Introduce bgsave cancel

src/commands.def

@@ -6318,6 +6318,7 @@ struct COMMAND_STRUCT ACL_Subcommands[] = {
 /* BGSAVE history */
 commandHistory BGSAVE_History[] = {
 {"3.2.2","Added the `SCHEDULE` option."},
+{"8.0.0","Added the `CANCEL` option."},
 };
 #endif
 
@@ -6331,9 +6332,15 @@ commandHistory BGSAVE_History[] = {
 #define BGSAVE_Keyspecs NULL
 #endif
 
+/* BGSAVE operation argument table */
+struct COMMAND_ARG BGSAVE_operation_Subargs[] = {
+{MAKE_ARG("schedule",ARG_TYPE_PURE_TOKEN,-1,"SCHEDULE",NULL,"3.2.2",CMD_ARG_NONE,0,NULL)},
+{MAKE_ARG("cancel",ARG_TYPE_PURE_TOKEN,-1,"CANCEL",NULL,"8.0.0",CMD_ARG_NONE,0,NULL)},
+};
+
 /* BGSAVE argument table */
 struct COMMAND_ARG BGSAVE_Args[] = {
-{MAKE_ARG("schedule",ARG_TYPE_PURE_TOKEN,-1,"SCHEDULE",NULL,"3.2.2",CMD_ARG_OPTIONAL,0,NULL)},
+{MAKE_ARG("operation",ARG_TYPE_ONEOF,-1,NULL,NULL,NULL,CMD_ARG_OPTIONAL,2,NULL),.subargs=BGSAVE_operation_Subargs},
 };
 
 /********** COMMAND COUNT ********************/
@@ -10899,7 +10906,7 @@ struct COMMAND_STRUCT serverCommandTable[] = {
 /* server */
 {MAKE_CMD("acl","A container for Access List Control commands.","Depends on subcommand.","6.0.0",CMD_DOC_NONE,NULL,NULL,"server",COMMAND_GROUP_SERVER,ACL_History,0,ACL_Tips,0,NULL,-2,CMD_SENTINEL,0,ACL_Keyspecs,0,NULL,0),.subcommands=ACL_Subcommands},
 {MAKE_CMD("bgrewriteaof","Asynchronously rewrites the append-only file to disk.","O(1)","1.0.0",CMD_DOC_NONE,NULL,NULL,"server",COMMAND_GROUP_SERVER,BGREWRITEAOF_History,0,BGREWRITEAOF_Tips,0,bgrewriteaofCommand,1,CMD_NO_ASYNC_LOADING|CMD_ADMIN|CMD_NOSCRIPT,0,BGREWRITEAOF_Keyspecs,0,NULL,0)},
-{MAKE_CMD("bgsave","Asynchronously saves the database(s) to disk.","O(1)","1.0.0",CMD_DOC_NONE,NULL,NULL,"server",COMMAND_GROUP_SERVER,BGSAVE_History,1,BGSAVE_Tips,0,bgsaveCommand,-1,CMD_NO_ASYNC_LOADING|CMD_ADMIN|CMD_NOSCRIPT,0,BGSAVE_Keyspecs,0,NULL,1),.args=BGSAVE_Args},
+{MAKE_CMD("bgsave","Asynchronously saves the database(s) to disk.","O(1)","1.0.0",CMD_DOC_NONE,NULL,NULL,"server",COMMAND_GROUP_SERVER,BGSAVE_History,2,BGSAVE_Tips,0,bgsaveCommand,-1,CMD_NO_ASYNC_LOADING|CMD_ADMIN|CMD_NOSCRIPT,0,BGSAVE_Keyspecs,0,NULL,1),.args=BGSAVE_Args},
 {MAKE_CMD("command","Returns detailed information about all commands.","O(N) where N is the total number of commands","2.8.13",CMD_DOC_NONE,NULL,NULL,"server",COMMAND_GROUP_SERVER,COMMAND_History,0,COMMAND_Tips,1,commandCommand,-1,CMD_LOADING|CMD_STALE|CMD_SENTINEL,ACL_CATEGORY_CONNECTION,COMMAND_Keyspecs,0,NULL,0),.subcommands=COMMAND_Subcommands},
 {MAKE_CMD("config","A container for server configuration commands.","Depends on subcommand.","2.0.0",CMD_DOC_NONE,NULL,NULL,"server",COMMAND_GROUP_SERVER,CONFIG_History,0,CONFIG_Tips,0,NULL,-2,0,0,CONFIG_Keyspecs,0,NULL,0),.subcommands=CONFIG_Subcommands},
 {MAKE_CMD("dbsize","Returns the number of keys in the database.","O(1)","1.0.0",CMD_DOC_NONE,NULL,NULL,"server",COMMAND_GROUP_SERVER,DBSIZE_History,0,DBSIZE_Tips,2,dbsizeCommand,1,CMD_READONLY|CMD_FAST,ACL_CATEGORY_KEYSPACE,DBSIZE_Keyspecs,0,NULL,0)},

src/commands/bgsave.json

@@ -10,6 +10,10 @@
             [
                 "3.2.2",
                 "Added the `SCHEDULE` option."
+            ],
+            [
+                "8.0.0",
+                "Added the `CANCEL` option."
             ]
         ],
         "command_flags": [
@@ -19,11 +23,23 @@
         ],
         "arguments": [
             {
-                "name": "schedule",
-                "token": "SCHEDULE",
-                "type": "pure-token",
+                "name": "operation",
+                "type": "oneof",
                 "optional": true,
-                "since": "3.2.2"
+                "arguments": [
+                    {
+                        "name": "schedule",
+                        "token": "SCHEDULE",
+                        "type": "pure-token",
+                        "since": "3.2.2"
+                    },
+                    {
+                        "name": "cancel",
+                        "token": "CANCEL",
+                        "type": "pure-token",
+                        "since": "8.0.0"
+                    }
+                ]
             }
         ],
         "reply_schema": {
@@ -33,6 +49,12 @@
                 },
                 {
                     "const": "Background saving scheduled"
+                },
+                {
+                    "const": "Background saving cancelled"
+                },
+                {
+                    "const": "Scheduled background saving cancelled"
                 }
             ]
         }

src/rdb.c

@@ -3645,6 +3645,21 @@ void bgsaveCommand(client *c) {
     if (c->argc > 1) {
         if (c->argc == 2 && !strcasecmp(c->argv[1]->ptr, "schedule")) {
             schedule = 1;
+        } else if (c->argc == 2 && !strcasecmp(c->argv[1]->ptr, "cancel")) {
+            /* Terminates an in progress BGSAVE */
+            if (server.child_type == CHILD_TYPE_RDB) {
+                /* There is an ongoing bgsave */
+                serverLog(LL_NOTICE, "Background saving will be aborted due to user request");
+                killRDBChild();
+                addReplyStatus(c, "Background saving cancelled");
+            } else if (server.rdb_bgsave_scheduled == 1) {
+                serverLog(LL_NOTICE, "Scheduled background saving will be cancelled due to user request");
+                server.rdb_bgsave_scheduled = 0;
+                addReplyStatus(c, "Scheduled background saving cancelled");
+            } else {
+                addReplyError(c, "Background saving is currently not in progress or scheduled");
+            }
+            return;
         } else {
             addReplyErrorObject(c, shared.syntaxerr);
             return;

tests/integration/rdb.tcl

@@ -170,6 +170,64 @@ start_server {} {
         }
         assert_equal [s rdb_changes_since_last_save] 0
     }
+
+    test {bgsave cancel aborts save} {
+        r config set save ""
+        # Generating RDB will take some 100 seconds
+        r config set rdb-key-save-delay 1000000
+        populate 100 "" 16
+
+        r bgsave
+        wait_for_condition 50 100 {
+            [s rdb_bgsave_in_progress] == 1
+        } else {
+            fail "bgsave did not start in time"
+        }
+        set fork_child_pid [get_child_pid 0]
+
+        assert {[r bgsave cancel] eq {Background saving cancelled}}
+        set temp_rdb [file join [lindex [r config get dir] 1] temp-${fork_child_pid}.rdb]
+        # Temp rdb must be deleted
+        wait_for_condition 50 100 {
+            ![file exists $temp_rdb]
+        } else {
+            fail "bgsave temp file was not deleted after cancel"
+        }
+
+         # Make sure no save is running and that bgsave return an error
+         wait_for_condition 50 100 {
+            [s rdb_bgsave_in_progress] == 0
+        } else {
+            fail "bgsave is currently running"
+        }
+        assert_error "ERR Background saving is currently not in progress or scheduled" {r bgsave cancel}
+    }
+
+    test {bgsave cancel schedulled request} {
+        r config set save ""
+        # Generating RDB will take some 100 seconds
+        r config set rdb-key-save-delay 1000000
+        populate 100 "" 16
+
+        # start a long AOF child
+        r bgrewriteaof
+        wait_for_condition 50 100 {
+            [s aof_rewrite_in_progress] == 1
+        } else {
+            fail "aof not started"
+        }
+
+        # Make sure cancel return valid status
+        assert {[r bgsave schedule] eq {Background saving scheduled}}
+
+        # Cancel the scheduled save
+        assert {[r bgsave cancel] eq {Scheduled background saving cancelled}}
+
+        # Make sure a second call to bgsave cancel return an error
+        assert_error "ERR Background saving is currently not in progress or scheduled" {r bgsave cancel}
+    }
+
+
 }
 
 test {client freed during loading} {