refactor(storage): add redis structs to storage impls (#1910)

crates/storage_impl/src/redis/kv_store.rs

@@ -0,0 +1,28 @@
+pub(crate) trait KvStorePartition {
+    fn partition_number(key: PartitionKey<'_>, num_partitions: u8) -> u32 {
+        crc32fast::hash(key.to_string().as_bytes()) % u32::from(num_partitions)
+    }
+
+    fn shard_key(key: PartitionKey<'_>, num_partitions: u8) -> String {
+        format!("shard_{}", Self::partition_number(key, num_partitions))
+    }
+}
+
+#[allow(unused)]
+pub(crate) enum PartitionKey<'a> {
+    MerchantIdPaymentId {
+        merchant_id: &'a str,
+        payment_id: &'a str,
+    },
+}
+
+impl<'a> std::fmt::Display for PartitionKey<'a> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match *self {
+            PartitionKey::MerchantIdPaymentId {
+                merchant_id,
+                payment_id,
+            } => f.write_str(&format!("mid_{merchant_id}_pid_{payment_id}")),
+        }
+    }
+}