discovery/azure: more robust handling of go routines
@@ -19,6 +19,7 @@ import (
"net"
"net/http"
"strings"
+ "sync"
"time"
"github.com/Azure/azure-sdk-for-go/arm/compute"
@@ -324,9 +325,12 @@ func (d *Discovery) refresh() (tg *targetgroup.Group, err error) {
err error
}
+ var wg sync.WaitGroup
+ wg.Add(len(machines))
ch := make(chan target, len(machines))
for i, vm := range machines {
go func(i int, vm virtualMachine) {
+ defer wg.Done()
r, err := newAzureResourceFromID(vm.ID, d.logger)
if err != nil {
ch <- target{labelSet: nil, err: err}
@@ -374,7 +378,6 @@ func (d *Discovery) refresh() (tg *targetgroup.Group, err error) {
// is a cheap and easy way to determine if a machine is allocated or not.
if networkInterface.Properties.Primary == nil {
level.Debug(d.logger).Log("msg", "Skipping deallocated virtual machine", "machine", vm.Name)
- ch <- target{}
return
}
@@ -395,15 +398,13 @@ func (d *Discovery) refresh() (tg *targetgroup.Group, err error) {
}
}
}
-
- // If we get here we haven't sent anything to the channel.
- // We need to send it something to release it.
- ch <- target{}
}(i, vm)
}
- for range machines {
- tgt := <-ch
+ wg.Wait()
+ close(ch)
+
+ for tgt := range ch {
if tgt.err != nil {
return nil, fmt.Errorf("unable to complete Azure service discovery: %s", err)
}
