Adding check for unsatisfyable requirements in a remote task

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

@@ -74,6 +74,8 @@ namespace daggy::executors::task {
 
     daggy_runner::Capacity getRunnerCapacity(const std::string &runnerURL);
 
+    std::vector<daggy_runner::Capacity> runnersMaxCapacities_;
+
     std::mutex runnersGuard_;
     std::condition_variable runnersCV_;
     std::unordered_map<std::string, daggy_runner::Capacity> runners_;

libdaggy/src/executors/task/DaggyRunnerTaskExecutor.cpp

@@ -113,6 +113,20 @@ bool DaggyRunnerTaskExecutor::validateTaskParameters(const ConfigValues &job)
 {
   daggy_runner::validateTaskParameters(job);
 
+  // Ensure the job is actually runable
+  auto cores    = std::stoll(std::get<std::string>(job.at("cores")));
+  auto memoryMB = std::stoll(std::get<std::string>(job.at("memoryMB")));
+
+  auto it =
+      std::find_if(runnersMaxCapacities_.begin(), runnersMaxCapacities_.end(),
+                   [&](const auto &cap) {
+                     return (cores <= cap.cores and memoryMB <= cap.memoryMB);
+                   });
+  if (it == runnersMaxCapacities_.end())
+    throw std::runtime_error("Task requires " + std::to_string(cores) +
+                             " cores and " + std::to_string(memoryMB) +
+                             " MB memory, but no runner "
+                             "can satisty those requirements");
   return true;
 }
 
@@ -219,7 +233,10 @@ daggy_runner::Capacity DaggyRunnerTaskExecutor::getRunnerCapacity(
 void DaggyRunnerTaskExecutor::addRunner(const std::string &url)
 {
   std::lock_guard<std::mutex> lock(runnersGuard_);
-  runners_.emplace(url, getRunnerCapacity(url));
+  auto maxCapacity = getRunnerCapacity(url);
+
+  runnersMaxCapacities_.push_back(maxCapacity);
+  runners_.emplace(url, maxCapacity);
 }
 
 void DaggyRunnerTaskExecutor::monitor()