valkey/tests/modules/blockedclient.c
Meir Shpilraien (Spielrein) adc3183cd2
Add Module API for version and compatibility checks (#7865)
* Introduce a new API's: RM_GetContextFlagsAll, and
RM_GetKeyspaceNotificationFlagsAll that will return the
full flags mask of each feature. The module writer can
check base on this value if the Flags he needs are
supported or not.

* For each flag, introduce a new value on redismodule.h,
this value represents the LAST value and should be there
as a reminder to update it when a new value is added,
also it will be used in the code to calculate the full
flags mask (assuming flags are incrementally increasing).
In addition, stated that the module writer should not use
the LAST flag directly and he should use the GetFlagAll API's.

* Introduce a new API: RM_IsSubEventSupported, that returns for a given
event and subevent, whether or not the subevent supported.

* Introduce a new macro RMAPI_FUNC_SUPPORTED(func) that returns whether
or not a function API is supported by comparing it to NULL.

* Introduce a new API: int RM_GetServerVersion();, that will return the
current Redis version in the format 0x00MMmmpp; e.g. 0x00060008;

* Changed unstable version from 999.999.999 to 255.255.255

Co-authored-by: Oran Agra <oran@redislabs.com>
Co-authored-by: Yossi Gottlieb <yossigo@gmail.com>
2020-10-11 17:21:58 +03:00

94 lines
2.6 KiB
C

#define REDISMODULE_EXPERIMENTAL_API
#include "redismodule.h"
#include <assert.h>
#include <stdio.h>
#include <pthread.h>
#define UNUSED(V) ((void) V)
void *sub_worker(void *arg) {
// Get Redis module context
RedisModuleCtx *ctx = (RedisModuleCtx *)arg;
// Try acquiring GIL
int res = RedisModule_ThreadSafeContextTryLock(ctx);
// GIL is already taken by the calling thread expecting to fail.
assert(res != REDISMODULE_OK);
return NULL;
}
void *worker(void *arg) {
// Retrieve blocked client
RedisModuleBlockedClient *bc = (RedisModuleBlockedClient *)arg;
// Get Redis module context
RedisModuleCtx *ctx = RedisModule_GetThreadSafeContext(bc);
// Acquire GIL
RedisModule_ThreadSafeContextLock(ctx);
// Create another thread which will try to acquire the GIL
pthread_t tid;
int res = pthread_create(&tid, NULL, sub_worker, ctx);
assert(res == 0);
// Wait for thread
pthread_join(tid, NULL);
// Release GIL
RedisModule_ThreadSafeContextUnlock(ctx);
// Reply to client
RedisModule_ReplyWithSimpleString(ctx, "OK");
// Unblock client
RedisModule_UnblockClient(bc, NULL);
// Free the Redis module context
RedisModule_FreeThreadSafeContext(ctx);
return NULL;
}
int acquire_gil(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
{
UNUSED(argv);
UNUSED(argc);
int flags = RedisModule_GetContextFlags(ctx);
int allFlags = RedisModule_GetContextFlagsAll();
if ((allFlags & REDISMODULE_CTX_FLAGS_MULTI) &&
(flags & REDISMODULE_CTX_FLAGS_MULTI)) {
RedisModule_ReplyWithSimpleString(ctx, "Blocked client is not supported inside multi");
return REDISMODULE_OK;
}
/* This command handler tries to acquire the GIL twice
* once in the worker thread using "RedisModule_ThreadSafeContextLock"
* second in the sub-worker thread
* using "RedisModule_ThreadSafeContextTryLock"
* as the GIL is already locked. */
RedisModuleBlockedClient *bc = RedisModule_BlockClient(ctx, NULL, NULL, NULL, 0);
pthread_t tid;
int res = pthread_create(&tid, NULL, worker, bc);
assert(res == 0);
return REDISMODULE_OK;
}
int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
REDISMODULE_NOT_USED(argv);
REDISMODULE_NOT_USED(argc);
if (RedisModule_Init(ctx, "blockedclient", 1, REDISMODULE_APIVER_1)== REDISMODULE_ERR)
return REDISMODULE_ERR;
if (RedisModule_CreateCommand(ctx, "acquire_gil", acquire_gil, "", 0, 0, 0) == REDISMODULE_ERR)
return REDISMODULE_ERR;
return REDISMODULE_OK;
}