.

//! # Wasm builder is a utility for building a project as a Wasm binary
//!
//! The Wasm builder is a tool that integrates the process of building the WASM binary of your
//! project into the main `cargo` build process.
//!
//! ## Project setup
//!
//! A project that should be compiled as a Wasm binary needs to:
//!
//! 1. Add a `build.rs` file.
//! 2. Add `wasm-builder` as dependency into `build-dependencies`.
//!
//! The `build.rs` file needs to contain the following code:
//!
//! ```no_run
//! use substrate_wasm_builder::WasmBuilder;
//!
//! fn main() {
//! WasmBuilder::new()
//! // Tell the builder to build the project (crate) this `build.rs` is part of.
//! .with_current_project()
//! // Make sure to export the `heap_base` global, this is required by Substrate
//! .export_heap_base()
//! // Build the Wasm file so that it imports the memory (need to be provided by at instantiation)
//! .import_memory()
//! // Build it.
//! .build()
//! }
//! ```
//!
//! As the final step, you need to add the following to your project:
//!
//! ```ignore
//! include!(concat!(env!("OUT_DIR"), "/wasm_binary.rs"));
//! ```
//!
//! This will include the generated Wasm binary as two constants `WASM_BINARY` and
//! `WASM_BINARY_BLOATY`. The former is a compact Wasm binary and the latter is the Wasm binary as
//! being generated by the compiler. Both variables have `Option<&'static [u8]>` as type.
//!
//! ### Feature
//!
//! Wasm builder supports to enable cargo features while building the Wasm binary. By default it
//! will enable all features in the wasm build that are enabled for the native build except the
//! `default` and `std` features. Besides that, wasm builder supports the special `runtime-wasm`
//! feature. This `runtime-wasm` feature will be enabled by the wasm builder when it compiles the
//! Wasm binary. If this feature is not present, it will not be enabled.
//!
//! ## Environment variables
//!
//! By using environment variables, you can configure which Wasm binaries are built and how:
//!
//! - `SKIP_WASM_BUILD` - Skips building any Wasm binary. This is useful when only native should be
//! recompiled. If this is the first run and there doesn't exist a Wasm binary, this will set both
//! variables to `None`.
//! - `WASM_BUILD_TYPE` - Sets the build type for building Wasm binaries. Supported values are
//! `release` or `debug`. By default the build type is equal to the build type used by the main
//! build.
//! - `FORCE_WASM_BUILD` - Can be set to force a Wasm build. On subsequent calls the value of the
//! variable needs to change. As wasm-builder instructs `cargo` to watch for file changes this
//! environment variable should only be required in certain circumstances.
//! - `WASM_BUILD_RUSTFLAGS` - Extend `RUSTFLAGS` given to `cargo build` while building the wasm
//! binary.
//! - `WASM_BUILD_NO_COLOR` - Disable color output of the wasm build.
//! - `WASM_TARGET_DIRECTORY` - Will copy any build Wasm binary to the given directory. The path
//! needs to be absolute.
//! - `WASM_BUILD_TOOLCHAIN` - The toolchain that should be used to build the Wasm binaries. The
//! format needs to be the same as used by cargo, e.g. `nightly-2020-02-20`.
//! - `WASM_BUILD_WORKSPACE_HINT` - Hint the workspace that is being built. This is normally not
//! required as we walk up from the target directory until we find a `Cargo.toml`. If the target
//! directory is changed for the build, this environment variable can be used to point to the
//! actual workspace.
//! - `WASM_BUILD_STD` - Sets whether the Rust's standard library crates will also be built. This is
//! necessary to make sure the standard library crates only use the exact WASM feature set that
//! our executor supports. Enabled by default.
//! - `CARGO_NET_OFFLINE` - If `true`, `--offline` will be passed to all processes launched to
//! prevent network access. Useful in offline environments.
//!
//! Each project can be skipped individually by using the environment variable
//! `SKIP_PROJECT_NAME_WASM_BUILD`. Where `PROJECT_NAME` needs to be replaced by the name of the
//! cargo project, e.g. `kitchensink-runtime` will be `NODE_RUNTIME`.
//!
//! ## Prerequisites:
//!
//! Wasm builder requires the following prerequisites for building the Wasm binary:
//!
//! - rust nightly + `wasm32-unknown-unknown` toolchain
//!
//! or
//!
//! - rust stable and version at least 1.68.0 + `wasm32-unknown-unknown` toolchain
//!
//! If a specific rust is installed with `rustup`, it is important that the wasm target is
//! installed as well. For example if installing the rust from 20.02.2020 using `rustup
//! install nightly-2020-02-20`, the wasm target needs to be installed as well `rustup target add
//! wasm32-unknown-unknown --toolchain nightly-2020-02-20`.
#![doc = include_str!("../README.md")]

use std::{
env, fs,
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