Add basic infrastructure to submit tasks to the brain.

Author: tli2

src/include/brain/brain.h

@@ -0,0 +1,64 @@
+//===----------------------------------------------------------------------===//
+//
+//                         Peloton
+//
+// brain.h
+//
+// Identification: src/include/brain/brain.h
+//
+// Copyright (c) 2015-2018, Carnegie Mellon University Database Group
+//
+//===----------------------------------------------------------------------===//
+
+#pragma once
+#include <unordered_map>
+#include <string>
+#include <cstdio>
+#include <utility>
+#include "common/notifiable_task.h"
+
+namespace peloton {
+namespace brain {
+
+class BrainEnvironment {
+  // TODO(tianyu): provide interface for accessing various resources of the brain,
+  // such as network connection to a peloton engine.
+};
+
+class BrainJob {
+ public:
+  // TODO(tianyu): Extend this interface for richer interaction
+  virtual void RunJob(BrainEnvironment &env) { printf("foo"); };
+};
+
+class Brain {
+ public:
+  // TODO(tianyu): Add necessary parameters to initialize the brain's resources
+  Brain() : scheduler_(0) {}
+
+  inline void RegisterJob(const struct timeval *period,
+                          std::string name,
+                          BrainJob &job) {
+    auto callback = [&](int, short, void *env) {
+      job.RunJob(*reinterpret_cast<BrainEnvironment *>(env));
+    };
+    job_handles_[name] =
+        scheduler_.RegisterPeriodicEvent(period, callback, &env);
+  }
+
+  inline void Run() {
+    scheduler_.EventLoop();
+  }
+
+  inline void Terminate() {
+    scheduler_.ExitLoop();
+  }
+
+ private:
+  NotifiableTask scheduler_;
+  std::unordered_map<std::string, struct event *> job_handles_;
+  // TODO(tianyu): May need to have multiple env instead of shared
+  BrainEnvironment env;
+};
+}
+}

src/include/brain/scheduler_task.h

@@ -156,6 +156,11 @@ SETTING_bool(brain,
             false,
             true, true)
 
+SETTING_string(peloton_address,
+               "ip and port of the peloton rpc service, address:port",
+               "127.0.0.1:15445",
+               false, false)
+
 // Size of the brain task queue
 SETTING_int(brain_task_queue_size,
             "Brain Task Queue Size (default: 32)",

src/include/settings/settings.h

@@ -17,10 +17,42 @@
 #include "common/logger.h"
 #include "network/peloton_server.h"
 #include "settings/settings_manager.h"
+#include "brain/brain.h"
 
 // For GFlag's built-in help message flag
 DECLARE_bool(help);
 
+void RunPelotonEngine() {
+  try {
+    // Setup
+    peloton::PelotonInit::Initialize();
+
+    peloton::network::PelotonServer peloton_server;
+
+    peloton::network::PelotonServer::LoadSSLFileSettings();
+    peloton::network::PelotonServer::SSLInit();
+
+    peloton_server.SetupServer().ServerLoop();
+  } catch (peloton::ConnectionException &exception) {
+    // Nothing to do here!
+  }
+
+  // Teardown
+  peloton::PelotonInit::Shutdown();
+}
+
+
+void RunPelotonBrain() {
+  // TODO(tianyu): boot up other peloton resources as needed here
+  peloton::brain::Brain brain;
+  evthread_use_pthreads();
+  // TODO(tianyu): register jobs here
+  struct timeval *one_minute;
+  one_minute->tv_sec = 60;
+  brain.RegisterJob(one_minute, "test", peloton::brain::BrainJob());
+  brain.Run();
+}
+
 int main(int argc, char *argv[]) {
 
   // Parse the command line flags
@@ -39,22 +71,10 @@ int main(int argc, char *argv[]) {
     settings.ShowInfo();
   }
 
-  try {
-    // Setup
-    peloton::PelotonInit::Initialize();
-
-    peloton::network::PelotonServer peloton_server;
-
-    peloton::network::PelotonServer::LoadSSLFileSettings();
-    peloton::network::PelotonServer::SSLInit();
-
-    peloton_server.SetupServer().ServerLoop();
-  } catch (peloton::ConnectionException &exception) {
-    // Nothing to do here!
-  }
-
-  // Teardown
-  peloton::PelotonInit::Shutdown();
-
+  if (peloton::settings::SettingsManager::GetBool(
+      peloton::settings::SettingId::brain))
+    RunPelotonBrain();
+  else
+    RunPelotonEngine();
   return 0;
 }