Adding support for remote execution daemons.

Squashed commit of the following:

commit 69d5ef7a256b86a86d46e5ae374c00fded1497ea
Author: Ian Roddis <tech@kinesin.ca>
Date:   Thu Dec 16 12:15:55 2021 -0400

    Updating readme

commit 94a9f676d0f9cc0b55cdc18c4927eaea40d82c77
Author: Ian Roddis <tech@kinesin.ca>
Date:   Thu Dec 16 12:05:36 2021 -0400

    Fixing serialization of attempt records when querying entire dag

commit 945e5f90b24abf07c9af1bc4c6bbcb33e93b8069
Author: Ian Roddis <tech@kinesin.ca>
Date:   Thu Dec 16 11:37:59 2021 -0400

    Compiles cleanly...

commit 8b23e46081d47fb80dc1a2d998fc6dc4bbf301a8
Author: Ian Roddis <tech@kinesin.ca>
Date:   Thu Dec 16 10:43:03 2021 -0400

    Adding in missing source file to cmake build list

commit 6d10d9791206e2bc15788beadeea580b8e43a853
Author: Ian Roddis <tech@kinesin.ca>
Date:   Thu Dec 16 10:41:43 2021 -0400

    Adding new executors

commit 42a2c67f4d6ae99df95d917c8621d78cd99837a1
Author: Ian Roddis <tech@kinesin.ca>
Date:   Thu Dec 16 10:27:14 2021 -0400

    Fixing missing curl cmake dependency

commit 394bc4c5d51ecee7bf14712f719c8bf7e97fb0fa
Author: Ian Roddis <tech@kinesin.ca>
Date:   Thu Dec 16 10:21:58 2021 -0400

    Fixing missing curl cmake dependency

commit dd9efc8e7e7770ea1bcbccb70a1af9cfcff0414c
Author: Ian Roddis <tech@kinesin.ca>
Date:   Wed Dec 15 17:15:38 2021 -0400

    Checkpointing progress

commit 3b3b55d6037bb96e46de6763f486f4ecb92fe6a0
Author: Ian Roddis <tech@kinesin.ca>
Date:   Wed Dec 15 14:21:18 2021 -0400

    updating readme

commit 303027c11452941b2a0c0d1b04ac5942e79efd74
Author: Ian Roddis <tech@kinesin.ca>
Date:   Wed Dec 15 14:17:16 2021 -0400

    Namespacing daggyd
    Adding more error checking around deserialization of parameters
    Adding tests for runner agent

commit c592eaeba12e2a449bae401e8c1d9ed236416d52
Author: Ian Roddis <tech@kinesin.ca>
Date:   Wed Dec 15 11:20:21 2021 -0400

    Checkpointing work

commit fb1862d1cefe2b53a98659cce3c8c73d88bf5d84
Author: Ian Roddis <tech@kinesin.ca>
Date:   Wed Dec 15 09:52:29 2021 -0400

    Copying daggyd for daggyr template, adding in basic routes

libdaggy/include/daggy/Utilities.hpp

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <curl/curl.h>
 #include <rapidjson/document.h>
 
 #include <string>
@@ -12,6 +13,8 @@
 #include "daggy/executors/task/TaskExecutor.hpp"
 #include "daggy/loggers/dag_run/DAGRunLogger.hpp"
 
+namespace rj = rapidjson;
+
 namespace daggy {
   using TaskDAG = DAG<std::string, Task>;
 
@@ -40,4 +43,48 @@ namespace daggy {
   void updateDAGFromTasks(TaskDAG &dag, const TaskSet &tasks);
 
   std::ostream &operator<<(std::ostream &os, const TimePoint &tp);
+
+  // HTTP helpers
+  enum HTTPCode : long
+  {
+    Ok             = 200,
+    Not_Found      = 404,
+    Not_Acceptable = 406
+  };
+
+  struct HTTPResponse
+  {
+    HTTPCode code;
+    std::string body;
+  };
+
+  HTTPResponse HTTP_REQUEST(const std::string &url,
+                            const std::string &payload = "",
+                            const std::string &method  = "GET",
+                            bool trace                 = false);
+
+  std::pair<HTTPCode, rj::Document> JSON_HTTP_REQUEST(
+      const std::string &url, const std::string &payload = "",
+      const std::string &method = "GET", bool trace = false);
 }  // namespace daggy
+
+template <typename T>
+void hash_combine(std::size_t &seed, T const &key)
+{
+  std::hash<T> hasher;
+  seed ^= hasher(key) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
+}
+
+namespace std {
+  template <typename T1, typename T2>
+  struct hash<std::pair<T1, T2>>
+  {
+    std::size_t operator()(std::pair<T1, T2> const &p) const
+    {
+      std::size_t seed(0);
+      ::hash_combine(seed, p.first);
+      ::hash_combine(seed, p.second);
+      return seed;
+    }
+  };
+}  // namespace std

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

@@ -0,0 +1,69 @@
+#pragma once
+
+#include <rapidjson/document.h>
+
+#include "TaskExecutor.hpp"
+
+namespace rj = rapidjson;
+
+namespace daggy::executors::task {
+
+  namespace daggy_runner {
+    struct Capacity
+    {
+      ssize_t cores;
+      ssize_t memoryMB;
+    };
+
+    std::string capacityToJSON(const Capacity &cap);
+    Capacity capacityFromJSON(const rj::Value &spec);
+    Capacity capacityFromTask(const Task &task);
+
+    void validateTaskParameters(const ConfigValues &job);
+  }  // namespace daggy_runner
+
+  class DaggyRunnerTaskExecutor : public TaskExecutor
+  {
+  public:
+    using Command = std::vector<std::string>;
+
+    DaggyRunnerTaskExecutor();
+    ~DaggyRunnerTaskExecutor() override;
+
+    // Validates the job to ensure that all required values are set and are of
+    // the right type,
+    bool validateTaskParameters(const ConfigValues &job) override;
+
+    std::vector<ConfigValues> expandTaskParameters(
+        const ConfigValues &job, const ConfigValues &expansionValues) override;
+
+    // Runs the task
+    std::future<AttemptRecord> execute(DAGRunID runID,
+                                       const std::string &taskName,
+                                       const Task &task) override;
+
+    bool stop(DAGRunID runID, const std::string &taskName) override;
+
+    void addRunner(const std::string &url);
+
+  private:
+    void monitor();
+
+    struct RunningTask
+    {
+      std::promise<AttemptRecord> prom;
+      DAGRunID runID;
+      std::string taskName;
+      std::string runnerURL;
+    };
+
+    // Resolves jobs through polling
+    std::atomic<bool> running_;
+    std::thread monitorWorker_;
+
+    std::unordered_set<std::string> runners_;
+    std::mutex rtGuard_;
+    std::unordered_map<std::pair<DAGRunID, std::string>, RunningTask>
+        runningTasks_;
+  };
+}  // namespace daggy::executors::task

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

@@ -5,6 +5,10 @@
 #include "TaskExecutor.hpp"
 
 namespace daggy::executors::task {
+  namespace forking_executor {
+    void validateTaskParameters(const ConfigValues &job);
+  }
+
   class ForkingTaskExecutor : public TaskExecutor
   {
   public: