Add opt-in to unstable wasip3 and warn when in use (#3322)

Signed-off-by: Brian Hardock <[email protected]>

Author: fibonacci1729

Cargo.lock

@@ -16,6 +16,7 @@ serde = { workspace = true }
 spin-app = { path = "../app", optional = true }
 spin-factor-outbound-http = { path = "../factor-outbound-http" }
 spin-http-routes = { path = "../routes" }
+terminal = { path = "../terminal" }
 tracing = { workspace = true }
 wasmtime = { workspace = true }
 wasmtime-wasi = { workspace = true }

crates/http/Cargo.toml

@@ -33,7 +33,7 @@ impl HttpTriggerConfig {
 ///
 /// If an executor is not specified, the inferred default is `HttpExecutor::Spin`.
 #[derive(Clone, Debug, Default, Deserialize, Serialize)]
-#[serde(deny_unknown_fields, rename_all = "lowercase", tag = "type")]
+#[serde(deny_unknown_fields, rename_all = "kebab-case", tag = "type")]
 pub enum HttpExecutorType {
     /// The component implements an HTTP based interface.
     ///
@@ -43,6 +43,8 @@ pub enum HttpExecutorType {
     Http,
     /// The component implements the Wagi CGI interface.
     Wagi(WagiTriggerConfig),
+    /// The component implements the WASIp3 HTTP interface (unstable).
+    Wasip3Unstable,
 }
 
 /// Wagi specific configuration for the http executor.

crates/http/src/config.rs

@@ -6,6 +6,8 @@ use wasmtime_wasi::p2::bindings::CommandIndices;
 use wasmtime_wasi_http::bindings::ProxyIndices;
 use wasmtime_wasi_http::p3::bindings::ProxyIndices as P3ProxyIndices;
 
+use crate::config::HttpExecutorType;
+
 #[derive(Clone, Debug, Default, Deserialize, Serialize)]
 #[serde(deny_unknown_fields)]
 pub struct Metadata {
@@ -83,4 +85,45 @@ impl HandlerType {
             ),
         }
     }
+
+    /// Validate that the [`HandlerType`] is compatible with the [`HttpExecutorType`].
+    pub fn validate_executor(&self, executor: &Option<HttpExecutorType>) -> anyhow::Result<()> {
+        match (self, executor) {
+            (HandlerType::Wasi0_3(_), Some(HttpExecutorType::Wasip3Unstable)) => {
+                terminal::warn!(
+                    "You’re using wasip3-unstable, an experimental executor for the \
+                    WASI Preview 3 RC interfaces, which will be removed in a future Spin release."
+                );
+                Ok(())
+            }
+            (HandlerType::Wasi0_3(_), Some(_) | None) => {
+                anyhow::bail!(
+                    "`{WASI_HTTP_EXPORT_0_3_0_RC_2025_09_16}` is currently unstable and will be \
+                    removed in a future Spin release. You can opt-in to this unstable interface \
+                    by adding `executor = {{ type = \"wasip3-unstable\" }}` to the appropriate \
+                    `[[trigger.http]]` section of your spin.toml file."
+                );
+            }
+            (handler_type, Some(HttpExecutorType::Wasip3Unstable)) => {
+                anyhow::bail!(
+                    "The wasip3-unstable trigger executor expected a component that \
+                    exports `{WASI_HTTP_EXPORT_0_3_0_RC_2025_09_16}` but found a \
+                    component with type {name}",
+                    name = handler_type.name(),
+                )
+            }
+            (_, _) => Ok(()),
+        }
+    }
+
+    fn name(&self) -> &str {
+        match self {
+            HandlerType::Spin => SPIN_HTTP_EXPORT,
+            HandlerType::Wasi0_2(_) => WASI_HTTP_EXPORT_0_2_PREFIX,
+            HandlerType::Wasi0_3(_) => WASI_HTTP_EXPORT_0_3_0_RC_2025_09_16,
+            HandlerType::Wasi2023_11_10(_) => WASI_HTTP_EXPORT_2023_11_10,
+            HandlerType::Wasi2023_10_18(_) => WASI_HTTP_EXPORT_2023_10_18,
+            _ => unreachable!(), // WAGI variant will never appear here
+        }
+    }
 }

crates/http/src/trigger.rs

@@ -151,7 +151,11 @@ impl<F: RuntimeFactors> HttpServer<F> {
     ) -> anyhow::Result<HandlerType> {
         let pre = trigger_app.get_instance_pre(component_id)?;
         let handler_type = match executor {
-            None | Some(HttpExecutorType::Http) => HandlerType::from_instance_pre(pre)?,
+            None | Some(HttpExecutorType::Http) | Some(HttpExecutorType::Wasip3Unstable) => {
+                let handler_type = HandlerType::from_instance_pre(pre)?;
+                handler_type.validate_executor(executor)?;
+                handler_type
+            }
             Some(HttpExecutorType::Wagi(wagi_config)) => {
                 anyhow::ensure!(
                     wagi_config.entrypoint == "_start",
@@ -367,7 +371,7 @@ impl<F: RuntimeFactors> HttpServer<F> {
         let executor = executor.as_ref().unwrap_or(&HttpExecutorType::Http);
 
         let res = match executor {
-            HttpExecutorType::Http => match handler_type {
+            HttpExecutorType::Http | HttpExecutorType::Wasip3Unstable => match handler_type {
                 HandlerType::Spin => {
                     SpinHttpExecutor
                         .execute(instance_builder, &route_match, req, client_addr)

crates/trigger-http/src/server.rs

@@ -9,6 +9,7 @@ version = "1.0.0"
 [[trigger.http]]
 route = "/..."
 component = "wasi-http-async"
+executor = { type = "wasip3-unstable" }
 
 [component.wasi-http-async]
 source = "%{source=integration-wasi-http-p3-streaming}"