Chris's Wiki :: blog/programming/GoAndPromisesPattern
This is my face when I realize I have a situation that 'promises'/asynchronously waitable objects would be great for, but I would have to build them by hand in Go. Oh well.
(I want asynchronous execution but to report the results in order, as each becomes available. With promises as I understand them, generate all the promises in an array, wait for each one in order, report results from it, done.)
A common pattern with work(er) pools in Go and elsewhere is that you want to submit requests to a pool of asynchronous workers and you're happy to handle the completion of that work in any order. This is easily handled in Go with a pair of channels, one for requests and the other for completions. However, this time around I wanted asynchronous requests but to be able to report on completed work in order.
(The specific context is that I've got a little Go program to do IP to name DNS lookups (it's in Go for reasons), and on the one hand it would be handy to do several DNS lookups in parallel because sometimes they take a while, but on the other hand I want to print the results in command line order because otherwise it gets confusing.)
