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Modules: block on keys: fix bugs in processing order.

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antirez 2019-10-31 12:23:55 +01:00
parent 629081f839
commit 66f55bc5c1
2 changed files with 23 additions and 0 deletions
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16
src/blocked.c
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@ -450,6 +450,22 @@ void serveClientsBlockedOnKeyByModule(readyList *rl) {
listNode *clientnode = listFirst(clients);
client *receiver = clientnode->value;
/* Put at the tail, so that at the next call
* we'll not run into it again: clients here may not be
* ready to be served, so they'll remain in the list
* sometimes. We want also be able to skip clients that are
* not blocked for the MODULE type safely. */
listDelNode(clients,clientnode);
listAddNodeTail(clients,receiver);
if (receiver->btype != BLOCKED_MODULE) continue;
/* Note that if *this* client cannot be served by this key,
* it does not mean that another client that is next into the
* list cannot be served as well: they may be blocked by
* different modules with different triggers to consider if a key
* is ready or not. This means we can't exit the loop but need
* to continue after the first failure. */
if (!moduleTryServeClientBlockedOnKey(receiver, rl->key)) continue;
moduleUnblockClient(receiver);

7
src/module.c
View File

@ -249,6 +249,7 @@ typedef struct RedisModuleBlockedClient {
in thread safe contexts. */
int dbid; /* Database number selected by the original client. */
int blocked_on_keys; /* If blocked via RM_BlockClientOnKeys(). */
int unblocked; /* Already on the moduleUnblocked list. */
} RedisModuleBlockedClient;
static pthread_mutex_t moduleUnblockedClientsMutex = PTHREAD_MUTEX_INITIALIZER;
@ -4037,6 +4038,7 @@ RedisModuleBlockedClient *moduleBlockClient(RedisModuleCtx *ctx, RedisModuleCmdF
bc->reply_client->flags |= CLIENT_MODULE;
bc->dbid = c->db->id;
bc->blocked_on_keys = keys != NULL;
bc->unblocked = 0;
c->bpop.timeout = timeout;
if (islua || ismulti) {
@ -4063,6 +4065,10 @@ RedisModuleBlockedClient *moduleBlockClient(RedisModuleCtx *ctx, RedisModuleCmdF
int moduleTryServeClientBlockedOnKey(client *c, robj *key) {
int served = 0;
RedisModuleBlockedClient *bc = c->bpop.module_blocked_handle;
/* Protect against re-processing: don't serve clients that are already
* in the unblocking list for any reason (including RM_UnblockClient()
* explicit call). */
if (bc->unblocked) return REDISMODULE_ERR;
RedisModuleCtx ctx = REDISMODULE_CTX_INIT;
ctx.flags |= REDISMODULE_CTX_BLOCKED_REPLY;
ctx.blocked_ready_key = key;
@ -4162,6 +4168,7 @@ void RM_SignalKeyAsReady(RedisModuleCtx *ctx, RedisModuleString *key) {
int moduleUnblockClientByHandle(RedisModuleBlockedClient *bc, void *privdata) {
pthread_mutex_lock(&moduleUnblockedClientsMutex);
if (!bc->blocked_on_keys) bc->privdata = privdata;
bc->unblocked = 1;
listAddNodeTail(moduleUnblockedClients,bc);
if (write(server.module_blocked_pipe[1],"A",1) != 1) {
/* Ignore the error, this is best-effort. */