From e1034f07492da4a9e50473a24a5138efa13fb0f3 Mon Sep 17 00:00:00 2001
From: Hiroshi Hatake <hatake@calyptia.com>
Date: Wed, 1 Nov 2023 13:35:20 +0900
Subject: [PATCH] filter_lua: Provide additional script validator before
 running as cb_pre_run

Signed-off-by: Hiroshi Hatake <hatake@calyptia.com>
---
 plugins/filter_lua/lua.c | 41 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/plugins/filter_lua/lua.c b/plugins/filter_lua/lua.c
index 89aa8cd478e..a42cca7ca4b 100644
--- a/plugins/filter_lua/lua.c
+++ b/plugins/filter_lua/lua.c
@@ -36,6 +36,46 @@
 #include "lua_config.h"
 #include "mpack/mpack.h"
 
+static int cb_lua_pre_run(struct flb_filter_instance *f_ins,
+                          struct flb_config *config, void *data)
+{
+    int ret;
+    (void) data;
+    struct lua_filter *ctx;
+    struct flb_luajit *lj;
+
+    /* Create context */
+    ctx = lua_config_create(f_ins, config);
+    if (!ctx) {
+        flb_error("[filter_lua] filter cannot be loaded");
+        return -1;
+    }
+
+    /* Create LuaJIT state/vm */
+    lj = flb_luajit_create(config);
+    if (!lj) {
+        lua_config_destroy(ctx);
+        return -1;
+    }
+    ctx->lua = lj;
+
+    /* Lua script source code */
+    if (ctx->code) {
+        ret = flb_luajit_load_buffer(ctx->lua,
+                                     ctx->code, flb_sds_len(ctx->code),
+                                     "fluentbit.lua");
+    }
+    else {
+        /* Load Script / file path*/
+        ret = flb_luajit_load_script(ctx->lua, ctx->script);
+    }
+
+    flb_luajit_destroy(ctx->lua);
+    lua_config_destroy(ctx);
+
+    return ret;
+}
+
 static int cb_lua_init(struct flb_filter_instance *f_ins,
                        struct flb_config *config,
                        void *data)
@@ -702,6 +742,7 @@ static struct flb_config_map config_map[] = {
 struct flb_filter_plugin filter_lua_plugin = {
     .name         = "lua",
     .description  = "Lua Scripting Filter",
+    .cb_pre_run   = cb_lua_pre_run,
     .cb_init      = cb_lua_init,
 #ifdef FLB_FILTER_LUA_USE_MPACK
     .cb_filter    = cb_lua_filter_mpack,