Add API UpdateRuntimeArgs for updating the module arguments during runtime

src/module.c

@@ -2255,6 +2255,27 @@ int moduleIsModuleCommand(void *module_handle, struct serverCommand *cmd) {
     return (cp->module == module_handle);
 }
 
+/* ValkeyModule_UpdateRuntimeArgs can be used to update the module argument values.
+ * The function parameter 'argc' indicates the number of updated arguments, and 'argv'
+ * represents the values of the updated arguments.
+ * Once 'CONFIG REWRITE' command is called, the updated argument values can be saved into conf file.
+ *
+ * The function always returns VALKEYMODULE_OK. */
+int VM_UpdateRuntimeArgs(ValkeyModuleCtx *ctx, ValkeyModuleString **argv, int argc) {
+    struct moduleLoadQueueEntry *loadmod = ctx->module->loadmod;
+    for (int i = 0; i < loadmod->argc; i++) {
+        decrRefCount(loadmod->argv[i]);
+    }
+    zfree(loadmod->argv);
+    loadmod->argv = argc - 1 ? zmalloc(sizeof(robj *) * (argc - 1)) : NULL;
+    loadmod->argc = argc - 1;
+    for (int i = 1; i < argc; i++) {
+        loadmod->argv[i - 1] = argv[i];
+        incrRefCount(loadmod->argv[i - 1]);
+    }
+    return VALKEYMODULE_OK;
+}
+
 /* --------------------------------------------------------------------------
  * ## Module information and time measurement
  * -------------------------------------------------------------------------- */
@@ -13560,6 +13581,7 @@ void moduleRegisterCoreAPI(void) {
     REGISTER_API(SetModuleAttribs);
     REGISTER_API(IsModuleNameBusy);
     REGISTER_API(WrongArity);
+    REGISTER_API(UpdateRuntimeArgs);
     REGISTER_API(ReplyWithLongLong);
     REGISTER_API(ReplyWithError);
     REGISTER_API(ReplyWithErrorFormat);

src/valkeymodule.h

@@ -967,6 +967,7 @@ VALKEYMODULE_API void (*ValkeyModule_SetModuleAttribs)(ValkeyModuleCtx *ctx, con
     VALKEYMODULE_ATTR;
 VALKEYMODULE_API int (*ValkeyModule_IsModuleNameBusy)(const char *name) VALKEYMODULE_ATTR;
 VALKEYMODULE_API int (*ValkeyModule_WrongArity)(ValkeyModuleCtx *ctx) VALKEYMODULE_ATTR;
+VALKEYMODULE_API int (*ValkeyModule_UpdateRuntimeArgs)(ValkeyModuleCtx *ctx, ValkeyModuleString **argv, int argc) VALKEYMODULE_ATTR;
 VALKEYMODULE_API int (*ValkeyModule_ReplyWithLongLong)(ValkeyModuleCtx *ctx, long long ll) VALKEYMODULE_ATTR;
 VALKEYMODULE_API int (*ValkeyModule_GetSelectedDb)(ValkeyModuleCtx *ctx) VALKEYMODULE_ATTR;
 VALKEYMODULE_API int (*ValkeyModule_SelectDb)(ValkeyModuleCtx *ctx, int newid) VALKEYMODULE_ATTR;
@@ -1673,6 +1674,7 @@ static int ValkeyModule_Init(ValkeyModuleCtx *ctx, const char *name, int ver, in
     VALKEYMODULE_GET_API(SetModuleAttribs);
     VALKEYMODULE_GET_API(IsModuleNameBusy);
     VALKEYMODULE_GET_API(WrongArity);
+    VALKEYMODULE_GET_API(UpdateRuntimeArgs);
     VALKEYMODULE_GET_API(ReplyWithLongLong);
     VALKEYMODULE_GET_API(ReplyWithError);
     VALKEYMODULE_GET_API(ReplyWithErrorFormat);

tests/modules/Makefile

@@ -58,6 +58,7 @@ TEST_MODULES = \
     eventloop.so \
     moduleconfigs.so \
     moduleconfigstwo.so \
+    moduleparameter.so \
     publish.so \
     usercall.so \
     postnotifications.so \

tests/modules/moduleparameter.c

@@ -0,0 +1,28 @@
+#include "valkeymodule.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <string.h>
+
+int test_module_update_parameter(ValkeyModuleCtx *ctx,
+                                 ValkeyModuleString **argv, int argc) {
+
+  ValkeyModule_UpdateRuntimeArgs(ctx, argv, argc);
+  return ValkeyModule_ReplyWithSimpleString(ctx, "OK");
+}
+
+int ValkeyModule_OnLoad(ValkeyModuleCtx *ctx, ValkeyModuleString **argv, int argc) {
+    VALKEYMODULE_NOT_USED(argv);
+    VALKEYMODULE_NOT_USED(argc);
+
+    if (ValkeyModule_Init(ctx, "moduleparameter", 1, VALKEYMODULE_APIVER_1) ==
+        VALKEYMODULE_ERR)
+      return VALKEYMODULE_ERR;
+
+    if (ValkeyModule_CreateCommand(ctx, "testmoduleparameter.update.parameter",
+                                   test_module_update_parameter, "fast", 0, 0,
+                                   0) == VALKEYMODULE_ERR)
+      return VALKEYMODULE_ERR;
+
+    return VALKEYMODULE_OK;
+}

tests/unit/moduleapi/moduleconfigs.tcl

@@ -1,5 +1,7 @@
 set testmodule [file normalize tests/modules/moduleconfigs.so]
 set testmoduletwo [file normalize tests/modules/moduleconfigstwo.so]
+set testmoduleparameter [file normalize tests/modules/moduleparameter.so]
+
 
 start_server {tags {"modules"}} {
     r module load $testmodule
@@ -243,5 +245,14 @@ start_server {tags {"modules"}} {
             assert_equal [r config get moduleconfigs.memory_numeric] "moduleconfigs.memory_numeric 1024"
         }
     }
-}
+    test {Module Update Args} {
+       r module load $testmoduleparameter 10 20 30
 
+       set t [r module list]
+       set modulename [lmap x [r module list] {dict get $x name}]
+       assert_not_equal [lsearch $modulename moduleparameter] -1
+       assert_equal "{10 20 30}" [lmap x [r module list] {dict get $x args}]
+       assert_equal OK [r testmoduleparameter.update.parameter 40 50 60 70]
+       assert_equal "{40 50 60 70}" [lmap x [r module list] {dict get $x args}]
+    }
+}