Reuse unioned_filesystem() for WCGI

lib/cli/src/commands/run.rs

@@ -403,7 +403,7 @@ impl RunWithPathBuf {
             .addr(self.wcgi.addr)
             .envs(self.wasi.env_vars.clone())
             .map_directories(self.wasi.mapped_dirs.clone());
-        if self.wcgi.forward_host_env {
+        if self.wasi.forward_host_env {
             runner.config().forward_host_env();
         }
         if runner.can_run_command(id, command).unwrap_or(false) {
@@ -700,16 +700,12 @@ pub(crate) struct WcgiOptions {
     /// The address to serve on.
     #[clap(long, short, env, default_value_t = ([127, 0, 0, 1], 8000).into())]
     pub(crate) addr: SocketAddr,
-    /// Forward all host env variables to the wcgi task.
-    #[clap(long)]
-    pub(crate) forward_host_env: bool,
 }
 
 impl Default for WcgiOptions {
     fn default() -> Self {
         Self {
             addr: ([127, 0, 0, 1], 8000).into(),
-            forward_host_env: false,
         }
     }
 }

lib/vfs/src/webc_fs.rs

@@ -197,8 +197,7 @@ where
         let start: usize = self.cursor.try_into().unwrap();
         let remaining = &bytes[start..];
         let bytes_read = remaining.len().min(buf.remaining());
-        let end = start + bytes_read;
-        let bytes = &bytes[start..end];
+        let bytes = &remaining[..bytes_read];
 
         buf.put_slice(bytes);
         self.cursor += u64::try_from(bytes_read).unwrap();

lib/wasi/src/runners/wasi.rs

@@ -132,13 +132,17 @@ impl WasiRunner {
         container: &WapmContainer,
         command: &str,
     ) -> Result<WasiEnvBuilder, anyhow::Error> {
-        let root_fs = unioned_filesystem(&self.mapped_dirs, container)?;
+        let fs = unioned_filesystem(&self.mapped_dirs, container)?;
+        let fs = container.container_fs();
 
         let mut builder = WasiEnv::builder(command)
             .args(&self.args)
-            .fs(Box::new(root_fs))
             .preopen_dir("/")?;
 
+        preopen(&fs, "/".as_ref(), &mut builder)?;
+
+        builder.set_fs(Box::new(fs));
+
         if self.forward_host_env {
             for (k, v) in std::env::vars() {
                 builder.add_env(k, v);
@@ -192,7 +196,7 @@ impl crate::runners::Runner for WasiRunner {
 
 /// Create a [`FileSystem`] which merges the WAPM container's volumes with any
 /// directories that were mapped from the host.
-fn unioned_filesystem(
+pub(crate) fn unioned_filesystem(
     mapped_dirs: &[MappedDirectory],
     container: &WapmContainer,
 ) -> Result<impl FileSystem, Error> {
@@ -236,6 +240,19 @@ fn unioned_filesystem(
     Ok(OverlayFileSystem::new(primary, [container.container_fs()]))
 }
 
+fn preopen(fs: &dyn FileSystem, path: &Path, builder: &mut WasiEnvBuilder) -> Result<(), Error> {
+    for result in fs.read_dir(path)? {
+        let entry = result?;
+
+        if entry.file_type()?.is_dir() {
+            builder.add_preopen_dir(&entry.path)?;
+            preopen(fs, &entry.path, builder)?;
+        }
+    }
+
+    Ok(())
+}
+
 fn create_dir_all(fs: &(impl FileSystem + ?Sized), path: &Path) -> Result<(), Error> {
     match fs.metadata(path) {
         Ok(meta) if meta.is_dir() => return Ok(()),
@@ -257,7 +274,6 @@ fn create_dir_all(fs: &(impl FileSystem + ?Sized), path: &Path) -> Result<(), Er
 mod tests {
     use tempfile::TempDir;
     use tokio::io::AsyncReadExt;
-    use wasmer_vfs::host_fs;
 
     use super::*;
 
@@ -313,6 +329,9 @@ mod tests {
             ]
         );
         let abc = read_file(&fs, "/lib/python3.6/collections/abc.py").await;
-        assert_eq!(abc, "from _collections_abc import *");
+        assert_eq!(
+            abc,
+            "from _collections_abc import *\nfrom _collections_abc import __all__\n"
+        );
     }
 }

lib/wasi/src/runners/wcgi/handler.rs

@@ -23,7 +23,7 @@ use wcgi_host::CgiDialect;
 use crate::{
     capabilities::Capabilities,
     http::HttpClientCapabilityV1,
-    runners::{wcgi::Callbacks, MappedDirectory},
+    runners::{wcgi::Callbacks, MappedDirectory, WapmContainer},
     Pipe, PluggableRuntimeImplementation, VirtualTaskManager, WasiEnv,
 };
 
@@ -134,37 +134,8 @@ impl Handler {
         Ok(response)
     }
 
-    fn fs(&self) -> Result<TmpFileSystem, Error> {
-        let root_fs = RootFileSystemBuilder::new().build();
-
-        if !self.mapped_dirs.is_empty() {
-            let fs_backing: Arc<dyn FileSystem + Send + Sync> =
-                Arc::new(PassthruFileSystem::new(crate::default_fs_backing()));
-
-            for MappedDirectory { host, guest } in self.mapped_dirs.iter() {
-                let guest = match guest.starts_with('/') {
-                    true => PathBuf::from(guest),
-                    false => Path::new("/").join(guest),
-                };
-                tracing::debug!(
-                    host=%host.display(),
-                    guest=%guest.display(),
-                    "mounting host directory",
-                );
-
-                root_fs
-                    .mount(guest.clone(), &fs_backing, host.clone())
-                    .with_context(|| {
-                        format!(
-                            "Unable to mount \"{}\" to \"{}\"",
-                            host.display(),
-                            guest.display()
-                        )
-                    })
-                    .unwrap();
-            }
-        }
-        Ok(root_fs)
+    fn fs(&self) -> Result<impl FileSystem, Error> {
+        crate::runners::wasi::unioned_filesystem(&self.mapped_dirs, &self.container)
     }
 }
 
@@ -255,6 +226,7 @@ pub(crate) struct SharedState {
     pub(crate) env: HashMap<String, String>,
     pub(crate) args: Vec<String>,
     pub(crate) mapped_dirs: Vec<MappedDirectory>,
+    pub(crate) container: WapmContainer,
     pub(crate) module: Module,
     pub(crate) dialect: CgiDialect,
     pub(crate) task_manager: Arc<dyn VirtualTaskManager>,

lib/wasi/src/runners/wcgi/runner.rs

@@ -148,6 +148,7 @@ impl WcgiRunner {
                 .clone()
                 .unwrap_or_else(|| Arc::new(TokioTaskManager::default())),
             module,
+            container: ctx.container.clone(),
             dialect,
             callbacks: Arc::clone(&self.config.callbacks),
         };
@@ -225,8 +226,8 @@ impl RunnerContext<'_> {
         &self.store
     }
 
-    fn volume(&self, _name: &str) -> Option<Box<dyn FileSystem>> {
-        todo!("Implement a read-only filesystem backed by a volume");
+    fn container_fs(&self) -> Box<dyn FileSystem + Send + Sync> {
+        self.container.container_fs()
     }
 
     fn get_atom(&self, name: &str) -> Option<&[u8]> {

tests/integration/cli/tests/run2.rs

@@ -15,6 +15,7 @@ use tempfile::TempDir;
 use wasmer_integration_tests_cli::get_wasmer_path;
 
 const RUST_LOG: &str = "info,wasmer_wasi::runners=debug";
+// const RUST_LOG: &str = "info,wasmer_wasi=trace";
 
 mod webc_on_disk {
     use super::*;
@@ -81,13 +82,15 @@ mod webc_on_disk {
         let assert = Command::new(get_wasmer_path())
             .arg("run2")
             .arg(fixtures::python())
-            .arg("--env")
-            .arg("SOME_VAR=Hello, World!")
+            .arg("--env=SOME_VAR=Hello, World!")
             .arg("--")
             .arg("-c")
             .arg("import os; print(os.environ['SOME_VAR'])")
+            .env("RUST_LOG", RUST_LOG)
             .assert();
 
+        panic!("{}", String::from_utf8_lossy(&assert.get_output().stderr));
+
         assert.success().stdout(contains("Hello, World!"));
     }