0.29.7

src/cache/model/entry.rs

@@ -188,6 +188,9 @@ impl Settings {
                 value.parse::<HeaderValue>().expect("validated cache Via header"),
             );
         }
+        if self.expose_only_hits && outcome != "HIT" {
+            return;
+        }
         if self.expose_status {
             headers.insert("x-cache", HeaderValue::from_static(outcome));
         }
@@ -222,7 +225,10 @@ impl Settings {
         }
     }
     pub fn annotate_transformed(&self, headers: &mut HeaderMap, transformed: bool) {
-        if !self.enabled || !self.expose_cache_status || !transformed {
+        if !self.enabled || !self.expose_cache_status || !transformed
+            || (self.expose_only_hits && !headers.get("cache-status")
+                .and_then(|value| value.to_str().ok())
+                .is_some_and(|value| value.starts_with("RustProxy; hit"))) {
             return;
         }
         let base = headers
@@ -249,7 +255,7 @@ impl Settings {
         reason: &'static str,
     ) {
         self.annotate(headers, outcome, hits, ttl);
-        if !self.enabled {
+        if !self.enabled || (self.expose_only_hits && outcome != "HIT") {
             return;
         }
         if self.expose_status {
@@ -333,6 +339,7 @@ pub struct Overrides {
     pub expose_hits: Option<bool>,
     pub expose_cache_status: Option<bool>,
     pub expose_resident_age: Option<bool>,
+    pub expose_only_hits: Option<bool>,
     /// Deliberately unavailable in the global cache configuration.
     pub unsafe_force: UnsafeForce,
 }
@@ -380,6 +387,9 @@ impl Overrides {
         if let Some(value) = self.expose_resident_age {
             result.expose_resident_age = value;
         }
+        if let Some(value) = self.expose_only_hits {
+            result.expose_only_hits = value;
+        }
         result.validate()?;
         Ok(result)
     }

src/cache/model/settings.rs

@@ -173,6 +173,8 @@ pub struct Settings {
     pub expose_hits: bool,
     pub expose_cache_status: bool,
     pub expose_resident_age: bool,
+    /// Emit cache diagnostics only for actual HIT responses, not MISS or BYPASS.
+    pub expose_only_hits: bool,
     /// Optional response Via field value added by RustProxy cache handling.
     /// `None` disables the header; the default is `Via: RustProxy`.
     pub via_header: Option<String>,
@@ -243,6 +245,7 @@ impl Default for Settings {
             expose_hits: false,
             expose_cache_status: false,
             expose_resident_age: false,
+            expose_only_hits: false,
             via_header: Some("RustProxy".into()),
         }
     }

src/cache/tests/dashboard_tests.rs

@@ -127,6 +127,39 @@ mod dashboard_tests {
         );
     }
     #[test]
+    fn hit_only_cache_diagnostics_hides_miss_bypass_and_preserves_hits() {
+        let global = Settings {
+            expose_status: true,
+            expose_hits: true,
+            expose_cache_status: true,
+            expose_resident_age: true,
+            expose_only_hits: true,
+            ..Settings::default()
+        };
+        let mut headers = HeaderMap::new();
+        headers.insert("x-cache", HeaderValue::from_static("untrusted-upstream"));
+        headers.insert("cache-status", HeaderValue::from_static("untrusted-upstream"));
+        global.annotate_reason(&mut headers, "MISS", 0, 0, "response_headers_policy");
+        global.annotate_transformed(&mut headers, true);
+        for name in ["x-cache", "x-cache-hits", "cache-status", "x-cache-reason", "x-cache-resident-age"] {
+            assert!(!headers.contains_key(name), "{name} leaked on MISS");
+        }
+        assert_eq!(headers["via"], "RustProxy"); // independent proxy policy
+        global.annotate_reason(&mut headers, "BYPASS", 0, 0, "request_cookie");
+        assert!(!headers.contains_key("cache-status"));
+        global.annotate_reason(&mut headers, "HIT", 4, 60, "cache_hit");
+        global.annotate_resident_age(&mut headers, 10);
+        assert_eq!(headers["x-cache"], "HIT");
+        assert_eq!(headers["x-cache-hits"], "4");
+        assert!(headers["cache-status"].to_str().unwrap().contains("; hit;"));
+        assert_eq!(headers["x-cache-resident-age"], "10");
+        let mut override_on = Overrides { expose_only_hits: Some(false), ..Default::default() };
+        let normal = override_on.resolve(&global).unwrap();
+        assert!(!normal.expose_only_hits);
+        override_on.expose_only_hits = Some(true);
+        assert!(override_on.resolve(&Settings::default()).unwrap().expose_only_hits);
+    }
+    #[test]
     fn via_header_is_configurable_and_preserves_upstream_chain() {
         let settings = Settings::default();
         let mut headers = HeaderMap::new();