Add CatchPanic (#214)

* Add `CatchPanic`

* support custom panic handler

* docs

* fix feature

* Add note about using panics for error handling

tower-http/CHANGELOG.md

@@ -9,7 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Added
 
-- None.
+- Added `CatchPanic` middleware which catches panics and converts them
+  into `500 Internal Server` responses
 
 ## Changed
 

tower-http/Cargo.toml

@@ -48,12 +48,14 @@ tokio = { version = "1", features = ["full"] }
 tower = { version = "0.4.10", features = ["buffer", "util", "retry", "make", "timeout"] }
 tracing-subscriber = "0.3"
 uuid = { version = "0.8", features = ["v4"] }
+serde_json = "1.0"
 
 [features]
 default = []
 full = [
     "add-extension",
     "auth",
+    "catch-panic",
     "compression-full",
     "cors",
     "decompression-full",
@@ -73,6 +75,7 @@ full = [
 
 add-extension = []
 auth = ["base64"]
+catch-panic = ["tracing", "futures-util/std"]
 cors = []
 follow-redirect = ["iri-string", "tower/util"]
 fs = ["tokio/fs", "tokio-util/io", "tokio/io-util", "mime_guess", "mime", "percent-encoding", "httpdate"]

tower-http/src/builder.rs

@@ -365,6 +365,19 @@ pub trait ServiceBuilderExt<L>: crate::sealed::Sealed<L> + Sized {
     ) -> ServiceBuilder<Stack<crate::request_id::PropagateRequestIdLayer, L>> {
         self.propagate_request_id(HeaderName::from_static(crate::request_id::X_REQUEST_ID))
     }
+
+    /// Catch panics and convert them into `500 Internal Server` responses.
+    ///
+    /// See [`tower_http::catch_panic`] for more details.
+    ///
+    /// [`tower_http::catch_panic`]: crate::catch_panic
+    #[cfg(feature = "catch-panic")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "catch-panic")))]
+    fn catch_panic(
+        self,
+    ) -> ServiceBuilder<
+        Stack<crate::catch_panic::CatchPanicLayer<crate::catch_panic::DefaultResponseForPanic>, L>,
+    >;
 }
 
 impl<L> crate::sealed::Sealed<L> for ServiceBuilder<L> {}
@@ -588,4 +601,14 @@ impl<L> ServiceBuilderExt<L> for ServiceBuilder<L> {
     ) -> ServiceBuilder<Stack<crate::request_id::PropagateRequestIdLayer, L>> {
         self.layer(crate::request_id::PropagateRequestIdLayer::new(header_name))
     }
+
+    #[cfg(feature = "catch-panic")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "catch-panic")))]
+    fn catch_panic(
+        self,
+    ) -> ServiceBuilder<
+        Stack<crate::catch_panic::CatchPanicLayer<crate::catch_panic::DefaultResponseForPanic>, L>,
+    > {
+        self.layer(crate::catch_panic::CatchPanicLayer::new())
+    }
 }