fix: increase the event observer max body size

.generated-sources/emily/client/rust/private/src/apis/deposit_api.rs

@@ -20,6 +20,7 @@ pub enum CreateDepositError {
     Status400(models::ErrorResponse),
     Status404(models::ErrorResponse),
     Status405(models::ErrorResponse),
+    Status409(models::ErrorResponse),
     Status500(models::ErrorResponse),
     UnknownValue(serde_json::Value),
 }

.generated-sources/emily/client/rust/public/src/apis/deposit_api.rs

@@ -20,6 +20,7 @@ pub enum CreateDepositError {
     Status400(models::ErrorResponse),
     Status404(models::ErrorResponse),
     Status405(models::ErrorResponse),
+    Status409(models::ErrorResponse),
     Status500(models::ErrorResponse),
     UnknownValue(serde_json::Value),
 }

.generated-sources/emily/client/rust/testing/src/apis/deposit_api.rs

@@ -20,6 +20,7 @@ pub enum CreateDepositError {
     Status400(models::ErrorResponse),
     Status404(models::ErrorResponse),
     Status405(models::ErrorResponse),
+    Status409(models::ErrorResponse),
     Status500(models::ErrorResponse),
     UnknownValue(serde_json::Value),
 }

signer/src/api/new_block.rs

@@ -51,6 +51,15 @@ use super::SBTC_REGISTRY_CONTRACT_NAME;
 /// See https://github.com/stacks-network/sbtc/issues/501.
 static SBTC_REGISTRY_IDENTIFIER: OnceLock<QualifiedContractIdentifier> = OnceLock::new();
 
+/// Maximum request body size for the event observer endpoint.
+///
+/// Stacks blocks have a limit of 2 MB, which is enforced at the p2p level, but
+/// event observer events can be larger than that since they contain the
+/// subscribed sbtc events. Luckily, the size of the sbtc events themselves are
+/// bounded by the size of the transactions that create them, so a limit of 8 MB
+/// will be fine since it is twice as high as required.
+pub const EVENT_OBSERVER_BODY_LIMIT: usize = 8 * 1024 * 1024;
+
 /// An enum representing the result of the event processing.
 /// This is used to send the results of the events to Emily.
 enum UpdateResult {
@@ -401,6 +410,9 @@ async fn handle_key_rotation(
 mod tests {
     use super::*;
 
+    use axum::body::Body;
+    use axum::http::Method;
+    use axum::http::Request;
     use bitcoin::OutPoint;
     use bitvec::array::BitArray;
     use clarity::vm::types::PrincipalData;
@@ -411,7 +423,9 @@ mod tests {
     use rand::SeedableRng as _;
     use secp256k1::SECP256K1;
     use test_case::test_case;
+    use tower::ServiceExt;
 
+    use crate::api::get_router;
     use crate::storage::in_memory::Store;
     use crate::storage::model::DepositRequest;
     use crate::storage::model::ScriptPubKey;
@@ -914,4 +928,53 @@ mod tests {
         assert_eq!(db.rotate_keys_transactions.len(), 1);
         assert!(db.rotate_keys_transactions.get(&txid).is_some());
     }
+
+    #[test_case(EVENT_OBSERVER_BODY_LIMIT, true; "event within limit")]
+    #[test_case(EVENT_OBSERVER_BODY_LIMIT + 1, false; "event over limit")]
+    #[tokio::test]
+    async fn test_big_event(event_size: usize, success: bool) {
+        let mut ctx = TestContext::builder()
+            .with_in_memory_storage()
+            .with_mocked_clients()
+            .build();
+
+        ctx.with_emily_client(|client| {
+            client.expect_update_deposits().returning(move |_| {
+                Box::pin(async { Ok(UpdateDepositsResponse { deposits: vec![] }) })
+            });
+            client.expect_update_withdrawals().returning(move |_| {
+                Box::pin(async { Ok(UpdateWithdrawalsResponse { withdrawals: vec![] }) })
+            });
+            client
+                .expect_create_withdrawals()
+                .returning(move |_| Box::pin(async { vec![] }));
+        })
+        .await;
+
+        let state = ApiState { ctx: ctx.clone() };
+        let app = get_router().with_state(state);
+
+        let db = ctx.inner_storage();
+        // We don't have anything here yet
+        assert!(db.lock().await.rotate_keys_transactions.is_empty());
+
+        let mut event: String = " ".repeat(event_size - ROTATE_KEYS_WEBHOOK.len());
+        event.push_str(ROTATE_KEYS_WEBHOOK);
+
+        let request = Request::builder()
+            .uri("/new_block")
+            .method(Method::POST)
+            .body(Body::from(event))
+            .unwrap();
+
+        let response = app.oneshot(request).await.unwrap();
+
+        if success {
+            assert_eq!(response.status(), StatusCode::OK);
+            assert!(!db.lock().await.rotate_keys_transactions.is_empty());
+        } else {
+            assert_eq!(response.status(), StatusCode::PAYLOAD_TOO_LARGE);
+            assert!(db.lock().await.rotate_keys_transactions.is_empty());
+        }
+    }
 }

signer/src/api/router.rs

@@ -2,6 +2,7 @@
 //!
 
 use axum::{
+    extract::DefaultBodyLimit,
     routing::{get, post},
     Router,
 };
@@ -20,7 +21,11 @@ async fn new_attachment_handler() -> StatusCode {
 pub fn get_router<C: Context + 'static>() -> Router<ApiState<C>> {
     Router::new()
         .route("/", get(status::status_handler))
-        .route("/new_block", post(new_block::new_block_handler))
+        .route(
+            "/new_block",
+            post(new_block::new_block_handler)
+                .layer(DefaultBodyLimit::max(new_block::EVENT_OBSERVER_BODY_LIMIT)),
+        )
         // TODO: remove this once https://github.com/stacks-network/stacks-core/issues/5558
         // is addressed
         .route("/attachments/new", post(new_attachment_handler))