Merge pull request #141 from richiMarchi/save_load_topology

load old topology at startup and save each modification to file

Author: frisso

Documentation/polycubed/polycubed.rst

@@ -54,7 +54,34 @@ If the same parameter is specified in both, the configuration file and the comma
     daemon: true
     #p: 6000 <-- this is NOT supported, only long options are
 
+
+
+Persistency
+^^^^^^^^^^^
+
+Polycubed has persistent capabilities, which means that (1) it can automatically load the configuration that was present when the daemon was shut down, (2) each time a configuration command is issued, it is automatically dumped on disk.
+This enables polycubed also to recover from failures, such as rebooting the machine.
+By default, the daemon keeps in memory an instance of all the topology, including the configuration of each individual service.
+Topology and configuration are automatically updated at each new command; the configuration is also dumped to disk, on file ``/etc/polycube/cubes.yaml``.
+The standard behavior of the daemon at startup is to load the latest topology that was active at the end of the previous execution.
+Users can load a different topology file by using the ``--cubes-dump`` flag followed by the path to the file.
+In case we want to start polycubed with an empty topology, avoiding any possible load at startup, we can launch polycubed with the ``--cubes-init`` flag. Beware that in this case any existing configuration in the default file will be overwritten.
+Finally, persistency can be disabled with the ``--cubes-nodump`` flag; this would also avoid any (very limited) performance penalty introduced by this feature.
+
+::
+
+    # start polycubed with custom cubes configuration
+    polycubed --cubes-dump ~/Desktop/myCubes.yaml
+
+    # start polycubed with an empty topology
+    polycubed --cubes-init
+
+    # start daemon without topology saving functionalities
+    polycubed --cubes-nodump
+
+
+
 Rest API
 ^^^^^^^^
 
-TODO...
+TODO...

src/libs/polycube/include/polycube/services/cube.h

@@ -120,6 +120,19 @@ std::shared_ptr<PortType> Cube<PortType>::add_port(const std::string &port_name,
 
     std::tie(iter, inserted) = ports_by_name_.emplace(port_name, port);
     ports_by_id_.emplace(port->index(), port);
+    /*
+     * When a transparent cube is attached to a port, it can query the service
+     * to get some port parameters (e.g., MAC address). If the transparent cube
+     * is attached while the port is being created these parameters will be not
+     * configured yet.
+     * This workaround first creates the port and then passes the configuration
+     * to attach the transparent cubes. The configuration that is passed
+     * in the constructor is ignored in the daemon.
+     * The solution for this workaround would be to implement the notification
+     * mechanishm, so when the parameters are configured those are pushed to the
+     * transparent cube.
+     */
+    port->set_conf(conf.getBase());
     return iter->second;
   } catch (const std::exception &ex) {
     cube_->remove_port(port_name);

src/polycubed/src/CMakeLists.txt

@@ -62,6 +62,7 @@ set(polycubed_sources
   utils/veth.cpp
   utils/netlink.cpp
   utils/utils.cpp
+  cubes_dump.cpp
   ${server_sources}
   ${CMAKE_CURRENT_BINARY_DIR}/load_services.cpp
   ${CMAKE_CURRENT_BINARY_DIR}/version.cpp)

src/polycubed/src/base_model.cpp

@@ -244,4 +244,24 @@ Response BaseModel::set_span(const std::string &cube_name,
   return Response{kOk, ::strdup("")};
 }
 
+Response BaseModel::get_port_tcubes(const std::string &cube_name,
+                                    const std::string &port_name) const {
+  auto cube_ = ServiceController::get_cube(cube_name);
+  if (cube_ == nullptr) {
+    return Response{kNoContent, ::strdup("Cube does not exist")};
+  }
+
+  // TODO: is this case even possible?
+  auto cube = std::dynamic_pointer_cast<CubeIface>(cube_);
+  if (cube == nullptr) {
+    return Response{kNoContent, ::strdup("Cube is transparent")};
+  }
+
+  auto port_ = cube->get_port(port_name);
+  auto port = std::dynamic_pointer_cast<Port>(port_);
+  nlohmann::json j = port->get_cubes_names();
+
+  return Response{kOk, ::strdup(j.dump().c_str())};
+}
+
 }  // namespace polycube::polycubed

src/polycubed/src/base_model.h

@@ -50,6 +50,8 @@ class BaseModel {
   Response get_span(const std::string &cube_name) const;
   Response set_span(const std::string &cube_name,
                       const nlohmann::json &json);
+  Response get_port_tcubes(const std::string &cube_name,
+                           const std::string &port_name) const;
 };
 
 }  // namespace polycube::polycubed

src/polycubed/src/config.cpp

@@ -32,13 +32,17 @@ namespace configuration {
 
 #define LOGLEVEL spdlog::level::level_enum::info
 #define DAEMON false
+#define CUBESINIT false
+#define CUBESNODUMP false
 #define PIDFILE "/var/run/polycube.pid"
 #define SERVER_PORT 9000
 #define SERVER_IP "localhost"
 #define LOGFILE "/var/log/polycube/polycubed.log"
 #define CONFIGFILEDIR "/etc/polycube"
 #define CONFIGFILENAME "polycubed.conf"
+#define CUBESDUMPFILE "cubes.yaml"
 #define CONFIGFILE (CONFIGFILEDIR "/" CONFIGFILENAME)
+#define CUBESDUMPFILEPATH (CONFIGFILEDIR "/" CUBESDUMPFILE)
 
 static void show_usage(const std::string &name) {
   std::cout << std::boolalpha;
@@ -64,6 +68,11 @@ static void show_usage(const std::string &name) {
             << ")" << std::endl;
   std::cout << "--configfile: configuration file (default: " << CONFIGFILE
             << ")" << std::endl;
+  std::cout << "--cubes-dump: file that keeps the last topology, "
+               "including the configuration of all cubes (default: " << CUBESDUMPFILEPATH
+            << ")" << std::endl;
+  std::cout << "--cubes-init: starts the daemon with an empty topology" << std::endl;
+  std::cout << "--cubes-nodump: starts the daemon without dumping updates to file" << std::endl;
   std::cout << "--cert-blacklist: path to black listed certificates"
             << std::endl;
   std::cout << "--cert-whitelist: path to white listed certificates"
@@ -95,7 +104,10 @@ Config::Config()
       server_port(SERVER_PORT),
       server_ip(SERVER_IP),
       logfile(LOGFILE),
-      configfile(CONFIGFILE) {}
+      configfile(CONFIGFILE),
+      cubes_dump_file(CUBESDUMPFILEPATH),
+      cubes_init(CUBESINIT),
+      cubes_nodump(CUBESNODUMP){}
 
 Config::~Config() {}
 
@@ -180,6 +192,31 @@ void Config::setLogFile(const std::string &value) {
   logfile = value;
 }
 
+std::string Config::getCubesDumpFilePath() const {
+  return cubes_dump_file;
+}
+
+void Config::setCubesDumpFilePath(const std::string &value) {
+  CHECK_OVERWRITE("cubes-dump", value, cubes_dump_file, CUBESDUMPFILEPATH);
+  cubes_dump_file = value;
+}
+
+bool Config::getCubesInitTopology() const {
+  return cubes_init;
+}
+
+void Config::setCubesInitTopology() {
+  cubes_init = true;
+}
+
+bool Config::getCubesNoDump() const {
+  return cubes_nodump;
+}
+
+void Config::setCubesNoDump() {
+  cubes_nodump = true;
+}
+
 std::string Config::getCertPath() const {
   return cert_path;
 }
@@ -246,6 +283,8 @@ void Config::create_configuration_file(const std::string &path) {
   file << "addr: " << server_ip << std::endl;
   file << "# file to save polycube logs" << std::endl;
   file << "logfile: " << logfile << std::endl;
+  file << "# file to save last topology" << std::endl;
+  file << "cubes-dump: " << cubes_dump_file << std::endl;
   file << "# Security related:" << std::endl;
   file << "# server certificate " << std::endl;
   file << "#cert: path_to_certificate_file" << std::endl;
@@ -270,6 +309,9 @@ void Config::dump() {
   logger->info(" port: {}", server_port);
   logger->info(" addr: {}", server_ip);
   logger->info(" logfile: {}", logfile);
+  logger->info(" cubes-dump: {}", cubes_dump_file);
+  logger->info(" cubes-init: {}", cubes_init);
+  logger->info(" cubes-nodump: {}", cubes_nodump);
   if (!cert_path.empty()) {
     logger->info(" cert: {}", cert_path);
   }
@@ -363,6 +405,9 @@ static struct option options[] = {
     {"cacert", required_argument, NULL, 5},
     {"cert-whitelist", required_argument, NULL, 6},
     {"cert-blacklist", required_argument, NULL, 7},
+    {"cubes-dump", required_argument, NULL, 8},
+    {"cubes-init", no_argument, NULL, 9},
+    {"cubes-nodump", no_argument, NULL, 10},
     {NULL, 0, NULL, 0},
 };
 
@@ -408,6 +453,15 @@ void Config::load_from_cli(int argc, char *argv[]) {
     case 7:
       setCertBlacklistPath(optarg);
       break;
+    case 8:
+      setCubesDumpFilePath(optarg);
+      break;
+    case 9:
+      setCubesInitTopology();
+      break;
+    case 10:
+      setCubesNoDump();
+      break;
     }
   }
 }

src/polycubed/src/config.h

@@ -53,6 +53,18 @@ class Config {
   std::string getLogFile() const;
   void setLogFile(const std::string &value);
 
+  // file where last topology is saved
+  std::string getCubesDumpFilePath() const;
+  void setCubesDumpFilePath(const std::string &value);
+
+  // set to get an empty topology
+  bool getCubesInitTopology() const;
+  void setCubesInitTopology();
+
+  // set to avoid daemon to dump updates to file
+  bool getCubesNoDump() const;
+  void setCubesNoDump();
+
   // path of certificate & key to be used in server
   std::string getCertPath() const;
   void setCertPath(const std::string &value);
@@ -80,11 +92,14 @@ class Config {
 
   spdlog::level::level_enum loglevel;
   bool daemon;
+  bool cubes_init;
+  bool cubes_nodump;
   std::string pidfile;
   uint16_t server_port;
   std::string server_ip;
   std::string logfile;
   std::string configfile;
+  std::string cubes_dump_file;
   std::string cert_path, key_path;
   std::string cacert_path;
   std::string cert_whitelist_path;