MULTI/EXEC with async about hiredis-cluster HOT 2 CLOSED

When using the regular API hiredis-cluster attempts to figure out which cluster node to send the command to
and currently it can't do that for MULTI since the command itself does not contain a key.
This means that redisClusterCommand() would fail when sending MULTI.
But, there is an alternative API which can be used to handle this, see existing tests for an example:

For async connections the above limitations currently also exists, but sending commands to a specific code will work in this case. See this testcase as an example (from the async-transaction-test branch not delivered to master yet):

from hiredis-cluster.

When using the regular API hiredis-cluster attempts to figure out which cluster node to send the command to and currently it can't do that for MULTI since the command itself does not contain a key. This means that redisClusterCommand() would fail when sending MULTI. But, there is an alternative API which can be used to handle this, see existing tests for an example:

hiredis-cluster/tests/ct_specific_nodes.c

Lines 46 to 69 in 6c0aecf

	void test_transaction(redisClusterContext *cc) {
	cluster_node *node = redisClusterGetNodeByKey(cc, "foo");
	assert(node);
	redisReply *reply;
	reply = redisClusterCommandToNode(cc, node, "MULTI");
	CHECK_REPLY_OK(cc, reply);
	freeReplyObject(reply);
	reply = redisClusterCommandToNode(cc, node, "SET foo 99");
	CHECK_REPLY_QUEUED(cc, reply);
	freeReplyObject(reply);
	reply = redisClusterCommandToNode(cc, node, "INCR foo");
	CHECK_REPLY_QUEUED(cc, reply);
	freeReplyObject(reply);
	reply = redisClusterCommandToNode(cc, node, "EXEC");
	CHECK_REPLY_ARRAY(cc, reply, 2);
	CHECK_REPLY_OK(cc, reply->element[0]);
	CHECK_REPLY_INT(cc, reply->element[1], 100);
	freeReplyObject(reply);
	}

For async connections the above limitations currently also exists, but sending commands to a specific code will work in this case. See this testcase as an example (from the async-transaction-test branch not delivered to master yet):

hiredis-cluster/tests/ct_specific_nodes.c

Lines 432 to 478 in e8f0d9b

	void test_async_transaction() {
	int status;
	redisClusterAsyncContext *acc = redisClusterAsyncContextInit();
	assert(acc);
	redisClusterAsyncSetConnectCallback(acc, callbackExpectOk);
	redisClusterAsyncSetDisconnectCallback(acc, callbackExpectOk);
	redisClusterSetOptionAddNodes(acc->cc, CLUSTER_NODE);
	redisClusterSetOptionMaxRetry(acc->cc, 1);
	redisClusterSetOptionRouteUseSlots(acc->cc);
	status = redisClusterConnect2(acc->cc);
	ASSERT_MSG(status == REDIS_OK, acc->errstr);
	struct event_base *base = event_base_new();
	status = redisClusterLibeventAttach(acc, base);
	assert(status == REDIS_OK);
	cluster_node *node = redisClusterGetNodeByKey(acc->cc, "foo");
	assert(node);
	ExpectedResult r1 = {.type = REDIS_REPLY_STATUS, .str = "OK"};
	status = redisClusterAsyncCommandToNode(acc, node, commandCallback, &r1,
	"MULTI");
	ASSERT_MSG(status == REDIS_OK, acc->errstr);
	ExpectedResult r2 = {.type = REDIS_REPLY_STATUS, .str = "QUEUED"};
	status = redisClusterAsyncCommandToNode(acc, node, commandCallback, &r2,
	"SET foo 99");
	ASSERT_MSG(status == REDIS_OK, acc->errstr);
	ExpectedResult r3 = {.type = REDIS_REPLY_STATUS, .str = "QUEUED"};
	status = redisClusterAsyncCommandToNode(acc, node, commandCallback, &r3,
	"INCR foo");
	ASSERT_MSG(status == REDIS_OK, acc->errstr);
	/* The EXEC command will return an array with result from 2 queued commands. */
	ExpectedResult r4 = {
	.type = REDIS_REPLY_ARRAY, .elements = 2, .disconnect = true};
	status = redisClusterAsyncCommandToNode(acc, node, commandCallback, &r4,
	"EXEC ");
	ASSERT_MSG(status == REDIS_OK, acc->errstr);
	event_base_dispatch(base);
	redisClusterAsyncFree(acc);
	event_base_free(base);
	}

Understood. Thank you for the support.

from hiredis-cluster.