Merge pull request #5945 from dvirsky/miss_notification

Added keyspace miss notifications support

src/db.c

@@ -83,6 +83,7 @@ robj *lookupKey(redisDb *db, robj *key, int flags) {
  * 1. A key gets expired if it reached it's TTL.
  * 2. The key last access time is updated.
  * 3. The global keys hits/misses stats are updated (reported in INFO).
+ * 4. If keyspace notifications are enabled, a "keymiss" notification is fired.
  *
  * This API should not be used when we write to the key after obtaining
  * the object linked to the key, but only for read only operations.
@@ -106,6 +107,7 @@ robj *lookupKeyReadWithFlags(redisDb *db, robj *key, int flags) {
          * to return NULL ASAP. */
         if (server.masterhost == NULL) {
             server.stat_keyspace_misses++;
+            notifyKeyspaceEvent(NOTIFY_KEY_MISS, "keymiss", key, db->id);
             return NULL;
         }
 
@@ -127,12 +129,15 @@ robj *lookupKeyReadWithFlags(redisDb *db, robj *key, int flags) {
             server.current_client->cmd->flags & CMD_READONLY)
         {
             server.stat_keyspace_misses++;
+            notifyKeyspaceEvent(NOTIFY_KEY_MISS, "keymiss", key, db->id);
             return NULL;
         }
     }
     val = lookupKey(db,key,flags);
-    if (val == NULL)
+    if (val == NULL) {
         server.stat_keyspace_misses++;
+        notifyKeyspaceEvent(NOTIFY_KEY_MISS, "keymiss", key, db->id);
+    }
     else
         server.stat_keyspace_hits++;
     return val;

src/modules/testmodule.c

@@ -109,9 +109,9 @@ int TestStringPrintf(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
     if (argc < 3) {
         return RedisModule_WrongArity(ctx);
     }
-    RedisModuleString *s = RedisModule_CreateStringPrintf(ctx, 
+    RedisModuleString *s = RedisModule_CreateStringPrintf(ctx,
-        "Got %d args. argv[1]: %s, argv[2]: %s", 
+        "Got %d args. argv[1]: %s, argv[2]: %s",
-        argc, 
+        argc,
         RedisModule_StringPtrLen(argv[1], NULL),
         RedisModule_StringPtrLen(argv[2], NULL)
     );
@@ -133,7 +133,7 @@ int TestUnlink(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
 
     RedisModuleKey *k = RedisModule_OpenKey(ctx, RedisModule_CreateStringPrintf(ctx, "unlinked"), REDISMODULE_WRITE | REDISMODULE_READ);
     if (!k) return failTest(ctx, "Could not create key");
-    
+
     if (REDISMODULE_ERR == RedisModule_StringSet(k, RedisModule_CreateStringPrintf(ctx, "Foobar"))) {
         return failTest(ctx, "Could not set string value");
     }
@@ -152,7 +152,7 @@ int TestUnlink(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
         return failTest(ctx, "Could not verify key to be unlinked");
     }
     return RedisModule_ReplyWithSimpleString(ctx, "OK");
-    
+
 }
 
 int NotifyCallback(RedisModuleCtx *ctx, int type, const char *event,
@@ -188,6 +188,10 @@ int TestNotifications(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
     RedisModule_Call(ctx, "LPUSH", "cc", "l", "y");
     RedisModule_Call(ctx, "LPUSH", "cc", "l", "y");
 
+    /* Miss some keys intentionally so we will get a "keymiss" notification. */
+    RedisModule_Call(ctx, "GET", "c", "nosuchkey");
+    RedisModule_Call(ctx, "SMEMBERS", "c", "nosuchkey");
+
     size_t sz;
     const char *rep;
     RedisModuleCallReply *r = RedisModule_Call(ctx, "HGET", "cc", "notifications", "foo");
@@ -225,6 +229,16 @@ int TestNotifications(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
         FAIL("Wrong reply for l");
     }
 
+    r = RedisModule_Call(ctx, "HGET", "cc", "notifications", "nosuchkey");
+    if (r == NULL || RedisModule_CallReplyType(r) != REDISMODULE_REPLY_STRING) {
+        FAIL("Wrong or no reply for nosuchkey");
+    } else {
+        rep = RedisModule_CallReplyStringPtr(r, &sz);
+        if (sz != 1 || *rep != '2') {
+            FAIL("Got reply '%.*s'. expected '2'", sz, rep);
+        }
+    }
+
     RedisModule_Call(ctx, "FLUSHDB", "");
 
     return RedisModule_ReplyWithSimpleString(ctx, "OK");
@@ -423,7 +437,7 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
     if (RedisModule_CreateCommand(ctx,"test.ctxflags",
         TestCtxFlags,"readonly",1,1,1) == REDISMODULE_ERR)
         return REDISMODULE_ERR;
-    
+
     if (RedisModule_CreateCommand(ctx,"test.unlink",
         TestUnlink,"write deny-oom",1,1,1) == REDISMODULE_ERR)
         return REDISMODULE_ERR;
@@ -435,7 +449,8 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
     RedisModule_SubscribeToKeyspaceEvents(ctx,
                                             REDISMODULE_NOTIFY_HASH |
                                             REDISMODULE_NOTIFY_SET |
-                                            REDISMODULE_NOTIFY_STRING,
+                                            REDISMODULE_NOTIFY_STRING |
+                                            REDISMODULE_NOTIFY_KEY_MISS,
                                         NotifyCallback);
     if (RedisModule_CreateCommand(ctx,"test.notify",
         TestNotifications,"write deny-oom",1,1,1) == REDISMODULE_ERR)

src/notify.c

@@ -55,6 +55,7 @@ int keyspaceEventsStringToFlags(char *classes) {
         case 'K': flags |= NOTIFY_KEYSPACE; break;
         case 'E': flags |= NOTIFY_KEYEVENT; break;
         case 't': flags |= NOTIFY_STREAM; break;
+        case 'm': flags |= NOTIFY_KEY_MISS; break;
         default: return -1;
         }
     }
@@ -81,6 +82,7 @@ sds keyspaceEventsFlagsToString(int flags) {
         if (flags & NOTIFY_EXPIRED) res = sdscatlen(res,"x",1);
         if (flags & NOTIFY_EVICTED) res = sdscatlen(res,"e",1);
         if (flags & NOTIFY_STREAM) res = sdscatlen(res,"t",1);
+        if (flags & NOTIFY_KEY_MISS) res = sdscatlen(res,"m",1);
     }
     if (flags & NOTIFY_KEYSPACE) res = sdscatlen(res,"K",1);
     if (flags & NOTIFY_KEYEVENT) res = sdscatlen(res,"E",1);
@@ -100,12 +102,12 @@ void notifyKeyspaceEvent(int type, char *event, robj *key, int dbid) {
     int len = -1;
     char buf[24];
 
-    /* If any modules are interested in events, notify the module system now. 
+    /* If any modules are interested in events, notify the module system now.
      * This bypasses the notifications configuration, but the module engine
      * will only call event subscribers if the event type matches the types
      * they are interested in. */
      moduleNotifyKeyspaceEvent(type, event, key, dbid);
-    
+
     /* If notifications for this class of events are off, return ASAP. */
     if (!(server.notify_keyspace_events & type)) return;
 

src/redismodule.h

@@ -98,7 +98,8 @@
 #define REDISMODULE_NOTIFY_EXPIRED (1<<8)     /* x */
 #define REDISMODULE_NOTIFY_EVICTED (1<<9)     /* e */
 #define REDISMODULE_NOTIFY_STREAM (1<<10)     /* t */
-#define REDISMODULE_NOTIFY_ALL (REDISMODULE_NOTIFY_GENERIC | REDISMODULE_NOTIFY_STRING | REDISMODULE_NOTIFY_LIST | REDISMODULE_NOTIFY_SET | REDISMODULE_NOTIFY_HASH | REDISMODULE_NOTIFY_ZSET | REDISMODULE_NOTIFY_EXPIRED | REDISMODULE_NOTIFY_EVICTED | REDISMODULE_NOTIFY_STREAM)      /* A */
+#define REDISMODULE_NOTIFY_KEY_MISS (1<<11)   /* m */
+#define REDISMODULE_NOTIFY_ALL (REDISMODULE_NOTIFY_GENERIC | REDISMODULE_NOTIFY_STRING | REDISMODULE_NOTIFY_LIST | REDISMODULE_NOTIFY_SET | REDISMODULE_NOTIFY_HASH | REDISMODULE_NOTIFY_ZSET | REDISMODULE_NOTIFY_EXPIRED | REDISMODULE_NOTIFY_EVICTED | REDISMODULE_NOTIFY_STREAM | REDISMODULE_NOTIFY_KEY_MISS)      /* A */
 
 
 /* A special pointer that we can use between the core and the module to signal

src/server.h

@@ -468,7 +468,8 @@ typedef long long mstime_t; /* millisecond time type. */
 #define NOTIFY_EXPIRED (1<<8)     /* x */
 #define NOTIFY_EVICTED (1<<9)     /* e */
 #define NOTIFY_STREAM (1<<10)     /* t */
-#define NOTIFY_ALL (NOTIFY_GENERIC | NOTIFY_STRING | NOTIFY_LIST | NOTIFY_SET | NOTIFY_HASH | NOTIFY_ZSET | NOTIFY_EXPIRED | NOTIFY_EVICTED | NOTIFY_STREAM) /* A flag */
+#define NOTIFY_KEY_MISS (1<<11)   /* m */
+#define NOTIFY_ALL (NOTIFY_GENERIC | NOTIFY_STRING | NOTIFY_LIST | NOTIFY_SET | NOTIFY_HASH | NOTIFY_ZSET | NOTIFY_EXPIRED | NOTIFY_EVICTED | NOTIFY_STREAM | NOTIFY_KEY_MISS) /* A flag */
 
 /* Get the first bind addr or NULL */
 #define NET_FIRST_BIND_ADDR (server.bindaddr_count ? server.bindaddr[0] : NULL)