From c75582889a49ed15524a05f855d2a6327451c8c6 Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Sun, 1 Apr 2018 16:36:32 +0200
Subject: [PATCH] Modules Cluster API: GetClusterSize() added.

---
 src/module.c      | 10 ++++++++++
 src/redismodule.h |  4 +++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/module.c b/src/module.c
index 78e6aea4..1aa39884 100644
--- a/src/module.c
+++ b/src/module.c
@@ -3968,6 +3968,15 @@ const char *RM_GetMyClusterID(void) {
     return server.cluster->myself->name;
 }
 
+/* Return the number of nodes in the cluster, regardless of their state
+ * (handshake, noaddress, ...) so that the number of active nodes may actually
+ * be smaller, but not greater than this number. If the instance is not in
+ * cluster mode, zero is returned. */
+size_t RM_GetClusterSize(void) {
+    if (!server.cluster_enabled) return 0;
+    return dictSize(server.cluster->nodes);
+}
+
 /* Populate the specified info for the node having as ID the specified 'id',
  * then returns REDISMODULE_OK. Otherwise if the node ID does not exist from
  * the POV of this local node, REDISMODULE_ERR is returned.
@@ -4565,4 +4574,5 @@ void moduleRegisterCoreAPI(void) {
     REGISTER_API(StopTimer);
     REGISTER_API(GetTimerInfo);
     REGISTER_API(GetMyClusterID);
+    REGISTER_API(GetClusterSize);
 }
diff --git a/src/redismodule.h b/src/redismodule.h
index e16031a4..d232c0fa 100644
--- a/src/redismodule.h
+++ b/src/redismodule.h
@@ -276,7 +276,8 @@ void REDISMODULE_API_FUNC(RedisModule_FreeClusterNodesList)(char **ids);
 RedisModuleTimerID REDISMODULE_API_FUNC(RedisModule_CreateTimer)(RedisModuleCtx *ctx, mstime_t period, RedisModuleTimerProc callback, void *data);
 int REDISMODULE_API_FUNC(RedisModule_StopTimer)(RedisModuleCtx *ctx, RedisModuleTimerID id, void **data);
 int REDISMODULE_API_FUNC(RedisModule_GetTimerInfo)(RedisModuleCtx *ctx, RedisModuleTimerID id, uint64_t *remaining, void **data);
-const char *REDISMODULE_API_FUNC(RM_GetMyClusterID)(void);
+const char *REDISMODULE_API_FUNC(RedisModule_GetMyClusterID)(void);
+size_t REDISMODULE_API_FUNC(RedisModule_GetClusterSize)(void);
 
 /* Experimental APIs */
 #ifdef REDISMODULE_EXPERIMENTAL_API
@@ -409,6 +410,7 @@ static int RedisModule_Init(RedisModuleCtx *ctx, const char *name, int ver, int
     REDISMODULE_GET_API(StopTimer);
     REDISMODULE_GET_API(GetTimerInfo);
     REDISMODULE_GET_API(GetMyClusterID);
+    REDISMODULE_GET_API(GetClusterSize);
 
 #ifdef REDISMODULE_EXPERIMENTAL_API
     REDISMODULE_GET_API(GetThreadSafeContext);