podman

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package buildah
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import (
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	"context"
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	"fmt"
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	"io"
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	"time"
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	"github.com/containers/buildah/define"
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	"github.com/containers/common/libimage"
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	"github.com/containers/common/pkg/config"
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	"github.com/containers/image/v5/types"
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	encconfig "github.com/containers/ocicrypt/config"
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	"github.com/containers/storage"
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)
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// PullOptions can be used to alter how an image is copied in from somewhere.
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type PullOptions struct {
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	// SignaturePolicyPath specifies an override location for the signature
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	// policy which should be used for verifying the new image as it is
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	// being written.  Except in specific circumstances, no value should be
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	// specified, indicating that the shared, system-wide default policy
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	// should be used.
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	SignaturePolicyPath string
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	// ReportWriter is an io.Writer which will be used to log the writing
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	// of the new image.
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	ReportWriter io.Writer
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	// Store is the local storage store which holds the source image.
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	Store storage.Store
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	// github.com/containers/image/types SystemContext to hold credentials
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	// and other authentication/authorization information.
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	SystemContext *types.SystemContext
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	// BlobDirectory is the name of a directory in which we'll attempt to
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	// store copies of layer blobs that we pull down, if any.  It should
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	// already exist.
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	BlobDirectory string
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	// AllTags is a boolean value that determines if all tagged images
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	// will be downloaded from the repository. The default is false.
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	AllTags bool
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	// RemoveSignatures causes any existing signatures for the image to be
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	// discarded when pulling it.
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	RemoveSignatures bool
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	// MaxRetries is the maximum number of attempts we'll make to pull any
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	// one image from the external registry if the first attempt fails.
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	MaxRetries int
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	// RetryDelay is how long to wait before retrying a pull attempt.
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	RetryDelay time.Duration
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	// OciDecryptConfig contains the config that can be used to decrypt an image if it is
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	// encrypted if non-nil. If nil, it does not attempt to decrypt an image.
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	OciDecryptConfig *encconfig.DecryptConfig
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	// PullPolicy takes the value PullIfMissing, PullAlways, PullIfNewer, or PullNever.
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	PullPolicy define.PullPolicy
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}
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// Pull copies the contents of the image from somewhere else to local storage.  Returns the
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// ID of the local image or an error.
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func Pull(ctx context.Context, imageName string, options PullOptions) (imageID string, err error) {
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	libimageOptions := &libimage.PullOptions{}
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	libimageOptions.SignaturePolicyPath = options.SignaturePolicyPath
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	libimageOptions.Writer = options.ReportWriter
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	libimageOptions.RemoveSignatures = options.RemoveSignatures
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	libimageOptions.OciDecryptConfig = options.OciDecryptConfig
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	libimageOptions.AllTags = options.AllTags
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	libimageOptions.RetryDelay = &options.RetryDelay
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	libimageOptions.DestinationLookupReferenceFunc = cacheLookupReferenceFunc(options.BlobDirectory, types.PreserveOriginal)
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	if options.MaxRetries > 0 {
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		retries := uint(options.MaxRetries)
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		libimageOptions.MaxRetries = &retries
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	}
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	pullPolicy, err := config.ParsePullPolicy(options.PullPolicy.String())
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	if err != nil {
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		return "", err
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	}
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	// Note: It is important to do this before we pull any images/create containers.
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	// The default backend detection logic needs an empty store to correctly detect
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	// that we can use netavark, if the store was not empty it will use CNI to not break existing installs.
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	_, err = getNetworkInterface(options.Store, "", "")
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	if err != nil {
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		return "", err
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	}
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	runtime, err := libimage.RuntimeFromStore(options.Store, &libimage.RuntimeOptions{SystemContext: options.SystemContext})
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	if err != nil {
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		return "", err
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	}
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	pulledImages, err := runtime.Pull(context.Background(), imageName, pullPolicy, libimageOptions)
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	if err != nil {
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		return "", err
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	}
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	if len(pulledImages) == 0 {
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		return "", fmt.Errorf("internal error pulling %s: no image pulled and no error", imageName)
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	}
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	return pulledImages[0].ID(), nil
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}
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