New script timeout semantics and SCRIPT KILL implemented. SHUTDOWN NOSAVE and...

New script timeout semantics and SCRIPT KILL implemented. SHUTDOWN NOSAVE and SHUTDOWN SAVE implemented.

src/db.c

@@ -328,8 +328,22 @@ void typeCommand(redisClient *c) {
 }
 
 void shutdownCommand(redisClient *c) {
-    if (prepareForShutdown() == REDIS_OK)
-        exit(0);
+    int flags = 0;
+
+    if (c->argc > 2) {
+        addReply(c,shared.syntaxerr);
+        return;
+    } else if (c->argc == 2) {
+        if (!strcasecmp(c->argv[1]->ptr,"nosave")) {
+            flags |= REDIS_SHUTDOWN_NOSAVE;
+        } else if (!strcasecmp(c->argv[1]->ptr,"save")) {
+            flags |= REDIS_SHUTDOWN_SAVE;
+        } else {
+            addReply(c,shared.syntaxerr);
+            return;
+        }
+    }
+    if (prepareForShutdown(flags) == REDIS_OK) exit(0);
     addReplyError(c,"Errors trying to SHUTDOWN. Check logs.");
 }
 

src/redis.c

@@ -187,7 +187,7 @@ struct redisCommand redisCommandTable[] = {
     {"save",saveCommand,1,"ar",0,NULL,0,0,0,0,0},
     {"bgsave",bgsaveCommand,1,"ar",0,NULL,0,0,0,0,0},
     {"bgrewriteaof",bgrewriteaofCommand,1,"ar",0,NULL,0,0,0,0,0},
-    {"shutdown",shutdownCommand,1,"ar",0,NULL,0,0,0,0,0},
+    {"shutdown",shutdownCommand,-1,"ar",0,NULL,0,0,0,0,0},
     {"lastsave",lastsaveCommand,1,"r",0,NULL,0,0,0,0,0},
     {"type",typeCommand,2,"r",0,NULL,1,1,1,0,0},
     {"multi",multiCommand,1,"rs",0,NULL,0,0,0,0,0},
@@ -628,7 +628,7 @@ int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
     /* We received a SIGTERM, shutting down here in a safe way, as it is
      * not ok doing so inside the signal handler. */
     if (server.shutdown_asap) {
-        if (prepareForShutdown() == REDIS_OK) exit(0);
+        if (prepareForShutdown(0) == REDIS_OK) exit(0);
         redisLog(REDIS_WARNING,"SIGTERM received but errors trying to shut down the server, check the logs for more information");
     }
 
@@ -805,7 +805,7 @@ void createSharedObjects(void) {
     shared.loadingerr = createObject(REDIS_STRING,sdsnew(
         "-LOADING Redis is loading the dataset in memory\r\n"));
     shared.slowscripterr = createObject(REDIS_STRING,sdsnew(
-        "-BUSY Redis is busy running a script. Please wait or stop the server with SHUTDOWN.\r\n"));
+        "-BUSY Redis is busy running a script. You can only call SCRIPT KILL or SHUTDOWN NOSAVE.\r\n"));
     shared.space = createObject(REDIS_STRING,sdsnew(" "));
     shared.colon = createObject(REDIS_STRING,sdsnew(":"));
     shared.plus = createObject(REDIS_STRING,sdsnew("+"));
@@ -884,6 +884,7 @@ void initServerConfig() {
     server.repl_timeout = REDIS_REPL_TIMEOUT;
     server.cluster_enabled = 0;
     server.cluster.configfile = zstrdup("nodes.conf");
+    server.lua_caller = NULL;
     server.lua_time_limit = REDIS_LUA_TIME_LIMIT;
     server.lua_client = NULL;
     server.lua_timedout = 0;
@@ -1232,8 +1233,15 @@ int processCommand(redisClient *c) {
         return REDIS_OK;
     }
 
-    /* Lua script too slow? */
-    if (server.lua_timedout && c->cmd->proc != shutdownCommand) {
+    /* Lua script too slow? Only allow SHUTDOWN NOSAVE and SCRIPT KILL. */
+    if (server.lua_timedout &&
+        !(c->cmd->proc != shutdownCommand &&
+          c->argc == 2 &&
+          tolower(((char*)c->argv[1]->ptr)[0]) == 'n') &&
+        !(c->cmd->proc == scriptCommand &&
+          c->argc == 2 &&
+          tolower(((char*)c->argv[1]->ptr)[0]) == 'k'))
+    {
         addReply(c, shared.slowscripterr);
         return REDIS_OK;
     }
@@ -1253,7 +1261,10 @@ int processCommand(redisClient *c) {
 
 /*================================== Shutdown =============================== */
 
-int prepareForShutdown() {
+int prepareForShutdown(int flags) {
+    int save = flags & REDIS_SHUTDOWN_SAVE;
+    int nosave = flags & REDIS_SHUTDOWN_NOSAVE;
+
     redisLog(REDIS_WARNING,"User requested shutdown...");
     /* Kill the saving child if there is a background saving in progress.
        We want to avoid race conditions, for instance our saving child may
@@ -1275,7 +1286,7 @@ int prepareForShutdown() {
         redisLog(REDIS_NOTICE,"Calling fsync() on the AOF file.");
         aof_fsync(server.appendfd);
     }
-    if (server.saveparamslen > 0) {
+    if ((server.saveparamslen > 0 && !nosave) || save) {
         redisLog(REDIS_NOTICE,"Saving the final RDB snapshot before exiting.");
         /* Snapshotting. Perform a SYNC SAVE and exit */
         if (rdbSave(server.dbfilename) != REDIS_OK) {

src/redis.h

@@ -215,6 +215,11 @@
 #define UNIT_SECONDS 0
 #define UNIT_MILLISECONDS 1
 
+/* SHUTDOWN flags */
+#define REDIS_SHUTDOWN_SAVE 1       /* Force SAVE on SHUTDOWN even if no save
+                                       points are configured. */
+#define REDIS_SHUTDOWN_NOSAVE 2     /* Don't SAVE on SHUTDOWN. */
+
 /* We can print the stacktrace, so our assert is defined this way: */
 #define redisAssertWithInfo(_c,_o,_e) ((_e)?(void)0 : (_redisAssertWithInfo(_c,_o,#_e,__FILE__,__LINE__),_exit(1)))
 #define redisAssert(_e) ((_e)?(void)0 : (_redisAssert(#_e,__FILE__,__LINE__),_exit(1)))
@@ -538,7 +543,7 @@ struct redisServer {
     off_t auto_aofrewrite_base_size;/* AOF size on latest startup or rewrite. */
     off_t appendonly_current_size;  /* AOF current size. */
     int aofrewrite_scheduled;       /* Rewrite once BGSAVE terminates. */
-    int shutdown_asap;
+    int shutdown_asap;              /* SHUTDOWN needed */
     int activerehashing;
     char *requirepass;
     /* Persistence */
@@ -615,13 +620,17 @@ struct redisServer {
     /* Scripting */
     lua_State *lua; /* The Lua interpreter. We use just one for all clients */
     redisClient *lua_client; /* The "fake client" to query Redis from Lua */
+    redisClient *lua_caller; /* The client running EVAL right now, or NULL */
     dict *lua_scripts; /* A dictionary of SHA1 -> Lua scripts */
     long long lua_time_limit;
     long long lua_time_start;
+    int lua_write_dirty;  /* True if a write command was called during the
+                             execution of the current script. */
     int lua_random_dirty; /* True if a random command was called during the
-                             exection of the current script. */
+                             execution of the current script. */
     int lua_timedout;     /* True if we reached the time limit for script
                              execution. */
+    int lua_kill;         /* Kill the script if true. */
 };
 
 typedef struct pubsubPattern {

src/scripting.c

@@ -187,6 +187,7 @@ int luaRedisGenericCommand(lua_State *lua, int raise_error) {
     }
 
     if (cmd->flags & REDIS_CMD_RANDOM) server.lua_random_dirty = 1;
+    if (cmd->flags & REDIS_CMD_WRITE) server.lua_write_dirty = 1;
 
     /* Run the command */
     cmd->proc(c);
@@ -277,11 +278,22 @@ void luaMaskCountHook(lua_State *lua, lua_Debug *ar) {
 
     elapsed = (ustime()/1000) - server.lua_time_start;
     if (elapsed >= server.lua_time_limit && server.lua_timedout == 0) {
-        redisLog(REDIS_WARNING,"Lua slow script detected: still in execution after %lld milliseconds. You can shut down the server using the SHUTDOWN command.",elapsed);
+        redisLog(REDIS_WARNING,"Lua slow script detected: still in execution after %lld milliseconds. You can try killing the script using the SCRIPT KILL command.",elapsed);
         server.lua_timedout = 1;
+        /* Once the script timeouts we reenter the event loop to permit others
+         * to call SCRIPT KILL or SHUTDOWN NOSAVE if needed. For this reason
+         * we need to mask the client executing the script from the event loop.
+         * If we don't do that the client may disconnect and could no longer be
+         * here when the EVAL command will return. */
+         aeDeleteFileEvent(server.el, server.lua_caller->fd, AE_READABLE);
     }
     if (server.lua_timedout)
         aeProcessEvents(server.el, AE_FILE_EVENTS|AE_DONT_WAIT);
+    if (server.lua_kill) {
+        redisLog(REDIS_WARNING,"Lua script killed by user with SCRIPT KILL.");
+        lua_pushstring(lua,"Script killed by user with SCRIPT KILL...");
+        lua_error(lua);
+    }
 }
 
 void luaLoadLib(lua_State *lua, const char *libname, lua_CFunction luafunc) {
@@ -553,6 +565,7 @@ void evalGenericCommand(redisClient *c, int evalsha) {
      * Thanks to this flag we'll raise an error every time a write command
      * is called after a random command was used. */
     server.lua_random_dirty = 0;
+    server.lua_write_dirty = 0;
 
     /* Get the number of arguments that are keys */
     if (getLongLongFromObjectOrReply(c,c->argv[2],&numkeys,NULL) != REDIS_OK)
@@ -610,7 +623,6 @@ void evalGenericCommand(redisClient *c, int evalsha) {
      * make the Lua script execution slower. */
     if (server.lua_time_limit > 0 && server.masterhost == NULL) {
         lua_sethook(lua,luaMaskCountHook,LUA_MASKCOUNT,100000);
-        server.lua_time_start = ustime()/1000;
     } else {
         lua_sethook(lua,luaMaskCountHook,0,0);
     }
@@ -618,8 +630,18 @@ void evalGenericCommand(redisClient *c, int evalsha) {
     /* At this point whatever this script was never seen before or if it was
      * already defined, we can call it. We have zero arguments and expect
      * a single return value. */
+    server.lua_caller = c;
+    server.lua_time_start = ustime()/1000;
+    server.lua_kill = 0;
     if (lua_pcall(lua,0,1,0)) {
-        server.lua_timedout = 0;
+        if (server.lua_timedout) {
+            server.lua_timedout = 0;
+            /* Restore the readable handler that was unregistered when the
+             * script timeout was detected. */
+            aeCreateFileEvent(server.el,c->fd,AE_READABLE,
+                              readQueryFromClient,c);
+        }
+        server.lua_caller = NULL;
         selectDb(c,server.lua_client->db->id); /* set DB ID from Lua client */
         addReplyErrorFormat(c,"Error running script (call to %s): %s\n",
             funcname, lua_tostring(lua,-1));
@@ -628,6 +650,7 @@ void evalGenericCommand(redisClient *c, int evalsha) {
         return;
     }
     server.lua_timedout = 0;
+    server.lua_caller = NULL;
     selectDb(c,server.lua_client->db->id); /* set DB ID from Lua client */
     luaReplyToRedisReply(c,lua);
     lua_gc(lua,LUA_GCSTEP,1);
@@ -743,6 +766,15 @@ void scriptCommand(redisClient *c) {
         }
         addReplyBulkCBuffer(c,funcname+2,40);
         sdsfree(sha);
+    } else if (c->argc == 2 && !strcasecmp(c->argv[1]->ptr,"kill")) {
+        if (server.lua_caller == NULL) {
+            addReplyError(c,"No scripts in execution right now.");
+        } else if (server.lua_write_dirty) {
+            addReplyError(c, "Sorry the script already executed write commands against the dataset. You can either wait the script termination or kill the server in an hard way using the SHUTDOWN NOSAVE command.");
+        } else {
+            server.lua_kill = 1;
+            addReply(c,shared.ok);
+        }
     } else {
         addReplyError(c, "Unknown SCRIPT subcommand or wrong # of args.");
     }