Adding in queuing in the daggyd process for more even distribution

libdaggy/include/daggy/executors/task/DaggyRunnerTaskExecutor.hpp

@@ -2,7 +2,8 @@
 
 #include <rapidjson/document.h>
 
-#include <random>
+#include <condition_variable>
+#include <deque>
 
 #include "TaskExecutor.hpp"
 
@@ -56,6 +57,7 @@ namespace daggy::executors::task {
 
   private:
     void monitor();
+    void dispatchQueuedTasks();
 
     struct RunningTask
     {
@@ -63,19 +65,32 @@ namespace daggy::executors::task {
       DAGRunID runID;
       std::string taskName;
       std::string runnerURL;
-      uint32_t retries;
       daggy_runner::Capacity resources;
     };
 
+    struct QueuedTask
+    {
+      Task task;
+      RunningTask rt;
+    };
+
+    std::mutex queuedGuard_;
+    std::condition_variable queuedCV_;
+    std::deque<QueuedTask> queuedTasks_;
+
     // Resolves jobs through polling
     std::atomic<bool> running_;
+    bool promptTask_;
     std::thread monitorWorker_;
+    std::thread dispatchWorker_;
 
     struct RunnerCapacity
     {
       daggy_runner::Capacity current;
       daggy_runner::Capacity total;
     };
+    RunnerCapacity getRunnerCapacity(const std::string &runnerURL);
+
     std::mutex runnersGuard_;
     std::unordered_map<std::string, RunnerCapacity> runners_;