Add a helper method to get a correct backend name

Author: Felixoid

src/cache/cache.rs

@@ -373,6 +373,12 @@ pub trait Storage: Send + Sync {
     /// Get the storage location.
     fn location(&self) -> String;
 
+    /// Get the cache backend type name (e.g., "disk", "redis", "s3").
+    /// Used for statistics and display purposes.
+    fn cache_type_name(&self) -> &'static str {
+        "unknown"
+    }
+
     /// Get the current storage usage, if applicable.
     async fn current_size(&self) -> Result<Option<u64>>;
 
@@ -588,6 +594,12 @@ impl Storage for RemoteStorage {
         )
     }
 
+    fn cache_type_name(&self) -> &'static str {
+        // Use opendal's scheme as the cache type name
+        // This returns "s3", "redis", "azure", "gcs", etc.
+        self.operator.info().scheme()
+    }
+
     async fn current_size(&self) -> Result<Option<u64>> {
         Ok(None)
     }

src/cache/disk.rs

@@ -137,6 +137,10 @@ impl Storage for DiskCache {
         format!("Local disk: {:?}", self.lru.lock().unwrap().path())
     }
 
+    fn cache_type_name(&self) -> &'static str {
+        "disk"
+    }
+
     async fn current_size(&self) -> Result<Option<u64>> {
         Ok(self.lru.lock().unwrap().get().map(|l| l.size()))
     }
@@ -185,3 +189,27 @@ impl Storage for DiskCache {
             .commit(f)?)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_disk_cache_type_name() {
+        let tempdir = tempfile::tempdir().unwrap();
+        let runtime = tokio::runtime::Builder::new_current_thread()
+            .build()
+            .unwrap();
+
+        let disk = DiskCache::new(
+            tempdir.path(),
+            1024 * 1024,
+            runtime.handle(),
+            PreprocessorCacheModeConfig::default(),
+            CacheMode::ReadWrite,
+            vec![],
+        );
+
+        assert_eq!(disk.cache_type_name(), "disk");
+    }
+}

src/cache/readonly.rs

@@ -49,6 +49,11 @@ impl Storage for ReadOnlyStorage {
         self.0.location()
     }
 
+    /// Get the cache backend type name.
+    fn cache_type_name(&self) -> &'static str {
+        self.0.cache_type_name()
+    }
+
     /// Get the current storage usage, if applicable.
     async fn current_size(&self) -> Result<Option<u64>> {
         self.0.current_size().await
@@ -188,4 +193,33 @@ mod test {
             );
         });
     }
+
+    #[test]
+    fn readonly_storage_forwards_cache_type_name() {
+        let runtime = tokio::runtime::Builder::new_current_thread()
+            .enable_all()
+            .worker_threads(1)
+            .build()
+            .unwrap();
+
+        let tempdir = tempfile::Builder::new()
+            .prefix("readonly_cache_type_name")
+            .tempdir()
+            .expect("Failed to create tempdir");
+        let cache_dir = tempdir.path().join("cache");
+        std::fs::create_dir(&cache_dir).unwrap();
+
+        let disk_cache = crate::cache::disk::DiskCache::new(
+            &cache_dir,
+            1024 * 1024,
+            runtime.handle(),
+            super::PreprocessorCacheModeConfig::default(),
+            super::CacheMode::ReadWrite,
+            vec![],
+        );
+
+        let readonly_storage = ReadOnlyStorage(std::sync::Arc::new(disk_cache));
+
+        assert_eq!(readonly_storage.cache_type_name(), "disk");
+    }
 }