feat(cache): add generic cache functions to populate and invalidate cache (#483)

crates/router/src/db.rs

@@ -1,4 +1,5 @@
 pub mod address;
+pub mod cache;
 pub mod configs;
 pub mod connector_response;
 pub mod customers;

crates/router/src/db/cache.rs

@@ -0,0 +1,57 @@
+#![allow(dead_code)]
+
+use error_stack::ResultExt;
+
+use super::Store;
+use crate::core::errors::{self, CustomResult};
+
+pub async fn get_or_populate_cache<T, F, Fut>(
+    store: &Store,
+    key: &str,
+    fun: F,
+) -> CustomResult<T, errors::StorageError>
+where
+    T: serde::Serialize + serde::de::DeserializeOwned + std::fmt::Debug,
+    F: FnOnce() -> Fut + Send,
+    Fut: futures::Future<Output = CustomResult<T, errors::StorageError>> + Send,
+{
+    let redis = &store.redis_conn;
+    let redis_val = redis
+        .get_and_deserialize_key::<T>(key, std::any::type_name::<T>())
+        .await;
+    match redis_val {
+        Err(err) => match err.current_context() {
+            errors::RedisError::NotFound => {
+                let data = fun().await?;
+                redis
+                    .serialize_and_set_key(key, &data)
+                    .await
+                    .change_context(errors::StorageError::KVError)?;
+                Ok(data)
+            }
+            _ => Err(err
+                .change_context(errors::StorageError::KVError)
+                .attach_printable("Error while fetching config")),
+        },
+        Ok(val) => Ok(val),
+    }
+}
+
+pub async fn redact_cache<T, F, Fut>(
+    store: &Store,
+    key: &str,
+    fun: F,
+) -> CustomResult<T, errors::StorageError>
+where
+    T: serde::Serialize + serde::de::DeserializeOwned + std::fmt::Debug,
+    F: FnOnce() -> Fut + Send,
+    Fut: futures::Future<Output = CustomResult<T, errors::StorageError>> + Send,
+{
+    let data = fun().await?;
+    store
+        .redis_conn
+        .delete_key(key)
+        .await
+        .change_context(errors::StorageError::KVError)?;
+    Ok(data)
+}