packer-cn/builder/azure/arm/config.go

//go:generate struct-markdown

package arm

import (
	"crypto/rand"
	"crypto/rsa"
	"crypto/x509"
	"crypto/x509/pkix"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"math/big"
	"regexp"
	"strings"
	"time"

	"github.com/Azure/azure-sdk-for-go/services/compute/mgmt/2018-04-01/compute"
	"github.com/Azure/go-autorest/autorest/to"
	"github.com/masterzen/winrm"

	"github.com/hashicorp/packer/builder/azure/common/constants"
	"github.com/hashicorp/packer/builder/azure/pkcs12"
	"github.com/hashicorp/packer/common"
	commonhelper "github.com/hashicorp/packer/helper/common"
	"github.com/hashicorp/packer/helper/communicator"
	"github.com/hashicorp/packer/helper/config"
	"github.com/hashicorp/packer/packer"
	"github.com/hashicorp/packer/template/interpolate"

	"golang.org/x/crypto/ssh"
)

const (
	DefaultImageVersion                      = "latest"
	DefaultUserName                          = "packer"
	DefaultPrivateVirtualNetworkWithPublicIp = false
	DefaultVMSize                            = "Standard_A1"
)

const (
	// https://docs.microsoft.com/en-us/azure/architecture/best-practices/naming-conventions#naming-rules-and-restrictions
	// Regular expressions in Go are not expressive enough, such that the regular expression returned by Azure
	// can be used (no backtracking).
	//
	//  -> ^[^_\W][\w-._]{0,79}(?<![-.])$
	//
	// This is not an exhaustive match, but it should be extremely close.
	validResourceGroupNameRe = "^[^_\\W][\\w-._\\(\\)]{0,89}$"
	validManagedDiskName     = "^[^_\\W][\\w-._)]{0,79}$"
)

var (
	reCaptureContainerName = regexp.MustCompile("^[a-z0-9][a-z0-9\\-]{2,62}$")
	reCaptureNamePrefix    = regexp.MustCompile("^[A-Za-z0-9][A-Za-z0-9_\\-\\.]{0,23}$")
	reManagedDiskName      = regexp.MustCompile(validManagedDiskName)
	reResourceGroupName    = regexp.MustCompile(validResourceGroupNameRe)
	reSnapshotName         = regexp.MustCompile("^[A-Za-z0-9_]{1,79}$")
	reSnapshotPrefix       = regexp.MustCompile("^[A-Za-z0-9_]{1,59}$")
)

type PlanInformation struct {
	PlanName          string `mapstructure:"plan_name"`
	PlanProduct       string `mapstructure:"plan_product"`
	PlanPublisher     string `mapstructure:"plan_publisher"`
	PlanPromotionCode string `mapstructure:"plan_promotion_code"`
}

type SharedImageGallery struct {
	Subscription  string `mapstructure:"subscription"`
	ResourceGroup string `mapstructure:"resource_group"`
	GalleryName   string `mapstructure:"gallery_name"`
	ImageName     string `mapstructure:"image_name"`
	// Specify a specific version of an OS to boot from.
	// Defaults to latest. There may be a difference in versions available
	// across regions due to image synchronization latency. To ensure a consistent
	// version across regions set this value to one that is available in all
	// regions where you are deploying.
	ImageVersion string `mapstructure:"image_version" required:"false"`
}

type SharedImageGalleryDestination struct {
	SigDestinationResourceGroup      string   `mapstructure:"resource_group"`
	SigDestinationGalleryName        string   `mapstructure:"gallery_name"`
	SigDestinationImageName          string   `mapstructure:"image_name"`
	SigDestinationImageVersion       string   `mapstructure:"image_version"`
	SigDestinationReplicationRegions []string `mapstructure:"replication_regions"`
}

type Config struct {
	common.PackerConfig `mapstructure:",squash"`

	// Authentication via OAUTH
	ClientConfig `mapstructure:",squash"`

	// Capture
	CaptureNamePrefix    string `mapstructure:"capture_name_prefix"`
	CaptureContainerName string `mapstructure:"capture_container_name"`
	// Use a [Shared Gallery
	// image](https://azure.microsoft.com/en-us/blog/announcing-the-public-preview-of-shared-image-gallery/)
	// as the source for this build. *VHD targets are incompatible with this
	// build type* - the target must be a *Managed Image*.
	//
	//     "shared_image_gallery": {
	//         "subscription": "00000000-0000-0000-0000-00000000000",
	//         "resource_group": "ResourceGroup",
	//         "gallery_name": "GalleryName",
	//         "image_name": "ImageName",
	//         "image_version": "1.0.0"
	//     }
	//     "managed_image_name": "TargetImageName",
	//     "managed_image_resource_group_name": "TargetResourceGroup"
	SharedGallery SharedImageGallery `mapstructure:"shared_image_gallery" required:"false"`
	// The name of the Shared Image Gallery under which the managed image will be published as Shared Gallery Image version.
	//
	// Following is an example.
	//
	// <!-- -->
	//
	//     "shared_image_gallery_destination": {
	//         "resource_group": "ResourceGroup",
	//         "gallery_name": "GalleryName",
	//         "image_name": "ImageName",
	//         "image_version": "1.0.0",
	//         "replication_regions": ["regionA", "regionB", "regionC"]
	//     }
	//     "managed_image_name": "TargetImageName",
	//     "managed_image_resource_group_name": "TargetResourceGroup"
	SharedGalleryDestination SharedImageGalleryDestination `mapstructure:"shared_image_gallery_destination"`
	// How long to wait for an image to be published to the shared image
	// gallery before timing out. If your Packer build is failing on the
	// Publishing to Shared Image Gallery step with the error `Original Error:
	// context deadline exceeded`, but the image is present when you check your
	// Azure dashboard, then you probably need to increase this timeout from
	// its default of "60m" (valid time units include `s` for seconds, `m` for
	// minutes, and `h` for hours.)
	SharedGalleryTimeout time.Duration `mapstructure:"shared_image_gallery_timeout"`
	// PublisherName for your base image. See
	// [documentation](https://azure.microsoft.com/en-us/documentation/articles/resource-groups-vm-searching/)
	// for details.
	//
	// CLI example `az vm image list-publishers --location westus`
	ImagePublisher string `mapstructure:"image_publisher" required:"true"`
	// Offer for your base image. See
	// [documentation](https://azure.microsoft.com/en-us/documentation/articles/resource-groups-vm-searching/)
	// for details.
	//
	// CLI example
	// `az vm image list-offers --location westus --publisher Canonical`
	ImageOffer string `mapstructure:"image_offer" required:"true"`
	// SKU for your base image. See
	// [documentation](https://azure.microsoft.com/en-us/documentation/articles/resource-groups-vm-searching/)
	// for details.
	//
	// CLI example
	// `az vm image list-skus --location westus --publisher Canonical --offer UbuntuServer`
	ImageSku string `mapstructure:"image_sku" required:"true"`
	// Specify a specific version of an OS to boot from.
	// Defaults to `latest`. There may be a difference in versions available
	// across regions due to image synchronization latency. To ensure a consistent
	// version across regions set this value to one that is available in all
	// regions where you are deploying.
	//
	// CLI example
	// `az vm image list --location westus --publisher Canonical --offer UbuntuServer --sku 16.04.0-LTS --all`
	ImageVersion string `mapstructure:"image_version" required:"false"`
	// Specify a custom VHD to use. If this value is set, do
	// not set image_publisher, image_offer, image_sku, or image_version.
	ImageUrl string `mapstructure:"image_url" required:"false"`
	// Specify the source managed image's resource group used to use. If this
	// value is set, do not set image\_publisher, image\_offer, image\_sku, or
	// image\_version. If this value is set, the value
	// `custom_managed_image_name` must also be set. See
	// [documentation](https://docs.microsoft.com/en-us/azure/storage/storage-managed-disks-overview#images)
	// to learn more about managed images.
	CustomManagedImageResourceGroupName string `mapstructure:"custom_managed_image_resource_group_name" required:"false"`
	// Specify the source managed image's name to use. If this value is set, do
	// not set image\_publisher, image\_offer, image\_sku, or image\_version.
	// If this value is set, the value
	// `custom_managed_image_resource_group_name` must also be set. See
	// [documentation](https://docs.microsoft.com/en-us/azure/storage/storage-managed-disks-overview#images)
	// to learn more about managed images.
	CustomManagedImageName string `mapstructure:"custom_managed_image_name" required:"false"`
	customManagedImageID   string

	Location string `mapstructure:"location"`
	// Size of the VM used for building. This can be changed when you deploy a
	// VM from your VHD. See
	// [pricing](https://azure.microsoft.com/en-us/pricing/details/virtual-machines/)
	// information. Defaults to `Standard_A1`.
	//
	// CLI example `az vm list-sizes --location westus`
	VMSize string `mapstructure:"vm_size" required:"false"`

	ManagedImageResourceGroupName string `mapstructure:"managed_image_resource_group_name"`
	ManagedImageName              string `mapstructure:"managed_image_name"`
	// Specify the storage account
	// type for a managed image. Valid values are Standard_LRS and Premium_LRS.
	// The default is Standard_LRS.
	ManagedImageStorageAccountType string `mapstructure:"managed_image_storage_account_type" required:"false"`
	managedImageStorageAccountType compute.StorageAccountTypes
	// If
	// managed_image_os_disk_snapshot_name is set, a snapshot of the OS disk
	// is created with the same name as this value before the VM is captured.
	ManagedImageOSDiskSnapshotName string `mapstructure:"managed_image_os_disk_snapshot_name" required:"false"`
	// If
	// managed_image_data_disk_snapshot_prefix is set, snapshot of the data
	// disk(s) is created with the same prefix as this value before the VM is
	// captured.
	ManagedImageDataDiskSnapshotPrefix string `mapstructure:"managed_image_data_disk_snapshot_prefix" required:"false"`
	manageImageLocation                string
	// Store the image in zone-resilient storage. You need to create it in a
	// region that supports [availability
	// zones](https://docs.microsoft.com/en-us/azure/availability-zones/az-overview).
	ManagedImageZoneResilient bool `mapstructure:"managed_image_zone_resilient" required:"false"`
	// the user can define up to 15
	// tags. Tag names cannot exceed 512 characters, and tag values cannot exceed
	// 256 characters. Tags are applied to every resource deployed by a Packer
	// build, i.e. Resource Group, VM, NIC, VNET, Public IP, KeyVault, etc.
	AzureTags         map[string]*string `mapstructure:"azure_tags" required:"false"`
	ResourceGroupName string             `mapstructure:"resource_group_name"`
	StorageAccount    string             `mapstructure:"storage_account"`
	// temporary name assigned to the VM. If this
	// value is not set, a random value will be assigned. Knowing the resource
	// group and VM name allows one to execute commands to update the VM during a
	// Packer build, e.g. attach a resource disk to the VM.
	TempComputeName            string `mapstructure:"temp_compute_name" required:"false"`
	TempResourceGroupName      string `mapstructure:"temp_resource_group_name"`
	BuildResourceGroupName     string `mapstructure:"build_resource_group_name"`
	storageAccountBlobEndpoint string
	// This value allows you to
	// set a virtual_network_name and obtain a public IP. If this value is not
	// set and virtual_network_name is defined Packer is only allowed to be
	// executed from a host on the same subnet / virtual network.
	PrivateVirtualNetworkWithPublicIp bool `mapstructure:"private_virtual_network_with_public_ip" required:"false"`
	// Use a pre-existing virtual network for the
	// VM. This option enables private communication with the VM, no public IP
	// address is used or provisioned (unless you set
	// private_virtual_network_with_public_ip).
	VirtualNetworkName string `mapstructure:"virtual_network_name" required:"false"`
	// If virtual_network_name is set,
	// this value may also be set. If virtual_network_name is set, and this
	// value is not set the builder attempts to determine the subnet to use with
	// the virtual network. If the subnet cannot be found, or it cannot be
	// disambiguated, this value should be set.
	VirtualNetworkSubnetName string `mapstructure:"virtual_network_subnet_name" required:"false"`
	// If virtual_network_name is
	// set, this value may also be set. If virtual_network_name is set, and
	// this value is not set the builder attempts to determine the resource group
	// containing the virtual network. If the resource group cannot be found, or
	// it cannot be disambiguated, this value should be set.
	VirtualNetworkResourceGroupName string `mapstructure:"virtual_network_resource_group_name" required:"false"`
	// Specify a file containing custom data to inject into the cloud-init
	// process. The contents of the file are read and injected into the ARM
	// template. The custom data will be passed to cloud-init for processing at
	// the time of provisioning. See
	// [documentation](http://cloudinit.readthedocs.io/en/latest/topics/examples.html)
	// to learn more about custom data, and how it can be used to influence the
	// provisioning process.
	CustomDataFile string `mapstructure:"custom_data_file" required:"false"`
	customData     string
	// Used for creating images from Marketplace images. Please refer to
	// [Deploy an image with Marketplace
	// terms](https://aka.ms/azuremarketplaceapideployment) for more details.
	// Not all Marketplace images support programmatic deployment, and support
	// is controlled by the image publisher.
	//
	// An example plan\_info object is defined below.
	//
	// ``` json
	// {
	//   "plan_info": {
	//       "plan_name": "rabbitmq",
	//       "plan_product": "rabbitmq",
	//       "plan_publisher": "bitnami"
	//   }
	// }
	// ```
	//
	// `plan_name` (string) - The plan name, required. `plan_product` (string) -
	// The plan product, required. `plan_publisher` (string) - The plan publisher,
	// required. `plan_promotion_code` (string) - Some images accept a promotion
	// code, optional.
	//
	// Images created from the Marketplace with `plan_info` **must** specify
	// `plan_info` whenever the image is deployed. The builder automatically adds
	// tags to the image to ensure this information is not lost. The following
	// tags are added.
	//
	// 1.  PlanName
	// 2.  PlanProduct
	// 3.  PlanPublisher
	// 4.  PlanPromotionCode
	//
	PlanInfo PlanInformation `mapstructure:"plan_info" required:"false"`
	// If either Linux or Windows is specified Packer will
	// automatically configure authentication credentials for the provisioned
	// machine. For Linux this configures an SSH authorized key. For Windows
	// this configures a WinRM certificate.
	OSType string `mapstructure:"os_type" required:"false"`
	// Specify the size of the OS disk in GB
	// (gigabytes). Values of zero or less than zero are ignored.
	OSDiskSizeGB int32 `mapstructure:"os_disk_size_gb" required:"false"`
	// The size(s) of any additional hard disks for the VM in gigabytes. If
	// this is not specified then the VM will only contain an OS disk. The
	// number of additional disks and maximum size of a disk depends on the
	// configuration of your VM. See
	// [Windows](https://docs.microsoft.com/en-us/azure/virtual-machines/windows/about-disks-and-vhds)
	// or
	// [Linux](https://docs.microsoft.com/en-us/azure/virtual-machines/linux/about-disks-and-vhds)
	// for more information.
	//
	// For VHD builds the final artifacts will be named
	// `PREFIX-dataDisk-<n>.UUID.vhd` and stored in the specified capture
	// container along side the OS disk. The additional disks are included in
	// the deployment template `PREFIX-vmTemplate.UUID`.
	//
	// For Managed build the final artifacts are included in the managed image.
	// The additional disk will have the same storage account type as the OS
	// disk, as specified with the `managed_image_storage_account_type`
	// setting.
	AdditionalDiskSize []int32 `mapstructure:"disk_additional_size" required:"false"`
	// Specify the disk caching type. Valid values
	// are None, ReadOnly, and ReadWrite. The default value is ReadWrite.
	DiskCachingType string `mapstructure:"disk_caching_type" required:"false"`
	diskCachingType compute.CachingTypes

	// Runtime Values
	UserName               string
	Password               string
	tmpAdminPassword       string
	tmpCertificatePassword string
	tmpResourceGroupName   string
	tmpComputeName         string
	tmpNicName             string
	tmpPublicIPAddressName string
	tmpDeploymentName      string
	tmpKeyVaultName        string
	tmpOSDiskName          string
	tmpSubnetName          string
	tmpVirtualNetworkName  string
	tmpWinRMCertificateUrl string

	// Authentication with the VM via SSH
	sshAuthorizedKey string

	// Authentication with the VM via WinRM
	winrmCertificate string

	Comm communicator.Config `mapstructure:",squash"`
	ctx  interpolate.Context
	// If you want packer to delete the
	// temporary resource group asynchronously set this value. It's a boolean
	// value and defaults to false. Important Setting this true means that
	// your builds are faster, however any failed deletes are not reported.
	AsyncResourceGroupDelete bool `mapstructure:"async_resourcegroup_delete" required:"false"`
}

type keyVaultCertificate struct {
	Data     string `json:"data"`
	DataType string `json:"dataType"`
	Password string `json:"password,omitempty"`
}

func (c *Config) toVMID() string {
	var resourceGroupName string
	if c.tmpResourceGroupName != "" {
		resourceGroupName = c.tmpResourceGroupName
	} else {
		resourceGroupName = c.BuildResourceGroupName
	}
	return fmt.Sprintf("/subscriptions/%s/resourceGroups/%s/providers/Microsoft.Compute/virtualMachines/%s", c.SubscriptionID, resourceGroupName, c.tmpComputeName)
}

func (c *Config) isManagedImage() bool {
	return c.ManagedImageName != ""
}

func (c *Config) toVirtualMachineCaptureParameters() *compute.VirtualMachineCaptureParameters {
	return &compute.VirtualMachineCaptureParameters{
		DestinationContainerName: &c.CaptureContainerName,
		VhdPrefix:                &c.CaptureNamePrefix,
		OverwriteVhds:            to.BoolPtr(false),
	}
}

func (c *Config) toImageParameters() *compute.Image {
	return &compute.Image{
		ImageProperties: &compute.ImageProperties{
			SourceVirtualMachine: &compute.SubResource{
				ID: to.StringPtr(c.toVMID()),
			},
			StorageProfile: &compute.ImageStorageProfile{
				ZoneResilient: to.BoolPtr(c.ManagedImageZoneResilient),
			},
		},
		Location: to.StringPtr(c.Location),
		Tags:     c.AzureTags,
	}
}

func (c *Config) createCertificate() (string, error) {
	privateKey, err := rsa.GenerateKey(rand.Reader, 2048)
	if err != nil {
		err = fmt.Errorf("Failed to Generate Private Key: %s", err)
		return "", err
	}

	host := fmt.Sprintf("%s.cloudapp.net", c.tmpComputeName)
	notBefore := time.Now()
	notAfter := notBefore.Add(24 * time.Hour)

	serialNumber, err := rand.Int(rand.Reader, new(big.Int).Lsh(big.NewInt(1), 128))
	if err != nil {
		err = fmt.Errorf("Failed to Generate Serial Number: %v", err)
		return "", err
	}

	template := x509.Certificate{
		SerialNumber: serialNumber,
		Issuer: pkix.Name{
			CommonName: host,
		},
		Subject: pkix.Name{
			CommonName: host,
		},
		NotBefore: notBefore,
		NotAfter:  notAfter,

		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
		BasicConstraintsValid: true,
	}

	derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, &privateKey.PublicKey, privateKey)
	if err != nil {
		err = fmt.Errorf("Failed to Create Certificate: %s", err)
		return "", err
	}

	pfxBytes, err := pkcs12.Encode(derBytes, privateKey, c.tmpCertificatePassword)
	if err != nil {
		err = fmt.Errorf("Failed to encode certificate as PFX: %s", err)
		return "", err
	}

	keyVaultDescription := keyVaultCertificate{
		Data:     base64.StdEncoding.EncodeToString(pfxBytes),
		DataType: "pfx",
		Password: c.tmpCertificatePassword,
	}

	bytes, err := json.Marshal(keyVaultDescription)
	if err != nil {
		err = fmt.Errorf("Failed to marshal key vault description: %s", err)
		return "", err
	}

	return base64.StdEncoding.EncodeToString(bytes), nil
}

func newConfig(raws ...interface{}) (*Config, []string, error) {
	var c Config
	c.ctx.Funcs = TemplateFuncs
	err := config.Decode(&c, &config.DecodeOpts{
		Interpolate:        true,
		InterpolateContext: &c.ctx,
	}, raws...)

	if err != nil {
		return nil, nil, err
	}

	provideDefaultValues(&c)
	setRuntimeValues(&c)
	setUserNamePassword(&c)
	err = c.ClientConfig.setCloudEnvironment()
	if err != nil {
		return nil, nil, err
	}

	err = setCustomData(&c)
	if err != nil {
		return nil, nil, err
	}

	// NOTE: if the user did not specify a communicator, then default to both
	// SSH and WinRM.  This is for backwards compatibility because the code did
	// not specifically force the user to set a communicator.
	if c.Comm.Type == "" || strings.EqualFold(c.Comm.Type, "ssh") {
		err = setSshValues(&c)
		if err != nil {
			return nil, nil, err
		}
	}

	if c.Comm.Type == "" || strings.EqualFold(c.Comm.Type, "winrm") {
		err = setWinRMCertificate(&c)
		if err != nil {
			return nil, nil, err
		}
	}

	var errs *packer.MultiError
	errs = packer.MultiErrorAppend(errs, c.Comm.Prepare(&c.ctx)...)

	assertRequiredParametersSet(&c, errs)
	assertTagProperties(&c, errs)
	if errs != nil && len(errs.Errors) > 0 {
		return nil, nil, errs
	}

	return &c, nil, nil
}

func setSshValues(c *Config) error {
	if c.Comm.SSHTimeout == 0 {
		c.Comm.SSHTimeout = 20 * time.Minute
	}

	if c.Comm.SSHPrivateKeyFile != "" {
		privateKeyBytes, err := c.Comm.ReadSSHPrivateKeyFile()
		if err != nil {
			return err
		}
		signer, err := ssh.ParsePrivateKey(privateKeyBytes)
		if err != nil {
			return err
		}

		publicKey := signer.PublicKey()
		c.sshAuthorizedKey = fmt.Sprintf("%s %s packer Azure Deployment%s",
			publicKey.Type(),
			base64.StdEncoding.EncodeToString(publicKey.Marshal()),
			time.Now().Format(time.RFC3339))
		c.Comm.SSHPrivateKey = privateKeyBytes

	} else {
		sshKeyPair, err := NewOpenSshKeyPair()
		if err != nil {
			return err
		}

		c.sshAuthorizedKey = sshKeyPair.AuthorizedKey()
		c.Comm.SSHPrivateKey = sshKeyPair.PrivateKey()
	}

	return nil
}

func setWinRMCertificate(c *Config) error {
	c.Comm.WinRMTransportDecorator =
		func() winrm.Transporter {
			return &winrm.ClientNTLM{}
		}

	cert, err := c.createCertificate()
	c.winrmCertificate = cert

	return err
}

func setRuntimeValues(c *Config) {
	var tempName = NewTempName()

	c.tmpAdminPassword = tempName.AdminPassword
	// store so that we can access this later during provisioning
	commonhelper.SetSharedState("winrm_password", c.tmpAdminPassword, c.PackerConfig.PackerBuildName)
	packer.LogSecretFilter.Set(c.tmpAdminPassword)

	c.tmpCertificatePassword = tempName.CertificatePassword
	if c.TempComputeName == "" {
		c.tmpComputeName = tempName.ComputeName
	} else {
		c.tmpComputeName = c.TempComputeName
	}
	c.tmpDeploymentName = tempName.DeploymentName
	// Only set tmpResourceGroupName if no name has been specified
	if c.TempResourceGroupName == "" && c.BuildResourceGroupName == "" {
		c.tmpResourceGroupName = tempName.ResourceGroupName
	} else if c.TempResourceGroupName != "" && c.BuildResourceGroupName == "" {
		c.tmpResourceGroupName = c.TempResourceGroupName
	}
	c.tmpNicName = tempName.NicName
	c.tmpPublicIPAddressName = tempName.PublicIPAddressName
	c.tmpOSDiskName = tempName.OSDiskName
	c.tmpSubnetName = tempName.SubnetName
	c.tmpVirtualNetworkName = tempName.VirtualNetworkName
	c.tmpKeyVaultName = tempName.KeyVaultName
}

func setUserNamePassword(c *Config) {
	if c.Comm.SSHUsername == "" {
		c.Comm.SSHUsername = DefaultUserName
	}

	c.UserName = c.Comm.SSHUsername

	if c.Comm.SSHPassword != "" {
		c.Password = c.Comm.SSHPassword
	} else {
		c.Password = c.tmpAdminPassword
	}
}

func setCustomData(c *Config) error {
	if c.CustomDataFile == "" {
		return nil
	}

	b, err := ioutil.ReadFile(c.CustomDataFile)
	if err != nil {
		return err
	}

	c.customData = base64.StdEncoding.EncodeToString(b)
	return nil
}

func provideDefaultValues(c *Config) {
	if c.VMSize == "" {
		c.VMSize = DefaultVMSize
	}

	if c.ManagedImageStorageAccountType == "" {
		c.managedImageStorageAccountType = compute.StorageAccountTypesStandardLRS
	}

	if c.DiskCachingType == "" {
		c.diskCachingType = compute.CachingTypesReadWrite
	}

	if c.ImagePublisher != "" && c.ImageVersion == "" {
		c.ImageVersion = DefaultImageVersion
	}

	c.provideDefaultValues()
}

func assertTagProperties(c *Config, errs *packer.MultiError) {
	if len(c.AzureTags) > 15 {
		errs = packer.MultiErrorAppend(errs, fmt.Errorf("a max of 15 tags are supported, but %d were provided", len(c.AzureTags)))
	}

	for k, v := range c.AzureTags {
		if len(k) > 512 {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("the tag name %q exceeds (%d) the 512 character limit", k, len(k)))
		}
		if len(*v) > 256 {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("the tag name %q exceeds (%d) the 256 character limit", *v, len(*v)))
		}
	}
}

func assertRequiredParametersSet(c *Config, errs *packer.MultiError) {
	c.ClientConfig.assertRequiredParametersSet(errs)

	/////////////////////////////////////////////
	// Capture
	if c.CaptureContainerName == "" && c.ManagedImageName == "" {
		errs = packer.MultiErrorAppend(errs, fmt.Errorf("A capture_container_name or managed_image_name must be specified"))
	}

	if c.CaptureNamePrefix == "" && c.ManagedImageResourceGroupName == "" {
		errs = packer.MultiErrorAppend(errs, fmt.Errorf("A capture_name_prefix or managed_image_resource_group_name must be specified"))
	}

	if (c.CaptureNamePrefix != "" || c.CaptureContainerName != "") && (c.ManagedImageResourceGroupName != "" || c.ManagedImageName != "") {
		errs = packer.MultiErrorAppend(errs, fmt.Errorf("Either a VHD or a managed image can be built, but not both. Please specify either capture_container_name and capture_name_prefix or managed_image_resource_group_name and managed_image_name."))
	}

	if c.CaptureContainerName != "" {
		if !reCaptureContainerName.MatchString(c.CaptureContainerName) {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("A capture_container_name must satisfy the regular expression %q.", reCaptureContainerName.String()))
		}

		if strings.HasSuffix(c.CaptureContainerName, "-") {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("A capture_container_name must not end with a hyphen, e.g. '-'."))
		}

		if strings.Contains(c.CaptureContainerName, "--") {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("A capture_container_name must not contain consecutive hyphens, e.g. '--'."))
		}

		if c.CaptureNamePrefix == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("A capture_name_prefix must be specified"))
		}

		if !reCaptureNamePrefix.MatchString(c.CaptureNamePrefix) {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("A capture_name_prefix must satisfy the regular expression %q.", reCaptureNamePrefix.String()))
		}

		if strings.HasSuffix(c.CaptureNamePrefix, "-") || strings.HasSuffix(c.CaptureNamePrefix, ".") {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("A capture_name_prefix must not end with a hyphen or period."))
		}
	}

	if c.TempResourceGroupName != "" && c.BuildResourceGroupName != "" {
		errs = packer.MultiErrorAppend(errs, fmt.Errorf("The settings temp_resource_group_name and build_resource_group_name cannot both be defined.  Please define one or neither."))
	}

	/////////////////////////////////////////////
	// Compute
	toInt := func(b bool) int {
		if b {
			return 1
		} else {
			return 0
		}
	}

	isImageUrl := c.ImageUrl != ""
	isCustomManagedImage := c.CustomManagedImageName != "" || c.CustomManagedImageResourceGroupName != ""
	isSharedGallery := c.SharedGallery.GalleryName != ""
	isPlatformImage := c.ImagePublisher != "" || c.ImageOffer != "" || c.ImageSku != ""

	countSourceInputs := toInt(isImageUrl) + toInt(isCustomManagedImage) + toInt(isPlatformImage) + toInt(isSharedGallery)

	if countSourceInputs > 1 {
		errs = packer.MultiErrorAppend(errs, fmt.Errorf("Specify either a VHD (image_url), Image Reference (image_publisher, image_offer, image_sku), a Managed Disk (custom_managed_disk_image_name, custom_managed_disk_resource_group_name), or a Shared Gallery Image (shared_image_gallery)"))
	}

	if isImageUrl && c.ManagedImageResourceGroupName != "" {
		errs = packer.MultiErrorAppend(errs, fmt.Errorf("A managed image must be created from a managed image, it cannot be created from a VHD."))
	}

	if c.SharedGallery.GalleryName != "" {
		if c.SharedGallery.Subscription == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("A shared_image_gallery.subscription must be specified"))
		}
		if c.SharedGallery.ResourceGroup == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("A shared_image_gallery.resource_group must be specified"))
		}
		if c.SharedGallery.ImageName == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("A shared_image_gallery.image_name must be specified"))
		}
		if c.CaptureContainerName != "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("VHD Target [capture_container_name] is not supported when using Shared Image Gallery as source. Use managed_image_resource_group_name instead."))
		}
		if c.CaptureNamePrefix != "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("VHD Target [capture_name_prefix] is not supported when using Shared Image Gallery as source. Use managed_image_name instead."))
		}
	} else if c.ImageUrl == "" && c.CustomManagedImageName == "" {
		if c.ImagePublisher == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("An image_publisher must be specified"))
		}
		if c.ImageOffer == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("An image_offer must be specified"))
		}
		if c.ImageSku == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("An image_sku must be specified"))
		}
	} else if c.ImageUrl == "" && c.ImagePublisher == "" {
		if c.CustomManagedImageResourceGroupName == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("A custom_managed_image_resource_group_name must be specified"))
		}
		if c.CustomManagedImageName == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("A custom_managed_image_name must be specified"))
		}
		if c.ManagedImageResourceGroupName == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("A managed_image_resource_group_name must be specified"))
		}
		if c.ManagedImageName == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("A managed_image_name must be specified"))
		}
	} else {
		if c.ImagePublisher != "" || c.ImageOffer != "" || c.ImageSku != "" || c.ImageVersion != "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("An image_url must not be specified if image_publisher, image_offer, image_sku, or image_version is specified"))
		}
	}

	/////////////////////////////////////////////
	// Deployment
	xor := func(a, b bool) bool {
		return (a || b) && !(a && b)
	}

	if !xor((c.StorageAccount != "" || c.ResourceGroupName != ""), (c.ManagedImageName != "" || c.ManagedImageResourceGroupName != "")) {
		errs = packer.MultiErrorAppend(errs, fmt.Errorf("Specify either a VHD (storage_account and resource_group_name) or Managed Image (managed_image_resource_group_name and managed_image_name) output"))
	}

	if !xor(c.Location != "", c.BuildResourceGroupName != "") {
		errs = packer.MultiErrorAppend(errs, fmt.Errorf("Specify either a location to create the resource group in or an existing build_resource_group_name, but not both."))
	}

	if c.ManagedImageName == "" && c.ManagedImageResourceGroupName == "" {
		if c.StorageAccount == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("A storage_account must be specified"))
		}
		if c.ResourceGroupName == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("A resource_group_name must be specified"))
		}
	}

	if c.TempResourceGroupName != "" {
		if ok, err := assertResourceGroupName(c.TempResourceGroupName, "temp_resource_group_name"); !ok {
			errs = packer.MultiErrorAppend(errs, err)
		}
	}

	if c.BuildResourceGroupName != "" {
		if ok, err := assertResourceGroupName(c.BuildResourceGroupName, "build_resource_group_name"); !ok {
			errs = packer.MultiErrorAppend(errs, err)
		}
	}

	if c.ManagedImageResourceGroupName != "" {
		if ok, err := assertResourceGroupName(c.ManagedImageResourceGroupName, "managed_image_resource_group_name"); !ok {
			errs = packer.MultiErrorAppend(errs, err)
		}
	}

	if c.ManagedImageName != "" {
		if ok, err := assertManagedImageName(c.ManagedImageName, "managed_image_name"); !ok {
			errs = packer.MultiErrorAppend(errs, err)
		}
	}

	if c.ManagedImageName != "" && c.ManagedImageResourceGroupName != "" && c.SharedGalleryDestination.SigDestinationGalleryName != "" {
		if c.SharedGalleryDestination.SigDestinationResourceGroup == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("A resource_group must be specified for shared_image_gallery_destination"))
		}
		if c.SharedGalleryDestination.SigDestinationImageName == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("An image_name must be specified for shared_image_gallery_destination"))
		}
		if c.SharedGalleryDestination.SigDestinationImageVersion == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("An image_version must be specified for shared_image_gallery_destination"))
		}
		if len(c.SharedGalleryDestination.SigDestinationReplicationRegions) == 0 {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("A list of replication_regions must be specified for shared_image_gallery_destination"))
		}
	}
	if c.SharedGalleryTimeout == 0 {
		// default to a one-hour timeout. In the sdk, the default is 15 m.
		c.SharedGalleryTimeout = 60 * time.Minute
	}

	if c.ManagedImageOSDiskSnapshotName != "" {
		if ok, err := assertManagedImageOSDiskSnapshotName(c.ManagedImageOSDiskSnapshotName, "managed_image_os_disk_snapshot_name"); !ok {
			errs = packer.MultiErrorAppend(errs, err)
		}
	}

	if c.ManagedImageDataDiskSnapshotPrefix != "" {
		if ok, err := assertManagedImageDataDiskSnapshotName(c.ManagedImageDataDiskSnapshotPrefix, "managed_image_data_disk_snapshot_prefix"); !ok {
			errs = packer.MultiErrorAppend(errs, err)
		}
	}

	if c.VirtualNetworkName == "" && c.VirtualNetworkResourceGroupName != "" {
		errs = packer.MultiErrorAppend(errs, fmt.Errorf("If virtual_network_resource_group_name is specified, so must virtual_network_name"))
	}
	if c.VirtualNetworkName == "" && c.VirtualNetworkSubnetName != "" {
		errs = packer.MultiErrorAppend(errs, fmt.Errorf("If virtual_network_subnet_name is specified, so must virtual_network_name"))
	}

	/////////////////////////////////////////////
	// Plan Info
	if c.PlanInfo.PlanName != "" || c.PlanInfo.PlanProduct != "" || c.PlanInfo.PlanPublisher != "" || c.PlanInfo.PlanPromotionCode != "" {
		if c.PlanInfo.PlanName == "" || c.PlanInfo.PlanProduct == "" || c.PlanInfo.PlanPublisher == "" {
			errs = packer.MultiErrorAppend(errs, fmt.Errorf("if either plan_name, plan_product, plan_publisher, or plan_promotion_code are defined then plan_name, plan_product, and plan_publisher must be defined"))
		} else {
			if c.AzureTags == nil {
				c.AzureTags = make(map[string]*string)
			}

			c.AzureTags["PlanInfo"] = &c.PlanInfo.PlanName
			c.AzureTags["PlanProduct"] = &c.PlanInfo.PlanProduct
			c.AzureTags["PlanPublisher"] = &c.PlanInfo.PlanPublisher
			c.AzureTags["PlanPromotionCode"] = &c.PlanInfo.PlanPromotionCode
		}
	}

	/////////////////////////////////////////////
	// OS
	if strings.EqualFold(c.OSType, constants.Target_Linux) {
		c.OSType = constants.Target_Linux
	} else if strings.EqualFold(c.OSType, constants.Target_Windows) {
		c.OSType = constants.Target_Windows
	} else if c.OSType == "" {
		errs = packer.MultiErrorAppend(errs, fmt.Errorf("An os_type must be specified"))
	} else {
		errs = packer.MultiErrorAppend(errs, fmt.Errorf("The os_type %q is invalid", c.OSType))
	}

	switch c.ManagedImageStorageAccountType {
	case "", string(compute.StorageAccountTypesStandardLRS):
		c.managedImageStorageAccountType = compute.StorageAccountTypesStandardLRS
	case string(compute.StorageAccountTypesPremiumLRS):
		c.managedImageStorageAccountType = compute.StorageAccountTypesPremiumLRS
	default:
		errs = packer.MultiErrorAppend(errs, fmt.Errorf("The managed_image_storage_account_type %q is invalid", c.ManagedImageStorageAccountType))
	}

	switch c.DiskCachingType {
	case string(compute.CachingTypesNone):
		c.diskCachingType = compute.CachingTypesNone
	case string(compute.CachingTypesReadOnly):
		c.diskCachingType = compute.CachingTypesReadOnly
	case "", string(compute.CachingTypesReadWrite):
		c.diskCachingType = compute.CachingTypesReadWrite
	default:
		errs = packer.MultiErrorAppend(errs, fmt.Errorf("The disk_caching_type %q is invalid", c.DiskCachingType))
	}
}

func assertManagedImageName(name, setting string) (bool, error) {
	if !isValidAzureName(reManagedDiskName, name) {
		return false, fmt.Errorf("The setting %s must match the regular expression %q, and not end with a '-' or '.'.", setting, validManagedDiskName)
	}
	return true, nil
}

func assertManagedImageOSDiskSnapshotName(name, setting string) (bool, error) {
	if !isValidAzureName(reSnapshotName, name) {
		return false, fmt.Errorf("The setting %s must only contain characters from a-z, A-Z, 0-9 and _ and the maximum length is 80 characters", setting)
	}
	return true, nil
}

func assertManagedImageDataDiskSnapshotName(name, setting string) (bool, error) {
	if !isValidAzureName(reSnapshotPrefix, name) {
		return false, fmt.Errorf("The setting %s must only contain characters from a-z, A-Z, 0-9 and _ and the maximum length (excluding the prefix) is 60 characters", setting)
	}
	return true, nil
}

func assertResourceGroupName(rgn, setting string) (bool, error) {
	if !isValidAzureName(reResourceGroupName, rgn) {
		return false, fmt.Errorf("The setting %s must match the regular expression %q, and not end with a '-' or '.'.", setting, validResourceGroupNameRe)
	}
	return true, nil
}

func isValidAzureName(re *regexp.Regexp, rgn string) bool {
	return re.Match([]byte(rgn)) &&
		!strings.HasSuffix(rgn, ".") &&
		!strings.HasSuffix(rgn, "-")
}

func (c *Config) validateLocationZoneResiliency(say func(s string)) {
	// Docs on regions that support Availibility Zones:
	//   https://docs.microsoft.com/en-us/azure/availability-zones/az-overview#regions-that-support-availability-zones
	// Query technical names for locations:
	//   az account list-locations --query '[].name' -o tsv

	var zones = make(map[string]struct{})
	zones["westeurope"] = struct{}{}
	zones["centralus"] = struct{}{}
	zones["eastus2"] = struct{}{}
	zones["francecentral"] = struct{}{}
	zones["northeurope"] = struct{}{}
	zones["southeastasia"] = struct{}{}
	zones["westus2"] = struct{}{}

	if _, ok := zones[c.Location]; !ok {
		say(fmt.Sprintf("WARNING: Zone resiliency may not be supported in %s, checkout the docs at https://docs.microsoft.com/en-us/azure/availability-zones/", c.Location))
	}
}