package chroot import ( "context" "errors" "fmt" "log" "os" "path/filepath" "strings" "syscall" "time" "github.com/hashicorp/packer/builder/azure/common/client" "github.com/Azure/azure-sdk-for-go/services/compute/mgmt/2019-07-01/compute" "github.com/Azure/go-autorest/autorest/azure" "github.com/Azure/go-autorest/autorest/to" ) type DiskAttacher interface { AttachDisk(ctx context.Context, disk string) (lun int32, err error) DiskPathForLun(lun int32) string WaitForDevice(ctx context.Context, i int32) (device string, err error) DetachDisk(ctx context.Context, disk string) (err error) WaitForDetach(ctx context.Context, diskID string) error } var NewDiskAttacher = func(azureClient client.AzureClientSet) DiskAttacher { return &diskAttacher{ azcli: azureClient, } } type diskAttacher struct { azcli client.AzureClientSet vm *client.ComputeInfo // store info about this VM so that we don't have to ask metadata service on every call } func (diskAttacher) DiskPathForLun(lun int32) string { return fmt.Sprintf("/dev/disk/azure/scsi1/lun%d", lun) } func (da diskAttacher) WaitForDevice(ctx context.Context, lun int32) (device string, err error) { path := da.DiskPathForLun(lun) for { link, err := os.Readlink(path) if err == nil { return filepath.Abs("/dev/disk/azure/scsi1/" + link) } else if err != os.ErrNotExist { if pe, ok := err.(*os.PathError); ok && pe.Err != syscall.ENOENT { return "", err } } select { case <-time.After(100 * time.Millisecond): // continue case <-ctx.Done(): return "", ctx.Err() } } } func (da *diskAttacher) DetachDisk(ctx context.Context, diskID string) error { log.Println("Fetching list of disks currently attached to VM") currentDisks, err := da.getDisks(ctx) if err != nil { return err } log.Printf("Removing %q from list of disks currently attached to VM", diskID) newDisks := []compute.DataDisk{} for _, disk := range currentDisks { if disk.ManagedDisk != nil && !strings.EqualFold(to.String(disk.ManagedDisk.ID), diskID) { newDisks = append(newDisks, disk) } } if len(currentDisks) == len(newDisks) { return DiskNotFoundError } log.Println("Updating new list of disks attached to VM") err = da.setDisks(ctx, newDisks) if err != nil { return err } return nil } func (da *diskAttacher) WaitForDetach(ctx context.Context, diskID string) error { for { // loop until disk is not attached, timeout or error list, err := da.getDisks(ctx) if err != nil { return err } if findDiskInList(list, diskID) == nil { log.Println("Disk is no longer in VM model, assuming detached") return nil } select { case <-time.After(time.Second): //continue case <-ctx.Done(): return ctx.Err() } } } var DiskNotFoundError = errors.New("Disk not found") func (da *diskAttacher) AttachDisk(ctx context.Context, diskID string) (int32, error) { dataDisks, err := da.getDisks(ctx) if err != nil { return -1, err } // check to see if disk is already attached, remember lun if found if disk := findDiskInList(dataDisks, diskID); disk != nil { // disk is already attached, just take this lun if disk.Lun == nil { return -1, errors.New("disk is attached, but lun was not set in VM model (possibly an error in the Azure APIs)") } return to.Int32(disk.Lun), nil } // disk was not found on VM, go and actually attach it var lun int32 = -1 findFreeLun: for lun = 0; lun < 64; lun++ { for _, v := range dataDisks { if to.Int32(v.Lun) == lun { continue findFreeLun } } // no datadisk is using this lun break } // append new data disk to collection dataDisks = append(dataDisks, compute.DataDisk{ CreateOption: compute.DiskCreateOptionTypesAttach, ManagedDisk: &compute.ManagedDiskParameters{ ID: to.StringPtr(diskID), }, Lun: to.Int32Ptr(lun), }) // prepare resource object for update operation err = da.setDisks(ctx, dataDisks) if err != nil { return -1, err } return lun, nil } func (da *diskAttacher) getThisVM(ctx context.Context) (compute.VirtualMachine, error) { // getting resource info for this VM if da.vm == nil { vm, err := da.azcli.MetadataClient().GetComputeInfo() if err != nil { return compute.VirtualMachine{}, err } da.vm = vm } // retrieve actual VM vmResource, err := da.azcli.VirtualMachinesClient().Get(ctx, da.vm.ResourceGroupName, da.vm.Name, "") if err != nil { return compute.VirtualMachine{}, err } if vmResource.StorageProfile == nil { return compute.VirtualMachine{}, errors.New("properties.storageProfile is not set on VM, this is unexpected") } return vmResource, nil } func (da diskAttacher) getDisks(ctx context.Context) ([]compute.DataDisk, error) { vmResource, err := da.getThisVM(ctx) if err != nil { return []compute.DataDisk{}, err } return *vmResource.StorageProfile.DataDisks, nil } func (da diskAttacher) setDisks(ctx context.Context, disks []compute.DataDisk) error { vmResource, err := da.getThisVM(ctx) if err != nil { return err } id, err := azure.ParseResourceID(to.String(vmResource.ID)) if err != nil { return err } vmResource.StorageProfile.DataDisks = &disks vmResource.Resources = nil // update the VM resource, attach disk _, err = da.azcli.VirtualMachinesClient().CreateOrUpdate(ctx, id.ResourceGroup, id.ResourceName, vmResource) return err } func findDiskInList(list []compute.DataDisk, diskID string) *compute.DataDisk { for _, disk := range list { if disk.ManagedDisk != nil && strings.EqualFold(to.String(disk.ManagedDisk.ID), diskID) { return &disk } } return nil }