require 'spec_helper'

describe 'fork reconnect' do
  require_fork
  only_mri

  # On multi-shard sharded clusters a succeeding write request does not
  # guarantee that the next operation will succeed (since it could be sent to
  # another shard with a dead connection).
  require_no_multi_shard

  # On Ruby 2.3 $?.exitstatus is sometimes nil after Process.wait returns which
  # is not supposed to happen.
  ruby_version_gte '2.4'

  let(:client) { authorized_client }
  let(:server) { client.cluster.next_primary }

  describe 'monitoring connection' do
    let(:monitor) do
      Mongo::Server::Monitor.new(server, [], Mongo::Monitoring.new, server.options)
    end

    it 'reconnects' do
      monitor.send(:do_scan).should be_a(Hash)

      socket = monitor.connection.send(:socket).send(:socket)
      (socket.is_a?(Socket) || socket.is_a?(OpenSSL::SSL::SSLSocket)).should be true

      if pid = fork
        pid, status = Process.wait2(pid)
        status.exitstatus.should == 0
      else
        monitor.send(:do_scan).should be_a(Hash)

        child_socket = monitor.connection.send(:socket).send(:socket)
        # fileno of child_socket may equal to fileno of socket,
        # as socket would've been closed first and file descriptors can be
        # reused by the kernel.
        child_socket.object_id.should_not == socket.object_id

        # Exec so that we do not close any clients etc. in the child.
        exec('/bin/true')
      end

      # Connection should remain serviceable in the parent.
      # The operation here will be invoked again, since the earlier invocation
      # was in the child process.
      monitor.send(:do_scan).should be_a(Hash)

      # The child closes the connection's socket, but this races with the
      # parent. The parent can retain the original socket for a while.
    end
  end

  describe 'non-monitoring connection' do
    let(:connection) do
      Mongo::Server::Connection.new(server, server.options)
    end

    let(:operation) do
      connection.ping.should be true
    end

    it 'does not reconnect' do
      connection.connect!

      socket = connection.send(:socket).send(:socket)
      (socket.is_a?(Socket) || socket.is_a?(OpenSSL::SSL::SSLSocket)).should be true

      if pid = fork
        pid, status = Process.wait2(pid)
        status.exitstatus.should == 0
      else
        Utils.wrap_forked_child do
          operation

          child_socket = connection.send(:socket).send(:socket)
          # fileno of child_socket may equal to fileno of socket,
          # as socket would've been closed first and file descriptors can be
          # reused by the kernel.
          child_socket.object_id.should == socket.object_id
        end
      end

      # The child closes the connection's socket, but this races with the
      # parent. The parent can retain the original socket for a while.
    end
  end

  describe 'connection pool' do

    it 'creates a new connection in child' do
      conn_id = server.with_connection do |connection|
        connection.id
      end

      if pid = fork
        pid, status = Process.wait2(pid)
        status.exitstatus.should == 0
      else
        Utils.wrap_forked_child do
          new_conn_id = server.with_connection do |connection|
            connection.id
          end

          new_conn_id.should_not == conn_id
        end
      end

      parent_conn_id = server.with_connection do |connection|
        connection.id
      end

      parent_conn_id.should == conn_id
    end
  end

  describe 'client' do
    it 'works after fork' do
      # Perform a write so that we discover the current primary.
      # Previous test may have stepped down the server that authorized client
      # considers the primary.
      # In standalone deployments there are no retries, hence execute the
      # operation twice manually.
      client['foo'].insert_one(test: 1) rescue nil
      client['foo'].insert_one(test: 1)

      if pid = fork
        pid, status = Process.wait2(pid)
        status.exitstatus.should == 0
      else
        Utils.wrap_forked_child do
          client.database.command(ismaster: 1).should be_a(Mongo::Operation::Result)
        end
      end

      # Perform a read which can be retried, so that the socket close
      # performed by the child is recovered from.
      client['foo'].find(test: 1)
    end
  end
end