Fixed a bug in lua debugger for 'server *' invocations and Removing R…

…edis from internal function names.

* Fixed a bug where 'server *' invocation from lua debugger was not working.
* I ran into difficulty understanding some fo the LUA functions due to lack of documentation. Trying to remedy that in this commit.
* I removed Redis from function names in eval.c and script_lua.c files. I did not touch log messages in this commit. I also did not touch references to "RedisProtocol".

Signed-off-by: Parth Patel <661497+parthpatel@users.noreply.github.com>

src/eval.c

@@ -99,7 +99,7 @@ struct ldbState {
     int bp[LDB_BREAKPOINTS_MAX]; /* An array of breakpoints line numbers. */
     int bpcount; /* Number of valid entries inside bp. */
     int step;   /* Stop at next line regardless of breakpoints. */
-    int luabp;  /* Stop at next line because redis.breakpoint() was called. */
+    int luabp;  /* Stop at next line because server.breakpoint() was called. */
     sds *src;   /* Lua script source code split by line. */
     int lines;  /* Number of lines in 'src'. */
     int currentline;    /* Current line number. */
@@ -114,7 +114,7 @@ struct ldbState {
 
 /* Perform the SHA1 of the input string. We use this both for hashing script
  * bodies in order to obtain the Lua function name, and in the implementation
- * of redis.sha1().
+ * of server.sha1().
  *
  * 'digest' should point to a 41 bytes buffer: 40 for SHA1 converted into an
  * hexadecimal number, plus 1 byte for null term. */
@@ -135,12 +135,12 @@ void sha1hex(char *digest, char *script, size_t len) {
     digest[40] = '\0';
 }
 
-/* redis.breakpoint()
+/* Adds server.breakpoint() function used by lua debugger.  
  *
  * Allows to stop execution during a debugging session from within
  * the Lua code implementation, like if a breakpoint was set in the code
  * immediately after the function. */
-int luaRedisBreakpointCommand(lua_State *lua) {
+int luaServerBreakpointCommand(lua_State *lua) {
     if (ldb.active) {
         ldb.luabp = 1;
         lua_pushboolean(lua,1);
@@ -150,12 +150,12 @@ int luaRedisBreakpointCommand(lua_State *lua) {
     return 1;
 }
 
-/* redis.debug()
+/* Adds server.debug() function used by lua debugger
  *
  * Log a string message into the output console.
  * Can take multiple arguments that will be separated by commas.
  * Nothing is returned to the caller. */
-int luaRedisDebugCommand(lua_State *lua) {
+int luaServerDebugCommand(lua_State *lua) {
     if (!ldb.active) return 0;
     int argc = lua_gettop(lua);
     sds log = sdscatprintf(sdsempty(),"<debug> line %d: ", ldb.currentline);
@@ -167,14 +167,14 @@ int luaRedisDebugCommand(lua_State *lua) {
     return 0;
 }
 
-/* redis.replicate_commands()
+/* Adds server.replicate_commands()
  *
  * DEPRECATED: Now do nothing and always return true.
  * Turn on single commands replication if the script never called
  * a write command so far, and returns true. Otherwise if the script
  * already started to write, returns false and stick to whole scripts
  * replication, which is our default. */
-int luaRedisReplicateCommandsCommand(lua_State *lua) {
+int luaServerReplicateCommandsCommand(lua_State *lua) {
     lua_pushboolean(lua,1);
     return 1;
 }
@@ -205,27 +205,27 @@ void scriptingInit(int setup) {
     lctx.lua_scripts_lru_list = listCreate();
     lctx.lua_scripts_mem = 0;
 
-    luaRegisterRedisAPI(lua);
+    luaRegisterServerAPI(lua);
 
-    /* register debug commands */
-    lua_getglobal(lua,"redis");
+    /* register debug commands. we only need to add it under 'server' as 'redis' is effectively aliased to 'server' table at this point. */
+    lua_getglobal(lua,"server");
 
-    /* redis.breakpoint */
+    /* server.breakpoint */
     lua_pushstring(lua,"breakpoint");
-    lua_pushcfunction(lua,luaRedisBreakpointCommand);
+    lua_pushcfunction(lua,luaServerBreakpointCommand);
     lua_settable(lua,-3);
 
-    /* redis.debug */
+    /* server.debug */
     lua_pushstring(lua,"debug");
-    lua_pushcfunction(lua,luaRedisDebugCommand);
+    lua_pushcfunction(lua,luaServerDebugCommand);
     lua_settable(lua,-3);
 
-    /* redis.replicate_commands */
+    /* server.replicate_commands */
     lua_pushstring(lua, "replicate_commands");
-    lua_pushcfunction(lua, luaRedisReplicateCommandsCommand);
+    lua_pushcfunction(lua, luaServerReplicateCommandsCommand);
     lua_settable(lua, -3);
 
-    lua_setglobal(lua,"redis");
+    lua_setglobal(lua,"server");
 
     /* Add a helper function we use for pcall error reporting.
      * Note that when the error is in the C function we want to report the
@@ -234,7 +234,7 @@ void scriptingInit(int setup) {
     {
         char *errh_func =       "local dbg = debug\n"
                                 "debug = nil\n"
-                                "function __redis__err__handler(err)\n"
+                                "function __server__err__handler(err)\n"
                                 "  local i = dbg.getinfo(2,'nSl')\n"
                                 "  if i and i.what == 'C' then\n"
                                 "    i = dbg.getinfo(3,'nSl')\n"
@@ -583,7 +583,7 @@ void evalGenericCommand(client *c, int evalsha) {
         evalCalcFunctionName(evalsha, c->argv[1]->ptr, funcname);
 
     /* Push the pcall error handler function on the stack. */
-    lua_getglobal(lua, "__redis__err__handler");
+    lua_getglobal(lua, "__server__err__handler");
 
     /* Try to lookup the Lua function */
     lua_getfield(lua, LUA_REGISTRYINDEX, funcname);
@@ -1375,7 +1375,7 @@ char *ldbRedisProtocolToHuman_Double(sds *o, char *reply) {
 /* Log a RESP reply as debugger output, in a human readable format.
  * If the resulting string is longer than 'len' plus a few more chars
  * used as prefix, it gets truncated. */
-void ldbLogRedisReply(char *reply) {
+void ldbLogServerReply(char *reply) {
     sds log = sdsnew("<reply> ");
     ldbRedisProtocolToHuman(&log,reply);
     ldbLogWithMaxLen(log);
@@ -1516,30 +1516,30 @@ void ldbEval(lua_State *lua, sds *argv, int argc) {
 }
 
 /* Implement the debugger "server" command. We use a trick in order to make
- * the implementation very simple: we just call the Lua redis.call() command
+ * the implementation very simple: we just call the Lua server.call() command
  * implementation, with ldb.step enabled, so as a side effect the command
  * and its reply are logged. */
-void ldbRedis(lua_State *lua, sds *argv, int argc) {
+void ldbServer(lua_State *lua, sds *argv, int argc) {
     int j;
 
     if (!lua_checkstack(lua, argc + 1)) {
         /* Increase the Lua stack if needed to make sure there is enough room
          * to push 'argc + 1' elements to the stack. On failure, return error.
          * Notice that we need, in worst case, 'argc + 1' elements because we push all the arguments
-         * given by the user (without the first argument) and we also push the 'redis' global table and
-         * 'redis.call' function so:
-         * (1 (redis table)) + (1 (redis.call function)) + (argc - 1 (all arguments without the first)) = argc + 1*/
-        ldbLogRedisReply("max lua stack reached");
+         * given by the user (without the first argument) and we also push the 'server' global table and
+         * 'server.call' function so:
+         * (1 (server table)) + (1 (server.call function)) + (argc - 1 (all arguments without the first)) = argc + 1*/
+        ldbLogServerReply("max lua stack reached");
         return;
     }
 
-    lua_getglobal(lua,"redis");
+    lua_getglobal(lua,"server");
     lua_pushstring(lua,"call");
-    lua_gettable(lua,-2);       /* Stack: redis, redis.call */
+    lua_gettable(lua,-2);       /* Stack: server, server.call */
     for (j = 1; j < argc; j++)
         lua_pushlstring(lua,argv[j],sdslen(argv[j]));
-    ldb.step = 1;               /* Force redis.call() to log. */
-    lua_pcall(lua,argc-1,1,0);  /* Stack: redis, result */
+    ldb.step = 1;               /* Force server.call() to log. */
+    lua_pcall(lua,argc-1,1,0);  /* Stack: server, result */
     ldb.step = 0;               /* Disable logging. */
     lua_pop(lua,2);             /* Discard the result and clean the stack. */
 }
@@ -1677,8 +1677,8 @@ ldbLog(sdsnew("                     next line of code."));
             luaPushError(lua, "script aborted for user request");
             luaError(lua);
         } else if (argc > 1 &&
-                   (!strcasecmp(argv[0],"r") || !strcasecmp(argv[0],"redis"))) {
-            ldbRedis(lua,argv,argc);
+                   (!strcasecmp(argv[0],"r") || !strcasecmp(argv[0],"redis") || !strcasecmp(argv[0],"server"))) {
+            ldbServer(lua,argv,argc);
             ldbSendLogs();
         } else if ((!strcasecmp(argv[0],"p") || !strcasecmp(argv[0],"print"))) {
             if (argc == 2)

src/function_lua.c

@@ -423,11 +423,11 @@ int luaEngineInitEngine(void) {
     luaEngineCtx *lua_engine_ctx = zmalloc(sizeof(*lua_engine_ctx));
     lua_engine_ctx->lua = lua_open();
 
-    luaRegisterRedisAPI(lua_engine_ctx->lua);
+    luaRegisterServerAPI(lua_engine_ctx->lua);
 
     /* Register the library commands table and fields and store it to registry */
     lua_newtable(lua_engine_ctx->lua); /* load library globals */
-    lua_newtable(lua_engine_ctx->lua); /* load library `redis` table */
+    lua_newtable(lua_engine_ctx->lua); /* load library `server` table */
 
     lua_pushstring(lua_engine_ctx->lua, "register_function");
     lua_pushcfunction(lua_engine_ctx->lua, luaRegisterFunction);