Validate unique component IDs in config (spinframework#340)

crates/loader/src/local/mod.rs

@@ -10,7 +10,7 @@ pub mod config;
 #[cfg(test)]
 mod tests;
 
-use anyhow::{anyhow, Context, Result};
+use anyhow::{anyhow, bail, Context, Result};
 use config::{RawAppInformation, RawAppManifest, RawAppManifestAnyVersion, RawComponentManifest};
 use futures::future;
 use path_absolutize::Absolutize;
@@ -63,6 +63,20 @@ async fn prepare_any_version(
     }
 }
 
+/// Iterates over a vector of RawComponentManifest structs and throws an error if any component ids are duplicated
+fn error_on_duplicate_ids(components: Vec<RawComponentManifest>) -> Result<()> {
+    let mut ids: Vec<String> = Vec::new();
+    for c in components {
+        let id = c.id;
+        if ids.contains(&id) {
+            bail!("cannot have duplicate component IDs: {}", id);
+        } else {
+            ids.push(id);
+        }
+    }
+    Ok(())
+}
+
 /// Converts a raw application manifest into Spin configuration.
 async fn prepare(
     mut raw: RawAppManifest,
@@ -71,6 +85,8 @@ async fn prepare(
 ) -> Result<Application<CoreComponent>> {
     let info = info(raw.info, &src);
 
+    error_on_duplicate_ids(raw.components.clone())?;
+
     let mut config_root = raw.config.unwrap_or_default();
     for component in &mut raw.components {
         if let Some(config) = component.config.take() {

crates/loader/src/local/tests.rs

@@ -139,3 +139,25 @@ fn test_wagi_executor_with_custom_entrypoint() -> Result<()> {
 
     Ok(())
 }
+
+#[tokio::test]
+async fn test_duplicate_component_id_is_rejected() -> Result<()> {
+    const MANIFEST: &str = "tests/invalid-manifest-duplicate-id.toml";
+
+    let temp_dir = tempfile::tempdir()?;
+    let dir = temp_dir.path();
+    let app = from_file(MANIFEST, dir).await;
+
+    assert!(
+        app.is_err(),
+        "Expected component IDs to be unique, but there were duplicates"
+    );
+
+    let e = app.unwrap_err().to_string();
+    assert!(
+        e.contains("hello"),
+        "Expected error to contain duplicate component ID `hello`"
+    );
+
+    Ok(())
+}

crates/loader/tests/invalid-manifest-duplicate-id.toml

@@ -0,0 +1,16 @@
+spin_version = "1"
+name = "spin-hello-world-duplicate"
+version = "1.0.0"
+trigger = { type = "http", base = "/" }
+
+[[component]]
+id = "hello"
+source = "path/to/wasm/file.wasm"
+[component.trigger]
+route = "/hello"
+
+[[component]]
+id = "hello"
+source = "path/to/wasm/file.wasm"
+[component.trigger]
+route = "/hello"