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fixup: order of callbacks
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@bjosv
bjosv committed Mar 18, 2024
1 parent a5a7573 commit a651ab7
Showing 1 changed file with 66 additions and 48 deletions.
114 changes: 66 additions & 48 deletions examples/src/clientside_caching_async.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@
* Simple example how to enable client tracking to implement client side caching.
* Tracking can be enabled via a registered connect callback and invalidation
* messages are received via the registered push callback.
* The disconnect callback should also be used as an indication of invalidation.
*/
#include <hiredis_cluster/adapters/libevent.h>
#include <hiredis_cluster/hircluster.h>
Expand All @@ -14,54 +15,69 @@
#define CLUSTER_NODE "127.0.0.1:7000"
#define KEY "key:1"

/* Helper to modify keys using a separate client. */
void modifyKey(const char *key, const char *value) {
printf("Modify key: '%s'\n", key);
redisClusterContext *cc = redisClusterContextInit();
int status = redisClusterSetOptionAddNodes(cc, CLUSTER_NODE);
assert(status == REDIS_OK);
status = redisClusterConnect2(cc);
void pushCallback(redisAsyncContext *ac, void *r);
void setCallback(redisClusterAsyncContext *acc, void *r, void *privdata);
void getCallback1(redisClusterAsyncContext *acc, void *r, void *privdata);
void getCallback2(redisClusterAsyncContext *acc, void *r, void *privdata);
void modifyKey(const char *key, const char *value);

/* The connect callback enables RESP3 and client tracking.
The non-const connect callback is used since we want to
set the push callback in the hiredis context. */
void connectCallbackNC(redisAsyncContext *ac, int status) {
assert(status == REDIS_OK);
redisAsyncSetPushCallback(ac, pushCallback);
redisAsyncCommand(ac, NULL, NULL, "HELLO 3");
redisAsyncCommand(ac, NULL, NULL, "CLIENT TRACKING ON");
printf("Connected to %s:%d\n", ac->c.tcp.host, ac->c.tcp.port);
}

redisReply *reply = redisClusterCommand(cc, "SET %s %s", key, value);
assert(reply != NULL);
freeReplyObject(reply);
/* The event callback issues a 'SET' command when the client is ready to accept
commands. A reply is expected via a call to 'setCallback()' */
void eventCallback(const redisClusterContext *cc, int event, void *privdata) {
(void)cc;
redisClusterAsyncContext *acc = (redisClusterAsyncContext *)privdata;

redisClusterFree(cc);
/* We send our commands when the client is ready to accept commands. */
if (event == HIRCLUSTER_EVENT_READY) {
printf("Client is ready to accept commands\n");

int status =
redisClusterAsyncCommand(acc, setCallback, NULL, "SET %s 1", KEY);
assert(status == REDIS_OK);
}
}

/* Message callback for 'set' commands. */
/* Message callback for 'SET' commands. Issues a 'GET' command and a reply is
expected as a call to 'getCallback()' */
void setCallback(redisClusterAsyncContext *acc, void *r, void *privdata) {
(void)privdata;
redisReply *reply = (redisReply *)r;
assert(reply != NULL);
printf("Callback for 'SET', reply: %s\n", reply->str);

printf("Callback for 'set', reply: %s\n", reply->str);
int status =
redisClusterAsyncCommand(acc, getCallback1, NULL, "GET %s", KEY);
assert(status == REDIS_OK);
}

/* Message callback for 'get' commands. */
void getCallback(redisClusterAsyncContext *acc, void *r, void *privdata) {
/* Message callback for the first 'GET' command. Modifies the key to
trigger Redis to send a key invalidation message and then sends another
'GET' command. */
void getCallback1(redisClusterAsyncContext *acc, void *r, void *privdata) {
(void)privdata;
redisReply *reply = (redisReply *)r;
assert(reply != NULL);

printf("Callback for 'get', reply: %s\n", reply->str);

/* Exit the eventloop after a couple of sent commands. */
static int cmdsSent = 0;
if (cmdsSent > 4) {
redisClusterAsyncDisconnect(acc);
return;
}
printf("Callback for first 'GET', reply: %s\n", reply->str);

/* Modify the key from another client which will invalidate a cached value.
Redis will send an invalidation message via a push message. */
modifyKey(KEY, "99");

int status =
redisClusterAsyncCommand(acc, getCallback, NULL, "GET %s", KEY);
redisClusterAsyncCommand(acc, getCallback2, NULL, "GET %s", KEY);
assert(status == REDIS_OK);
cmdsSent++;
}

/* Push message callback handling invalidation messages. */
Expand All @@ -85,38 +101,40 @@ void pushCallback(redisAsyncContext *ac, void *r) {
}
}

/* Connect callback that enables RESP3 and client tracking.
The non-const connect callback is used since we want to
set the push callback in the hiredis context. */
void connectCallbackNC(redisAsyncContext *ac, int status) {
assert(status == REDIS_OK);
redisAsyncSetPushCallback(ac, pushCallback);
redisAsyncCommand(ac, NULL, NULL, "HELLO 3");
redisAsyncCommand(ac, NULL, NULL, "CLIENT TRACKING ON");
printf("Connected to %s:%d\n", ac->c.tcp.host, ac->c.tcp.port);
/* Message callback for 'GET' commands. Exits program. */
void getCallback2(redisClusterAsyncContext *acc, void *r, void *privdata) {
(void)privdata;
redisReply *reply = (redisReply *)r;
assert(reply != NULL);

printf("Callback for second 'GET', reply: %s\n", reply->str);

/* Exit the eventloop after a couple of sent commands. */
redisClusterAsyncDisconnect(acc);
}

/* A disconnect callback should invalidate all cached keys. */
void disconnectCallback(const redisAsyncContext *ac, int status) {
assert(status == REDIS_OK);
printf("Disconnected from %s:%d\n", ac->c.tcp.host, ac->c.tcp.port);

printf("Invalidate all\n");
}

void eventCallback(const redisClusterContext *cc, int event, void *privdata) {
(void)cc;
redisClusterAsyncContext *acc = (redisClusterAsyncContext *)privdata;
/* Helper to modify keys using a separate client. */
void modifyKey(const char *key, const char *value) {
printf("Modify key: '%s'\n", key);
redisClusterContext *cc = redisClusterContextInit();
int status = redisClusterSetOptionAddNodes(cc, CLUSTER_NODE);
assert(status == REDIS_OK);
status = redisClusterConnect2(cc);
assert(status == REDIS_OK);

/* We send our commands when the client is ready to accept commands. */
if (event == HIRCLUSTER_EVENT_READY) {
printf("Client is ready to accept commands\n");
int status;
redisReply *reply = redisClusterCommand(cc, "SET %s %s", key, value);
assert(reply != NULL);
freeReplyObject(reply);

status =
redisClusterAsyncCommand(acc, setCallback, NULL, "SET %s 1", KEY);
assert(status == REDIS_OK);
status =
redisClusterAsyncCommand(acc, getCallback, NULL, "GET %s", KEY);
assert(status == REDIS_OK);
}
redisClusterFree(cc);
}

int main(int argc, char **argv) {
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