Goroutines are not threads: https://rcoh.me/posts/why-you-can-have-a-million-go-routines...

Goroutines are probably closer to Fibers which D also has:

https://en.wikipedia.org/wiki/Fiber_(computer_science)

They used to be closer to fibers years ago, when they were running on a single thread by default. Now they behave exactly like normal threads with the same problems. And fibers are threads anyway.

Care to share a reference to them no longer being lightweight?

They still start with tiny stacks, if that's what you are asking. I believe it's somewhere around 2 KB nowadays.

goroutines are anything but threads.

Here's a 40min talk explaining how Go's scheduler works:

https://youtu.be/YHRO5WQGh0k

No, they are threads. It doesn't matter if they start with tiny growing stacks and whether blocking syscall wrappers call into the scheduler. Those are just implementation details.

I mean, sure, but they have all the same problems as threads for most / application-level developers. They're indeed quite different when you get into calling out to C or other kinds of FFI, but relatively few developers need to do so directly. For everyone else, they come with very nearly exactly the same semantics as threads.

I have used both and its hard to argue that goroutines and channels are as easy to use as async/await.

On the surface, perhaps, but when you factor in the gotchas of both approaches and the debugging difficulty, I much prefer goroutines. In particular, I’ve never witnessed someone DOS a fleet of servers in Go by scheduling a task was making a sync call under the covers, by doing an intensive computation in the event loop, or by scheduling tens of thousands of tiny events. We also have a lot of bugs involving accidentally putting the task/coroutine into a variable instead of the result of the task because the programmer forgot the “await” keyword, but that’s a dynamic typing problem.

Goroutines are not threads. Async await behind the scenes uses threads.

Does it? https://blog.stephencleary.com/2013/11/there-is-no-thread.ht...

In that case and in some others it doesn’t, but in general it does: https://stackoverflow.com/questions/17661428/async-stay-on-t... Probably it makes sense to say that async await can try to use a continuation passing style or run on a different thread because there is no actual guarantee that it will use one or the other.