英文:
natsClient.Subscribe("some_subject", some_callback): Does the 'some_callback' callback run in its own subroutine in Golang?
问题
基本上，主题说的是。我想知道每次调用回调方法时，nats-lib for golang 是否确保回调在自己的 goroutine 中运行（我有99%的把握，但我需要确认，因为我找不到 nats 中明确说明的文档片段 - 如果我漏掉了什么，请随意复制粘贴任何链接）。
如果回调确实在自己的 goroutine 中运行，我还想知道：
a. 每个特定订阅是否每次都使用相同的 goroutine
或者 b. 每次回调触发时是否创建一个临时的 goroutine：在这种情况下，回调完成后该 goroutine 将被销毁。
英文:
Essentially what the subject says. I'm interested to know whether each time the callback method is invoked the nats-lib for golang ensures that the callback will run on its very own goroutine (I'm 99% sure that it does but I need to make sure because I can't find any explicit piece of documentation in nats that conclusively states it so - feel free to copy paste any links if I've missed something).
If the callback does indeed run in it's own goroutine I'm also interested to know whether:
a. the same goroutine is used every time for a specific subscription
or b. an ephimeral goroutine is created for each firing of the callback: in this case the goroutine gets disposed of after the callback has done its work
答案1
得分: 2
当你调用conn.Subscribe("some_subject", someCallback)时，如果定义了回调函数，它会执行以下代码：
// 如果有异步回调函数，启动一个特定的Go协程来传递消息。
if cb != nil {
sub.typ = AsyncSubscription
sub.pCond = sync.NewCond(&sub.mu)
go nc.waitForMsgs(sub)
}
它为创建的订阅启动了一个Go协程。当消息到达时，它会在waitForMsgs协程中执行定义的回调函数。
简而言之，答案是a. 对于特定的订阅，它每次都使用相同的Go协程。
英文:
When you call conn.Subscribe("some_subject", someCallback), it executes this piece of code if the callback is defined:
// If we have an async callback, start up a sub specific
// Go routine to deliver the messages.
if cb != nil {
sub.typ = AsyncSubscription
sub.pCond = sync.NewCond(&sub.mu)
go nc.waitForMsgs(sub)
}
It launches a goroutine for the created subscription. When a message arrives, it executes the defined callback inside the waitForMsgs goroutine.
In short, the answer is a., it uses the same goroutine every time for a specific subscription.
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