Pre-compile each layer individually

Makefile

@@ -239,8 +239,8 @@ test/k8s/deploy-workload-oci-%: test/k8s/clean test/k8s/cluster-% dist/img-oci.t
 	kubectl --context=kind-$(KIND_CLUSTER_NAME) wait deployment wasi-demo --for condition=Available=True --timeout=5s
 	@if [ "$*" = "wasmtime" ]; then \
 		set -e; \
-		echo "checking for pre-compiled label and ensuring can scale"; \
-		docker exec $(KIND_CLUSTER_NAME)-control-plane ctr -n k8s.io i ls | grep "runwasi.io/precompiled"; \
+		echo "checking for pre-compiled labels and ensuring can scale after pre-compile"; \
+		docker exec $(KIND_CLUSTER_NAME)-control-plane ctr -n k8s.io content ls | grep "runwasi.io/precompiled"; \
 		kubectl --context=kind-$(KIND_CLUSTER_NAME) scale deployment wasi-demo --replicas=4; \
 		kubectl --context=kind-$(KIND_CLUSTER_NAME) wait deployment wasi-demo --for condition=Available=True --timeout=5s; \
 	fi
@@ -297,8 +297,8 @@ test/k3s-oci-%: dist/img-oci.tar bin/k3s dist-%
 	sudo bin/k3s kubectl get pods -o wide
 	@if [ "$*" = "wasmtime" ]; then \
 		set -e; \
-		echo "checking for pre-compiled label and ensuring can scale"; \
-		sudo bin/k3s ctr -n k8s.io i ls | grep "runwasi.io/precompiled"; \
+		echo "checking for pre-compiled labels and ensuring can scale"; \
+		sudo bin/k3s ctr -n k8s.io content ls | grep "runwasi.io/precompiled"; \
 		sudo bin/k3s kubectl scale deployment wasi-demo --replicas=4; \
 		sudo bin/k3s kubectl wait deployment wasi-demo --for condition=Available=True --timeout=5s; \
 	fi

crates/containerd-shim-wasm/Cargo.toml

@@ -35,7 +35,7 @@ futures = { version = "0.3.30" }
 wasmparser = "0.200.0"
 tokio-stream = { version = "0.1" }
 prost-types = "0.11" # should match version in containerd-shim
-sha256 = "1.4.0"
+sha256 = { workspace = true }
 
 [target.'cfg(unix)'.dependencies]
 caps = "0.5"
@@ -56,6 +56,7 @@ containerd-shim-wasm-test-modules = { workspace = true }
 env_logger = { workspace = true }
 tempfile = { workspace = true }
 oci-tar-builder = { workspace = true}
+rand= "0.8" 
 
 [features]
 testing = ["dep:containerd-shim-wasm-test-modules", "dep:env_logger", "dep:tempfile", "dep:oci-tar-builder"]

crates/containerd-shim-wasm/src/container/engine.rs

@@ -5,6 +5,7 @@ use anyhow::{bail, Context, Result};
 
 use super::Source;
 use crate::container::{PathResolve, RuntimeContext};
+use crate::sandbox::oci::WasmLayer;
 use crate::sandbox::Stdio;
 
 pub trait Engine: Clone + Send + Sync + 'static {
@@ -53,12 +54,14 @@ pub trait Engine: Clone + Send + Sync + 'static {
         &["application/vnd.bytecodealliance.wasm.component.layer.v0+wasm"]
     }
 
-    /// Precompiles a module that is in the WASM OCI layer format
-    /// This is used to precompile a module before it is run and will be called if can_precompile returns true.
+    /// Precompile passes supported OCI layers to engine for compilation
+    /// This is used to precompile the layers before they are run and will be called if `can_precompile` returns `true`.
     /// It is called only the first time a module is run and the resulting bytes will be cached in the containerd content store.  
-    /// The cached, precompiled module will be reloaded on subsequent runs.
-    fn precompile(&self, _layers: &[Vec<u8>]) -> Result<Vec<u8>> {
-        bail!("precompilation not supported for this runtime")
+    /// The cached, precompiled layers will be reloaded on subsequent runs.
+    /// The runtime is expected to return the same number of layers passed in, if the layer cannot be precompiled it should return `None` for that layer.
+    /// In some edge cases it is possible that the layers may already be precompiled and None should be returned in this case.
+    fn precompile(&self, _layers: &[WasmLayer]) -> Result<Vec<Option<Vec<u8>>>> {
+        bail!("precompile not supported");
     }
 
     /// Can_precompile lets the shim know if the runtime supports precompilation.