Keyspace events notification API.

redis.conf

@@ -464,6 +464,23 @@ slowlog-log-slower-than 10000
 # You can reclaim memory used by the slow log with SLOWLOG RESET.
 slowlog-max-len 128
 
+############################# Event notification ##############################
+
+# Redis can notify Pub/Sub clients about events happening in the key space.
+# This feature is documented at http://redis.io/topics/keyspace-events
+# 
+# For instance if keyspace events notification is enabled, and a client
+# performs a DEL operation on key "foo" stored in the Database 0, two
+# messages will be published via Pub/Sub:
+#
+# PUBLISH __keyspace@0__:foo del
+# PUBLISH __keyevent@0__:del foo
+#
+# While the overhead of this feature is relatively small most users don't
+# need it so it is disabled by default. You can enable it setting the
+# following configuration option to yes.
+notify-keyspace-events no
+
 ############################### ADVANCED CONFIG ###############################
 
 # Hashes are encoded using a memory efficient data structure when they have a

src/Makefile

@@ -99,7 +99,7 @@ endif
 
 REDIS_SERVER_NAME= redis-server
 REDIS_SENTINEL_NAME= redis-sentinel
-REDIS_SERVER_OBJ= adlist.o ae.o anet.o dict.o redis.o sds.o zmalloc.o lzf_c.o lzf_d.o pqsort.o zipmap.o sha1.o ziplist.o release.o networking.o util.o object.o db.o replication.o rdb.o t_string.o t_list.o t_set.o t_zset.o t_hash.o config.o aof.o pubsub.o multi.o debug.o sort.o intset.o syncio.o cluster.o crc16.o endianconv.o slowlog.o scripting.o bio.o rio.o rand.o memtest.o crc64.o bitops.o sentinel.o
+REDIS_SERVER_OBJ= adlist.o ae.o anet.o dict.o redis.o sds.o zmalloc.o lzf_c.o lzf_d.o pqsort.o zipmap.o sha1.o ziplist.o release.o networking.o util.o object.o db.o replication.o rdb.o t_string.o t_list.o t_set.o t_zset.o t_hash.o config.o aof.o pubsub.o multi.o debug.o sort.o intset.o syncio.o cluster.o crc16.o endianconv.o slowlog.o scripting.o bio.o rio.o rand.o memtest.o crc64.o bitops.o sentinel.o notify.o
 REDIS_CLI_NAME= redis-cli
 REDIS_CLI_OBJ= anet.o sds.o adlist.o redis-cli.o zmalloc.o release.o anet.o ae.o crc64.o
 REDIS_BENCHMARK_NAME= redis-benchmark

src/Makefile.dep

@@ -43,6 +43,9 @@ networking.o: networking.c redis.h fmacros.h config.h \
   ../deps/lua/src/lua.h ../deps/lua/src/luaconf.h ae.h sds.h dict.h \
   adlist.h zmalloc.h anet.h ziplist.h intset.h version.h util.h rdb.h \
   rio.h
+notify.o: notify.c redis.h fmacros.h config.h ../deps/lua/src/lua.h \
+  ../deps/lua/src/luaconf.h ae.h sds.h dict.h adlist.h zmalloc.h anet.h \
+  ziplist.h intset.h version.h util.h rdb.h rio.h
 object.o: object.c redis.h fmacros.h config.h ../deps/lua/src/lua.h \
   ../deps/lua/src/luaconf.h ae.h sds.h dict.h adlist.h zmalloc.h anet.h \
   ziplist.h intset.h version.h util.h rdb.h rio.h

src/config.c

@@ -391,6 +391,10 @@ void loadServerConfigFromString(char *config) {
             }
         } else if (!strcasecmp(argv[0],"slave-priority") && argc == 2) {
             server.slave_priority = atoi(argv[1]);
+        } else if (!strcasecmp(argv[0],"notify-keyspace-events") && argc == 2) {
+            if ((server.notify_keyspace_events = yesnotoi(argv[1])) == -1) {
+                err = "argument must be 'yes' or 'no'"; goto loaderr;
+            }
         } else if (!strcasecmp(argv[0],"sentinel")) {
             /* argc == 1 is handled by main() as we need to enter the sentinel
              * mode ASAP. */
@@ -709,11 +713,11 @@ void configSetCommand(redisClient *c) {
 
         if (yn == -1) goto badfmt;
         server.rdb_compression = yn;
-    } else if (!strcasecmp(c->argv[2]->ptr,"rdbchecksum")) {
+    } else if (!strcasecmp(c->argv[2]->ptr,"notify-keyspace-events")) {
         int yn = yesnotoi(o->ptr);
 
         if (yn == -1) goto badfmt;
-        server.rdb_checksum = yn;
+        server.notify_keyspace_events = yn;
     } else if (!strcasecmp(c->argv[2]->ptr,"slave-priority")) {
         if (getLongLongFromObject(o,&ll) == REDIS_ERR ||
             ll <= 0) goto badfmt;
@@ -823,6 +827,7 @@ void configGetCommand(redisClient *c) {
     config_get_bool_field("rdbcompression", server.rdb_compression);
     config_get_bool_field("rdbchecksum", server.rdb_checksum);
     config_get_bool_field("activerehashing", server.activerehashing);
+    config_get_bool_field("notify-keyspace-events", server.notify_keyspace_events);
 
     /* Everything we can't handle with macros follows. */
 

src/notify.c

@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2013, 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 "redis.h"
+
+/* This file implements keyspace events notification via Pub/Sub ad
+ * described at http://redis.io/topics/keyspace-events.
+ *
+ * The API provided to the rest of the Redis core is a simple function:
+ *
+ * notifyKeyspaceEvent(char *event, robj *key, int dbid);
+ *
+ * 'event' is a C string representing the event name.
+ * 'key' is a Redis object representing the key name.
+ * 'dbid' is the database ID where the key lives.
+ */
+
+void notifyKeyspaceEvent(char *event, robj *key, int dbid) {
+    sds keyspace_chan, keyevent_chan;
+    int len;
+    char buf[24];
+    robj *chan1, *chan2, *eventobj;
+
+    /* The prefix of the two channels is identical if not for
+     * 'keyspace' that is 'keyevent' in the event channel name, so
+     * we build a single prefix and overwrite 'event' with 'space'. */
+    keyspace_chan = sdsnewlen("__keyspace@",11);
+    len = ll2string(buf,sizeof(buf),dbid);
+    keyspace_chan = sdscatlen(keyspace_chan, buf, len);
+    keyspace_chan = sdscatlen(keyspace_chan, "__:", 3);
+    keyevent_chan = sdsdup(keyspace_chan); /* Dup the prefix. */
+    memcpy(keyevent_chan+5,"event",5); /* Fix it. */
+
+    eventobj = createStringObject(event,strlen(event));
+
+    /* The keyspace channel name has a trailing key name, while
+     * the keyevent channel name has a trailing event name. */
+    keyspace_chan = sdscatsds(keyspace_chan, key->ptr);
+    keyevent_chan = sdscatsds(keyspace_chan, eventobj->ptr);
+    chan1 = createObject(REDIS_STRING, keyspace_chan);
+    chan2 = createObject(REDIS_STRING, keyevent_chan);
+
+    /* Finally publish the two notifications. */
+    pubsubPublishMessage(chan1, eventobj);
+    pubsubPublishMessage(chan2, key);
+
+    /* Release objects. */
+    decrRefCount(eventobj);
+    decrRefCount(keyspace_chan);
+    decrRefCount(keyevent_chan);
+}

src/redis.c

@@ -1158,6 +1158,7 @@ void initServerConfig() {
     server.rdb_compression = 1;
     server.rdb_checksum = 1;
     server.activerehashing = 1;
+    server.notify_keyspace_events = 0;
     server.maxclients = REDIS_MAX_CLIENTS;
     server.bpop_blocked_clients = 0;
     server.maxmemory = 0;

src/redis.h

@@ -776,6 +776,7 @@ struct redisServer {
     /* Pubsub */
     dict *pubsub_channels;  /* Map channels to list of subscribed clients */
     list *pubsub_patterns;  /* A list of pubsub_patterns */
+    int notify_keyspace_events; /* Propagate keyspace events via Pub/Sub. */
     /* Cluster */
     int cluster_enabled;    /* Is cluster enabled? */
     clusterState cluster;   /* State of the cluster */
@@ -1134,6 +1135,7 @@ int pubsubUnsubscribeAllPatterns(redisClient *c, int notify);
 void freePubsubPattern(void *p);
 int listMatchPubsubPattern(void *a, void *b);
 int pubsubPublishMessage(robj *channel, robj *message);
+void notifyKeyspaceEvent(char *event, robj *key, int dbid);
 
 /* Configuration */
 void loadServerConfig(char *filename, char *options);