几天前我问 Does it have a crystal-lang Queue? ,而@Johannes Mller回答我使用 Channel::Buffered(T) . 现在,我有一个小小的另一个问题。如果我有多个制作人怎么办?所有人都使用相同的 Channel ?

例如:

channel = Channel(String).new

# first producer
spawn do
  5.times do |i|
    puts "first producer #{i}"
    channel.send "first #{i}"
    sleep 0.1
  end
end

# second producer, that send data to the same with first producer channel
spawn do
  5.times do |i|
    puts "second producer #{i}"
    channel.send "second #{i}"
    sleep 0.1
  end
end

# consumer
spawn do
  loop do
    data = channel.receive
    puts "receive: #{data}"
    sleep 0.5
  end
end

sleep 6

输出将为:

$ crystal ./test.cr
first producer 0 # ok. first produced 0
second producer 0 # ok. second produced 0
receive: first 0 # ok. received from the first producer
first producer 1 # o_O. Where received data from the second producer?
receive: first 1 
first producer 2
receive: first 2
first producer 3
receive: first 3
first producer 4
receive: first 4
receive: second 0 # aa. It's here... Why it's happend only, when the first producer was produced all?
second producer 1 
receive: second 1
second producer 2
receive: second 2
second producer 3
receive: second 3
second producer 4
receive: second 4

正如您所见,“第二个制作人”几乎与第一个同时发送第一个包,但直到第一个制作人完成工作之前,它都被忽略了。不管通道是否已缓冲。

为什么他们没有始终如一地工作?如果第一个生产者以一个永恒的周期工作,则从未收到来自第二个生产者的数据。

也许这种行为应该是这样的,并将数据从几个地方发送到一个地方-显然是不好的做法?