Add spin-factors-executor

Signed-off-by: Lann Martin <lann.martin@fermyon.com>

crates/core/src/lib.rs

@@ -16,13 +16,12 @@ use std::{path::PathBuf, time::Duration};
 use anyhow::Result;
 use crossbeam_channel::Sender;
 use tracing::instrument;
-use wasmtime::component::{InstancePre, Linker};
 use wasmtime::{InstanceAllocationStrategy, PoolingAllocationConfig};
 
 pub use async_trait::async_trait;
 pub use wasmtime::{
     self,
-    component::{Component, Instance},
+    component::{Component, Instance, InstancePre, Linker},
     Instance as ModuleInstance, Module, Trap,
 };
 

crates/factors-executor/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "spin-factors-executor"
+version.workspace = true
+authors.workspace = true
+edition.workspace = true
+license.workspace = true
+homepage.workspace = true
+repository.workspace = true
+rust-version.workspace = true
+
+[dependencies]
+anyhow = "1"
+spin-app = { path = "../app" }
+spin-core = { path = "../core" }
+spin-factors = { path = "../factors" }
+
+[dev-dependencies]
+spin-factor-wasi = { path = "../factor-wasi" }
+spin-factors-test = { path = "../factors-test" }
+tokio = { version = "1", features = ["macros", "rt"] }
+
+[lints]
+workspace = true

crates/factors-executor/src/lib.rs

@@ -0,0 +1,223 @@
+use std::collections::HashMap;
+
+use anyhow::Context;
+use spin_app::{App, AppComponent};
+use spin_core::Component;
+use spin_factors::{AsInstanceState, ConfiguredApp, RuntimeFactors, RuntimeFactorsInstanceState};
+
+/// A FactorsExecutor manages execution of a Spin app.
+///
+/// `Factors` is the executor's [`RuntimeFactors`]. `ExecutorInstanceState`
+/// holds any other per-instance state needed by the caller.
+pub struct FactorsExecutor<T: RuntimeFactors, U = ()> {
+    factors: T,
+    core_engine: spin_core::Engine<InstanceState<T::InstanceState, U>>,
+    configured_app: ConfiguredApp<T>,
+    // Maps component IDs -> InstancePres
+    component_instance_pres: HashMap<String, InstancePre<T, U>>,
+}
+
+type InstancePre<T, U> =
+    spin_core::InstancePre<InstanceState<<T as RuntimeFactors>::InstanceState, U>>;
+
+impl<T: RuntimeFactors, U: Send + 'static> FactorsExecutor<T, U> {
+    /// Constructs a new executor.
+    pub fn new(
+        core_config: &spin_core::Config,
+        mut factors: T,
+        app: App,
+        mut component_loader: impl ComponentLoader,
+        runtime_config: T::RuntimeConfig,
+    ) -> anyhow::Result<Self> {
+        let core_engine = {
+            let mut builder =
+                spin_core::Engine::builder(core_config).context("failed to initialize engine")?;
+            factors
+                .init(builder.linker())
+                .context("failed to initialize factors")?;
+            builder.build()
+        };
+
+        let configured_app = factors
+            .configure_app(app, runtime_config)
+            .context("failed to configure app")?;
+
+        let component_instance_pres = configured_app
+            .app()
+            .components()
+            .map(|app_component| {
+                let component =
+                    component_loader.load_component(core_engine.as_ref(), &app_component)?;
+                let instance_pre = core_engine.instantiate_pre(&component)?;
+                Ok((app_component.id().to_string(), instance_pre))
+            })
+            .collect::<anyhow::Result<HashMap<_, _>>>()?;
+
+        Ok(Self {
+            factors,
+            core_engine,
+            configured_app,
+            component_instance_pres,
+        })
+    }
+
+    /// Returns an instance builder for the given component ID.
+    pub fn prepare(&mut self, component_id: &str) -> anyhow::Result<FactorsInstanceBuilder<T, U>> {
+        let app_component = self
+            .configured_app
+            .app()
+            .get_component(component_id)
+            .with_context(|| format!("no such component {component_id:?}"))?;
+        let instance_pre = self.component_instance_pres.get(component_id).unwrap();
+        let factor_builders = self.factors.prepare(&self.configured_app, component_id)?;
+        let store_builder = self.core_engine.store_builder();
+        Ok(FactorsInstanceBuilder {
+            store_builder,
+            factor_builders,
+            instance_pre,
+            app_component,
+            factors: &self.factors,
+        })
+    }
+}
+
+/// A ComponentLoader is responsible for loading Wasmtime [`Component`]s.
+pub trait ComponentLoader {
+    /// Loads a [`Component`] for the given [`AppComponent`].
+    fn load_component(
+        &mut self,
+        engine: &spin_core::wasmtime::Engine,
+        component: &AppComponent,
+    ) -> anyhow::Result<Component>;
+}
+
+/// A FactorsInstanceBuilder manages the instantiation of a Spin component
+/// instance.
+pub struct FactorsInstanceBuilder<'a, T: RuntimeFactors, U> {
+    app_component: AppComponent<'a>,
+    store_builder: spin_core::StoreBuilder,
+    factor_builders: T::InstanceBuilders,
+    instance_pre: &'a InstancePre<T, U>,
+    factors: &'a T,
+}
+
+impl<'a, T: RuntimeFactors, U: Send> FactorsInstanceBuilder<'a, T, U> {
+    /// Returns the app component for the instance.
+    pub fn app_component(&self) -> &AppComponent {
+        &self.app_component
+    }
+
+    /// Returns the store builder for the instance.
+    pub fn store_builder(&mut self) -> &mut spin_core::StoreBuilder {
+        &mut self.store_builder
+    }
+
+    /// Returns the factor instance builders for the instance.
+    pub fn factor_builders(&mut self) -> &mut T::InstanceBuilders {
+        &mut self.factor_builders
+    }
+
+    /// Instantiates the instance with the given executor instance state
+    pub async fn instantiate(
+        self,
+        executor_instance_state: U,
+    ) -> anyhow::Result<(
+        spin_core::Instance,
+        spin_core::Store<InstanceState<T::InstanceState, U>>,
+    )> {
+        let instance_state = InstanceState {
+            core: Default::default(),
+            factors: self.factors.build_instance_state(self.factor_builders)?,
+            executor: executor_instance_state,
+        };
+        let mut store = self.store_builder.build(instance_state)?;
+        let instance = self.instance_pre.instantiate_async(&mut store).await?;
+        Ok((instance, store))
+    }
+}
+
+/// InstanceState is the [`spin_core::Store`] `data` for an instance.
+pub struct InstanceState<FactorsState, ExecutorInstanceState> {
+    core: spin_core::State,
+    factors: FactorsState,
+    executor: ExecutorInstanceState,
+}
+
+impl<T, U> InstanceState<T, U> {
+    /// Provides access to the `ExecutorInstanceState`.
+    pub fn executor_instance_state(&mut self) -> &mut U {
+        &mut self.executor
+    }
+}
+
+impl<T, U> spin_core::AsState for InstanceState<T, U> {
+    fn as_state(&mut self) -> &mut spin_core::State {
+        &mut self.core
+    }
+}
+
+impl<T: RuntimeFactorsInstanceState, U> AsInstanceState<T> for InstanceState<T, U> {
+    fn as_instance_state(&mut self) -> &mut T {
+        &mut self.factors
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use spin_factor_wasi::{DummyFilesMounter, WasiFactor};
+    use spin_factors::RuntimeFactors;
+    use spin_factors_test::TestEnvironment;
+
+    use super::*;
+
+    #[derive(RuntimeFactors)]
+    struct TestFactors {
+        wasi: WasiFactor,
+    }
+
+    #[tokio::test]
+    async fn instance_builder_works() -> anyhow::Result<()> {
+        let factors = TestFactors {
+            wasi: WasiFactor::new(DummyFilesMounter),
+        };
+        let env = TestEnvironment::new(factors);
+        let locked = env.build_locked_app().await?;
+        let app = App::new("test-app", locked);
+
+        let mut executor = FactorsExecutor::new(
+            &Default::default(),
+            env.factors,
+            app,
+            DummyComponentLoader,
+            Default::default(),
+        )?;
+
+        let mut instance_builder = executor.prepare("empty")?;
+
+        assert_eq!(instance_builder.app_component().id(), "empty");
+
+        instance_builder.store_builder().max_memory_size(1_000_000);
+
+        instance_builder
+            .factor_builders()
+            .wasi
+            .as_mut()
+            .unwrap()
+            .args(["foo"]);
+
+        let (_instance, _store) = instance_builder.instantiate(()).await?;
+        Ok(())
+    }
+
+    struct DummyComponentLoader;
+
+    impl ComponentLoader for DummyComponentLoader {
+        fn load_component(
+            &mut self,
+            engine: &spin_core::wasmtime::Engine,
+            _component: &AppComponent,
+        ) -> anyhow::Result<Component> {
+            Component::new(engine, "(component)")
+        }
+    }
+}