And if you prefer a talk, there is one by Bryan C. Mills, https://www.youtube.com/watch?v=5zXAHh5tJqQ
which describes common concurrency patterns and how to apply them. In your case, a buffered channel can work as a (counting) semaphore. The invariant is: the number of tokens in the channel is the number of currently active workers. If the channel is full and you block, all worker slots are occupied. As workers complete, they remove a token from the channel, making room for another worker. Finalization is important. You end by _filling_ the semaphore with tokens. These tokens have no workers associated with them, but are "virtual dummy sentinels" in a sense. Once the channel is full of these sentinel tokens, all the real workers must have exited, so you can go on[0]. You can also see this as vacant seats in a restaurant, say. As the restaurant wants to close, it starts filling up the seats with bulbasaurs. Once all seats have bulbasaurs in them, the restaurant can close. [0] The section is at https://youtu.be/5zXAHh5tJqQ?t=1902 but the whole talk is definitely worth it. On Sat, Jun 8, 2019 at 8:25 AM Krzysztof Kowalczyk <kkowalc...@gmail.com> wrote: > See > https://www.programming-books.io/essential/go/limiting-concurrency-with-a-semaphore-26ac6084d7404f7385e4eccaa3fd20de > for > one way that uses a channel as a semaphore to limit concurrency. > > On Friday, June 7, 2019 at 6:28:01 PM UTC-7, Joseph Wang wrote: >> >> Hi everyone >> >> I have a simple question about go routines. >> >> So I have a function like this >> >> Func1() { >> >> for n := range array { >> go fun2() >> } >> } >> >> So as I can not make sure array has a fix size, then I cannot control go >> routines number. Does any one have some elegant ways that I can limit this >> function1 create fix number go routines? >> >> Best >> >> Joseph >> > -- > You received this message because you are subscribed to the Google Groups > "golang-nuts" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to golang-nuts+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/ceb52644-b7a7-4ab1-aa74-dd5b60fbd55c%40googlegroups.com > <https://groups.google.com/d/msgid/golang-nuts/ceb52644-b7a7-4ab1-aa74-dd5b60fbd55c%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- J. -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/CAGrdgiWDF1eB4D_9U9k9sTm-PVbJKaYABeL%3D4H_jDk4EUbY%3DUg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
