feat: able to build modules

Signed-off-by: Andrew Steurer <94206073+asteurer@users.noreply.github.com>

Author: asteurer

examples/wasip1/Makefile

@@ -0,0 +1,6 @@
+build:
+	@componentize-go build --wasip1
+
+.PHONY: run
+run: build
+	@wasmtime run main.wasm

examples/wasip1/README.md

@@ -0,0 +1,14 @@
+# `wasip1` Example
+
+## Usage
+
+### Prerequisites
+
+- [**componentize-go**](https://github.com/bytecodealliance/componentize-go) - Latest version
+- [**go**](https://go.dev/dl/) - v1.25+
+- [**wasmtime**](https://github.com/bytecodealliance/wasmtime) - v40.0.2
+
+### Run
+
+```sh
+make run

examples/wasip1/main.go

@@ -0,0 +1,7 @@
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Println("Hello, World!")
+}

examples/wasip2/README.md

@@ -9,6 +9,7 @@
 - [**wasmtime**](https://github.com/bytecodealliance/wasmtime)  - v40.0.2
 
 ### Run
+
 ```sh
 # Start the application
 make run
@@ -18,6 +19,7 @@ curl localhost:8080
 ```
 
 ### Run unit tests
+
 ```sh
 make run-tests
 ```

examples/wasip3/README.md

@@ -1,4 +1,5 @@
 # `wasip3` Example
+
 This demonstrates how to implement a `wasi:http@0.3.0-rc-2025-09-16` handler
 using Go, based on a new `wit-bindgen-go` bindings generator which supports
 idiomatic, goroutine-based concurrency on top of the [Component Model
@@ -11,7 +12,9 @@ Go](https://github.com/dicej/go/releases/tag/go1.25.5-wasi-on-idle).  Once
 everything is merged, we'll be able to switch to the upstream releases.
 
 ## Building and Running
+
 ### Prerequisites
+
 - [**componentize-go**](https://github.com/bytecodealliance/componentize-go) - Latest version
 - [**go**](https://github.com/dicej/go/releases/tag/go1.25.5-wasi-on-idle) - The [Makefile](./Makefile) installs the patched version of Go.
 - [**wasmtime**](https://github.com/bytecodealliance/wasmtime)  - v40.0.2
@@ -56,4 +59,5 @@ curl -i \
 ```
 
 ## Note
+
 This was originally built by [@dicej](https://github.com/dicej) and has been adapted from the [original example](https://github.com/dicej/go-wasi-http-example/tree/main) to use componentize-go.

src/cmd_build.rs

@@ -44,13 +44,12 @@ pub fn build_module(
         None => ".",
     };
 
-    // TODO: for when/if we decide to allow users to build wasm modules without componentizing them
-    #[allow(unused_variables)]
+    // The -buildmode flag mutes the module's output, so it is ommitted
     let module_args = [
         "build",
         "-C",
         module_path,
-        "-buildmode=c-shared",
+        "-ldflags=-checklinkname=0",
         "-o",
         out_path,
     ];
@@ -66,9 +65,6 @@ pub fn build_module(
     ];
 
     let output = if only_wasip1 {
-        unimplemented!("Building wasip1 Go apps isn't supported quite yet.");
-        // TODO: for when/if we decide to allow users to build wasm modules without componentizing them
-        #[allow(unreachable_code)]
         Command::new(&go)
             .args(module_args)
             .env("GOOS", "wasip1")

src/cmd_test.rs

@@ -74,7 +74,9 @@ pub fn build_test_module(
             .env("GOARCH", "wasm")
             .output()?
     } else {
-        unimplemented!("Please use the --wasip1 flag when building unit tests");
+        unimplemented!(
+            "Building Go test components is not yet supported. Please use the --wasip1 flag when building unit tests."
+        );
 
         // TODO: for when we figure out how wasip2 tests are to be run
         #[allow(unreachable_code)]

tests/src/lib.rs

@@ -92,76 +92,88 @@ mod tests {
         go_bin
     }
 
-    struct App<'a> {
+    struct App {
         /// The path to the example application
         path: String,
         /// The WIT world to target
-        world: String,
+        world: Option<String>,
         /// The output path of the wasm file
         wasm_path: String,
         /// The path to the directory containing the WIT files
-        wit_path: String,
+        wit_path: Option<String>,
         /// The child process ID of a running wasm app
         process: Option<Child>,
         /// Any tests that need to be compiled and run as such
-        tests: Option<&'a [Test<'a>]>,
+        tests: Option<Vec<Test>>,
     }
 
-    struct Test<'a> {
+    #[derive(Clone)]
+    struct Test {
         should_fail: bool,
-        pkg_path: &'a str,
+        pkg_path: String,
     }
 
-    impl<'a> App<'a> {
+    impl App {
         /// Create a new app runner.
-        fn new(path: &'a str, world: &'a str, tests: Option<&'a [Test<'a>]>) -> Self {
+        fn new(
+            path: &str,
+            world: Option<&str>,
+            tests: Option<Vec<Test>>,
+            is_component: bool,
+        ) -> Self {
             let path = componentize_go::utils::make_path_absolute(&PathBuf::from(path))
                 .expect("failed to make app path absolute");
 
+            let world = if is_component {
+                Some(world.expect("WIT world must be specified").to_string())
+            } else {
+                None
+            };
+
+            let wit_path = if is_component {
+                Some(
+                    path.join("wit")
+                        .to_str()
+                        .expect("wit_path is not valid unicode")
+                        .to_string(),
+                )
+            } else {
+                None
+            };
+
             App {
                 path: path
                     .clone()
                     .to_str()
                     .expect("app path is not valid unicode")
                     .to_string(),
-                world: world.to_string(),
+                world,
                 wasm_path: path
                     .join("main.wasm")
                     .to_str()
                     .expect("wasm_path is not valid unicode")
                     .to_string(),
-                wit_path: path
-                    .join("wit")
-                    .to_str()
-                    .expect("wit_path is not valid unicode")
-                    .to_string(),
+                wit_path,
                 process: None,
                 tests,
             }
         }
 
-        // Build unit tests with componentize-go
-        fn build_tests(&self, go: Option<&PathBuf>) -> Result<()> {
-            let test_pkgs = if let Some(pkgs) = self.tests {
-                pkgs
-            } else {
-                return Err(anyhow!(
-                    "Please include the test_pkg_paths when creating App::new()"
-                ));
-            };
+        fn build_test_modules(&self, go: Option<&PathBuf>) -> Result<()> {
+            let test_pkgs = self.tests.as_ref().expect("missing test_pkg_paths");
 
             self.generate_bindings(go)?;
 
             let mut test_cmd = Command::new(COMPONENTIZE_GO_PATH.as_path());
             test_cmd
-                .args(["-w", &self.world])
-                .args(["-d", &self.wit_path])
+                .args(["-w", self.world.as_ref().expect("missing WIT world")])
+                .args(["-d", self.wit_path.as_ref().expect("missing WIT path")])
                 .arg("test")
                 .arg("--wasip1");
 
             // Add all the paths to the packages that have unit tests to compile
             for test in test_pkgs.iter() {
-                test_cmd.args(["--pkg", test.pkg_path]);
+                test_cmd.args(["--pkg", &test.pkg_path]);
             }
 
             // `go test -c` needs to be in the same path as the go.mod file.
@@ -183,13 +195,30 @@ mod tests {
             Ok(())
         }
 
-        fn run_tests(&self) -> Result<()> {
+        fn run_module(&self) -> Result<()> {
+            let output = Command::new("wasmtime")
+                .arg("run")
+                .arg(&self.wasm_path)
+                .output()?;
+
+            if !output.status.success() {
+                return Err(anyhow!(
+                    "Failed to run wasm module for application at '{}':\n{} ",
+                    &self.wasm_path,
+                    String::from_utf8_lossy(&output.stdout)
+                ));
+            }
+
+            Ok(())
+        }
+
+        fn run_test_modules(&self) -> Result<()> {
             let example_dir = PathBuf::from(&self.path);
-            if let Some(tests) = self.tests {
+            if let Some(tests) = &self.tests {
                 let mut test_errors: Vec<String> = vec![];
                 for test in tests.iter() {
                     let wasm_file = example_dir.join(componentize_go::cmd_test::get_test_filename(
-                        &PathBuf::from(test.pkg_path),
+                        &PathBuf::from(&test.pkg_path),
                     ));
                     match Command::new("wasmtime")
                         .args(["run", wasm_file.to_str().unwrap()])
@@ -233,15 +262,45 @@ mod tests {
             Ok(())
         }
 
-        /// Build the app with componentize-go.
-        fn build(&self, go: Option<&PathBuf>) -> Result<()> {
+        fn build_module(&self, go: Option<&PathBuf>) -> Result<()> {
+            // Build component
+            let mut build_cmd = Command::new(COMPONENTIZE_GO_PATH.as_path());
+            build_cmd
+                .arg("build")
+                .arg("--wasip1")
+                .args(["-o", &self.wasm_path]);
+
+            if let Some(go_path) = go.as_ref() {
+                build_cmd.args(["--go", go_path.to_str().unwrap()]);
+            }
+
+            // Run `go build` in the same directory as the go.mod file.
+            build_cmd.current_dir(&self.path);
+
+            let build_output = build_cmd.output().expect(&format!(
+                "failed to execute componentize-go for \"{}\"",
+                self.path
+            ));
+
+            if !build_output.status.success() {
+                return Err(anyhow!(
+                    "failed to build application \"{}\": {}",
+                    self.path,
+                    String::from_utf8_lossy(&build_output.stderr)
+                ));
+            }
+
+            Ok(())
+        }
+
+        fn build_component(&self, go: Option<&PathBuf>) -> Result<()> {
             self.generate_bindings(go)?;
 
             // Build component
             let mut build_cmd = Command::new(COMPONENTIZE_GO_PATH.as_path());
             build_cmd
-                .args(["-w", &self.world])
-                .args(["-d", &self.wit_path])
+                .args(["-w", self.world.as_ref().expect("missing WIT world")])
+                .args(["-d", self.wit_path.as_ref().expect("missing WIT path")])
                 .arg("build")
                 .args(["-o", &self.wasm_path]);
 
@@ -270,8 +329,8 @@ mod tests {
 
         fn generate_bindings(&self, go: Option<&PathBuf>) -> Result<()> {
             let bindings_output = Command::new(COMPONENTIZE_GO_PATH.as_path())
-                .args(["-w", &self.world])
-                .args(["-d", &self.wit_path])
+                .args(["-w", self.world.as_ref().expect("missing WIT world")])
+                .args(["-d", self.wit_path.as_ref().expect("missing WIT path")])
                 .arg("bindings")
                 .args(["-o", &self.path])
                 .current_dir(&self.path)
@@ -307,7 +366,7 @@ mod tests {
         }
 
         /// Run the app and check the output.
-        async fn run(&mut self, route: &str, expected_response: &str) -> Result<()> {
+        async fn run_component(&mut self, route: &str, expected_response: &str) -> Result<()> {
             let listener = TcpListener::bind("127.0.0.1:0").expect("Failed to bind to a free port");
             let addr = listener.local_addr().expect("Failed to get local address");
             let port = addr.port();
@@ -345,48 +404,60 @@ mod tests {
         }
     }
 
-    impl<'a> Drop for App<'a> {
+    impl Drop for App {
         fn drop(&mut self) {
             if let Some(child) = &mut self.process {
                 _ = child.kill()
             }
         }
     }
 
+    #[test]
+    fn example_wasip1() {
+        let app = App::new("../examples/wasip1", None, None, false);
+        app.build_module(None).expect("failed to build app module");
+        app.run_module().expect("failed to run app module");
+    }
+
     #[tokio::test]
     async fn example_wasip2() {
-        let unit_tests = [
+        let unit_tests = vec![
             Test {
                 should_fail: false,
-                pkg_path: "./unit_tests_should_pass",
+                pkg_path: String::from("./unit_tests_should_pass"),
             },
             Test {
                 should_fail: true,
-                pkg_path: "./unit_tests_should_fail",
+                pkg_path: String::from("./unit_tests_should_fail"),
             },
         ];
 
-        let mut app = App::new("../examples/wasip2", "wasip2-example", Some(&unit_tests));
+        let mut app = App::new(
+            "../examples/wasip2",
+            Some("wasip2-example"),
+            Some(unit_tests),
+            true,
+        );
 
-        app.build(None).expect("failed to build app");
+        app.build_component(None).expect("failed to build app");
 
-        app.run("/", "Hello, world!")
+        app.run_component("/", "Hello, world!")
             .await
             .expect("app failed to run");
 
-        app.build_tests(None)
+        app.build_test_modules(None)
             .expect("failed to build app unit tests");
 
-        app.run_tests()
+        app.run_test_modules()
             .expect("tests succeeded/failed when they should not have");
     }
 
     #[tokio::test]
     async fn example_wasip3() {
-        let mut app = App::new("../examples/wasip3", "wasip3-example", None);
-        app.build(Some(&patched_go_path().await))
+        let mut app = App::new("../examples/wasip3", Some("wasip3-example"), None, true);
+        app.build_component(Some(&patched_go_path().await))
             .expect("failed to build app");
-        app.run("/hello", "Hello, world!")
+        app.run_component("/hello", "Hello, world!")
             .await
             .expect("app failed to run");
     }