Output simplification

The Output is now chosen globally (for all rules), on the command line.

userspace/digwatch/digwatch.cpp

@@ -31,6 +31,8 @@ static void signal_callback(int signal)
 }
 
 
+std::vector<string> valid_output_names {"stdout", "syslog"};
+
 //
 // Program help
 //
@@ -44,6 +46,7 @@ static void usage()
 	   "                    Name of lua compiler main file\n"
 	   "                    (default: rules_loader.lua)\n"
 	   " -N                 Don't convert port numbers to names.\n"
+	   " -o                 Output type (options are 'stdout', 'syslog', default is 'stdout')\n"
 	   "                    process or into a script.\n"
 	   "\n"
     );
@@ -56,6 +59,7 @@ string lua_on_event = "on_event";
 //
 void do_inspect(sinsp* inspector,
 		digwatch_rules* rules,
+		string output_name,
 		lua_State* ls)
 {
 	int32_t res;
@@ -105,8 +109,9 @@ void do_inspect(sinsp* inspector,
 		{
 			lua_pushlightuserdata(ls, ev);
 			lua_pushnumber(ls, ev->get_check_id());
+			lua_pushstring(ls, output_name.c_str());
 
-			if(lua_pcall(ls, 2, 0, 0) != 0)
+			if(lua_pcall(ls, 3, 0, 0) != 0)
 			{
 				const char* lerr = lua_tostring(ls, -1);
 				string err = "Error invoking function output: " + string(lerr);
@@ -163,6 +168,7 @@ int digwatch_init(int argc, char **argv)
 	sinsp_evt::param_fmt event_buffer_format = sinsp_evt::PF_NORMAL;
 	int long_index = 0;
 	string lua_main_filename;
+	string output_name = "stdout";
 	string lua_dir = DIGWATCH_INSTALLATION_DIR;
 	lua_State* ls = NULL;
 
@@ -176,13 +182,13 @@ int digwatch_init(int argc, char **argv)
 	try
 	{
 		inspector = new sinsp();
-
+		bool valid;
 
 		//
 		// Parse the args
 		//
 		while((op = getopt_long(argc, argv,
-                                        "hm:N",
+                                        "hm:No:",
                                         long_options, &long_index)) != -1)
 		{
 			switch(op)
@@ -196,6 +202,14 @@ int digwatch_init(int argc, char **argv)
 			case 'N':
 				inspector->set_hostname_and_port_resolution_mode(false);
 				break;
+			case 'o':
+				valid = std::find(valid_output_names.begin(), valid_output_names.end(), optarg) != valid_output_names.end();
+				if (!valid)
+				{
+					throw sinsp_exception(string("Invalid output name ") + optarg);
+				}
+				output_name = optarg;
+				break;
 			case '?':
 				result = EXIT_FAILURE;
 				goto exit;
@@ -280,6 +294,7 @@ int digwatch_init(int argc, char **argv)
 
 		do_inspect(inspector,
 			   rules,
+			   output_name,
 			   ls);
 
 		inspector->close();

userspace/digwatch/lua/output.lua

@@ -1,8 +1,14 @@
 local mod = {}
 
+function mod.stdout(evt, level, format)
+   format = "%evt.time: "..level.." "..format
+   formatter = digwatch.formatter(format)
+   msg = digwatch.format_event(evt, formatter)
+   print (msg)
+end
+
 function mod.syslog(evt, level, format)
    nixio = require("nixio")
-   format = "%evt.time: "..format
    formatter = digwatch.formatter(format)
    msg = digwatch.format_event(evt, formatter)
    nixio.syslog(level, msg)

userspace/digwatch/lua/rule_loader.lua

@@ -113,11 +113,8 @@ function set_output(output_ast)
 	 format = output_ast.value
       end
 
-      state.outputs[state.n_rules] = {type="format", formatter=digwatch.formatter("%evt.time: "..format)}
+      state.outputs[state.n_rules] = {format=format, level = output_ast.level}
 
-   elseif (output_ast.type == "FunctionCall") then
-      require(output_ast.mname)
-      state.outputs[state.n_rules] = {type="function", mname = output_ast.mname, source=output_ast.source}
    else
       error ("Unexpected type in set_output: ".. output_ast.type)
    end
@@ -162,18 +159,17 @@ function on_done()
    io.flush()
 end
 
-evt = nil
-function on_event(evt_, rule_id)
+local outputs = require('output')
+
+function on_event(evt_, rule_id, output_name)
+   if not (type(outputs[output_name]) == 'function') then
+      error("rule_loader.on_event(): invalid output_name: ", output_name)
+   end
+
    if state.outputs[rule_id] == nil then
       error ("rule_loader.on_event(): event with invalid rule_id: ", rule_id)
    end
 
-   if state.outputs[rule_id].type == "format" then
-      print(digwatch.format_event(evt_, state.outputs[rule_id].formatter))
-   elseif state.outputs[rule_id].type == "function" then
-      local reqmod =  "local "..state.outputs[rule_id].mname.." = require('" ..state.outputs[rule_id].mname .. "')";
-      evt = evt_
-      assert(loadstring(reqmod .. state.outputs[rule_id].source))()
-   end
+   outputs[output_name](evt_, state.outputs[rule_id].level, state.outputs[rule_id].format)
 end