Add ability for modules to know which client is being cmd filtered (#12219)

Adds API
- RedisModule_CommandFilterGetClientId()

Includes addition to commandfilter test module to validate that it works
by performing the same command from 2 different clients

src/module.c

@@ -356,6 +356,7 @@ typedef struct RedisModuleCommandFilterCtx {
     RedisModuleString **argv;
     int argv_len;
     int argc;
+    client *c;
 } RedisModuleCommandFilterCtx;
 
 typedef void (*RedisModuleCommandFilterFunc) (RedisModuleCommandFilterCtx *filter);
@@ -10645,7 +10646,8 @@ void moduleCallCommandFilters(client *c) {
     RedisModuleCommandFilterCtx filter = {
         .argv = c->argv,
         .argv_len = c->argv_len,
-        .argc = c->argc
+        .argc = c->argc,
+        .c = c
     };
 
     while((ln = listNext(&li))) {
@@ -10738,6 +10740,11 @@ int RM_CommandFilterArgDelete(RedisModuleCommandFilterCtx *fctx, int pos)
     return REDISMODULE_OK;
 }
 
+/* Get Client ID for client that issued the command we are filtering */
+unsigned long long RM_CommandFilterGetClientId(RedisModuleCommandFilterCtx *fctx) {
+    return fctx->c->id;
+}
+
 /* For a given pointer allocated via RedisModule_Alloc() or
  * RedisModule_Realloc(), return the amount of memory allocated for it.
  * Note that this may be different (larger) than the memory we allocated
@@ -13722,6 +13729,7 @@ void moduleRegisterCoreAPI(void) {
     REGISTER_API(CommandFilterArgInsert);
     REGISTER_API(CommandFilterArgReplace);
     REGISTER_API(CommandFilterArgDelete);
+    REGISTER_API(CommandFilterGetClientId);
     REGISTER_API(Fork);
     REGISTER_API(SendChildHeartbeat);
     REGISTER_API(ExitFromChild);

src/redismodule.h

@@ -1259,6 +1259,7 @@ REDISMODULE_API RedisModuleString * (*RedisModule_CommandFilterArgGet)(RedisModu
 REDISMODULE_API int (*RedisModule_CommandFilterArgInsert)(RedisModuleCommandFilterCtx *fctx, int pos, RedisModuleString *arg) REDISMODULE_ATTR;
 REDISMODULE_API int (*RedisModule_CommandFilterArgReplace)(RedisModuleCommandFilterCtx *fctx, int pos, RedisModuleString *arg) REDISMODULE_ATTR;
 REDISMODULE_API int (*RedisModule_CommandFilterArgDelete)(RedisModuleCommandFilterCtx *fctx, int pos) REDISMODULE_ATTR;
+REDISMODULE_API unsigned long long (*RedisModule_CommandFilterGetClientId)(RedisModuleCommandFilterCtx *fctx) REDISMODULE_ATTR;
 REDISMODULE_API int (*RedisModule_Fork)(RedisModuleForkDoneHandler cb, void *user_data) REDISMODULE_ATTR;
 REDISMODULE_API void (*RedisModule_SendChildHeartbeat)(double progress) REDISMODULE_ATTR;
 REDISMODULE_API int (*RedisModule_ExitFromChild)(int retcode) REDISMODULE_ATTR;
@@ -1619,6 +1620,7 @@ static int RedisModule_Init(RedisModuleCtx *ctx, const char *name, int ver, int
     REDISMODULE_GET_API(CommandFilterArgInsert);
     REDISMODULE_GET_API(CommandFilterArgReplace);
     REDISMODULE_GET_API(CommandFilterArgDelete);
+    REDISMODULE_GET_API(CommandFilterGetClientId);
     REDISMODULE_GET_API(Fork);
     REDISMODULE_GET_API(SendChildHeartbeat);
     REDISMODULE_GET_API(ExitFromChild);

tests/modules/commandfilter.c

@@ -8,8 +8,11 @@ static const char log_command_name[] = "commandfilter.log";
 static const char ping_command_name[] = "commandfilter.ping";
 static const char retained_command_name[] = "commandfilter.retained";
 static const char unregister_command_name[] = "commandfilter.unregister";
+static const char unfiltered_clientid_name[] = "unfilter_clientid";
 static int in_log_command = 0;
 
+unsigned long long unfiltered_clientid = 0;
+
 static RedisModuleCommandFilter *filter, *filter1;
 static RedisModuleString *retained;
 
@@ -89,6 +92,26 @@ int CommandFilter_LogCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int
     return REDISMODULE_OK;
 }
 
+int CommandFilter_UnfilteredClientdId(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
+{
+    if (argc < 2)
+        return RedisModule_WrongArity(ctx);
+
+    long long id;
+    if (RedisModule_StringToLongLong(argv[1], &id) != REDISMODULE_OK) {
+        RedisModule_ReplyWithError(ctx, "invalid client id");
+        return REDISMODULE_OK;
+    }
+    if (id < 0) {
+        RedisModule_ReplyWithError(ctx, "invalid client id");
+        return REDISMODULE_OK;
+    }
+
+    unfiltered_clientid = id;
+    RedisModule_ReplyWithSimpleString(ctx, "OK");
+    return REDISMODULE_OK;
+}
+
 /* Filter to protect against Bug #11894 reappearing
  *
  * ensures that the filter is only run the first time through, and not on reprocessing
@@ -117,6 +140,9 @@ void CommandFilter_BlmoveSwap(RedisModuleCommandFilterCtx *filter)
 
 void CommandFilter_CommandFilter(RedisModuleCommandFilterCtx *filter)
 {
+    unsigned long long id = RedisModule_CommandFilterGetClientId(filter);
+    if (id == unfiltered_clientid) return;
+
     if (in_log_command) return;  /* don't process our own RM_Call() from CommandFilter_LogCommand() */
 
     /* Fun manipulations:
@@ -192,6 +218,10 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
                 CommandFilter_UnregisterCommand,"write deny-oom",1,1,1) == REDISMODULE_ERR)
             return REDISMODULE_ERR;
 
+    if (RedisModule_CreateCommand(ctx, unfiltered_clientid_name,
+                CommandFilter_UnfilteredClientdId, "admin", 1,1,1) == REDISMODULE_ERR)
+            return REDISMODULE_ERR;
+
     if ((filter = RedisModule_RegisterCommandFilter(ctx, CommandFilter_CommandFilter, 
                     noself ? REDISMODULE_CMDFILTER_NOSELF : 0))
             == NULL) return REDISMODULE_ERR;

tests/unit/moduleapi/commandfilter.tcl

@@ -139,5 +139,27 @@ test {Blocking Commands don't run through command filter when reprocessed} {
         assert_equal [$rd read] 1
         # validate that we moved the correct elements to the correct side of the list
         assert_equal [r lpop list2{t}] 1
+
+        $rd close
     }
 }
+
+test {Filtering based on client id} {
+    start_server {tags {"modules"}} {
+        r module load $testmodule log-key 0
+
+        set rr [redis_client]
+        set cid [$rr client id]
+        r unfilter_clientid $cid
+
+        r rpush mylist elem1 @replaceme elem2
+        assert_equal [r lrange mylist 0 -1] {elem1 --replaced-- elem2}
+
+        r del mylist
+
+        assert_equal [$rr rpush mylist elem1 @replaceme elem2] 3
+        assert_equal [r lrange mylist 0 -1] {elem1 @replaceme elem2}
+
+        $rr close
+    }
+}