1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
|
/*
* Copyright (c) 2020, Michael Grunder <michael dot grunder at gmail dot com>
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Redis nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <hiredis.h>
#define KEY_COUNT 5
#define panicAbort(fmt, ...) \
do { \
fprintf(stderr, "%s:%d:%s(): " fmt, __FILE__, __LINE__, __func__, __VA_ARGS__); \
exit(-1); \
} while (0)
static void assertReplyAndFree(redisContext *context, redisReply *reply, int type) {
if (reply == NULL)
panicAbort("NULL reply from server (error: %s)", context->errstr);
if (reply->type != type) {
if (reply->type == REDIS_REPLY_ERROR)
fprintf(stderr, "Redis Error: %s\n", reply->str);
panicAbort("Expected reply type %d but got type %d", type, reply->type);
}
freeReplyObject(reply);
}
/* Switch to the RESP3 protocol and enable client tracking */
static void enableClientTracking(redisContext *c) {
redisReply *reply = redisCommand(c, "HELLO 3");
if (reply == NULL || c->err) {
panicAbort("NULL reply or server error (error: %s)", c->errstr);
}
if (reply->type != REDIS_REPLY_MAP) {
fprintf(stderr, "Error: Can't send HELLO 3 command. Are you sure you're ");
fprintf(stderr, "connected to redis-server >= 6.0.0?\nRedis error: %s\n",
reply->type == REDIS_REPLY_ERROR ? reply->str : "(unknown)");
exit(-1);
}
freeReplyObject(reply);
/* Enable client tracking */
reply = redisCommand(c, "CLIENT TRACKING ON");
assertReplyAndFree(c, reply, REDIS_REPLY_STATUS);
}
void pushReplyHandler(void *privdata, void *r) {
redisReply *reply = r;
int *invalidations = privdata;
/* Sanity check on the invalidation reply */
if (reply->type != REDIS_REPLY_PUSH || reply->elements != 2 ||
reply->element[1]->type != REDIS_REPLY_ARRAY ||
reply->element[1]->element[0]->type != REDIS_REPLY_STRING)
{
panicAbort("%s", "Can't parse PUSH message!");
}
/* Increment our invalidation count */
*invalidations += 1;
printf("pushReplyHandler(): INVALIDATE '%s' (invalidation count: %d)\n",
reply->element[1]->element[0]->str, *invalidations);
freeReplyObject(reply);
}
/* We aren't actually freeing anything here, but it is included to show that we can
* have hiredis call our data destructor when freeing the context */
void privdata_dtor(void *privdata) {
unsigned int *icount = privdata;
printf("privdata_dtor(): In context privdata dtor (invalidations: %u)\n", *icount);
}
int main(int argc, char **argv) {
unsigned int j, invalidations = 0;
redisContext *c;
redisReply *reply;
const char *hostname = (argc > 1) ? argv[1] : "127.0.0.1";
int port = (argc > 2) ? atoi(argv[2]) : 6379;
redisOptions o = {0};
REDIS_OPTIONS_SET_TCP(&o, hostname, port);
/* Set our context privdata to the address of our invalidation counter. Each
* time our PUSH handler is called, hiredis will pass the privdata for context.
*
* This could also be done after we create the context like so:
*
* c->privdata = &invalidations;
* c->free_privdata = privdata_dtor;
*/
REDIS_OPTIONS_SET_PRIVDATA(&o, &invalidations, privdata_dtor);
/* Set our custom PUSH message handler */
o.push_cb = pushReplyHandler;
c = redisConnectWithOptions(&o);
if (c == NULL || c->err)
panicAbort("Connection error: %s", c ? c->errstr : "OOM");
/* Enable RESP3 and turn on client tracking */
enableClientTracking(c);
/* Set some keys and then read them back. Once we do that, Redis will deliver
* invalidation push messages whenever the key is modified */
for (j = 0; j < KEY_COUNT; j++) {
reply = redisCommand(c, "SET key:%d initial:%d", j, j);
assertReplyAndFree(c, reply, REDIS_REPLY_STATUS);
reply = redisCommand(c, "GET key:%d", j);
assertReplyAndFree(c, reply, REDIS_REPLY_STRING);
}
/* Trigger invalidation messages by updating keys we just read */
for (j = 0; j < KEY_COUNT; j++) {
printf(" main(): SET key:%d update:%d\n", j, j);
reply = redisCommand(c, "SET key:%d update:%d", j, j);
assertReplyAndFree(c, reply, REDIS_REPLY_STATUS);
printf(" main(): SET REPLY OK\n");
}
printf("\nTotal detected invalidations: %d, expected: %d\n", invalidations, KEY_COUNT);
/* PING server */
redisFree(c);
}
|
