router: Set Sentry transaction field before calling the request handler

This disables the `router` feature of `sentry-conduit` and instead calls `set_transaction()` of Sentry manually before calling the route handler itself. This has the advantage of also adding the `transaction` field to Sentry issues that are not reported by the `sentry-conduit` middleware itself.

Author: Turbo87

Cargo.lock

@@ -74,7 +74,7 @@ reqwest = { version = "0.11", features = ["blocking", "gzip", "json"] }
 scheduled-thread-pool = "0.2.0"
 semver = { version = "1.0.3", features = ["serde"] }
 sentry = { version = "0.23.0", features = ["tracing"] }
-sentry-conduit = "0.2.0"
+sentry-conduit = { version = "0.2.0", default-features = false }
 serde = { version = "1.0.0", features = ["derive"] }
 serde_json = "1.0.0"
 sha2 = "0.9"

Cargo.toml

@@ -151,11 +151,17 @@ struct C(pub fn(&mut dyn RequestExt) -> EndpointResult);
 
 impl Handler for C {
     fn call(&self, req: &mut dyn RequestExt) -> HandlerResult {
-        // Allow blocking individual routes by their pattern through the `BLOCKED_ROUTES`
-        // environment variable. This is not in a middleware because we need access to
-        // `RoutePattern` before executing the response handler.
         if let Some(pattern) = req.extensions().find::<RoutePattern>() {
-            if req.app().config.blocked_routes.contains(pattern.pattern()) {
+            let pattern = pattern.pattern();
+
+            // Configure the Sentry `transaction` field *before* we handle the request,
+            // but *after* the conduit-router has figured out which handler to use.
+            sentry::configure_scope(|scope| scope.set_transaction(Some(pattern)));
+
+            // Allow blocking individual routes by their pattern through the `BLOCKED_ROUTES`
+            // environment variable. This is not in a middleware because we need access to
+            // `RoutePattern` before executing the response handler.
+            if req.app().config.blocked_routes.contains(pattern) {
                 return Ok(RouteBlocked.response().unwrap());
             }
         }