feat: implement TTL support

CMakeLists.txt

@@ -11,7 +11,7 @@ set(THREADS_PREFER_PTHREAD_FLAG ON)
 find_package(Threads REQUIRED)
 
 if(APPLE)
-  add_executable(fkvs-server src/memory.c src/counter.c src/client.c src/core/list.c src/config.c src/networking/networking.c src/server.c src/core/hashtable.c src/commands/common/command_registry.c src/commands/server/server_command_handlers.c src/io/event_dispatcher_kqueue.c)
+  add_executable(fkvs-server src/memory.c src/counter.c src/client.c src/core/list.c src/config.c src/networking/networking.c src/server.c src/core/hashtable.c src/commands/common/command_registry.c src/commands/server/server_command_handlers.c src/io/event_dispatcher_kqueue.c src/ttl.c)
   target_compile_definitions(fkvs-server PRIVATE SERVER)
 
   add_executable(fkvs-benchmark src/string_utils.c src/fkvs-benchmark.c src/client.c src/core/list.c src/networking/networking.c src/commands/common/command_parser.c src/commands/client/client_command_handlers.c)
@@ -20,11 +20,11 @@ elseif(LINUX)
   find_library(LIBURING liburing)
 
   if(LIBURING)
-    add_executable(fkvs-server src/memory.c src/counter.c src/client.c src/core/list.c src/config.c src/networking/networking.c src/server.c src/core/hashtable.c src/commands/common/command_registry.c src/commands/server/server_command_handlers.c src/io/event_dispatcher_io_uring.c)
+    add_executable(fkvs-server src/memory.c src/counter.c src/client.c src/core/list.c src/config.c src/networking/networking.c src/server.c src/core/hashtable.c src/commands/common/command_registry.c src/commands/server/server_command_handlers.c src/io/event_dispatcher_io_uring.c src/ttl.c)
     target_link_libraries(fkvs-server PRIVATE LIBURING)
     target_compile_definitions(fkvs-server PRIVATE SERVER IO_URING_ENABLED)
   else()
-    add_executable(fkvs-server src/memory.c src/counter.c src/client.c src/core/list.c src/config.c src/networking/networking.c src/server.c src/core/hashtable.c src/commands/common/command_registry.c src/commands/server/server_command_handlers.c src/io/event_dispatcher_epoll.c)
+    add_executable(fkvs-server src/memory.c src/counter.c src/client.c src/core/list.c src/config.c src/networking/networking.c src/server.c src/core/hashtable.c src/commands/common/command_registry.c src/commands/server/server_command_handlers.c src/io/event_dispatcher_epoll.c src/ttl.c)
     target_compile_definitions(fkvs-server PRIVATE SERVER)
   endif()
 
@@ -35,7 +35,7 @@ endif()
 # Add test executable
 add_executable(test_counter tests/test_counter.c src/counter.c)
 add_executable(test_string_utils tests/test_string_utils.c src/string_utils.c)
-add_executable(test_integration tests/test_integration.c src/core/hashtable.c src/commands/common/command_registry.c src/commands/common/command_parser.c src/commands/server/server_command_handlers.c src/counter.c)
+add_executable(test_integration tests/test_integration.c src/core/hashtable.c src/commands/common/command_registry.c src/commands/common/command_parser.c src/commands/server/server_command_handlers.c src/counter.c src/ttl.c)
 target_compile_definitions(test_integration PRIVATE SERVER)
 target_link_libraries(test_counter)
 target_link_libraries(test_string_utils)

README.md

@@ -90,14 +90,32 @@ $ ./fkvs-cli -h 127.0.0.1 -p 5995 --non-interactive
 
 ### Supported commands
 
-- PING | PING "value"
-- SET key value
-- GET key
-- INCR key
-- INCRBY key value
-- DECR key
-- DECRBY key value
-- INFO
+#### Strings
+
+| Command | Usage | Description |
+|---|---|---|
+| `SET` | `SET key value [EX seconds]` | Store a key-value pair, optionally setting a TTL atomically |
+| `GET` | `GET key` | Retrieve the value of a key |
+| `DEL` | `DEL key` | Delete a key |
+| `INCR` | `INCR key` | Increment the integer value of a key by 1 |
+| `INCRBY` | `INCRBY key amount` | Increment the integer value of a key by a given amount |
+| `DECR` | `DECR key` | Decrement the integer value of a key by 1 |
+| `DECRBY` | `DECRBY key amount` | Decrement the integer value of a key by a given amount |
+
+#### Expiration (TTL)
+
+| Command | Usage | Description |
+|---|---|---|
+| `EXPIRE` | `EXPIRE key seconds` | Set a timeout on a key (in seconds) |
+| `TTL` | `TTL key` | Get the remaining time-to-live of a key (-1 = no TTL, -2 = key missing) |
+| `PERSIST` | `PERSIST key` | Remove the timeout from a key |
+
+#### Server
+
+| Command | Usage | Description |
+|---|---|---|
+| `PING` | `PING` or `PING value` | Test connectivity; returns `PONG` or echoes the value |
+| `INFO` | `INFO` | Display server statistics (uptime, memory, connected clients) |
 
 ## Documentation
 

src/commands/client/client_command_handlers.c

@@ -54,16 +54,25 @@ void cmd_set(const command_args_t args, void (*response_cb)(client_t *client))
 
     char value[MAX_VALUE_LEN];
     char key[MAX_KEY_LEN];
-    if (sscanf(args.cmd, "SET %511s %511s", key, value) == 2) {
+    char ex_keyword[4];
+    char seconds[MAX_VALUE_LEN];
 
+    size_t cmd_len;
+    unsigned char *binary_cmd = NULL;
+
+    int nfields = sscanf(args.cmd, "SET %511s %511s %3s %511s", key, value,
+                         ex_keyword, seconds);
+
+    if (nfields == 4 && strcasecmp(ex_keyword, "EX") == 0) {
+        binary_cmd = construct_set_ex_command(key, value, seconds, &cmd_len);
+    } else if (nfields == 2) {
+        binary_cmd = construct_set_command(key, value, &cmd_len);
     } else {
-        printf("(error) ERR wrong number of arguments for 'set' command\n");
-        printf("(info) Usage: SET <key> <value>\n");
+        printf("(error) ERR syntax error in 'set' command\n");
+        printf("(info) Usage: SET <key> <value> [EX seconds]\n");
         return;
     }
 
-    size_t cmd_len;
-    unsigned char *binary_cmd = construct_set_command(key, value, &cmd_len);
     if (binary_cmd == NULL) {
         fprintf(stderr, "Failed to construct SET command\n");
         return;
@@ -263,6 +272,119 @@ void cmd_decr_by(const command_args_t args,
     response_cb(args.client);
 }
 
+void cmd_del(const command_args_t args, void (*response_cb)(client_t *client))
+{
+    if (strncasecmp(args.cmd, "DEL ", 4) != 0) {
+        return;
+    }
+
+    char key[MAX_KEY_LEN];
+    if (sscanf(args.cmd, "DEL %511s", key) != 1) {
+        printf("(error) ERR wrong number of arguments for 'del' command\n");
+        printf("(info) Usage: DEL <key>\n");
+        return;
+    }
+
+    size_t cmd_len;
+    unsigned char *binary_cmd = construct_del_command(key, &cmd_len);
+    if (binary_cmd == NULL) {
+        fprintf(stderr, "Failed to construct DEL command\n");
+        return;
+    }
+
+    assert(cmd_len > 0);
+    assert(args.client->fd > 0);
+
+    send(args.client->fd, binary_cmd, cmd_len, 0);
+    free(binary_cmd);
+    response_cb(args.client);
+}
+
+void cmd_expire(const command_args_t args, void (*response_cb)(client_t *client))
+{
+    if (strncasecmp(args.cmd, "EXPIRE ", 7) != 0) {
+        return;
+    }
+
+    char key[MAX_KEY_LEN];
+    char seconds[MAX_VALUE_LEN];
+    if (sscanf(args.cmd, "EXPIRE %511s %511s", key, seconds) != 2) {
+        printf("(error) ERR wrong number of arguments for 'expire' command\n");
+        printf("(info) Usage: EXPIRE <key> <seconds>\n");
+        return;
+    }
+
+    size_t cmd_len;
+    unsigned char *binary_cmd = construct_expire_command(key, seconds, &cmd_len);
+    if (binary_cmd == NULL) {
+        fprintf(stderr, "Failed to construct EXPIRE command\n");
+        return;
+    }
+
+    assert(cmd_len > 0);
+    assert(args.client->fd > 0);
+
+    send(args.client->fd, binary_cmd, cmd_len, 0);
+    free(binary_cmd);
+    response_cb(args.client);
+}
+
+void cmd_ttl(const command_args_t args, void (*response_cb)(client_t *client))
+{
+    if (strncasecmp(args.cmd, "TTL ", 4) != 0) {
+        return;
+    }
+
+    char key[MAX_KEY_LEN];
+    if (sscanf(args.cmd, "TTL %511s", key) != 1) {
+        printf("(error) ERR wrong number of arguments for 'ttl' command\n");
+        printf("(info) Usage: TTL <key>\n");
+        return;
+    }
+
+    size_t cmd_len;
+    unsigned char *binary_cmd = construct_ttl_command(key, &cmd_len);
+    if (binary_cmd == NULL) {
+        fprintf(stderr, "Failed to construct TTL command\n");
+        return;
+    }
+
+    assert(cmd_len > 0);
+    assert(args.client->fd > 0);
+
+    send(args.client->fd, binary_cmd, cmd_len, 0);
+    free(binary_cmd);
+    response_cb(args.client);
+}
+
+void cmd_persist(const command_args_t args, void (*response_cb)(client_t *client))
+{
+    if (strncasecmp(args.cmd, "PERSIST ", 8) != 0) {
+        return;
+    }
+
+    char key[MAX_KEY_LEN];
+    if (sscanf(args.cmd, "PERSIST %511s", key) != 1) {
+        printf("(error) ERR wrong number of arguments for 'persist' command\n");
+        printf("(info) Usage: PERSIST <key>\n");
+        return;
+    }
+
+    size_t cmd_len;
+    unsigned char *binary_cmd = construct_persist_command(key, &cmd_len);
+    if (binary_cmd == NULL) {
+        fprintf(stderr, "Failed to construct PERSIST command\n");
+        return;
+    }
+
+    assert(cmd_len > 0);
+    assert(args.client->fd > 0);
+
+    send(args.client->fd, binary_cmd, cmd_len, 0);
+    free(binary_cmd);
+    response_cb(args.client);
+}
+
 /*
  * TODO: This approach works but is cumbersome to maintain. For future
  * reference, lets implement a solution that doesn't require us to have a
@@ -278,17 +400,23 @@ void cmd_unknown(const command_args_t args,
         strncmp(args.cmd, "PING", 4) &&
         strncmp(args.cmd, "PING ", 5) &&
         strncmp(args.cmd, "DECR ", 5) &&
-		strncmp(args.cmd, "DECRBY ", 7) &&
+        strncmp(args.cmd, "DECRBY ", 7) &&
+        strncmp(args.cmd, "DEL ", 4) &&
+        strncmp(args.cmd, "EXPIRE ", 7) &&
+        strncmp(args.cmd, "TTL ", 4) &&
+        strncmp(args.cmd, "PERSIST ", 8) &&
         strncmp(args.cmd, "INFO", 5)) {
         printf("Unknown command \n");
     }
 }
 
 const cmd_t command_table[] = {
     {"cmd_set", cmd_set},         {"cmd_get", cmd_get},
-    {"cmd_decr", cmd_decr},		  {"cmd_decr_by", cmd_decr_by},
+    {"cmd_decr", cmd_decr},       {"cmd_decr_by", cmd_decr_by},
     {"cmd_incr", cmd_incr},
     {"cmd_incr_by", cmd_incr_by}, {"cmd_ping", cmd_ping},
+    {"cmd_del", cmd_del},         {"cmd_expire", cmd_expire},
+    {"cmd_ttl", cmd_ttl},         {"cmd_persist", cmd_persist},
     {"cmd_unknown", cmd_unknown},
     {"cmd_info", cmd_info}};
 

src/commands/client/client_command_handlers.h

@@ -46,6 +46,14 @@ void cmd_info(command_args_t args, void (*response_cb)(client_t *client));
 
 void cmd_unknown(command_args_t args, void (*response_cb)(client_t *client));
 
+void cmd_del(command_args_t args, void (*response_cb)(client_t *client));
+
+void cmd_expire(command_args_t args, void (*response_cb)(client_t *client));
+
+void cmd_ttl(command_args_t args, void (*response_cb)(client_t *client));
+
+void cmd_persist(command_args_t args, void (*response_cb)(client_t *client));
+
 void command_response_handler(client_t *client);
 
 #endif // CLIENT_COMMAND_HANDLERS

src/commands/common/command_defs.h

@@ -9,5 +9,9 @@
 #define CMD_DECR 0x06
 #define CMD_INFO 0x07
 #define CMD_DECR_BY 0x08
+#define CMD_DEL     0x09
+#define CMD_EXPIRE  0x0A
+#define CMD_TTL     0x0B
+#define CMD_PERSIST 0x0C
 
 #endif // COMMAND_DEFS_H