1 /* Helloworld cluster -- A ping/pong cluster API example.
2  *
3  * -----------------------------------------------------------------------------
4  *
5  * Copyright (c) 2018, Salvatore Sanfilippo <antirez at gmail dot com>
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions are met:
10  *
11  *   * Redistributions of source code must retain the above copyright notice,
12  *     this list of conditions and the following disclaimer.
13  *   * Redistributions in binary form must reproduce the above copyright
14  *     notice, this list of conditions and the following disclaimer in the
15  *     documentation and/or other materials provided with the distribution.
16  *   * Neither the name of Redis nor the names of its contributors may be used
17  *     to endorse or promote products derived from this software without
18  *     specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
21  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
24  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30  * POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 #define REDISMODULE_EXPERIMENTAL_API
34 #include "../redismodule.h"
35 #include <stdio.h>
36 #include <stdlib.h>
37 #include <ctype.h>
38 #include <string.h>
39 
40 #define MSGTYPE_PING 1
41 #define MSGTYPE_PONG 2
42 
43 /* HELLOCLUSTER.PINGALL */
44 int PingallCommand_RedisCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
45     REDISMODULE_NOT_USED(argv);
46     REDISMODULE_NOT_USED(argc);
47 
48     RedisModule_SendClusterMessage(ctx,NULL,MSGTYPE_PING,(unsigned char*)"Hey",3);
49     return RedisModule_ReplyWithSimpleString(ctx, "OK");
50 }
51 
52 /* HELLOCLUSTER.LIST */
53 int ListCommand_RedisCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
54     REDISMODULE_NOT_USED(argv);
55     REDISMODULE_NOT_USED(argc);
56 
57     size_t numnodes;
58     char **ids = RedisModule_GetClusterNodesList(ctx,&numnodes);
59     if (ids == NULL) {
60         return RedisModule_ReplyWithError(ctx,"Cluster not enabled");
61     }
62 
63     RedisModule_ReplyWithArray(ctx,numnodes);
64     for (size_t j = 0; j < numnodes; j++) {
65         int port;
66         RedisModule_GetClusterNodeInfo(ctx,ids[j],NULL,NULL,&port,NULL);
67         RedisModule_ReplyWithArray(ctx,2);
68         RedisModule_ReplyWithStringBuffer(ctx,ids[j],REDISMODULE_NODE_ID_LEN);
69         RedisModule_ReplyWithLongLong(ctx,port);
70     }
71     RedisModule_FreeClusterNodesList(ids);
72     return REDISMODULE_OK;
73 }
74 
75 /* Callback for message MSGTYPE_PING */
76 void PingReceiver(RedisModuleCtx *ctx, const char *sender_id, uint8_t type, const unsigned char *payload, uint32_t len) {
77     RedisModule_Log(ctx,"notice","PING (type %d) RECEIVED from %.*s: '%.*s'",
78         type,REDISMODULE_NODE_ID_LEN,sender_id,(int)len, payload);
79     RedisModule_SendClusterMessage(ctx,NULL,MSGTYPE_PONG,(unsigned char*)"Ohi!",4);
80     RedisModule_Call(ctx, "INCR", "c", "pings_received");
81 }
82 
83 /* Callback for message MSGTYPE_PONG. */
84 void PongReceiver(RedisModuleCtx *ctx, const char *sender_id, uint8_t type, const unsigned char *payload, uint32_t len) {
85     RedisModule_Log(ctx,"notice","PONG (type %d) RECEIVED from %.*s: '%.*s'",
86         type,REDISMODULE_NODE_ID_LEN,sender_id,(int)len, payload);
87 }
88 
89 /* This function must be present on each Redis module. It is used in order to
90  * register the commands into the Redis server. */
91 int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
92     REDISMODULE_NOT_USED(argv);
93     REDISMODULE_NOT_USED(argc);
94 
95     if (RedisModule_Init(ctx,"hellocluster",1,REDISMODULE_APIVER_1)
96         == REDISMODULE_ERR) return REDISMODULE_ERR;
97 
98     if (RedisModule_CreateCommand(ctx,"hellocluster.pingall",
99         PingallCommand_RedisCommand,"readonly",0,0,0) == REDISMODULE_ERR)
100         return REDISMODULE_ERR;
101 
102     if (RedisModule_CreateCommand(ctx,"hellocluster.list",
103         ListCommand_RedisCommand,"readonly",0,0,0) == REDISMODULE_ERR)
104         return REDISMODULE_ERR;
105 
106     /* Disable Redis Cluster sharding and redirections. This way every node
107      * will be able to access every possible key, regardless of the hash slot.
108      * This way the PING message handler will be able to increment a specific
109      * variable. Normally you do that in order for the distributed system
110      * you create as a module to have total freedom in the keyspace
111      * manipulation. */
112     RedisModule_SetClusterFlags(ctx,REDISMODULE_CLUSTER_FLAG_NO_REDIRECTION);
113 
114     /* Register our handlers for different message types. */
115     RedisModule_RegisterClusterMessageReceiver(ctx,MSGTYPE_PING,PingReceiver);
116     RedisModule_RegisterClusterMessageReceiver(ctx,MSGTYPE_PONG,PongReceiver);
117     return REDISMODULE_OK;
118 }
119