Fix schema map deserialize (#285)

Author: trueleo

server/src/storage/object_storage.rs

@@ -41,7 +41,6 @@ use itertools::kmerge_by;
 use lazy_static::__Deref;
 use relative_path::RelativePath;
 use relative_path::RelativePathBuf;
-use serde::Serialize;
 use serde_json::Value;
 
 use std::{
@@ -149,9 +148,29 @@ pub trait ObjectStorage: Sync + 'static {
         &self,
         stream_name: &str,
     ) -> Result<HashMap<String, Arc<Schema>>, ObjectStorageError> {
-        let schema = self.get_object(&schema_path(stream_name)).await?;
-        let schema = serde_json::from_slice(&schema).expect("schema map is valid json");
-        Ok(schema)
+        let schema_map = self.get_object(&schema_path(stream_name)).await?;
+        if let Ok(schema_map) = serde_json::from_slice(&schema_map) {
+            Ok(schema_map)
+        } else {
+            // fix for schema metadata serialize
+            let mut schema_map: serde_json::Value =
+                serde_json::from_slice(&schema_map).expect("valid json");
+
+            for schema in schema_map
+                .as_object_mut()
+                .expect("schema map is json object")
+                .values_mut()
+            {
+                let map = schema.as_object_mut().unwrap();
+                map.insert(
+                    "metadata".to_string(),
+                    Value::Object(serde_json::Map::new()),
+                );
+            }
+
+            Ok(serde_json::from_value(schema_map)
+                .expect("should be deserializable after alteration"))
+        }
     }
 
     async fn get_alerts(&self, stream_name: &str) -> Result<Alerts, ObjectStorageError> {
@@ -380,7 +399,7 @@ impl MergedRecordReader {
 }
 
 #[inline(always)]
-fn to_bytes(any: &(impl ?Sized + Serialize)) -> Bytes {
+fn to_bytes(any: &(impl ?Sized + serde::Serialize)) -> Bytes {
     serde_json::to_vec(any)
         .map(|any| any.into())
         .expect("serialize cannot fail")