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authorantirez <antirez@gmail.com>2016-10-07 16:35:06 +0200
committerantirez <antirez@gmail.com>2016-10-07 16:35:06 +0200
commit7dde8bf3ab721b87f1e48b277dcdc39aab4c8b4c (patch)
treef65bd2a7337733bde6d6536d8ed76c029ee6f3c8
parent34599691b373151c77854b20b3c7a621077f6c64 (diff)
downloadredis-7dde8bf3ab721b87f1e48b277dcdc39aab4c8b4c.tar.gz
Modules: blocking command example added.module-blocking-commands
-rw-r--r--src/modules/helloblock.c115
1 files changed, 115 insertions, 0 deletions
diff --git a/src/modules/helloblock.c b/src/modules/helloblock.c
new file mode 100644
index 000000000..f3764be46
--- /dev/null
+++ b/src/modules/helloblock.c
@@ -0,0 +1,115 @@
+/* Helloblock module -- An example of blocking command implementation
+ * with threads.
+ *
+ * -----------------------------------------------------------------------------
+ *
+ * Copyright (c) 2016, Salvatore Sanfilippo <antirez 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 "../redismodule.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <unistd.h>
+
+/* Reply callback for blocking command HELLO.BLOCK */
+int HelloBlock_Reply(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+ int *myint = RedisModule_GetBlockedClientPrivateData(ctx);
+ return RedisModule_ReplyWithLongLong(ctx,*myint);
+}
+
+/* Timeout callback for blocking command HELLO.BLOCK */
+int HelloBlock_Timeout(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+ return RedisModule_ReplyWithSimpleString(ctx,"Request timedout");
+}
+
+/* Private data freeing callback for HELLO.BLOCK command. */
+void HelloBlock_FreeData(void *privdata) {
+ RedisModule_Free(privdata);
+}
+
+/* The thread entry point that actually executes the blocking part
+ * of the command HELLO.BLOCK. */
+void *HelloBlock_ThreadMain(void *arg) {
+ void **targ = arg;
+ RedisModuleBlockedClient *bc = targ[0];
+ long long delay = (unsigned long)targ[1];
+ RedisModule_Free(targ);
+
+ sleep(delay);
+ int *r = RedisModule_Alloc(sizeof(int));
+ *r = rand();
+ RedisModule_UnblockClient(bc,r);
+ return NULL;
+}
+
+/* HELLO.BLOCK <delay> <timeout> -- Block for <count> seconds, then reply with
+ * a random number. Timeout is the command timeout, so that you can test
+ * what happens when the delay is greater than the timeout. */
+int HelloBlock_RedisCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+ if (argc != 3) return RedisModule_WrongArity(ctx);
+ long long delay;
+ long long timeout;
+
+ if (RedisModule_StringToLongLong(argv[1],&delay) != REDISMODULE_OK) {
+ return RedisModule_ReplyWithError(ctx,"ERR invalid count");
+ }
+
+ if (RedisModule_StringToLongLong(argv[2],&timeout) != REDISMODULE_OK) {
+ return RedisModule_ReplyWithError(ctx,"ERR invalid count");
+ }
+
+ pthread_t tid;
+ RedisModuleBlockedClient *bc = RedisModule_BlockClient(ctx,HelloBlock_Reply,HelloBlock_Timeout,HelloBlock_FreeData,timeout);
+
+ /* Now that we setup a blocking client, we need to pass the control
+ * to the thread. However we need to pass arguments to the thread:
+ * the delay and a reference to the blocked client handle. */
+ void **targ = RedisModule_Alloc(sizeof(void*)*2);
+ targ[0] = bc;
+ targ[1] = (void*)(unsigned long) delay;
+
+ if (pthread_create(&tid,NULL,HelloBlock_ThreadMain,targ) != 0) {
+ /* RedisModule_BlockedClientAbort(bc); */
+ return RedisModule_ReplyWithError(ctx,"-ERR Can't start thread");
+ }
+ return REDISMODULE_OK;
+}
+
+/* This function must be present on each Redis module. It is used in order to
+ * register the commands into the Redis server. */
+int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+ if (RedisModule_Init(ctx,"helloblock",1,REDISMODULE_APIVER_1)
+ == REDISMODULE_ERR) return REDISMODULE_ERR;
+
+ if (RedisModule_CreateCommand(ctx,"hello.block",
+ HelloBlock_RedisCommand,"",0,0,0) == REDISMODULE_ERR)
+ return REDISMODULE_ERR;
+
+ return REDISMODULE_OK;
+}