delay creating the engine

Signed-off-by: Jorge Prendes <[email protected]>
containerd · Dec 20, 2024 · 7d16085 · 7d16085
1 parent 1082ac4
commit 7d16085
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Showing 2 changed files with 13 additions and 10 deletions.
diff --git a/crates/containerd-shim-wasm/src/sys/unix/container/executor.rs b/crates/containerd-shim-wasm/src/sys/unix/container/executor.rs
@@ -25,15 +25,15 @@ enum InnerExecutor {
 }
 
 #[derive(Clone)]
-pub(crate) struct Executor<E: Engine> {
-    engine: E,
+pub(crate) struct Executor<E: Engine + Default> {
+    engine: OnceCell<E>,
     stdio: Stdio,
     inner: OnceCell<InnerExecutor>,
     wasm_layers: Vec<WasmLayer>,
     platform: Platform,
 }
 
-impl<E: Engine> LibcontainerExecutor for Executor<E> {
+impl<E: Engine + Default> LibcontainerExecutor for Executor<E> {
     #[cfg_attr(feature = "tracing", tracing::instrument(parent = tracing::Span::current(), skip_all, level = "Info"))]
     fn validate(&self, spec: &Spec) -> Result<(), ExecutorValidationError> {
         // We can handle linux container. We delegate wasm container to the engine.
@@ -56,7 +56,7 @@ impl<E: Engine> LibcontainerExecutor for Executor<E> {
             }
             InnerExecutor::Wasm => {
                 log::info!("calling start function");
-                match self.engine.run_wasi(&self.ctx(spec), self.stdio.take()) {
+                match self.engine().run_wasi(&self.ctx(spec), self.stdio.take()) {
                     Ok(code) => std::process::exit(code),
                     Err(err) => {
                         log::info!("error running start function: {err}");
@@ -83,10 +83,10 @@ impl<E: Engine> LibcontainerExecutor for Executor<E> {
     }
 }
 
-impl<E: Engine> Executor<E> {
-    pub fn new(engine: E, stdio: Stdio, wasm_layers: Vec<WasmLayer>, platform: Platform) -> Self {
+impl<E: Engine + Default> Executor<E> {
+    pub fn new(stdio: Stdio, wasm_layers: Vec<WasmLayer>, platform: Platform) -> Self {
         Self {
-            engine,
+            engine: Default::default(),
             stdio,
             inner: Default::default(),
             wasm_layers,
@@ -111,7 +111,7 @@ impl<E: Engine> Executor<E> {
                 Ok(_) => InnerExecutor::Linux,
                 Err(err) => {
                     log::debug!("error checking if linux container: {err}. Fallback to wasm container");
-                    match self.engine.can_handle(ctx) {
+                    match self.engine().can_handle(ctx) {
                         Ok(_) => InnerExecutor::Wasm,
                         Err(err) => {
                             // log an error and return
@@ -123,6 +123,10 @@ impl<E: Engine> Executor<E> {
             }
         })
     }
+
+    fn engine(&self) -> &E {
+        self.engine.get_or_init(|| E::default())
+    }
 }
 
 fn is_linux_container(ctx: &impl RuntimeContext) -> Result<()> {

diff --git a/crates/containerd-shim-wasm/src/sys/unix/container/instance.rs b/crates/containerd-shim-wasm/src/sys/unix/container/instance.rs
@@ -38,7 +38,6 @@ impl<E: Engine + Default> SandboxInstance for Instance<E> {
 
     #[cfg_attr(feature = "tracing", tracing::instrument(parent = tracing::Span::current(), skip_all, level = "Info"))]
     fn new(id: String, cfg: &InstanceConfig) -> Result<Self, SandboxError> {
-        let engine = Self::Engine::default();
         let bundle = cfg.get_bundle().to_path_buf();
         let namespace = cfg.get_namespace();
         let rootdir = Path::new(DEFAULT_CONTAINER_ROOT_DIR).join(E::name());
@@ -55,7 +54,7 @@ impl<E: Engine + Default> SandboxInstance for Instance<E> {
             });
 
         let container = ContainerBuilder::new(id.clone(), SyscallType::Linux)
-            .with_executor(Executor::new(engine, stdio, modules, platform))
+            .with_executor(Executor::<E>::new(stdio, modules, platform))
             .with_root_path(rootdir.clone())?
             .as_init(&bundle)
             .with_systemd(false)