Redis storage: return an error if a non serializable value is sent.

.changesets/fix_igni_safely_deal_with_invalid_redis_keys.md

@@ -0,0 +1,6 @@
+### Redis storage: return an error instead if a non serializable value is sent. ([#3594](https://github.com/apollographql/router/issues/3594))
+
+This changeset returns an error if a value couldn't be serialized before being sent to the redis storage backend.
+It also logs the error in console and prompts you to open an issue (This message showing up would be a router bug!).
+
+By [@o0Ignition0o](https://github.com/o0Ignition0o) in https://github.com/apollographql/router/pull/3597

apollo-router/src/cache/redis.rs

@@ -101,8 +101,13 @@ where
     type Error = RedisError;
 
     fn try_into(self) -> Result<fred::types::RedisValue, Self::Error> {
-        let v = serde_json::to_vec(&self.0)
-            .expect("JSON serialization should not fail for redis values");
+        let v = serde_json::to_vec(&self.0).map_err(|e| {
+            tracing::error!("couldn't serialize value to redis {}. This is a bug in the router, please file an issue: https://github.com/apollographql/router/issues/new", e);
+            RedisError::new(
+                RedisErrorKind::Parse,
+                format!("couldn't serialize value to redis {}", e),
+            )
+        })?;
 
         Ok(fred::types::RedisValue::Bytes(v.into()))
     }
@@ -332,3 +337,25 @@ impl RedisCacheStorage {
         tracing::trace!("insert result {:?}", r);
     }
 }
+
+#[cfg(test)]
+mod test {
+    use std::time::SystemTime;
+
+    #[test]
+    fn ensure_invalid_payload_serialization_doesnt_fail() {
+        #[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
+        struct Stuff {
+            time: SystemTime,
+        }
+
+        let invalid_json_payload = super::RedisValue(Stuff {
+            // this systemtime is invalid, serialization will fail
+            time: std::time::UNIX_EPOCH - std::time::Duration::new(1, 0),
+        });
+
+        let as_value: Result<fred::types::RedisValue, _> = invalid_json_payload.try_into();
+
+        assert!(as_value.is_err());
+    }
+}