new(userspace/falco): initial grpc server implementation

Co-Authored-By: Leonardo Di Donato <leodidonato@gmail.com>
Signed-off-by: Lorenzo Fontana <lo@linux.com>

userspace/falco/falco.cpp

@@ -47,6 +47,7 @@ limitations under the License.
 #include "config_falco.h"
 #include "statsfilewriter.h"
 #include "webserver.h"
+#include "grpc_server.h"
 
 typedef function<void(sinsp* inspector)> open_t;
 
@@ -1162,6 +1163,10 @@ int falco_init(int argc, char **argv)
 			webserver.start();
 		}
 
+		// grpc server
+		// TODO: this is blocking now, not what we want, falco must go on. Just an experiment for now.
+		start_grpc_server(5060, 1);
+
 		if(!trace_filename.empty() && !trace_is_scap)
 		{
 			read_k8s_audit_trace_file(engine,

userspace/falco/grpc_server.cpp

@@ -0,0 +1,119 @@
+/*
+Copyright (C) 2016-2019 The Falco Authors
+
+This file is part of falco.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+#include <iostream>
+#include <memory>
+#include <string>
+#include <thread>
+
+#ifdef GRPC_INCLUDE_IS_GRPCPP
+#include <grpcpp/grpcpp.h>
+#else
+#include <grpc++/grpc++.h>
+#endif
+
+#include "grpc_server.h"
+#include "falco_output.grpc.pb.h"
+#include "falco_output.pb.h"
+
+bool grpc_server_impl::is_running()
+{
+	// TODO: this must act as a switch to shut down the server
+	return true;
+}
+
+class grpc_server : public grpc_server_impl
+{
+public:
+	grpc_server(const char* server_addr, int threadiness):
+		server_addr(server_addr),
+		threadiness(threadiness)
+	{
+	}
+
+	virtual ~grpc_server() = default;
+
+	// Run() is blocked. It doesn't return until Stop() is called from another thread.
+	void Run();
+
+	void thread_process(int threadIndex)
+	{
+		// TODO: is this right? That's what we want?
+		// Tell pthread to not handle termination signals in the current thread
+		sigset_t set;
+		sigemptyset(&set);
+		sigaddset(&set, SIGHUP);
+		sigaddset(&set, SIGINT);
+		pthread_sigmask(SIG_BLOCK, &set, nullptr);
+
+		void* tag = nullptr;
+		bool eventReadSuccess = false;
+		while(completion_queue->Next(&tag, &eventReadSuccess))
+		{
+			if(tag == nullptr)
+			{
+				// TODO: empty tag returned, log, what to do?
+				continue;
+			}
+		}
+	}
+
+	// There is no shutdown handling in this code.
+	void run()
+	{
+		grpc::ServerBuilder builder;
+		// Listen on the given address without any authentication mechanism.
+		builder.AddListeningPort(server_addr, grpc::InsecureServerCredentials());
+		// builder.RegisterService(&falco_output_svc); // TODO: enable this when we do the impl
+
+		completion_queue = builder.AddCompletionQueue();
+		server = builder.BuildAndStart();
+		std::cout << "Server listening on " << server_addr << std::endl;
+
+		// int context_count = threadiness * 10;
+
+		threads.resize(threadiness);
+
+		int thread_idx = 0;
+		for(std::thread& thread : threads)
+		{
+			thread = std::thread(&grpc_server::thread_process, this, thread_idx++);
+		}
+
+		while(is_running())
+		{
+		}
+	}
+
+private:
+	// FalcoOutputService::AsyncService falco_output_svc;
+	std::unique_ptr<grpc::Server> server;
+	std::string server_addr;
+	int threadiness = 0;
+	std::unique_ptr<grpc::ServerCompletionQueue> completion_queue;
+	std::vector<std::thread> threads;
+};
+
+bool start_grpc_server(unsigned short port, int threadiness)
+{
+	// TODO: make bind address configurable
+	std::string server_addr = "0.0.0.0:" + std::to_string(port);
+	grpc_server srv(server_addr.c_str(), threadiness);
+	srv.run();
+	return true;
+}

userspace/falco/grpc_server.h

@@ -0,0 +1,31 @@
+/*
+Copyright (C) 2016-2019 The Falco Authors
+
+This file is part of falco.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+#pragma once
+
+class grpc_server_impl
+{
+public:
+	grpc_server_impl() = default;
+	~grpc_server_impl() = default;
+
+protected:
+	bool is_running();
+};
+
+bool start_grpc_server(unsigned short port, int threadiness);