Keep machine stats even when a machine is removed from the machines file

Dependencies

• [2] 4I2HF4L3 Unindent
• [3] 5AIYUMTB Basic remote building
• [4] SODOV2CM Automatically reload $NIX_REMOTE_SYSTEMS when it changes
• [*] MHVIT4JY Split hydra-queue-runner.cc more
• [*] 24BMQDZA Start of single-process hydra-queue-runner
• [*] PLOZBRTR Add command ‘hydra-queue-runner --status’ to show current status
• [*] HJOEIMLR Refactor

Change contents

• edit in src/hydra-queue-runner/dispatcher.cc at line 92
  [2.1342]

  [2.1342]
  + if (!m.second->enabled) continue;
• replacement in src/hydra-queue-runner/hydra-queue-runner.cc at line 77
  [3.3150]→[3.3150:3210](∅→∅)
  − if (newMachines.find(m.first) == newMachines.end())
  [3.3150]

  [3.3210]
  + if (newMachines.find(m.first) == newMachines.end()) {
• edit in src/hydra-queue-runner/hydra-queue-runner.cc at line 79
  [3.3289]

  [3.9371]
  + /* Add a disabled Machine object to make sure stats are

  + maintained. */

  + auto machine = std::make_shared<Machine>(*(m.second));

  + machine->enabled = false;

  + newMachines[m.first] = machine;

  + }
• edit in src/hydra-queue-runner/hydra-queue-runner.cc at line 498
  [8.1878]

  [3.4578]
  + nested2.attr("enabled", m->enabled);
• edit in src/hydra-queue-runner/state.hh at line 203
  [9.3325]

  [9.3325]
  +

  + bool enabled{true};