Go multiplexes goroutines onto the available threads which is determined by the GOMAXPROCS
environment setting. As a result if this is set to 1 then a single goroutine can hog the single thread Go has available to it until it yields control back to the Go runtime. More than likely doSomeBackgroundWork
is hogging all the time on a single thread which is preventing the http handler from getting scheduled.
There are a number of ways to fix this.
First, as a general rule when using goroutines, you should set GOMAXPROCS
to the number of CPUs your system has or to whichever is bigger.
Second, you can yield control in a goroutine by doing any of the following:
runtime.Gosched()
ch <- foo
foo := <-ch
select { ... }
mutex.Lock()
mutex.Unlock()
All of these will yield back to the Go runtime scheduler giving other goroutines a chance to work.