func()

in discovery/azure/azure.go [243:373]
102 lines of code
23 McCabe index (conditional complexity)

func (d *Discovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
	defer level.Debug(d.logger).Log("msg", "Azure discovery completed")

	client, err := createAzureClient(*d.cfg)
	if err != nil {
		return nil, errors.Wrap(err, "could not create Azure client")
	}

	machines, err := client.getVMs(ctx)
	if err != nil {
		return nil, errors.Wrap(err, "could not get virtual machines")
	}

	level.Debug(d.logger).Log("msg", "Found virtual machines during Azure discovery.", "count", len(machines))

	// Load the vms managed by scale sets.
	scaleSets, err := client.getScaleSets(ctx)
	if err != nil {
		return nil, errors.Wrap(err, "could not get virtual machine scale sets")
	}

	for _, scaleSet := range scaleSets {
		scaleSetVms, err := client.getScaleSetVMs(ctx, scaleSet)
		if err != nil {
			return nil, errors.Wrap(err, "could not get virtual machine scale set vms")
		}
		machines = append(machines, scaleSetVms...)
	}

	// We have the slice of machines. Now turn them into targets.
	// Doing them in go routines because the network interface calls are slow.
	type target struct {
		labelSet model.LabelSet
		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}
				return
			}

			labels := model.LabelSet{
				azureLabelSubscriptionID:       model.LabelValue(d.cfg.SubscriptionID),
				azureLabelTenantID:             model.LabelValue(d.cfg.TenantID),
				azureLabelMachineID:            model.LabelValue(vm.ID),
				azureLabelMachineName:          model.LabelValue(vm.Name),
				azureLabelMachineOSType:        model.LabelValue(vm.OsType),
				azureLabelMachineLocation:      model.LabelValue(vm.Location),
				azureLabelMachineResourceGroup: model.LabelValue(r.ResourceGroup),
			}

			if vm.ScaleSet != "" {
				labels[azureLabelMachineScaleSet] = model.LabelValue(vm.ScaleSet)
			}

			if vm.Tags != nil {
				for k, v := range vm.Tags {
					name := strutil.SanitizeLabelName(k)
					labels[azureLabelMachineTag+model.LabelName(name)] = model.LabelValue(*v)
				}
			}

			// Get the IP address information via separate call to the network provider.
			for _, nicID := range vm.NetworkInterfaces {
				networkInterface, err := client.getNetworkInterfaceByID(ctx, nicID)

				if err != nil {
					level.Error(d.logger).Log("msg", "Unable to get network interface", "name", nicID, "err", err)
					ch <- target{labelSet: nil, err: err}
					// Get out of this routine because we cannot continue without a network interface.
					return
				}

				if networkInterface.InterfacePropertiesFormat == nil {
					continue
				}

				// Unfortunately Azure does not return information on whether a VM is deallocated.
				// This information is available via another API call however the Go SDK does not
				// yet support this. On deallocated machines, this value happens to be nil so it
				// is a cheap and easy way to determine if a machine is allocated or not.
				if networkInterface.Primary == nil {
					level.Debug(d.logger).Log("msg", "Skipping deallocated virtual machine", "machine", vm.Name)
					return
				}

				if *networkInterface.Primary {
					for _, ip := range *networkInterface.IPConfigurations {
						if ip.PublicIPAddress != nil && ip.PublicIPAddress.PublicIPAddressPropertiesFormat != nil {
							labels[azureLabelMachinePublicIP] = model.LabelValue(*ip.PublicIPAddress.IPAddress)
						}
						if ip.PrivateIPAddress != nil {
							labels[azureLabelMachinePrivateIP] = model.LabelValue(*ip.PrivateIPAddress)
							address := net.JoinHostPort(*ip.PrivateIPAddress, fmt.Sprintf("%d", d.port))
							labels[model.AddressLabel] = model.LabelValue(address)
							ch <- target{labelSet: labels, err: nil}
							return
						}
						// If we made it here, we don't have a private IP which should be impossible.
						// Return an empty target and error to ensure an all or nothing situation.
						err = errors.Errorf("unable to find a private IP for VM %s", vm.Name)
						ch <- target{labelSet: nil, err: err}
						return
					}
				}
			}
		}(i, vm)
	}

	wg.Wait()
	close(ch)

	var tg targetgroup.Group
	for tgt := range ch {
		if tgt.err != nil {
			return nil, errors.Wrap(err, "unable to complete Azure service discovery")
		}
		if tgt.labelSet != nil {
			tg.Targets = append(tg.Targets, tgt.labelSet)
		}
	}

	return []*targetgroup.Group{&tg}, nil
}