feat: add hostname field in gRPC output

Signed-off-by: Adrián Arroyo Calle <adrian.arroyocalle@gmail.com>

userspace/falco/falco_outputs.cpp

@@ -146,6 +146,12 @@ void falco_outputs::handle_event(gen_event *ev, string &rule, string &source,
 
 	std::lock_guard<std::mutex> guard(m_ls_semaphore);
 	lua_getglobal(m_ls, m_lua_output_event.c_str());
+	char hostname[1024];
+	int err = gethostname(hostname, sizeof(hostname));
+	if(err != 0){
+		string err = "Failed to get hostname";
+		throw falco_exception(err);
+	}
 	if(lua_isfunction(m_ls, -1))
 	{
 		lua_pushlightuserdata(m_ls, ev);
@@ -154,8 +160,9 @@ void falco_outputs::handle_event(gen_event *ev, string &rule, string &source,
 		lua_pushstring(m_ls, falco_common::priority_names[priority].c_str());
 		lua_pushnumber(m_ls, priority);
 		lua_pushstring(m_ls, format.c_str());
+		lua_pushstring(m_ls, hostname);
 
-		if(lua_pcall(m_ls, 6, 0, 0) != 0)
+		if(lua_pcall(m_ls, 7, 0, 0) != 0)
 		{
 			const char* lerr = lua_tostring(m_ls, -1);
 			string err = "Error invoking function output: " + string(lerr);
@@ -300,12 +307,13 @@ int falco_outputs::handle_http(lua_State *ls)
 int falco_outputs::handle_grpc(lua_State *ls)
 {
 	// check parameters
-	if(!lua_islightuserdata(ls, -7) ||
+	if(!lua_islightuserdata(ls, -8) ||
+	   !lua_isstring(ls, -7) ||
 	   !lua_isstring(ls, -6) ||
 	   !lua_isstring(ls, -5) ||
 	   !lua_isstring(ls, -4) ||
-	   !lua_isstring(ls, -3) ||
+	   !lua_istable(ls, -3) ||
-	   !lua_istable(ls, -2) ||
+	   !lua_isstring(ls, -2) ||
 	   !lua_istable(ls, -1))
 	{
 		lua_pushstring(ls, "Invalid arguments passed to handle_grpc()");
@@ -355,6 +363,9 @@ int falco_outputs::handle_grpc(lua_State *ls)
 	}
 	lua_pop(ls, 1); // pop table
 
+	// hostname
+	grpc_res.set_hostname((char* )lua_tostring(ls, 7));
+
 	falco::output::queue::get().push(grpc_res);
 
 	return 1;

userspace/falco/lua/output.lua

@@ -17,7 +17,7 @@ local mod = {}
 
 local outputs = {}
 
-function mod.stdout(event, rule, source, priority, priority_num, msg, format, options)
+function mod.stdout(event, rule, source, priority, priority_num, msg, format, hostname, options)
    mod.stdout_message(priority, priority_num, msg, outputs)
 end
 
@@ -57,7 +57,7 @@ function mod.file_open(options)
    end
 end
 
-function mod.file(event, rule, source, priority, priority_num, msg, format, options)
+function mod.file(event, rule, source, priority, priority_num, msg, format, hostname, options)
    mod.file_message(priority, priority_num, msg, options)
 end
 
@@ -91,7 +91,7 @@ function mod.file_reopen(options)
    end
 end
 
-function mod.syslog(event, rule, source, priority, priority_num, msg, format, options)
+function mod.syslog(event, rule, source, priority, priority_num, msg, format, hostname, options)
    mod.syslog_message(priority, priority_num, msg, options)
 end
 
@@ -114,7 +114,7 @@ function mod.program_open(options)
    end
 end
 
-function mod.program(event, rule, source, priority, priority_num, msg, format, options)
+function mod.program(event, rule, source, priority, priority_num, msg, format, hostname, options)
    mod.program_message(priority, priority_num, msg, options)
 end
 
@@ -153,7 +153,7 @@ function mod.program_reopen(options)
    end
 end
 
-function mod.http(event, rule, source, priority, priority_num, msg, format, options)
+function mod.http(event, rule, source, priority, priority_num, msg, format, hostname, options)
    mod.http_message(priority, priority_num, msg, options)
 end
 
@@ -167,9 +167,9 @@ end
 function mod.http_reopen()
 end
 
-function mod.grpc(event, rule, source, priority, priority_num, msg, format, options)
+function mod.grpc(event, rule, source, priority, priority_num, msg, format, hostname, options)
    fields = formats.resolve_tokens(event, source, format)
-   c_outputs.handle_grpc(event, rule, source, priority, msg, fields, options)
+   c_outputs.handle_grpc(event, rule, source, priority, msg, fields, hostname, options)
 end
 
 function mod.grpc_message(priority, priority_num, msg, options)
@@ -183,7 +183,7 @@ end
 function mod.grpc_reopen()
 end
 
-function output_event(event, rule, source, priority, priority_num, format)
+function output_event(event, rule, source, priority, priority_num, format, hostname)
    -- If format starts with a *, remove it, as we're adding our own
    -- prefix here.
    if format:sub(1, 1) == "*" then
@@ -215,7 +215,7 @@ function output_event(event, rule, source, priority, priority_num, format)
    msg = formats.format_event(event, rule, source, priority, format)
 
    for index, o in ipairs(outputs) do
-      o.output(event, rule, source, priority, priority_num, msg, format, o.options)
+      o.output(event, rule, source, priority, priority_num, msg, format, hostname, o.options)
    end
 end
 

userspace/falco/output.proto

@@ -35,5 +35,6 @@ message response {
   string rule = 4;
   string output = 5;
   map<string, string> output_fields = 6;
-  // repeated string tags = 7; // TODO(leodido,fntlnz): tags not supported yet, keeping for reference
+  string hostname = 7;
+  // repeated string tags = 8; // TODO(leodido,fntlnz): tags not supported yet, keeping for reference
 }