- Fix #850: [FR] Ability to use specific database in Redis, with new

redis-logical-db configuration option.

cachedb/redis.c

@@ -59,11 +59,28 @@ struct redis_moddata {
 	const char* server_path; /* server's unix path, or "", NULL if unused */
 	const char* server_password; /* server's AUTH password, or "", NULL if unused */
 	struct timeval timeout;	 /* timeout for connection setup and commands */
+	int logical_db;		/* the redis logical database to use */
 };
 
 static redisReply* redis_command(struct module_env*, struct cachedb_env*,
 	const char*, const uint8_t*, size_t);
 
+static void
+moddata_clean(struct redis_moddata** moddata) {
+	if(!moddata || !*moddata)
+		return;
+	if((*moddata)->ctxs) {
+		int i;
+		for(i = 0; i < (*moddata)->numctxs; i++) {
+			if((*moddata)->ctxs[i])
+				redisFree((*moddata)->ctxs[i]);
+		}
+		free((*moddata)->ctxs);
+	}
+	free(*moddata);
+	*moddata = NULL;
+}
+
 static redisContext*
 redis_connect(const struct redis_moddata* moddata)
 {
@@ -97,10 +114,21 @@ redis_connect(const struct redis_moddata* moddata)
 		}
 		freeReplyObject(rep);
 	}
+	if(moddata->logical_db > 0) {
+		redisReply* rep;
+		rep = redisCommand(ctx, "SELECT %d", moddata->logical_db);
+		if(!rep || rep->type == REDIS_REPLY_ERROR) {
+			log_err("failed to set logical database (%d)",
+				moddata->logical_db);
+			freeReplyObject(rep);
+			goto fail;
+		}
+		freeReplyObject(rep);
+	}
 	verbose(VERB_OPS, "Connection to Redis established");
 	return ctx;
 
-  fail:
+fail:
 	if(ctx)
 		redisFree(ctx);
 	return NULL;
@@ -117,14 +145,13 @@ redis_init(struct module_env* env, struct cachedb_env* cachedb_env)
 	moddata = calloc(1, sizeof(struct redis_moddata));
 	if(!moddata) {
 		log_err("out of memory");
-		return 0;
+		goto fail;
 	}
 	moddata->numctxs = env->cfg->num_threads;
 	moddata->ctxs = calloc(env->cfg->num_threads, sizeof(redisContext*));
 	if(!moddata->ctxs) {
 		log_err("out of memory");
-		free(moddata);
-		return 0;
+		goto fail;
 	}
 	/* note: server_host is a shallow reference to configured string.
 	 * we don't have to free it in this module. */
@@ -134,8 +161,15 @@ redis_init(struct module_env* env, struct cachedb_env* cachedb_env)
 	moddata->server_password = env->cfg->redis_server_password;
 	moddata->timeout.tv_sec = env->cfg->redis_timeout / 1000;
 	moddata->timeout.tv_usec = (env->cfg->redis_timeout % 1000) * 1000;
-	for(i = 0; i < moddata->numctxs; i++)
-		moddata->ctxs[i] = redis_connect(moddata);
+	moddata->logical_db = env->cfg->redis_logical_db;
+	for(i = 0; i < moddata->numctxs; i++) {
+		redisContext* ctx = redis_connect(moddata);
+		if(!ctx) {
+			log_err("redis_init: failed to init redis");
+			goto fail;
+		}
+		moddata->ctxs[i] = ctx;
+	}
 	cachedb_env->backend_data = moddata;
 	if(env->cfg->redis_expire_records) {
 		redisReply* rep = NULL;
@@ -148,7 +182,7 @@ redis_init(struct module_env* env, struct cachedb_env* cachedb_env)
 			log_err("redis_init: failed to init redis, the "
 				"redis-expire-records option requires the SETEX command "
 				"(redis >= 2.0.0)");
-			return 0;
+			goto fail;
 		}
 		redis_reply_type = rep->type;
 		freeReplyObject(rep);
@@ -160,11 +194,14 @@ redis_init(struct module_env* env, struct cachedb_env* cachedb_env)
 			log_err("redis_init: failed to init redis, the "
 				"redis-expire-records option requires the SETEX command "
 				"(redis >= 2.0.0)");
-			return 0;
+			goto fail;
 		}
 	}
-
 	return 1;
+
+fail:
+	moddata_clean(&moddata);
+	return 0;
 }
 
 static void
@@ -175,18 +212,7 @@ redis_deinit(struct module_env* env, struct cachedb_env* cachedb_env)
 	(void)env;
 
 	verbose(VERB_OPS, "Redis deinitialization");
-
-	if(!moddata)
-		return;
-	if(moddata->ctxs) {
-		int i;
-		for(i = 0; i < moddata->numctxs; i++) {
-			if(moddata->ctxs[i])
-				redisFree(moddata->ctxs[i]);
-		}
-		free(moddata->ctxs);
-	}
-	free(moddata);
+	moddata_clean(&moddata);
 }
 
 /*

doc/Changelog

@@ -1,3 +1,7 @@
+11 October 2023: George
+	- Fix #850: [FR] Ability to use specific database in Redis, with new
+	  redis-logical-db configuration option.
+
 10 October 2023: George
 	- Fix infinite loop when reading multiple lines of input on a broken
 	  remote control socket. Addesses #947 and #948.

doc/example.conf.in

@@ -1236,6 +1236,8 @@ remote-control:
 #     redis-timeout: 100
 #     # set timeout on redis records based on DNS response TTL
 #     redis-expire-records: no
+#     # redis logical database to use, 0 is the default database.
+#     redis-logical-db: 0
 
 # IPSet
 # Add specify domain into set via ipset.

doc/unbound.conf.5.in

@@ -2707,6 +2707,17 @@ Unbound is configured with \fBserve-expired\fR and \fBserve-expired-ttl\fR is 0,
 this option is internally reverted to "no".  Redis SETEX support is required
 for this option (Redis >= 2.0.0).
 This option defaults to no.
+.TP
+.B redis-logical-db: \fI<logical database index>
+The logical database in Redis to use.
+These are databases in the same Redis instance sharing the same configuration
+and persisted in the same RDB/AOF file.
+If unsure about using this option, Redis documentation
+(https://redis.io/commands/select/) suggests not to use a single Redis instance
+for multiple unrelated applications.
+The default database in Redis is 0 while other logical databases need to be
+explicitly SELECT'ed upon connecting.
+This option defaults to 0.
 .SS DNSTAP Logging Options
 DNSTAP support, when compiled in by using \fB\-\-enable\-dnstap\fR, is enabled
 in the \fBdnstap:\fR section.

util/config_file.c

@@ -388,6 +388,7 @@ config_create(void)
 	cfg->redis_timeout = 100;
 	cfg->redis_server_port = 6379;
 	cfg->redis_expire_records = 0;
+	cfg->redis_logical_db = 0;
 #endif  /* USE_REDIS */
 #endif  /* USE_CACHEDB */
 #ifdef USE_IPSET
@@ -1313,6 +1314,7 @@ config_get_option(struct config_file* cfg, const char* opt,
 	else O_STR(opt, "redis-server-password", redis_server_password)
 	else O_DEC(opt, "redis-timeout", redis_timeout)
 	else O_YNO(opt, "redis-expire-records", redis_expire_records)
+	else O_DEC(opt, "redis-logical-db", redis_logical_db)
 #endif  /* USE_REDIS */
 #endif  /* USE_CACHEDB */
 #ifdef USE_IPSET

util/config_file.h

@@ -712,6 +712,8 @@ struct config_file {
 	int redis_timeout;
 	/** set timeout on redis records based on DNS response ttl */
 	int redis_expire_records;
+	/** set the redis logical database upon connection */
+	int redis_logical_db;
 #endif
 #endif
 	/** Downstream DNS Cookies */

util/configlexer.lex

@@ -563,6 +563,7 @@ redis-server-path{COLON}	{ YDVAR(1, VAR_CACHEDB_REDISPATH) }
 redis-server-password{COLON}	{ YDVAR(1, VAR_CACHEDB_REDISPASSWORD) }
 redis-timeout{COLON}		{ YDVAR(1, VAR_CACHEDB_REDISTIMEOUT) }
 redis-expire-records{COLON}	{ YDVAR(1, VAR_CACHEDB_REDISEXPIRERECORDS) }
+redis-logical-db{COLON}		{ YDVAR(1, VAR_CACHEDB_REDISLOGICALDB) }
 ipset{COLON}			{ YDVAR(0, VAR_IPSET) }
 name-v4{COLON}			{ YDVAR(1, VAR_IPSET_NAME_V4) }
 name-v6{COLON}			{ YDVAR(1, VAR_IPSET_NAME_V6) }

util/configparser.y

@@ -179,6 +179,7 @@ extern struct config_parser_state* cfg_parser;
 %token VAR_CACHEDB VAR_CACHEDB_BACKEND VAR_CACHEDB_SECRETSEED
 %token VAR_CACHEDB_REDISHOST VAR_CACHEDB_REDISPORT VAR_CACHEDB_REDISTIMEOUT
 %token VAR_CACHEDB_REDISEXPIRERECORDS VAR_CACHEDB_REDISPATH VAR_CACHEDB_REDISPASSWORD
+%token VAR_CACHEDB_REDISLOGICALDB
 %token VAR_UDP_UPSTREAM_WITHOUT_DOWNSTREAM VAR_FOR_UPSTREAM
 %token VAR_AUTH_ZONE VAR_ZONEFILE VAR_MASTER VAR_URL VAR_FOR_DOWNSTREAM
 %token VAR_FALLBACK_ENABLED VAR_TLS_ADDITIONAL_PORT VAR_LOW_RTT VAR_LOW_RTT_PERMIL
@@ -3701,7 +3702,8 @@ contents_cachedb: contents_cachedb content_cachedb
 	| ;
 content_cachedb: cachedb_backend_name | cachedb_secret_seed |
 	redis_server_host | redis_server_port | redis_timeout |
-	redis_expire_records | redis_server_path | redis_server_password
+	redis_expire_records | redis_server_path | redis_server_password |
+	redis_logical_db
 	;
 cachedb_backend_name: VAR_CACHEDB_BACKEND STRING_ARG
 	{
@@ -3804,6 +3806,21 @@ redis_expire_records: VAR_CACHEDB_REDISEXPIRERECORDS STRING_ARG
 		free($2);
 	}
 	;
+redis_logical_db: VAR_CACHEDB_REDISLOGICALDB STRING_ARG
+	{
+	#if defined(USE_CACHEDB) && defined(USE_REDIS)
+		int db;
+		OUTYY(("P(redis_logical_db:%s)\n", $2));
+		db = atoi($2);
+		if((db == 0 && strcmp($2, "0") != 0) || db < 0)
+			yyerror("valid redis logical database index expected");
+		else cfg_parser->cfg->redis_logical_db = db;
+	#else
+		OUTYY(("P(Compiled without cachedb or redis, ignoring)\n"));
+	#endif
+		free($2);
+	}
+	;
 server_tcp_connection_limit: VAR_TCP_CONNECTION_LIMIT STRING_ARG STRING_ARG
 	{
 		OUTYY(("P(server_tcp_connection_limit:%s %s)\n", $2, $3));