Add a package.metadata.component.proxy setting. (#221)

This commit adds a `package.metadata.component.proxy` setting to `Cargo.toml`
that controls whether or not to use the `wasi:http/proxy` specific adapter.

This option can be set when creating a project with `cargo component new --lib
--proxy`.

The `wasi:http/proxy` adapter is now built-in to `cargo-component`; it adapters
from preview1 in a way that ensures the resulting component conforms to the
`wasi:http/proxy` world.

Additionally, the `--command` option has been renamed to `--bin`, with an alias
for `--command` for backwards compatibility.

Cargo.toml

@@ -58,6 +58,7 @@ wasmparser = { workspace = true }
 wat = { workspace = true }
 warg-server = { workspace = true }
 tempfile = { workspace = true }
+wasmprinter = { workspace = true }
 
 [workspace]
 members = ["crates/core", "crates/wit"]
@@ -104,3 +105,4 @@ predicates = "3.1.0"
 wasmparser = "0.120.0"
 wat = "1.0.84"
 warg-server = "0.2.0"
+wasmprinter = "0.2.77"

src/commands/new.rs

@@ -47,13 +47,17 @@ pub struct NewCommand {
     pub vcs: Option<String>,
 
     /// Create a CLI command component [default]
-    #[clap(long = "command", conflicts_with("lib"))]
-    pub command: bool,
+    #[clap(long = "bin", alias = "command", conflicts_with = "lib")]
+    pub bin: bool,
 
     /// Create a library (reactor) component
     #[clap(long = "lib", alias = "reactor")]
     pub lib: bool,
 
+    /// Use the built-in `wasi:http/proxy` module adapter
+    #[clap(long = "proxy", requires = "lib")]
+    pub proxy: bool,
+
     /// Edition to set for the generated crate
     #[clap(long = "edition", value_name = "YEAR", value_parser = ["2015", "2018", "2021"])]
     pub edition: Option<String>,
@@ -277,6 +281,10 @@ impl NewCommand {
             component["registries"] = Item::Table(table);
         }
 
+        if self.proxy {
+            component["proxy"] = value(true);
+        }
+
         let mut metadata = Table::new();
         metadata.set_implicit(true);
         metadata.set_position(doc.len());
@@ -315,7 +323,7 @@ impl NewCommand {
     }
 
     fn is_command(&self) -> bool {
-        self.command || !self.lib
+        self.bin || !self.lib
     }
 
     fn generate_source(

src/lib.rs

@@ -606,8 +606,18 @@ async fn generate_package_bindings(
     Ok(())
 }
 
-fn adapter_bytes(metadata: &ComponentMetadata, binary: bool) -> Result<Cow<[u8]>> {
+fn adapter_bytes<'a>(
+    config: &Config,
+    metadata: &'a ComponentMetadata,
+    binary: bool,
+) -> Result<Cow<'a, [u8]>> {
     if let Some(adapter) = &metadata.section.adapter {
+        if metadata.section.proxy {
+            config.terminal().warn(
+                "ignoring `proxy` setting due to `adapter` setting being present in `Cargo.toml`",
+            )?;
+        }
+
         return Ok(fs::read(adapter)
             .with_context(|| {
                 format!(
@@ -619,11 +629,23 @@ fn adapter_bytes(metadata: &ComponentMetadata, binary: bool) -> Result<Cow<[u8]>
     }
 
     if binary {
+        if metadata.section.proxy {
+            config
+                .terminal()
+                .warn("ignoring `proxy` setting in `Cargo.toml` for command component")?;
+        }
+
         Ok(Cow::Borrowed(include_bytes!(concat!(
             "../adapters/",
             env!("WASI_ADAPTER_VERSION"),
             "/wasi_snapshot_preview1.command.wasm"
         ))))
+    } else if metadata.section.proxy {
+        Ok(Cow::Borrowed(include_bytes!(concat!(
+            "../adapters/",
+            env!("WASI_ADAPTER_VERSION"),
+            "/wasi_snapshot_preview1.proxy.wasm"
+        ))))
     } else {
         Ok(Cow::Borrowed(include_bytes!(concat!(
             "../adapters/",
@@ -663,7 +685,10 @@ fn create_component(
 
     let encoder = ComponentEncoder::default()
         .module(&module)?
-        .adapter("wasi_snapshot_preview1", &adapter_bytes(metadata, binary)?)
+        .adapter(
+            "wasi_snapshot_preview1",
+            &adapter_bytes(config, metadata, binary)?,
+        )
         .with_context(|| {
             format!(
                 "failed to load adapter module `{path}`",

src/metadata.rs

@@ -280,6 +280,10 @@ pub struct ComponentSection {
     pub registries: HashMap<String, Url>,
     /// The configuration for bindings generation.
     pub bindings: Bindings,
+    /// Whether to use the built-in `wasi:http/proxy` adapter for the component.
+    ///
+    /// This should only be `true` when `adapter` is None.
+    pub proxy: bool,
 }
 
 /// Represents cargo metadata for a WebAssembly component.

tests/build.rs

@@ -834,3 +834,67 @@ fn it_builds_with_versioned_wit() -> Result<()> {
 
     Ok(())
 }
+
+#[test]
+fn it_warns_on_proxy_setting_for_command() -> Result<()> {
+    let project = Project::new_bin("foo")?;
+    project.update_manifest(|mut doc| {
+        doc["package"]["metadata"]["component"]["proxy"] = value(true);
+        Ok(doc)
+    })?;
+
+    project
+        .cargo_component("build")
+        .assert()
+        .stderr(contains(
+            "warning: ignoring `proxy` setting in `Cargo.toml` for command component",
+        ))
+        .success();
+
+    validate_component(&project.debug_wasm("foo"))?;
+
+    Ok(())
+}
+
+#[test]
+fn it_warns_with_proxy_and_adapter_settings() -> Result<()> {
+    let project = Project::new("foo")?;
+    project.update_manifest(|mut doc| {
+        doc["package"]["metadata"]["component"]["proxy"] = value(true);
+        doc["package"]["metadata"]["component"]["adapter"] =
+            value(adapter_path().to_str().unwrap());
+        Ok(doc)
+    })?;
+
+    project
+        .cargo_component("build")
+        .assert()
+        .stderr(contains("warning: ignoring `proxy` setting due to `adapter` setting being present in `Cargo.toml`"))
+        .success();
+
+    validate_component(&project.debug_wasm("foo"))?;
+
+    Ok(())
+}
+
+#[test]
+fn it_builds_with_proxy_adapter() -> Result<()> {
+    let dir = Rc::new(TempDir::new()?);
+    let project = Project::with_dir(dir.clone(), "foo", "--proxy")?;
+
+    project
+        .cargo_component("build")
+        .assert()
+        .stderr(contains("Finished dev [unoptimized + debuginfo] target(s)"))
+        .success();
+
+    validate_component(&project.debug_wasm("foo"))?;
+
+    let text = wasmprinter::print_file(project.debug_wasm("foo"))?;
+    assert!(
+        !text.contains("wasi:cli/environment"),
+        "proxy wasm should have no reference to `wasi:cli/environment`"
+    );
+
+    Ok(())
+}

tests/new.rs

@@ -23,7 +23,7 @@ fn help() {
 fn it_creates_the_expected_files_for_bin() -> Result<()> {
     let dir = TempDir::new()?;
 
-    cargo_component("new --command foo")
+    cargo_component("new --bin foo")
         .current_dir(dir.path())
         .assert()
         .stderr(contains("Updated manifest of package `foo"))
@@ -179,6 +179,18 @@ async fn it_errors_if_target_does_not_exist() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn it_supports_the_command_option() -> Result<()> {
+    let dir = TempDir::new()?;
+
+    cargo_component("new --command foo")
+        .current_dir(dir.path())
+        .assert()
+        .try_success()?;
+
+    Ok(())
+}
+
 #[test]
 fn it_supports_the_reactor_option() -> Result<()> {
     let dir = TempDir::new()?;
@@ -190,3 +202,17 @@ fn it_supports_the_reactor_option() -> Result<()> {
 
     Ok(())
 }
+
+#[test]
+fn it_supports_the_proxy_option() -> Result<()> {
+    let dir: TempDir = TempDir::new()?;
+
+    cargo_component("new --lib --proxy foo")
+        .current_dir(dir.path())
+        .assert()
+        .try_success()?;
+
+    assert!(fs::read_to_string(dir.path().join("foo/Cargo.toml"))?.contains("proxy = true"));
+
+    Ok(())
+}