passing object info information with redis module (#138)

* adding object broadcast channel; published on each object table add

* publishing data size to the bcast channel

* bug fix: objectkey

* update object tests to test for data size: C + py

* remove debug

* clang format

* Minor changes.

* Fix error.

* merging with Robert's comments

* clang format for the object table test upgrade

src/common/redis_module/ray_redis_module.c

@@ -25,6 +25,7 @@
 #define OBJECT_LOCATION_PREFIX "OL:"
 #define OBJECT_NOTIFICATION_PREFIX "ON:"
 #define TASK_PREFIX "TT:"
+#define OBJECT_BCAST "BCAST"
 
 #define OBJECT_CHANNEL_PREFIX "OC:"
 
@@ -228,11 +229,26 @@ int ObjectTableLookup_RedisCommand(RedisModuleCtx *ctx,
 bool PublishObjectNotification(RedisModuleCtx *ctx,
                                RedisModuleString *client_id,
                                RedisModuleString *object_id,
+                               RedisModuleString *data_size,
                                RedisModuleKey *key) {
   /* Create a string formatted as "<object id> MANAGERS <manager id1>
    * <manager id2> ..." */
   RedisModuleString *manager_list =
       RedisModule_CreateStringFromString(ctx, object_id);
+  long long data_size_value;
+  if (RedisModule_StringToLongLong(data_size, &data_size_value) !=
+      REDISMODULE_OK) {
+    return RedisModule_ReplyWithError(ctx, "data_size must be integer");
+  }
+
+  /* Add a space to the payload for human readability. */
+  RedisModule_StringAppendBuffer(ctx, manager_list, " ", strlen(" "));
+
+  /* Append binary data size for this object. */
+  RedisModule_StringAppendBuffer(ctx, manager_list,
+                                 (const char *) &data_size_value,
+                                 sizeof(data_size_value));
+
   RedisModule_StringAppendBuffer(ctx, manager_list, " MANAGERS",
                                  strlen(" MANAGERS"));
 
@@ -328,6 +344,16 @@ int ObjectTableAdd_RedisCommand(RedisModuleCtx *ctx,
   /* Sets are not implemented yet, so we use ZSETs instead. */
   RedisModule_ZsetAdd(table_key, 0.0, manager, NULL);
 
+  RedisModuleString *bcast_client_str =
+      RedisModule_CreateString(ctx, OBJECT_BCAST, strlen(OBJECT_BCAST));
+  bool success = PublishObjectNotification(ctx, bcast_client_str, object_id,
+                                           data_size, table_key);
+  if (!success) {
+    /* The publish failed somehow. */
+    return RedisModule_ReplyWithError(ctx, "PUBLISH BCAST unsuccessful");
+  }
+  RedisModule_FreeString(ctx, bcast_client_str);
+
   /* Get the zset of clients that requested a notification about the
    * availability of this object. */
   RedisModuleKey *object_notification_key =
@@ -344,14 +370,15 @@ int ObjectTableAdd_RedisCommand(RedisModuleCtx *ctx,
     /* Iterate over the list of clients that requested notifiations about the
      * availability of this object, and publish notifications to their object
      * notification channels. */
+
     do {
       RedisModuleString *client_id =
           RedisModule_ZsetRangeCurrentElement(object_notification_key, NULL);
       /* TODO(rkn): Some computation could be saved by batching the string
        * constructions in the multiple calls to PublishObjectNotification
        * together. */
-      bool success =
-          PublishObjectNotification(ctx, client_id, object_id, table_key);
+      bool success = PublishObjectNotification(ctx, client_id, object_id,
+                                               data_size, table_key);
       if (!success) {
         /* The publish failed somehow. */
         RedisModule_CloseKey(object_notification_key);
@@ -420,7 +447,23 @@ int ObjectTableRequestNotifications_RedisCommand(RedisModuleCtx *ctx,
       RedisModule_CloseKey(object_notification_key);
     } else {
       /* Publish a notification to the client's object notification channel. */
-      bool success = PublishObjectNotification(ctx, client_id, object_id, key);
+      /* Extract the data_size first. */
+      RedisModuleKey *object_info_key;
+      object_info_key =
+          OpenPrefixedKey(ctx, OBJECT_INFO_PREFIX, object_id, REDISMODULE_READ);
+      int keytype = RedisModule_KeyType(key);
+      if (keytype == REDISMODULE_KEYTYPE_EMPTY) {
+        RedisModule_CloseKey(object_info_key);
+        RedisModule_CloseKey(key);
+        return RedisModule_ReplyWithError(ctx, "requested object not found");
+      }
+      RedisModuleString *existing_data_size;
+      RedisModule_HashGet(object_info_key, REDISMODULE_HASH_CFIELDS,
+                          "data_size", &existing_data_size, NULL);
+      RedisModule_CloseKey(object_info_key); /* No longer needed. */
+
+      bool success = PublishObjectNotification(ctx, client_id, object_id,
+                                               existing_data_size, key);
       if (!success) {
         /* The publish failed somehow. */
         RedisModule_CloseKey(key);