merger notification process order testing

fixtures/merger.json

@@ -1213,21 +1213,6 @@
                             "    '00000000-0000-0000-0000-000000000000'",
                             ")"
                         ],
-                        [
-                            "SELECT pg_notify('entity', '{",
-                            "    \"complete\":{",
-                            "        \"created_at\":\"{{timestamp}}\",",
-                            "        \"created_by\":\"00000000-0000-0000-0000-000000000000\",",
-                            "        \"date_of_birth\":\"2000-01-01\",",
-                            "        \"first_name\":\"Bob\",",
-                            "        \"id\":\"{{uuid:customer_id}}\",",
-                            "        \"last_name\":\"Smith\",",
-                            "        \"modified_at\":\"{{timestamp}}\",",
-                            "        \"modified_by\":\"00000000-0000-0000-0000-000000000000\",",
-                            "        \"type\":\"person\"",
-                            "    }",
-                            "}')"
-                        ],
                         [
                             "INSERT INTO agreego.\"entity\" (",
                             "    \"created_at\",",
@@ -1295,6 +1280,21 @@
                             "        \"type\":\"order\"",
                             "    }",
                             "}')"
+                        ],
+                        [
+                            "SELECT pg_notify('entity', '{",
+                            "    \"complete\":{",
+                            "        \"created_at\":\"{{timestamp}}\",",
+                            "        \"created_by\":\"00000000-0000-0000-0000-000000000000\",",
+                            "        \"date_of_birth\":\"2000-01-01\",",
+                            "        \"first_name\":\"Bob\",",
+                            "        \"id\":\"{{uuid:customer_id}}\",",
+                            "        \"last_name\":\"Smith\",",
+                            "        \"modified_at\":\"{{timestamp}}\",",
+                            "        \"modified_by\":\"00000000-0000-0000-0000-000000000000\",",
+                            "        \"type\":\"person\"",
+                            "    }",
+                            "}')"
                         ]
                     ]
                 }

src/merger/mod.rs

@@ -21,63 +21,87 @@ impl Merger {
   }
 
   pub fn merge(&self, data: Value) -> crate::drop::Drop {
-    match self.merge_internal(data) {
+    let mut val_resolved = Value::Null;
+    let mut notifications_queue = Vec::new();
+    
+    let result = self.merge_internal(data, &mut notifications_queue);
+
+    match result {
       Ok(val) => {
-        let stripped_val = match val {
+        val_resolved = val;
-          Value::Object(mut map) => {
+      }
+      Err(msg) => {
+        return crate::drop::Drop::with_errors(vec![crate::drop::Error {
+          code: "MERGE_FAILED".to_string(),
+          message: msg,
+          details: crate::drop::ErrorDetails {
+            path: "".to_string(),
+          },
+        }]);
+      }
+    };
+
+    // Execute the globally collected, pre-ordered notifications last! 
+    for notify_sql in notifications_queue {
+      if let Err(e) = self.db.execute(&notify_sql, None) {
+        return crate::drop::Drop::with_errors(vec![crate::drop::Error {
+          code: "MERGE_FAILED".to_string(),
+          message: format!("Executor Error in pre-ordered notify: {:?}", e),
+          details: crate::drop::ErrorDetails {
+            path: "".to_string(),
+          },
+        }]);
+      }
+    }
+
+    let stripped_val = match val_resolved {
+      Value::Object(mut map) => {
+        let mut out = serde_json::Map::new();
+        if let Some(id) = map.remove("id") {
+          out.insert("id".to_string(), id);
+        }
+        Value::Object(out)
+      }
+      Value::Array(arr) => {
+        let mut out_arr = Vec::new();
+        for item in arr {
+          if let Value::Object(mut map) = item {
             let mut out = serde_json::Map::new();
             if let Some(id) = map.remove("id") {
               out.insert("id".to_string(), id);
             }
-            Value::Object(out)
+            out_arr.push(Value::Object(out));
+          } else {
+            out_arr.push(Value::Null);
           }
-          Value::Array(arr) => {
+        }
-            let mut out_arr = Vec::new();
+        Value::Array(out_arr)
-            for item in arr {
-              if let Value::Object(mut map) = item {
-                let mut out = serde_json::Map::new();
-                if let Some(id) = map.remove("id") {
-                  out.insert("id".to_string(), id);
-                }
-                out_arr.push(Value::Object(out));
-              } else {
-                out_arr.push(Value::Null);
-              }
-            }
-            Value::Array(out_arr)
-          }
-          other => other,
-        };
-        crate::drop::Drop::success_with_val(stripped_val)
       }
-      Err(msg) => crate::drop::Drop::with_errors(vec![crate::drop::Error {
+      other => other,
-        code: "MERGE_FAILED".to_string(),
+    };
-        message: msg,
+    crate::drop::Drop::success_with_val(stripped_val)
-        details: crate::drop::ErrorDetails {
-          path: "".to_string(),
-        },
-      }]),
-    }
   }
 
-  pub(crate) fn merge_internal(&self, data: Value) -> Result<Value, String> {
+  pub(crate) fn merge_internal(&self, data: Value, notifications: &mut Vec<String>) -> Result<Value, String> {
     match data {
-      Value::Array(items) => self.merge_array(items),
+      Value::Array(items) => self.merge_array(items, notifications),
-      Value::Object(map) => self.merge_object(map),
+      Value::Object(map) => self.merge_object(map, notifications),
       _ => Err("Invalid merge payload: root must be an Object or Array".to_string()),
     }
   }
 
-  fn merge_array(&self, items: Vec<Value>) -> Result<Value, String> {
+  fn merge_array(&self, items: Vec<Value>, notifications: &mut Vec<String>) -> Result<Value, String> {
     let mut resolved_items = Vec::new();
     for item in items {
-      let resolved = self.merge_internal(item)?;
+      let resolved = self.merge_internal(item, notifications)?;
       resolved_items.push(resolved);
     }
     Ok(Value::Array(resolved_items))
   }
 
-  fn merge_object(&self, obj: serde_json::Map<String, Value>) -> Result<Value, String> {
+  fn merge_object(&self, obj: serde_json::Map<String, Value>, notifications: &mut Vec<String>) -> Result<Value, String> {
+    let queue_start = notifications.len();
+
     let type_name = match obj.get("type").and_then(|v| v.as_str()) {
       Some(t) => t.to_string(),
       None => return Err("Missing required 'type' field on object".to_string()),
@@ -147,7 +171,7 @@ impl Merger {
             }
           }
 
-          let merged_relative = match self.merge_internal(Value::Object(relative))? {
+          let merged_relative = match self.merge_internal(Value::Object(relative), notifications)? {
             Value::Object(m) => m,
             _ => continue,
           };
@@ -174,7 +198,7 @@ impl Merger {
             &entity_fields,
           );
 
-          let merged_relative = match self.merge_internal(Value::Object(relative))? {
+          let merged_relative = match self.merge_internal(Value::Object(relative), notifications)? {
             Value::Object(m) => m,
             _ => continue,
           };
@@ -242,7 +266,7 @@ impl Merger {
               &entity_fields,
             );
 
-            let merged_relative = match self.merge_internal(Value::Object(relative_item))? {
+            let merged_relative = match self.merge_internal(Value::Object(relative_item), notifications)? {
               Value::Object(m) => m,
               _ => continue,
             };
@@ -255,7 +279,7 @@ impl Merger {
     }
 
     // 7. Perform change tracking
-    self.merge_entity_change(
+    let notify_sql = self.merge_entity_change(
       &entity_fields,
       entity_fetched.as_ref(),
       entity_change_kind.as_deref(),
@@ -263,6 +287,10 @@ impl Merger {
       &timestamp,
     )?;
 
+    if let Some(sql) = notify_sql {
+      notifications.insert(queue_start, sql);
+    }
+
     // Produce the full tree response
     let mut final_response = serde_json::Map::new();
     if let Some(fetched) = entity_fetched {
@@ -614,10 +642,10 @@ impl Merger {
     entity_change_kind: Option<&str>,
     user_id: &str,
     timestamp: &str,
-  ) -> Result<(), String> {
+  ) -> Result<Option<String>, String> {
     let change_kind = match entity_change_kind {
       Some(k) => k,
-      None => return Ok(()),
+      None => return Ok(None),
     };
 
     let id_str = entity_fields.get("id").unwrap();
@@ -697,12 +725,8 @@ impl Merger {
       .db
       .execute(&change_sql, None)
       .map_err(|e| format!("Executor Error in change: {:?}", e))?;
-    self
-      .db
-      .execute(&notify_sql, None)
-      .map_err(|e| format!("Executor Error in notify: {:?}", e))?;
 
-    Ok(())
+    Ok(Some(notify_sql))
   }
 
   fn compare_entities(