Eager command line argument validation for wasmtime serve

src/commands/serve.rs

@@ -73,6 +73,30 @@ pub struct ServeCommand {
 impl ServeCommand {
     /// Start a server to run the given wasi-http proxy component
     pub fn execute(self) -> Result<()> {
+        // We force cli errors before starting to listen for connections so tha we don't
+        // accidentally delay them to the first request.
+        if self.run.common.wasi.nn == Some(true) {
+            #[cfg(not(feature = "wasi-nn"))]
+            {
+                bail!("Cannot enable wasi-nn when the binary is not compiled with this feature.");
+            }
+        }
+
+        if let Some(Profile::Guest { .. }) = &self.run.profile {
+            bail!("Cannot use the guest profiler with components");
+        }
+
+        if self.run.common.wasi.nn == Some(true) {
+            #[cfg(not(feature = "wasi-nn"))]
+            {
+                bail!("Cannot enable wasi-nn when the binary is not compiled with this feature.");
+            }
+        }
+
+        if self.run.common.wasi.threads == Some(true) {
+            bail!("wasi-threads does not support components yet")
+        }
+
         let runtime = tokio::runtime::Builder::new_multi_thread()
             .enable_time()
             .enable_io()
@@ -110,10 +134,6 @@ impl ServeCommand {
         };
 
         if self.run.common.wasi.nn == Some(true) {
-            #[cfg(not(feature = "wasi-nn"))]
-            {
-                bail!("Cannot enable wasi-nn when the binary is not compiled with this feature.");
-            }
             #[cfg(feature = "wasi-nn")]
             {
                 let graphs = self
@@ -131,17 +151,19 @@ impl ServeCommand {
 
         let mut store = Store::new(engine, host);
 
-        if let Some(Profile::Guest { .. }) = &self.run.profile {
-            bail!("Cannot use the guest profiler with components");
-        }
-
         if self.run.common.wasm.timeout.is_some() {
             store.set_epoch_deadline(1);
         }
 
         store.data_mut().limits = self.run.store_limits();
         store.limiter(|t| &mut t.limits);
 
+        // If fuel has been configured, we want to add the configured
+        // fuel amount to this store.
+        if let Some(fuel) = self.run.common.wasm.fuel {
+            store.add_fuel(fuel)?;
+        }
+
         Ok(store)
     }
 
@@ -153,20 +175,12 @@ impl ServeCommand {
         wasmtime_wasi_http::proxy::add_to_linker(linker)?;
 
         if self.run.common.wasi.nn == Some(true) {
-            #[cfg(not(feature = "wasi-nn"))]
-            {
-                bail!("Cannot enable wasi-nn when the binary is not compiled with this feature.");
-            }
             #[cfg(feature = "wasi-nn")]
             {
                 wasmtime_wasi_nn::wit::ML::add_to_linker(linker, |host| host.nn.as_mut().unwrap())?;
             }
         }
 
-        if self.run.common.wasi.threads == Some(true) {
-            bail!("wasi-threads does not support components yet")
-        }
-
         Ok(())
     }
 
@@ -187,9 +201,10 @@ impl ServeCommand {
             Some(Profile::Native(s)) => {
                 config.profiler(s);
             }
-            Some(Profile::Guest { .. }) => {
-                bail!("guest profiling not yet available with components");
-            }
+
+            // We bail early in `execute` if the guest profiler is configured.
+            Some(Profile::Guest { .. }) => unreachable!(),
+
             None => {}
         }