Compile and load digwatch rules!

lua/compiler.lua

@@ -453,17 +453,17 @@ end
    to the line-oriented compiler.
 --]]
 function compiler.init()
-   return {macros={}}
+   return {macros={}, ast=nil}
 end
 
 --[[
-   Compiles a digwatch filter or macro
+   Compiles a single line from a digwatch ruleset and updates the passed-in state object. Returns the AST of the line.
 --]]
 function compiler.compile_line(line, state)
    local ast, error_msg = compiler.parser.parse_line(line)
 
    if (error_msg) then
-      return nil, error_msg
+      error(error_msg)
    end
 
    local macros = get_macros(ast.value, {})
@@ -474,20 +474,31 @@ function compiler.compile_line(line, state)
    end
 
    if (ast.type == "MacroDef") then
+      -- Parsed line is a macro definition, so update our dictionary of macros and
+      -- return
       state.macros[ast.name] = ast.value
-      return ast, error_msg
+      return ast
+
    elseif (ast.type == "Filter") then
+      -- Line is a filter, so expand in-clauses and macro references, then
+      -- stitch it into global ast
+
       expand_in(ast)
 
       repeat
          expanded  = expand_macros(ast, state.macros, false)
       until expanded == false
 
+      if (state.ast == nil) then
+	 state.ast = ast
+      else
+	 state.ast = { type = "BinaryBoolOp", operator = "or", left = state.ast, right = ast }
+      end
    else
       error("Unexpected top-level AST type: "..ast.type)
    end
 
-   return ast, error_msg
+   return ast
 end
 
 

lua/rule_loader.lua

@@ -0,0 +1,78 @@
+--[[
+   Compile and install digwatch rules.
+
+   This module exports functions that are called from digwatch c++-side to compile and install a set of rules.
+
+--]]
+
+local compiler = require "compiler"
+
+local function install_filter(node)
+   local t = node.type
+
+   if t == "Filter" then
+      install_filter(node.value)
+
+   elseif t == "BinaryBoolOp" then
+      filter.nest() --io.write("(")
+      install_filter(node.left)
+      filter.bool_op(node.operator) --io.write(" "..node.operator.." ")
+      install_filter(node.right)
+      filter.unnest() --io.write(")")
+
+
+   elseif t == "UnaryBoolOp" then
+      filter.nest() --io.write("(")
+      filter.bool_op(node.operator) -- io.write(" "..node.operator.." ")
+      install_filter(node.argument)
+      filter.unnest() -- io.write(")")
+
+   elseif t == "BinaryRelOp" then
+      filter.rel_expr(node.left.value, node.operator, node.right.value)
+      -- io.write(node.left.value.." "..node.operator.." "..node.right.value)
+
+      -- xxx still need to handle case where node.right.type=="list"
+
+   elseif t == "UnaryRelOp"  then
+      filter.rel_expr(node.argument.value, node.operator)
+      --io.write(node.argument.value.." "..node.operator)
+
+   elseif t == "List" then
+      error("Not handling List yet")
+
+   elseif t == "FieldName" or t == "Number" or t == "String" or t == "BareString" or t == "Macro" then
+      error ("Unexpected type: "..t)
+
+      io.write(t.." "..node.value)
+
+   elseif t == "MacroDef" then
+      error ("Unexpected type: "..t)
+   else
+      error ("Unexpected type: "..t)
+   end
+end
+
+
+-- filter.rel_expr("proc.name",  "=", "cat")
+-- filter.bool_op("and")
+-- filter.nest()
+-- filter.nest()
+-- filter.rel_expr("fd.num",  "=", "1")
+-- filter.bool_op("or")
+-- filter.rel_expr("fd.num",  "=", "2")
+-- filter.unnest()
+-- filter.unnest()
+
+local state
+
+
+function load_rule(r)
+   if (state == nil) then
+      state = compiler.init()
+   end
+   compiler.compile_line(r, state)
+end
+
+function on_done()
+   install_filter(state.ast)
+end

lua/test.lua

@@ -1,4 +1,4 @@
-local compiler = require "sysdig-parser"
+local compiler = require "compiler"
 
 if #arg ~= 1 then
     print("Usage: test.lua <string>")
@@ -8,18 +8,19 @@ end
 local state = compiler.init()
 
 local function doit(line)
-   local ast, error_msg = compiler.compile_line(line, state)
+   local ast = compiler.compile_line(line, state)
 
    if not ast then
       print("error", error_msg)
       os.exit(1)
    end
 
-   compiler.parser.print_ast(ast)
 end
 for str in string.gmatch(arg[1], "([^;]+)") do
    doit(str)
 end
 
+compiler.parser.print_ast(state.ast)
+
 os.exit(0)
 

userspace/digwatch/digwatch.cpp

@@ -33,7 +33,7 @@ static void usage()
 	   " -h, --help         Print this page\n"
 	   " -m <filename>, --main-lua <filename>\n"
 	   "                    Name of lua compiler main file\n"
-	   "                    (default: rules_loader.lua\n"
+	   "                    (default: rules_loader.lua)\n"
 	   " -M <num_seconds>   Stop collecting after <num_seconds> reached.\n"
 	   " -N                 Don't convert port numbers to names.\n"
 	   " -n <num>, --numevents=<num>\n"
@@ -244,18 +244,18 @@ int digwatch_init(int argc, char **argv)
 		//
 		sinsp_evt_formatter formatter(inspector, output_format);
 
-		trim(lua_main_filename);
-		if (lua_main_filename.size() == 0)
-		{
-			lua_main_filename = DIGWATCH_LUA_MAIN;
-		}
-
 		char* env_lua_dir = getenv("DIGWATCH_LUA_DIR");
 		if (env_lua_dir)
 		{
 			lua_dir = string(env_lua_dir);
 		}
 
+		trim(lua_main_filename);
+		if (lua_main_filename.size() == 0)
+		{
+			lua_main_filename = lua_dir + DIGWATCH_LUA_MAIN;
+		}
+
 		rules = new digwatch_rules(inspector, lua_main_filename, lua_dir);
 
 		rules->load_rules(rules_file);

userspace/digwatch/rules.cpp

@@ -67,18 +67,18 @@ void digwatch_rules::load_rules(string rules_filename)
 		throw sinsp_exception("can't open file " + rules_filename);
 	}
 
-	lua_getglobal(m_ls, m_lua_compiler_cb.c_str());
+	lua_getglobal(m_ls, m_lua_load_rule.c_str());
 	if(lua_isfunction(m_ls, -1))
 	{
 		lua_pop(m_ls, 1);
 	} else {
-		throw sinsp_exception("No function " + m_lua_compiler_cb + " found in lua compiler module");
+		throw sinsp_exception("No function " + m_lua_load_rule + " found in lua compiler module");
 	}
 
 	std::string line;
 	while (std::getline(is, line))
 	{
-		lua_getglobal(m_ls, m_lua_compiler_cb.c_str());
+		lua_getglobal(m_ls, m_lua_load_rule.c_str());
 		lua_pushstring(m_ls, line.c_str());
 
 		if(lua_pcall(m_ls, 1, 0, 0) != 0)
@@ -89,6 +89,18 @@ void digwatch_rules::load_rules(string rules_filename)
 		}
 	}
 
+	lua_getglobal(m_ls, m_lua_on_done.c_str());
+	if(lua_isfunction(m_ls, -1))
+	{
+		if(lua_pcall(m_ls, 0, 0, 0) != 0)
+		{
+			const char* lerr = lua_tostring(m_ls, -1);
+			string err = "Error installing rules: " + string(lerr);
+			throw sinsp_exception(err);
+		}
+	} else {
+		throw sinsp_exception("No function " + m_lua_on_done + " found in lua compiler module");
+	}
 
 }
 

userspace/digwatch/rules.h

@@ -17,6 +17,6 @@ class digwatch_rules
 
 	lua_parser* m_lua_parser;
 	lua_State* m_ls;
-	string m_lua_compiler_cb = "load_rules";
-	string m_lua_;
+	string m_lua_load_rule = "load_rule";
+	string m_lua_on_done = "on_done";
 };