Lua parser refactoring

Move compiler loading out of libsinsp/lua_parser.cpp and into a new
class in digwatch/rules.cpp.

This way the libsinsp support is strictly about providing a lua API for
scripts to setup filters. Loading the actual parser and rules is logic
that belongs in the app (digwatch in this case, maybe sysdig down the
line) rather than there.

CMakeLists.txt

@@ -33,6 +33,9 @@ add_subdirectory(${SYSDIG_DIR} ${PROJECT_BINARY_DIR}/sysdig)
 set(CURL_BUNDLE_DIR "${sysdig_BINARY_DIR}/curl-prefix/src/curl")
 set(CURL_INCLUDE_DIR "${CURL_BUNDLE_DIR}/include/")
 set(CURL_LIBRARIES "${CURL_BUNDLE_DIR}/lib/.libs/libcurl.a")
+
+set(LUAJIT_INCLUDE_DIR "${sysdig_BINARY_DIR}/luajit-prefix/src/luajit/src")
+
 if(NOT USE_BUNDLED_OPENSSL)
 	set(CURL_SSL_OPTION "")
 else()

userspace/digwatch/CMakeLists.txt

@@ -1,4 +1,5 @@
 include_directories(${PROJECT_SOURCE_DIR}/../sysdig/userspace/libsinsp/third-party/jsoncpp)
+include_directories("${LUAJIT_INCLUDE_DIR}")
 
 if(NOT APPLE)
     include_directories("${CURL_INCLUDE_DIR}")
@@ -8,7 +9,7 @@ endif()
 include_directories(${PROJECT_SOURCE_DIR}/../sysdig/userspace/libscap)
 include_directories(${PROJECT_SOURCE_DIR}/../sysdig/userspace/libsinsp)
 
-add_executable(digwatch digwatch.cpp)
+add_executable(digwatch rules.cpp digwatch.cpp)
 
 target_link_libraries(digwatch sinsp)
 

userspace/digwatch/digwatch.cpp

@@ -8,15 +8,13 @@
 #include <algorithm>
 
 #include <sinsp.h>
-#include "lua_parser.h"
+#include "rules.h"
 #include "digwatch.h"
 #include "utils.h"
 
 #include <unistd.h>
 #include <getopt.h>
 
-lua_parser* g_lua_parser;
-
 static void usage();
 
 //
@@ -127,6 +125,7 @@ int digwatch_init(int argc, char **argv)
 {
 	int result;
 	sinsp* inspector = NULL;
+	digwatch_rules* rules = NULL;
 	int op;
 	uint64_t cnt = -1;
 	sinsp_evt::param_fmt event_buffer_format = sinsp_evt::PF_NORMAL;
@@ -234,9 +233,9 @@ int digwatch_init(int argc, char **argv)
 		//
 		sinsp_evt_formatter formatter(inspector, output_format);
 
-		g_lua_parser = new lua_parser(inspector, user_parser);
+		rules = new digwatch_rules(inspector, user_parser);
 
-		inspector->set_filter(g_lua_parser->m_filter);
+		inspector->set_filter(rules->get_filter());
 		inspector->open("");
 
 		cinfo = do_inspect(inspector,

userspace/digwatch/rules.cpp

@@ -0,0 +1,45 @@
+#include "rules.h"
+
+extern "C" {
+#include "lua.h"
+#include "lualib.h"
+#include "lauxlib.h"
+}
+
+digwatch_rules::digwatch_rules(sinsp* inspector, string compiler_filename)
+{
+	m_lua_parser = new lua_parser(inspector);
+	m_ls = m_lua_parser->m_ls;
+
+	trim(compiler_filename);
+
+	ifstream is;
+	is.open(compiler_filename);
+	if(!is.is_open())
+	{
+		throw sinsp_exception("can't open file " + compiler_filename);
+	}
+
+	string scriptstr((istreambuf_iterator<char>(is)),
+			 istreambuf_iterator<char>());
+
+	//
+	// Load the compiler script
+	//
+	if(luaL_loadstring(m_ls, scriptstr.c_str()) || lua_pcall(m_ls, 0, 0, 0))
+	{
+		throw sinsp_exception("Failed to load script " +
+			compiler_filename + ": " + lua_tostring(m_ls, -1));
+	}
+}
+
+sinsp_filter* digwatch_rules::get_filter()
+{
+	return m_lua_parser->get_filter();
+}
+
+digwatch_rules::~digwatch_rules()
+{
+	delete m_lua_parser;
+}
+

userspace/digwatch/rules.h

@@ -0,0 +1,17 @@
+#pragma once
+
+#include "sinsp.h"
+#include "lua_parser.h"
+
+class digwatch_rules
+{
+ public:
+	digwatch_rules(sinsp* inspector, string compiler_filename);
+	~digwatch_rules();
+	void load(string rules_filename);
+	sinsp_filter* get_filter();
+
+ private:
+	lua_parser* m_lua_parser;
+	lua_State* m_ls;
+};