feat: wasi-component-adapter

hermes/Cargo.toml

@@ -3,6 +3,7 @@ resolver = "2"
 members = [
     "bin",
     "crates/cardano-chain-follower",
+    "crates/wasi-component-adapter",
 ]
 
 [workspace.package]

hermes/Earthfile

@@ -6,12 +6,24 @@ VERSION 0.7
 fork-wasi-component-adapter:
     LOCALLY
 
-    RUN if [ -e crates/wasi-component-adapter/Earthfile ]; then mv crates/wasi-component-adapter/Earthfile crates/Earthfile-tmp; fi && \
-        rm -rf crates/wasi-component-adapter/ || true && \
+    # The location the Earthfile for the local `wasi` crate.
+    ARG wasi_earthfile=crates/wasi-component-adapter/Earthfile
+    # The location to store the Earthfile during running the script.
+    ARG wasi_tmp_earthfile=crates/Earthfile-tmp
+    # The local directory to place the extracted `wasi` crate.
+    ARG wasi_local_dir=crates/wasi-component-adapter
+    # The location after the `wasmtime` repo was cloned.
+    ARG wasi_git_dir=wasmtime/crates/wasi-preview1-component-adapter
+
+    # First, it needs to move the existing Earthfile to the temporary location.
+    # Then remove the existing local one. Clone and extract it from the repo.
+    # And finally move the Earthfile back.
+    RUN if [ -e $wasi_earthfile ]; then mv $wasi_earthfile $wasi_tmp_earthfile; fi && \
+        rm -rf $wasi_local_dir/ || true && \
         git clone --depth 1 https://github.com/bytecodealliance/wasmtime.git && \
-        mv wasmtime/crates/wasi-preview1-component-adapter crates/wasi-component-adapter && \
+        mv $wasi_git_dir $wasi_local_dir && \
         rm -rf wasmtime/ && \
-        if [ -e crates/Earthfile-tmp ]; then mv crates/Earthfile-tmp crates/wasi-component-adapter/Earthfile; fi
+        if [ -e $wasi_tmp_earthfile ]; then mv $wasi_tmp_earthfile $wasi_earthfile; fi
 
 # Set up our target toolchains, and copy our files.
 builder:

hermes/crates/wasi-component-adapter/Cargo.toml

@@ -0,0 +1,29 @@
+[package]
+name = "wasi-preview1-component-adapter"
+version.workspace = true
+authors.workspace = true
+edition.workspace = true
+publish = false
+
+[lints]
+workspace = true
+
+[dependencies]
+wasi = { version = "0.11.0", default-features = false }
+wit-bindgen = { workspace = true, default-features = false, features = ["macros"] }
+byte-array-literals = { workspace = true }
+
+[build-dependencies]
+wasm-encoder = { workspace = true }
+object = { workspace = true, default-features = false, features = ["archive"] }
+
+[lib]
+test = false
+crate-type = ["cdylib"]
+name = "wasi_snapshot_preview1"
+
+[features]
+default = ["reactor"]
+reactor = []
+command = []
+proxy = []

hermes/crates/wasi-component-adapter/Earthfile

@@ -0,0 +1,3 @@
+# Set up our target toolchains, and copy our files.
+builder:
+    FROM github.com/input-output-hk/catalyst-ci/earthly/rust:v2.0.3+rust-base

hermes/crates/wasi-component-adapter/README.md

@@ -0,0 +1,63 @@
+# `wasi_snapshot_preview1.wasm`
+
+> **Note**: This repository is a work in progress. This is intended to be an
+> internal tool which not everyone has to look at but many might rely on. You
+> may need to reach out via issues or
+> [Zulip](https://bytecodealliance.zulipchat.com/) to learn more about this
+> repository.
+
+This repository currently contains an implementation of a WebAssembly module:
+`wasi_snapshot_preview1.wasm`. This module bridges the `wasi_snapshot_preview1`
+ABI to the preview2 ABI of the component model. At this time the preview2 APIs
+themselves are not done being specified so a local copy of `wit/*.wit` is used
+instead.
+
+## Building
+
+This adapter can be built with:
+
+```sh
+$ cargo build -p wasi-preview1-component-adapter --target wasm32-unknown-unknown --release
+```
+
+And the artifact will be located at
+`target/wasm32-unknown-unknown/release/wasi_snapshot_preview1.wasm`.
+
+This by default builds a "reactor" adapter which means that it only provides
+adaptation from preview1 to preview2. Alternatively you can also build a
+"command" adapter by passing `--features command --no-default-features` which
+will additionally export a `run` function entrypoint. This is suitable for use
+with preview1 binaries that export a `_start` function.
+
+Alternatively the latest copy of the command and reactor adapters can be
+[downloaded from the `dev` tag assets][dev-tag]
+
+[dev-tag]: https://github.com/bytecodealliance/wasmtime/releases/tag/dev
+
+## Using
+
+With a `wasi_snapshot_preview1.wasm` file on-hand you can create a component
+from a module that imports WASI functions using the [`wasm-tools`
+CLI](https://github.com/bytecodealliance/wasm-tools)
+
+```sh
+$ cat foo.rs
+fn main() {
+    println!("Hello, world!");
+}
+$ rustc foo.rs --target wasm32-wasi
+$ wasm-tools print foo.wasm | grep '(import'
+  (import "wasi_snapshot_preview1" "fd_write" (func ...
+  (import "wasi_snapshot_preview1" "environ_get" (func ...
+  (import "wasi_snapshot_preview1" "environ_sizes_get" ...
+  (import "wasi_snapshot_preview1" "proc_exit" (func ...
+$ wasm-tools component new foo.wasm --adapt wasi_snapshot_preview1.wasm -o component.wasm
+
+# Inspect the generated `component.wasm`
+$ wasm-tools validate component.wasm --features component-model
+$ wasm-tools component wit component.wasm
+```
+
+Here the `component.wasm` that's generated is a ready-to-run component which
+imports wasi preview2 functions and is compatible with the wasi-preview1-using
+module internally.