fix(events): Ensure Event timestamp is sent as epoch milliseconds

.changeset/moody-lions-approve.md

@@ -0,0 +1,6 @@
+---
+"eppo_core": patch
+"ruby-sdk": patch
+---
+
+[Unstable] Event Ingestion: Fix JSON serialization of Event timestamp field

eppo_core/src/event_ingestion/event.rs

@@ -1,11 +1,18 @@
-use crate::timestamp::Timestamp;
 use serde::{Deserialize, Serialize};
+use serde_with::serde_as;
+
+use crate::timestamp::Timestamp;
 
+#[serde_as]
 #[derive(Debug, Serialize, Deserialize, Clone, PartialEq, Eq, Hash)]
 pub(super) struct Event {
     pub uuid: uuid::Uuid,
+
+    #[serde(with = "chrono::serde::ts_milliseconds")]
     pub timestamp: Timestamp,
+
     #[serde(rename = "type")]
     pub event_type: String,
+
     pub payload: serde_json::Value,
-}
+}

eppo_core/src/event_ingestion/event_delivery.rs

@@ -183,7 +183,7 @@ mod tests {
             .and(body_json(&json!({
                 "eppo_events": [{
                     "uuid": uuid,
-                    "timestamp": timestamp,
+                    "timestamp": timestamp.timestamp_millis(),
                     "type": "test",
                     "payload": {
                         "user_id": "user123",

eppo_core/src/lib.rs

@@ -56,7 +56,6 @@ pub mod configuration_fetcher;
 pub mod configuration_poller;
 pub mod configuration_store;
 pub mod eval;
-mod sdk_key;
 #[cfg(feature = "event_ingestion")]
 pub mod event_ingestion;
 pub mod events;
@@ -70,6 +69,7 @@ mod configuration;
 mod error;
 mod obfuscation;
 mod precomputed;
+mod sdk_key;
 mod sdk_metadata;
 mod str;