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Problems with Go channels (2016)

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159 points mpweiher | 2 comments | 13 Apr 25 05:43 UTC | HN request time: 0.463s | source
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anacrolix ◴[13 Apr 25 12:52 UTC] No.43672435[source]▶
I've been using Go since 2011. One year less than the author. Channels are bad. No prioritization. No combining with other synchronisation primitives without extra goroutines. In Go, no way to select on a variable number of channels (without more goroutines). The poor type system doesn't let you improve abstractions. Basically anywhere I see a channel in most people's code particular in the public interface, I know it's going to be buggy. And I've seen so many bugs. Lots of abandoned projects are because they started with channels and never dug themselves out.

The lure to use channels is too strong for new users.

The nil and various strange shapes of channel methods aren't really a problem they're just hard for newbs.

Channels in Go should really only be used for signalling, and only if you intend to use a select. They can also act as reducers, fan out in certain cases. Very often in those cases you have a very specific buffer size, and you're still only using them to avoid adding extra goroutines and reverting to pure signalling.

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1. politician ◴[13 Apr 25 13:12 UTC] No.43672565[source]▶
One nit: reflect.Select supports a dynamic set of channels. Very few programs need it though, so a rough API isn’t a bad trade-off. In my entire experience with Go, I’ve needed it once, and it worked perfectly.
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2. lanstin ◴[13 Apr 25 20:20 UTC] No.43675560[source]▶
I almost always only use Channels as the data path between fixed sized pools of workers. At each point I can control if blocking or not, and my code uses all the (allocated) CPUs pretty evenly. Channels are excellent for this data flow design use case.

I have a little pain when I do a cli as the work appears during the run and it’s tricky to guarantee you exit when all the work is done and not before. Usually Ihave a sleep one second, wait for wait group, sleep one more second at the end of the CLI main. If my work doesn’t take minutes or hours to run, I generally don’t use Go.