Cluster: collect more specific bus messages stats.

First step in order to change Cluster in order to use less messages.
Related to issue #3929.

src/cluster.c

@@ -423,8 +423,10 @@ void clusterInit(void) {
     server.cluster->failover_auth_epoch = 0;
     server.cluster->cant_failover_reason = CLUSTER_CANT_FAILOVER_NONE;
     server.cluster->lastVoteEpoch = 0;
-    server.cluster->stats_bus_messages_sent = 0;
+    for (int i = 0; i < CLUSTERMSG_TYPE_COUNT; i++) {
-    server.cluster->stats_bus_messages_received = 0;
+        server.cluster->stats_bus_messages_sent[i] = 0;
+        server.cluster->stats_bus_messages_received[i] = 0;
+    }
     memset(server.cluster->slots,0, sizeof(server.cluster->slots));
     clusterCloseAllSlots();
 
@@ -1583,7 +1585,8 @@ int clusterProcessPacket(clusterLink *link) {
     uint32_t totlen = ntohl(hdr->totlen);
     uint16_t type = ntohs(hdr->type);
 
-    server.cluster->stats_bus_messages_received++;
+    if (type < CLUSTERMSG_TYPE_COUNT)
+        server.cluster->stats_bus_messages_received[type]++;
     serverLog(LL_DEBUG,"--- Processing packet of type %d, %lu bytes",
         type, (unsigned long) totlen);
 
@@ -2130,7 +2133,12 @@ void clusterSendMessage(clusterLink *link, unsigned char *msg, size_t msglen) {
                     clusterWriteHandler,link);
 
     link->sndbuf = sdscatlen(link->sndbuf, msg, msglen);
-    server.cluster->stats_bus_messages_sent++;
+
+    /* Populate sent messages stats. */
+    clusterMsg *hdr = (clusterMsg*) msg;
+    uint16_t type = ntohs(hdr->type);
+    if (type < CLUSTERMSG_TYPE_COUNT)
+        server.cluster->stats_bus_messages_sent[type]++;
 }
 
 /* Send a message to all the nodes that are part of the cluster having
@@ -3877,6 +3885,21 @@ sds clusterGenNodesDescription(int filter) {
  * CLUSTER command
  * -------------------------------------------------------------------------- */
 
+const char *clusterGetMessageTypeString(int type) {
+    switch(type) {
+    case CLUSTERMSG_TYPE_PING: return "ping";
+    case CLUSTERMSG_TYPE_PONG: return "pong";
+    case CLUSTERMSG_TYPE_MEET: return "meet";
+    case CLUSTERMSG_TYPE_FAIL: return "fail";
+    case CLUSTERMSG_TYPE_PUBLISH: return "publish";
+    case CLUSTERMSG_TYPE_FAILOVER_AUTH_REQUEST: return "auth-req";
+    case CLUSTERMSG_TYPE_FAILOVER_AUTH_ACK: return "auth-ack";
+    case CLUSTERMSG_TYPE_UPDATE: return "update";
+    case CLUSTERMSG_TYPE_MFSTART: return "mfstart";
+    }
+    return "unknown";
+}
+
 int getSlotOrReply(client *c, robj *o) {
     long long slot;
 
@@ -4208,8 +4231,6 @@ void clusterCommand(client *c) {
             "cluster_size:%d\r\n"
             "cluster_current_epoch:%llu\r\n"
             "cluster_my_epoch:%llu\r\n"
-            "cluster_stats_messages_sent:%lld\r\n"
-            "cluster_stats_messages_received:%lld\r\n"
             , statestr[server.cluster->state],
             slots_assigned,
             slots_ok,
@@ -4218,10 +4239,36 @@ void clusterCommand(client *c) {
             dictSize(server.cluster->nodes),
             server.cluster->size,
             (unsigned long long) server.cluster->currentEpoch,
-            (unsigned long long) myepoch,
+            (unsigned long long) myepoch
-            server.cluster->stats_bus_messages_sent,
-            server.cluster->stats_bus_messages_received
         );
+
+        /* Show stats about messages sent and received. */
+        long long tot_msg_sent = 0;
+        long long tot_msg_received = 0;
+
+        for (int i = 0; i < CLUSTERMSG_TYPE_COUNT; i++) {
+            if (server.cluster->stats_bus_messages_sent[i] == 0) continue;
+            tot_msg_sent += server.cluster->stats_bus_messages_sent[i];
+            info = sdscatprintf(info,
+                "cluster_stats_messages_%s_sent:%lld\r\n",
+                clusterGetMessageTypeString(i),
+                server.cluster->stats_bus_messages_sent[i]);
+        }
+        info = sdscatprintf(info,
+            "cluster_stats_messages_sent:%lld\r\n", tot_msg_sent);
+
+        for (int i = 0; i < CLUSTERMSG_TYPE_COUNT; i++) {
+            if (server.cluster->stats_bus_messages_received[i] == 0) continue;
+            tot_msg_received += server.cluster->stats_bus_messages_received[i];
+            info = sdscatprintf(info,
+                "cluster_stats_messages_%s_received:%lld\r\n",
+                clusterGetMessageTypeString(i),
+                server.cluster->stats_bus_messages_received[i]);
+        }
+        info = sdscatprintf(info,
+            "cluster_stats_messages_received:%lld\r\n", tot_msg_received);
+
+        /* Produce the reply protocol. */
         addReplySds(c,sdscatprintf(sdsempty(),"$%lu\r\n",
             (unsigned long)sdslen(info)));
         addReplySds(c,info);

src/cluster.h

@@ -73,6 +73,29 @@ typedef struct clusterLink {
 #define CLUSTER_CANT_FAILOVER_WAITING_VOTES 4
 #define CLUSTER_CANT_FAILOVER_RELOG_PERIOD (60*5) /* seconds. */
 
+/* clusterState todo_before_sleep flags. */
+#define CLUSTER_TODO_HANDLE_FAILOVER (1<<0)
+#define CLUSTER_TODO_UPDATE_STATE (1<<1)
+#define CLUSTER_TODO_SAVE_CONFIG (1<<2)
+#define CLUSTER_TODO_FSYNC_CONFIG (1<<3)
+
+/* Message types.
+ *
+ * Note that the PING, PONG and MEET messages are actually the same exact
+ * kind of packet. PONG is the reply to ping, in the exact format as a PING,
+ * while MEET is a special PING that forces the receiver to add the sender
+ * as a node (if it is not already in the list). */
+#define CLUSTERMSG_TYPE_PING 0          /* Ping */
+#define CLUSTERMSG_TYPE_PONG 1          /* Pong (reply to Ping) */
+#define CLUSTERMSG_TYPE_MEET 2          /* Meet "let's join" message */
+#define CLUSTERMSG_TYPE_FAIL 3          /* Mark node xxx as failing */
+#define CLUSTERMSG_TYPE_PUBLISH 4       /* Pub/Sub Publish propagation */
+#define CLUSTERMSG_TYPE_FAILOVER_AUTH_REQUEST 5 /* May I failover? */
+#define CLUSTERMSG_TYPE_FAILOVER_AUTH_ACK 6     /* Yes, you have my vote */
+#define CLUSTERMSG_TYPE_UPDATE 7        /* Another node slots configuration */
+#define CLUSTERMSG_TYPE_MFSTART 8       /* Pause clients for manual failover */
+#define CLUSTERMSG_TYPE_COUNT 9         /* Total number of message types. */
+
 /* This structure represent elements of node->fail_reports. */
 typedef struct clusterNodeFailReport {
     struct clusterNode *node;  /* Node reporting the failure condition. */
@@ -139,32 +162,13 @@ typedef struct clusterState {
     /* The followign fields are used by masters to take state on elections. */
     uint64_t lastVoteEpoch;     /* Epoch of the last vote granted. */
     int todo_before_sleep; /* Things to do in clusterBeforeSleep(). */
-    long long stats_bus_messages_sent;  /* Num of msg sent via cluster bus. */
+    /* Messages received and sent by type. */
-    long long stats_bus_messages_received; /* Num of msg rcvd via cluster bus.*/
+    long long stats_bus_messages_sent[CLUSTERMSG_TYPE_COUNT];
+    long long stats_bus_messages_received[CLUSTERMSG_TYPE_COUNT];
 } clusterState;
 
-/* clusterState todo_before_sleep flags. */
-#define CLUSTER_TODO_HANDLE_FAILOVER (1<<0)
-#define CLUSTER_TODO_UPDATE_STATE (1<<1)
-#define CLUSTER_TODO_SAVE_CONFIG (1<<2)
-#define CLUSTER_TODO_FSYNC_CONFIG (1<<3)
-
 /* Redis cluster messages header */
 
-/* Note that the PING, PONG and MEET messages are actually the same exact
- * kind of packet. PONG is the reply to ping, in the exact format as a PING,
- * while MEET is a special PING that forces the receiver to add the sender
- * as a node (if it is not already in the list). */
-#define CLUSTERMSG_TYPE_PING 0          /* Ping */
-#define CLUSTERMSG_TYPE_PONG 1          /* Pong (reply to Ping) */
-#define CLUSTERMSG_TYPE_MEET 2          /* Meet "let's join" message */
-#define CLUSTERMSG_TYPE_FAIL 3          /* Mark node xxx as failing */
-#define CLUSTERMSG_TYPE_PUBLISH 4       /* Pub/Sub Publish propagation */
-#define CLUSTERMSG_TYPE_FAILOVER_AUTH_REQUEST 5 /* May I failover? */
-#define CLUSTERMSG_TYPE_FAILOVER_AUTH_ACK 6     /* Yes, you have my vote */
-#define CLUSTERMSG_TYPE_UPDATE 7        /* Another node slots configuration */
-#define CLUSTERMSG_TYPE_MFSTART 8       /* Pause clients for manual failover */
-
 /* Initially we don't know our "name", but we'll find it once we connect
  * to the first node, using the getsockname() function. Then we'll use this
  * address for all the next messages. */