Add GETPXT (Get with millisecond expiration) command

Returns null if the value not found or expired.
Returns an array of length 2 as [<string key value>, <integer expiration>].
If expiration is not set on the key, expiration returned is -1.

Added tests to cover

Signed-off-by: Arcadiy Ivanov <[email protected]>

Author: arcivanov

src/commands.def

@@ -10354,6 +10354,30 @@ struct COMMAND_ARG GETEX_Args[] = {
 {MAKE_ARG("expiration",ARG_TYPE_ONEOF,-1,NULL,NULL,NULL,CMD_ARG_OPTIONAL,5,NULL),.subargs=GETEX_expiration_Subargs},
 };
 
+/********** GETPXT ********************/
+
+#ifndef SKIP_CMD_HISTORY_TABLE
+/* GETPXT history */
+#define GETPXT_History NULL
+#endif
+
+#ifndef SKIP_CMD_TIPS_TABLE
+/* GETPXT tips */
+#define GETPXT_Tips NULL
+#endif
+
+#ifndef SKIP_CMD_KEY_SPECS_TABLE
+/* GETPXT key specs */
+keySpec GETPXT_Keyspecs[1] = {
+{NULL,CMD_KEY_RO|CMD_KEY_ACCESS,KSPEC_BS_INDEX,.bs.index={1},KSPEC_FK_RANGE,.fk.range={0,1,0}}
+};
+#endif
+
+/* GETPXT argument table */
+struct COMMAND_ARG GETPXT_Args[] = {
+{MAKE_ARG("key",ARG_TYPE_KEY,0,NULL,NULL,NULL,CMD_ARG_NONE,0,NULL)},
+};
+
 /********** GETRANGE ********************/
 
 #ifndef SKIP_CMD_HISTORY_TABLE
@@ -11131,6 +11155,7 @@ struct COMMAND_STRUCT serverCommandTable[] = {
 {MAKE_CMD("get","Returns the string value of a key.","O(1)","1.0.0",CMD_DOC_NONE,NULL,NULL,"string",COMMAND_GROUP_STRING,GET_History,0,GET_Tips,0,getCommand,2,CMD_READONLY|CMD_FAST,ACL_CATEGORY_STRING,GET_Keyspecs,1,NULL,1),.args=GET_Args},
 {MAKE_CMD("getdel","Returns the string value of a key after deleting the key.","O(1)","6.2.0",CMD_DOC_NONE,NULL,NULL,"string",COMMAND_GROUP_STRING,GETDEL_History,0,GETDEL_Tips,0,getdelCommand,2,CMD_WRITE|CMD_FAST,ACL_CATEGORY_STRING,GETDEL_Keyspecs,1,NULL,1),.args=GETDEL_Args},
 {MAKE_CMD("getex","Returns the string value of a key after setting its expiration time.","O(1)","6.2.0",CMD_DOC_NONE,NULL,NULL,"string",COMMAND_GROUP_STRING,GETEX_History,0,GETEX_Tips,0,getexCommand,-2,CMD_WRITE|CMD_FAST,ACL_CATEGORY_STRING,GETEX_Keyspecs,1,NULL,2),.args=GETEX_Args},
+{MAKE_CMD("getpxt","Returns the string value of a key and the expiration time as a Unix milliseconds timestamp, if set.","O(1)","8.0.2",CMD_DOC_NONE,NULL,NULL,"string",COMMAND_GROUP_STRING,GETPXT_History,0,GETPXT_Tips,0,getpxtCommand,2,CMD_READONLY|CMD_FAST,ACL_CATEGORY_STRING|ACL_CATEGORY_KEYSPACE,GETPXT_Keyspecs,1,NULL,1),.args=GETPXT_Args},
 {MAKE_CMD("getrange","Returns a substring of the string stored at a key.","O(N) where N is the length of the returned string. The complexity is ultimately determined by the returned length, but because creating a substring from an existing string is very cheap, it can be considered O(1) for small strings.","2.4.0",CMD_DOC_NONE,NULL,NULL,"string",COMMAND_GROUP_STRING,GETRANGE_History,0,GETRANGE_Tips,0,getrangeCommand,4,CMD_READONLY,ACL_CATEGORY_STRING,GETRANGE_Keyspecs,1,NULL,3),.args=GETRANGE_Args},
 {MAKE_CMD("getset","Returns the previous string value of a key after setting it to a new value.","O(1)","1.0.0",CMD_DOC_DEPRECATED,"`SET` with the `!GET` argument","6.2.0","string",COMMAND_GROUP_STRING,GETSET_History,0,GETSET_Tips,0,getsetCommand,3,CMD_WRITE|CMD_DENYOOM|CMD_FAST,ACL_CATEGORY_STRING,GETSET_Keyspecs,1,NULL,2),.args=GETSET_Args},
 {MAKE_CMD("incr","Increments the integer value of a key by one. Uses 0 as initial value if the key doesn't exist.","O(1)","1.0.0",CMD_DOC_NONE,NULL,NULL,"string",COMMAND_GROUP_STRING,INCR_History,0,INCR_Tips,0,incrCommand,2,CMD_WRITE|CMD_DENYOOM|CMD_FAST,ACL_CATEGORY_STRING,INCR_Keyspecs,1,NULL,1),.args=INCR_Args},

src/commands/getpxt.json

@@ -0,0 +1,80 @@
+{
+    "GETPXT": {
+        "summary": "Returns the string value of a key and the expiration time as a Unix milliseconds timestamp, if set.",
+        "complexity": "O(1)",
+        "group": "string",
+        "since": "8.0.2",
+        "arity": 2,
+        "function": "getpxtCommand",
+        "command_flags": [
+            "READONLY",
+            "FAST"
+        ],
+        "acl_categories": [
+            "STRING",
+            "KEYSPACE"
+        ],
+        "key_specs": [
+            {
+                "flags": [
+                    "RO",
+                    "ACCESS"
+                ],
+                "begin_search": {
+                    "index": {
+                        "pos": 1
+                    }
+                },
+                "find_keys": {
+                    "range": {
+                        "lastkey": 0,
+                        "step": 1,
+                        "limit": 0
+                    }
+                }
+            }
+        ],
+        "reply_schema": {
+            "oneOf": [
+                {
+                    "type": "array",
+                    "items": {
+                        "type": "array",
+                        "minItems": 2,
+                        "maxItems": 2,
+                        "items": [
+                            {
+                                "description": "The value of the key.",
+                                "type": "string"
+                            },
+                            {
+                                "oneOf": [
+                                    {
+                                        "type": "integer",
+                                        "description": "Expiration Unix timestamp in milliseconds.",
+                                        "minimum": 0
+                                    },
+                                    {
+                                        "const": -1,
+                                        "description": "The key exists but has no associated expiration time."
+                                    }
+                                ]
+                            }
+                        ]
+                    }
+                },
+                {
+                    "description": "Key does not exist.",
+                    "type": "null"
+                }
+            ]
+        },
+        "arguments": [
+            {
+                "name": "key",
+                "type": "key",
+                "key_spec_index": 0
+            }
+        ]
+    }
+}

src/server.h

@@ -3784,6 +3784,7 @@ void psetexCommand(client *c);
 void getCommand(client *c);
 void getexCommand(client *c);
 void getdelCommand(client *c);
+void getpxtCommand(client *c);
 void delCommand(client *c);
 void unlinkCommand(client *c);
 void existsCommand(client *c);

src/t_string.c

@@ -393,6 +393,34 @@ void getCommand(client *c) {
     getGenericCommand(c);
 }
 
+void getExpireGenericCommand(client *c, int output_ms) {
+    long long expire;
+    robj *o;
+
+    if ((o = lookupKeyReadOrReply(c, c->argv[1], shared.null[c->resp])) == NULL)
+        return;
+
+    if (checkType(c, o, OBJ_STRING)) {
+        return;
+    }
+
+    addReplyArrayLen(c, 2);
+    addReplyBulk(c, o);
+
+    /* The key exists. Return -1 if it has no expire, or the actual
+     * expire value otherwise. */
+    expire = getExpire(c->db, c->argv[1]);
+    if (expire == -1) {
+        addReplyLongLong(c, -1);
+    } else {
+        addReplyLongLong(c, output_ms ? expire : ((expire + 500) / 1000));
+    }
+}
+
+void getpxtCommand(client *c) {
+    getExpireGenericCommand(c, 1);
+}
+
 /*
  * GETEX <key> [PERSIST][EX seconds][PX milliseconds][EXAT seconds-timestamp][PXAT milliseconds-timestamp]
  *

tests/unit/type/string.tcl

@@ -658,6 +658,23 @@ if {[string match {*jemalloc*} [s mem_allocator]]} {
         assert_range [r ttl foo] 5 10
     }
 
+    test "GETPXT after SET PXAT" {
+        r del foo
+        r set foo bar pxat 17344823940230
+        r getpxt foo
+    } {bar 17344823940230}
+
+    test "GETPXT after SET" {
+        r del foo
+        r set foo bar
+        r getpxt foo
+    } {bar -1}
+
+    test "GETPXT with no entry" {
+        r del foo
+        r getpxt foo
+    } {}
+
     test "SET EXAT / PXAT Expiration time is expired" {
         r debug set-active-expire 0
         set repl [attach_to_replication_stream]