perq - Persistent Queue

Header-only persistent queue implementation based on RocksDB key-value storage.

Install

• Header-only usage
• C++-14 supporting compiler
• RocksDB
• Boost Filesystem, only for testing

How to

More examples could be found in tests/tests.cpp.

class MyQueueService {
public:
  MyQueueService() {
    auto temp_db = (rocksdb::DB*){};
    rocksdb::Options options;
    options.create_if_missing = true;
    rocksdb::Status status = rocksdb::DB::Open(options, "/tmp/perq", &temp_db);
    if (!status.ok())
      throw std::runtime_error("Failed to open the storage");
    _db.reset(temp_db);
    _queue_a.Initialize(_db.get());
    _queue_b.Initialize(_db.get());
  }

  std::string Top(uint8_t topic) {
    switch (topic) {
    case 32:
      return _queue_a.Top().first;
    case 231:
      return _queue_b.Top().first;
    default:
      throw std::runtime_error("Invalid topic");
    }
  }

  void Pop(uint8_t topic) {
    switch (topic) {
    case 32:
      _queue_a.Pop();
      break;
    case 231:
      _queue_b.Pop();
      break;
    default:
      throw std::runtime_error("Invalid topic");
    }
  }

  std::string Poll(uint8_t topic) {
    switch (topic) {
    case 32:
      return _queue_a.Poll().first;
    case 231:
      return _queue_b.Poll().first;
    default:
      throw std::runtime_error("Invalid topic");
    }
  }

  void Push(uint8_t topic, std::string const& value) {
    switch (topic) {
    case 32:
      _queue_a.Push(value);
      break;
    case 231:
      _queue_b.Push(value);
      break;
    default:
      throw std::runtime_error("Invalid topic");
    }
  }

  std::unique_ptr<rocksdb::DB> _db;
  PersistentQueue<uint64_t, uint8_t, 32> _queue_a;
  PersistentQueue<uint64_t, uint8_t, 231> _queue_b;
};