feat: add webassembly component model

docs/antora.yml

@@ -11,6 +11,8 @@ nav:
 
   - modules/policies/nav.adoc
 
+  - modules/component-model/nav.adoc
+
   - modules/examples/nav.adoc
 
   - modules/faq/nav.adoc

docs/modules/component-model/nav.adoc

@@ -0,0 +1 @@
+** xref:component_model.adoc[`Component Model`]

docs/modules/component-model/pages/component_model.adoc

@@ -0,0 +1,79 @@
+= WebAssembly Component Model
+
+This is a work in progress with the goal being to provide a WebAssembly
+component for the policy engine.
+
+This example uses wit-bindgen macros to generate the Rust types, but this can
+also be done manually using the wit-bindgen-cli. First we need to install
+wit-bindgen-cli:
+[listing]
+$ cargo install --git https://github.com/bytecodealliance/wit-bindgen wit-bindgen-cli
+
+== WebAssembly Interface Types
+The main interface is defined in link:https://github.com/seedwing-io/seedwing-policy/tree/main/engine/wit/engine-world.wit[wit/engine-world.wit]
+which contains on the exposed functions. The data types are defined in 
+link:https://github.com/seedwing-io/seedwing-policy/tree/main/engine/wit/engine-types.wit[wit/engine-types.wit].
+
+== Building
+To build the WebAssembly component:
+[listing]
+$ make wit-compile 
+cargo b -p seedwing-policy-engine --target=wasm32-wasi --no-default-features --features=""
+
+Note that `wit` stands for `WebAssembly Interface Types`.
+
+The above compilation will generate a core WebAssembly module which can be found
+in the `target` directory in the root of the checked out github repository.
+
+The next step is to create the WebAssembly component using this core WebAssembly
+module:
+[listing]
+$ make wit-component
+wasm-tools component new -v ../target/wasm32-wasi/debug/seedwing_policy_engine.wasm --adapt wasi_snapshot_preview1.wasm -o seedwing_policy-engine-component.wasm
+
+The above will build an optimized release build which is needed or the execution
+of the Rust example will be very slow. But is can be nice to build an
+unopptimized version:
+[listing]
+$ make wit-compile Build=debug
+
+Just make sure to also use `Build=debug` for the Rust targets or it will default
+to a release build and you might get an runtime error depending on what changes
+that have been made to the source code.
+
+== JavaScript example
+The directory link:https://github.com/seedwing-io/seedwing-policy/tree/main/engine/wit-examples/javascript/README.md[javascript]
+contains a JavaScript example of using the webassembly component. There are more
+details in the readme, but the example can be run directly using:
+[listing]
+$ make wit-java-bindings
+$ make wit-java-run
+
+== Python example
+The directory link:https://github.com/seedwing-io/seedwing-policy/tree/main/engine/wit-examples/python/README.md[python] contains a Python example of using
+the webassembly component. There are more details in the readme, but the example
+can be run directly
+using:
+[listing]
+$ make wit-python-bindings
+$ make wit-python-run
+
+== Rust example
+The directory link:https://github.com/seedwing-io/seedwing-policy/tree/main/engine/wit-examples/rust/README.md[rust] contains
+a Rust example of using the webassembly component. There are more details in the
+readme, but the example can be run directly
+using:
+[listing]
+$ make wit-rust-bindings
+$ make wit-rust-run
+
+This example uses wit-bindgen macros so the bindings step is not required here
+which is done for the other examples.
+
+== Go example
+There is project named https://github.com/bytecodealliance/wasmtime-go[wasmtime-go]
+which looked like it would be able to to do the same/simlar thing as the other
+examples. But it turns out that it does not support the WebAssembly Component
+Model yet as mentioned in
+https://github.com/bytecodealliance/wasmtime-go/issues/170[issue-170].
+

engine/.cargo/config.toml

@@ -0,0 +1,2 @@
+[target.wasm32-wasi]
+rustflags = ["--cfg=tokio_unstable"]

engine/.gitignore

@@ -0,0 +1 @@
+engine.rs

engine/Cargo.toml

@@ -45,12 +45,10 @@ cidr = "0.2.1"
 http = "0.2.8"
 iref = "2.2.3"
 chrono = { version = "0.4.23", features = ["serde"] }
-reqwest = { version = "0.11.14", features = ["json"] }
 uuid = { version = "1.3.0", features = ["v4"] }
 openvex = "0.1.0"
 spdx = "0.10.0"
 csaf = { version = "0.4.0", default-features = false }
-guac-rs = { git = "https://github.com/dejanb/guac-rs.git", rev = "67a70e98ffaa17200d256e1afc5c88756b56d5e2" }
 semver = "1.0"
 
 
@@ -59,6 +57,12 @@ prometheus = { version = "0.13.3", optional = true }
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 home = "0.5.4"
+reqwest = { version = "0.11.14", features = ["json"] }
+guac-rs = { git = "https://github.com/dejanb/guac-rs.git", rev = "67a70e98ffaa17200d256e1afc5c88756b56d5e2" }
+
+[target.'cfg(all(target_arch = "wasm32", target_os = "wasi"))'.dependencies]
+wit-bindgen = { version = "0.8.0", default-features = true, features = ['macros'] }
+futures = "0.3"
 
 [features]
 default = ["sigstore", "monitor", "showcase", "intoto"]
@@ -78,3 +82,6 @@ env_logger = { version = "0.10.0", default-features = false }
 [[bench]]
 name = "engine"
 harness = false
+
+[lib]
+crate-type = ["cdylib", "rlib"]

engine/Makefile

@@ -0,0 +1,76 @@
+
+ifeq ($(Build), debug)
+	BUILD_TYPE = debug
+else
+	BUILD_TYPE = release
+	BUILD = "--$(BUILD_TYPE)"
+endif
+
+corewasm=../target/wasm32-wasi/${BUILD_TYPE}/seedwing_policy_engine.wasm
+component=../target/seedwing-policy-engine-component.wasm
+
+
+# Seedwing WebAssembly Component targets
+wit-compile:
+	cargo b ${BUILD} -p seedwing-policy-engine --target=wasm32-wasi --no-default-features --features=""
+
+# Can be used to inspect the custom section "component-type::engine-world"
+objdump-core-module:
+	@wasm-tools objdump $(corewasm)
+
+test_from_engine_runtime:
+	cargo t -p seedwing-policy-engine --target=wasm32-wasi \
+	--no-default-features --features="" \
+	--lib core::wit::test::from_engine_runtime -- --exact --show-output
+
+wit-component:
+	wasm-tools component new \
+	-v $(corewasm) \
+	--adapt wasi_snapshot_preview1=wit-lib/wasi_preview1_component_adapter.wasm \
+	-o $(component)
+	@wasm-tools strip $(component) -o $(component)
+
+wit-print-wat:
+	wasm-tools print $(component)
+
+wit-print:
+	@wasm-tools component wit $(component)
+
+objdump-component:
+	@wasm-tools objdump $(component)
+
+# Can be used to generate the Rust source for that the bindgen::generate
+# macro will produce.
+wit-bindgen:
+	wit-bindgen rust wit/
+
+# Can be useful to inspect the expanded wit-bindgen macros
+cargo-expand:
+	cargo expand -p seedwing-policy-engine --target=wasm32-wasi --no-default-features --features=""
+
+# JavaScript targets
+wit-javascript-bindings:
+	cd wit-examples/javascript && npm run bindings
+
+wit-javascript-run:
+	cd wit-examples/javascript && npm start
+
+wit-javascript-all: wit-compile wit-component wit-js-build
+
+# Python targets
+wit-python-bindings:
+	@cd wit-examples/python && make --no-print-directory bindings
+
+wit-python-run:
+	@cd wit-examples/python && make --no-print-directory run
+
+wit-python-all: wit-compile wit-component wit-python-bindings wit-python-run
+
+# Rust targets
+wit-rust-bindings:
+	cd wit-examples/rust && cargo b ${BUILD}
+
+wit-rust-run:
+	cd wit-examples/rust && cargo r ${BUILD}
+
+wit-rust-all: wit-rust-run

engine/src/core/mod.rs

@@ -19,7 +19,9 @@ pub mod cyclonedx;
 pub mod data;
 #[cfg(feature = "debug")]
 pub mod debug;
+#[cfg(not(target_arch = "wasm32"))]
 pub mod external;
+#[cfg(not(target_arch = "wasm32"))]
 pub mod guac;
 #[cfg(feature = "intoto")]
 pub mod intoto;
@@ -31,9 +33,12 @@ pub mod lang;
 pub mod list;
 pub mod maven;
 pub mod net;
+#[cfg(not(target_arch = "wasm32"))]
 pub mod openvex;
+#[cfg(not(target_arch = "wasm32"))]
 pub mod osv;
 pub mod pem;
+#[cfg(not(target_arch = "wasm32"))]
 pub mod rhsa;
 pub mod semver;
 #[cfg(feature = "showcase")]

engine/src/data/mod.rs

@@ -3,6 +3,7 @@
 //! A data source is a way to provide mostly static data available to the engine to use during evaluation.
 use crate::runtime::RuntimeError;
 use crate::value::RuntimeValue;
+use std::collections::HashMap;
 
 use std::fmt::Debug;
 use std::fs::File;
@@ -15,6 +16,37 @@ pub trait DataSource: Send + Sync + Debug {
     fn get(&self, path: &str) -> Result<Option<RuntimeValue>, RuntimeError>;
 }
 
+#[derive(Debug)]
+pub enum MemDataSourceType {
+    String(String),
+    Bytes(Vec<u8>),
+}
+
+/// A source of data read from a strings.
+///
+#[derive(Debug)]
+pub struct MemDataSource {
+    map: HashMap<String, MemDataSourceType>,
+}
+
+impl MemDataSource {
+    pub fn new(map: HashMap<String, MemDataSourceType>) -> Self {
+        Self { map }
+    }
+}
+
+impl DataSource for MemDataSource {
+    fn get(&self, path: &str) -> Result<Option<RuntimeValue>, RuntimeError> {
+        match self.map.get(path) {
+            Some(dst) => match dst {
+                MemDataSourceType::String(string) => Ok(Some(string.as_str().into())),
+                MemDataSourceType::Bytes(bytes) => Ok(Some(RuntimeValue::Octets(bytes.clone()))),
+            },
+            None => Err(RuntimeError::NoSuchPath(path.to_string())),
+        }
+    }
+}
+
 /// A source of data read from a directory.
 ///
 /// The path parameter is used to locate the source file within the root directory.

engine/src/lang/hir/mod.rs

@@ -387,11 +387,14 @@ impl World {
         world.add_package(crate::core::kafka::package());
         world.add_package(crate::core::pem::package());
         world.add_package(crate::core::net::package());
+        #[cfg(not(target_arch = "wasm32"))]
         world.add_package(crate::core::openvex::package());
+        #[cfg(not(target_arch = "wasm32"))]
         world.add_package(crate::core::osv::package());
         world.add_package(crate::core::uri::package());
         world.add_package(crate::core::timestamp::package());
         world.add_package(crate::core::csaf::package());
+        #[cfg(not(target_arch = "wasm32"))]
         world.add_package(crate::core::rhsa::package());
         world.add_package(crate::core::slsa::package());
         #[cfg(feature = "intoto")]
@@ -401,7 +404,9 @@ impl World {
         world.add_package(crate::core::debug::package());
 
         world.add_package(crate::core::maven::package());
+        #[cfg(not(target_arch = "wasm32"))]
         world.add_package(crate::core::external::package());
+        #[cfg(not(target_arch = "wasm32"))]
         world.add_package(crate::core::guac::package());
         world.add_package(crate::core::semver::package());
 

engine/src/lib.rs

@@ -1,7 +1,10 @@
 #![doc = include_str!("../../README.md")]
 //#![deny(warnings)]
 //#![warn(missing_docs)]
+#[cfg(all(target_arch = "wasm32", target_os = "wasi"))]
+mod wit;
 
+#[cfg(not(target_arch = "wasm32"))]
 pub mod client;
 mod core;
 pub mod data;

engine/src/runtime/mod.rs

@@ -243,9 +243,12 @@ pub enum RuntimeError {
     #[error("error reading file: {0}")]
     FileUnreadable(PathBuf),
     #[error("remote client failed: {0}")]
+    #[cfg(not(target_arch = "wasm32"))]
     RemoteClient(#[from] crate::client::Error),
     #[error("recursion limit reached: {0}")]
     RecursionLimit(usize),
+    #[error("no such path: {0}")]
+    NoSuchPath(String),
 }
 
 #[derive(Clone, Debug)]