github.com/devdivbcp/moby@v17.12.0-ce-rc1.0.20200726071732-2d4bfdc789ad+incompatible/daemon/cluster/services.go (about)

     1  package cluster // import "github.com/docker/docker/daemon/cluster"
     2  
     3  import (
     4  	"context"
     5  	"encoding/base64"
     6  	"encoding/json"
     7  	"fmt"
     8  	"io"
     9  	"os"
    10  	"strconv"
    11  	"strings"
    12  	"time"
    13  
    14  	"github.com/docker/distribution/reference"
    15  	apitypes "github.com/docker/docker/api/types"
    16  	"github.com/docker/docker/api/types/backend"
    17  	types "github.com/docker/docker/api/types/swarm"
    18  	timetypes "github.com/docker/docker/api/types/time"
    19  	"github.com/docker/docker/daemon/cluster/convert"
    20  	"github.com/docker/docker/errdefs"
    21  	runconfigopts "github.com/docker/docker/runconfig/opts"
    22  	swarmapi "github.com/docker/swarmkit/api"
    23  	gogotypes "github.com/gogo/protobuf/types"
    24  	"github.com/pkg/errors"
    25  	"github.com/sirupsen/logrus"
    26  	"google.golang.org/grpc"
    27  )
    28  
    29  // GetServices returns all services of a managed swarm cluster.
    30  func (c *Cluster) GetServices(options apitypes.ServiceListOptions) ([]types.Service, error) {
    31  	c.mu.RLock()
    32  	defer c.mu.RUnlock()
    33  
    34  	state := c.currentNodeState()
    35  	if !state.IsActiveManager() {
    36  		return nil, c.errNoManager(state)
    37  	}
    38  
    39  	// We move the accepted filter check here as "mode" filter
    40  	// is processed in the daemon, not in SwarmKit. So it might
    41  	// be good to have accepted file check in the same file as
    42  	// the filter processing (in the for loop below).
    43  	accepted := map[string]bool{
    44  		"name":    true,
    45  		"id":      true,
    46  		"label":   true,
    47  		"mode":    true,
    48  		"runtime": true,
    49  	}
    50  	if err := options.Filters.Validate(accepted); err != nil {
    51  		return nil, err
    52  	}
    53  
    54  	if len(options.Filters.Get("runtime")) == 0 {
    55  		// Default to using the container runtime filter
    56  		options.Filters.Add("runtime", string(types.RuntimeContainer))
    57  	}
    58  
    59  	filters := &swarmapi.ListServicesRequest_Filters{
    60  		NamePrefixes: options.Filters.Get("name"),
    61  		IDPrefixes:   options.Filters.Get("id"),
    62  		Labels:       runconfigopts.ConvertKVStringsToMap(options.Filters.Get("label")),
    63  		Runtimes:     options.Filters.Get("runtime"),
    64  	}
    65  
    66  	ctx, cancel := c.getRequestContext()
    67  	defer cancel()
    68  
    69  	r, err := state.controlClient.ListServices(
    70  		ctx,
    71  		&swarmapi.ListServicesRequest{Filters: filters},
    72  		grpc.MaxCallRecvMsgSize(defaultRecvSizeForListResponse),
    73  	)
    74  	if err != nil {
    75  		return nil, err
    76  	}
    77  
    78  	services := make([]types.Service, 0, len(r.Services))
    79  
    80  	for _, service := range r.Services {
    81  		if options.Filters.Contains("mode") {
    82  			var mode string
    83  			switch service.Spec.GetMode().(type) {
    84  			case *swarmapi.ServiceSpec_Global:
    85  				mode = "global"
    86  			case *swarmapi.ServiceSpec_Replicated:
    87  				mode = "replicated"
    88  			}
    89  
    90  			if !options.Filters.ExactMatch("mode", mode) {
    91  				continue
    92  			}
    93  		}
    94  		svcs, err := convert.ServiceFromGRPC(*service)
    95  		if err != nil {
    96  			return nil, err
    97  		}
    98  		services = append(services, svcs)
    99  	}
   100  
   101  	return services, nil
   102  }
   103  
   104  // GetService returns a service based on an ID or name.
   105  func (c *Cluster) GetService(input string, insertDefaults bool) (types.Service, error) {
   106  	var service *swarmapi.Service
   107  	if err := c.lockedManagerAction(func(ctx context.Context, state nodeState) error {
   108  		s, err := getService(ctx, state.controlClient, input, insertDefaults)
   109  		if err != nil {
   110  			return err
   111  		}
   112  		service = s
   113  		return nil
   114  	}); err != nil {
   115  		return types.Service{}, err
   116  	}
   117  	svc, err := convert.ServiceFromGRPC(*service)
   118  	if err != nil {
   119  		return types.Service{}, err
   120  	}
   121  	return svc, nil
   122  }
   123  
   124  // CreateService creates a new service in a managed swarm cluster.
   125  func (c *Cluster) CreateService(s types.ServiceSpec, encodedAuth string, queryRegistry bool) (*apitypes.ServiceCreateResponse, error) {
   126  	var resp *apitypes.ServiceCreateResponse
   127  	err := c.lockedManagerAction(func(ctx context.Context, state nodeState) error {
   128  		err := c.populateNetworkID(ctx, state.controlClient, &s)
   129  		if err != nil {
   130  			return err
   131  		}
   132  
   133  		serviceSpec, err := convert.ServiceSpecToGRPC(s)
   134  		if err != nil {
   135  			return errdefs.InvalidParameter(err)
   136  		}
   137  
   138  		resp = &apitypes.ServiceCreateResponse{}
   139  
   140  		switch serviceSpec.Task.Runtime.(type) {
   141  		case *swarmapi.TaskSpec_Attachment:
   142  			return fmt.Errorf("invalid task spec: spec type %q not supported", types.RuntimeNetworkAttachment)
   143  		// handle other runtimes here
   144  		case *swarmapi.TaskSpec_Generic:
   145  			switch serviceSpec.Task.GetGeneric().Kind {
   146  			case string(types.RuntimePlugin):
   147  				if !c.config.Backend.HasExperimental() {
   148  					return fmt.Errorf("runtime type %q only supported in experimental", types.RuntimePlugin)
   149  				}
   150  				if s.TaskTemplate.PluginSpec == nil {
   151  					return errors.New("plugin spec must be set")
   152  				}
   153  
   154  			default:
   155  				return fmt.Errorf("unsupported runtime type: %q", serviceSpec.Task.GetGeneric().Kind)
   156  			}
   157  
   158  			r, err := state.controlClient.CreateService(ctx, &swarmapi.CreateServiceRequest{Spec: &serviceSpec})
   159  			if err != nil {
   160  				return err
   161  			}
   162  
   163  			resp.ID = r.Service.ID
   164  		case *swarmapi.TaskSpec_Container:
   165  			ctnr := serviceSpec.Task.GetContainer()
   166  			if ctnr == nil {
   167  				return errors.New("service does not use container tasks")
   168  			}
   169  			if encodedAuth != "" {
   170  				ctnr.PullOptions = &swarmapi.ContainerSpec_PullOptions{RegistryAuth: encodedAuth}
   171  			}
   172  
   173  			// retrieve auth config from encoded auth
   174  			authConfig := &apitypes.AuthConfig{}
   175  			if encodedAuth != "" {
   176  				authReader := strings.NewReader(encodedAuth)
   177  				dec := json.NewDecoder(base64.NewDecoder(base64.URLEncoding, authReader))
   178  				if err := dec.Decode(authConfig); err != nil {
   179  					logrus.Warnf("invalid authconfig: %v", err)
   180  				}
   181  			}
   182  
   183  			// pin image by digest for API versions < 1.30
   184  			// TODO(nishanttotla): The check on "DOCKER_SERVICE_PREFER_OFFLINE_IMAGE"
   185  			// should be removed in the future. Since integration tests only use the
   186  			// latest API version, so this is no longer required.
   187  			if os.Getenv("DOCKER_SERVICE_PREFER_OFFLINE_IMAGE") != "1" && queryRegistry {
   188  				digestImage, err := c.imageWithDigestString(ctx, ctnr.Image, authConfig)
   189  				if err != nil {
   190  					logrus.Warnf("unable to pin image %s to digest: %s", ctnr.Image, err.Error())
   191  					// warning in the client response should be concise
   192  					resp.Warnings = append(resp.Warnings, digestWarning(ctnr.Image))
   193  
   194  				} else if ctnr.Image != digestImage {
   195  					logrus.Debugf("pinning image %s by digest: %s", ctnr.Image, digestImage)
   196  					ctnr.Image = digestImage
   197  
   198  				} else {
   199  					logrus.Debugf("creating service using supplied digest reference %s", ctnr.Image)
   200  
   201  				}
   202  
   203  				// Replace the context with a fresh one.
   204  				// If we timed out while communicating with the
   205  				// registry, then "ctx" will already be expired, which
   206  				// would cause UpdateService below to fail. Reusing
   207  				// "ctx" could make it impossible to create a service
   208  				// if the registry is slow or unresponsive.
   209  				var cancel func()
   210  				ctx, cancel = c.getRequestContext()
   211  				defer cancel()
   212  			}
   213  
   214  			r, err := state.controlClient.CreateService(ctx, &swarmapi.CreateServiceRequest{Spec: &serviceSpec})
   215  			if err != nil {
   216  				return err
   217  			}
   218  
   219  			resp.ID = r.Service.ID
   220  		}
   221  		return nil
   222  	})
   223  
   224  	return resp, err
   225  }
   226  
   227  // UpdateService updates existing service to match new properties.
   228  func (c *Cluster) UpdateService(serviceIDOrName string, version uint64, spec types.ServiceSpec, flags apitypes.ServiceUpdateOptions, queryRegistry bool) (*apitypes.ServiceUpdateResponse, error) {
   229  	var resp *apitypes.ServiceUpdateResponse
   230  
   231  	err := c.lockedManagerAction(func(ctx context.Context, state nodeState) error {
   232  
   233  		err := c.populateNetworkID(ctx, state.controlClient, &spec)
   234  		if err != nil {
   235  			return err
   236  		}
   237  
   238  		serviceSpec, err := convert.ServiceSpecToGRPC(spec)
   239  		if err != nil {
   240  			return errdefs.InvalidParameter(err)
   241  		}
   242  
   243  		currentService, err := getService(ctx, state.controlClient, serviceIDOrName, false)
   244  		if err != nil {
   245  			return err
   246  		}
   247  
   248  		resp = &apitypes.ServiceUpdateResponse{}
   249  
   250  		switch serviceSpec.Task.Runtime.(type) {
   251  		case *swarmapi.TaskSpec_Attachment:
   252  			return fmt.Errorf("invalid task spec: spec type %q not supported", types.RuntimeNetworkAttachment)
   253  		case *swarmapi.TaskSpec_Generic:
   254  			switch serviceSpec.Task.GetGeneric().Kind {
   255  			case string(types.RuntimePlugin):
   256  				if spec.TaskTemplate.PluginSpec == nil {
   257  					return errors.New("plugin spec must be set")
   258  				}
   259  			}
   260  		case *swarmapi.TaskSpec_Container:
   261  			newCtnr := serviceSpec.Task.GetContainer()
   262  			if newCtnr == nil {
   263  				return errors.New("service does not use container tasks")
   264  			}
   265  
   266  			encodedAuth := flags.EncodedRegistryAuth
   267  			if encodedAuth != "" {
   268  				newCtnr.PullOptions = &swarmapi.ContainerSpec_PullOptions{RegistryAuth: encodedAuth}
   269  			} else {
   270  				// this is needed because if the encodedAuth isn't being updated then we
   271  				// shouldn't lose it, and continue to use the one that was already present
   272  				var ctnr *swarmapi.ContainerSpec
   273  				switch flags.RegistryAuthFrom {
   274  				case apitypes.RegistryAuthFromSpec, "":
   275  					ctnr = currentService.Spec.Task.GetContainer()
   276  				case apitypes.RegistryAuthFromPreviousSpec:
   277  					if currentService.PreviousSpec == nil {
   278  						return errors.New("service does not have a previous spec")
   279  					}
   280  					ctnr = currentService.PreviousSpec.Task.GetContainer()
   281  				default:
   282  					return errors.New("unsupported registryAuthFrom value")
   283  				}
   284  				if ctnr == nil {
   285  					return errors.New("service does not use container tasks")
   286  				}
   287  				newCtnr.PullOptions = ctnr.PullOptions
   288  				// update encodedAuth so it can be used to pin image by digest
   289  				if ctnr.PullOptions != nil {
   290  					encodedAuth = ctnr.PullOptions.RegistryAuth
   291  				}
   292  			}
   293  
   294  			// retrieve auth config from encoded auth
   295  			authConfig := &apitypes.AuthConfig{}
   296  			if encodedAuth != "" {
   297  				if err := json.NewDecoder(base64.NewDecoder(base64.URLEncoding, strings.NewReader(encodedAuth))).Decode(authConfig); err != nil {
   298  					logrus.Warnf("invalid authconfig: %v", err)
   299  				}
   300  			}
   301  
   302  			// pin image by digest for API versions < 1.30
   303  			// TODO(nishanttotla): The check on "DOCKER_SERVICE_PREFER_OFFLINE_IMAGE"
   304  			// should be removed in the future. Since integration tests only use the
   305  			// latest API version, so this is no longer required.
   306  			if os.Getenv("DOCKER_SERVICE_PREFER_OFFLINE_IMAGE") != "1" && queryRegistry {
   307  				digestImage, err := c.imageWithDigestString(ctx, newCtnr.Image, authConfig)
   308  				if err != nil {
   309  					logrus.Warnf("unable to pin image %s to digest: %s", newCtnr.Image, err.Error())
   310  					// warning in the client response should be concise
   311  					resp.Warnings = append(resp.Warnings, digestWarning(newCtnr.Image))
   312  				} else if newCtnr.Image != digestImage {
   313  					logrus.Debugf("pinning image %s by digest: %s", newCtnr.Image, digestImage)
   314  					newCtnr.Image = digestImage
   315  				} else {
   316  					logrus.Debugf("updating service using supplied digest reference %s", newCtnr.Image)
   317  				}
   318  
   319  				// Replace the context with a fresh one.
   320  				// If we timed out while communicating with the
   321  				// registry, then "ctx" will already be expired, which
   322  				// would cause UpdateService below to fail. Reusing
   323  				// "ctx" could make it impossible to update a service
   324  				// if the registry is slow or unresponsive.
   325  				var cancel func()
   326  				ctx, cancel = c.getRequestContext()
   327  				defer cancel()
   328  			}
   329  		}
   330  
   331  		var rollback swarmapi.UpdateServiceRequest_Rollback
   332  		switch flags.Rollback {
   333  		case "", "none":
   334  			rollback = swarmapi.UpdateServiceRequest_NONE
   335  		case "previous":
   336  			rollback = swarmapi.UpdateServiceRequest_PREVIOUS
   337  		default:
   338  			return fmt.Errorf("unrecognized rollback option %s", flags.Rollback)
   339  		}
   340  
   341  		_, err = state.controlClient.UpdateService(
   342  			ctx,
   343  			&swarmapi.UpdateServiceRequest{
   344  				ServiceID: currentService.ID,
   345  				Spec:      &serviceSpec,
   346  				ServiceVersion: &swarmapi.Version{
   347  					Index: version,
   348  				},
   349  				Rollback: rollback,
   350  			},
   351  		)
   352  		return err
   353  	})
   354  	return resp, err
   355  }
   356  
   357  // RemoveService removes a service from a managed swarm cluster.
   358  func (c *Cluster) RemoveService(input string) error {
   359  	return c.lockedManagerAction(func(ctx context.Context, state nodeState) error {
   360  		service, err := getService(ctx, state.controlClient, input, false)
   361  		if err != nil {
   362  			return err
   363  		}
   364  
   365  		_, err = state.controlClient.RemoveService(ctx, &swarmapi.RemoveServiceRequest{ServiceID: service.ID})
   366  		return err
   367  	})
   368  }
   369  
   370  // ServiceLogs collects service logs and writes them back to `config.OutStream`
   371  func (c *Cluster) ServiceLogs(ctx context.Context, selector *backend.LogSelector, config *apitypes.ContainerLogsOptions) (<-chan *backend.LogMessage, error) {
   372  	c.mu.RLock()
   373  	defer c.mu.RUnlock()
   374  
   375  	state := c.currentNodeState()
   376  	if !state.IsActiveManager() {
   377  		return nil, c.errNoManager(state)
   378  	}
   379  
   380  	swarmSelector, err := convertSelector(ctx, state.controlClient, selector)
   381  	if err != nil {
   382  		return nil, errors.Wrap(err, "error making log selector")
   383  	}
   384  
   385  	// set the streams we'll use
   386  	stdStreams := []swarmapi.LogStream{}
   387  	if config.ShowStdout {
   388  		stdStreams = append(stdStreams, swarmapi.LogStreamStdout)
   389  	}
   390  	if config.ShowStderr {
   391  		stdStreams = append(stdStreams, swarmapi.LogStreamStderr)
   392  	}
   393  
   394  	// Get tail value squared away - the number of previous log lines we look at
   395  	var tail int64
   396  	// in ContainerLogs, if the tail value is ANYTHING non-integer, we just set
   397  	// it to -1 (all). i don't agree with that, but i also think no tail value
   398  	// should be legitimate. if you don't pass tail, we assume you want "all"
   399  	if config.Tail == "all" || config.Tail == "" {
   400  		// tail of 0 means send all logs on the swarmkit side
   401  		tail = 0
   402  	} else {
   403  		t, err := strconv.Atoi(config.Tail)
   404  		if err != nil {
   405  			return nil, errors.New("tail value must be a positive integer or \"all\"")
   406  		}
   407  		if t < 0 {
   408  			return nil, errors.New("negative tail values not supported")
   409  		}
   410  		// we actually use negative tail in swarmkit to represent messages
   411  		// backwards starting from the beginning. also, -1 means no logs. so,
   412  		// basically, for api compat with docker container logs, add one and
   413  		// flip the sign. we error above if you try to negative tail, which
   414  		// isn't supported by docker (and would error deeper in the stack
   415  		// anyway)
   416  		//
   417  		// See the logs protobuf for more information
   418  		tail = int64(-(t + 1))
   419  	}
   420  
   421  	// get the since value - the time in the past we're looking at logs starting from
   422  	var sinceProto *gogotypes.Timestamp
   423  	if config.Since != "" {
   424  		s, n, err := timetypes.ParseTimestamps(config.Since, 0)
   425  		if err != nil {
   426  			return nil, errors.Wrap(err, "could not parse since timestamp")
   427  		}
   428  		since := time.Unix(s, n)
   429  		sinceProto, err = gogotypes.TimestampProto(since)
   430  		if err != nil {
   431  			return nil, errors.Wrap(err, "could not parse timestamp to proto")
   432  		}
   433  	}
   434  
   435  	stream, err := state.logsClient.SubscribeLogs(ctx, &swarmapi.SubscribeLogsRequest{
   436  		Selector: swarmSelector,
   437  		Options: &swarmapi.LogSubscriptionOptions{
   438  			Follow:  config.Follow,
   439  			Streams: stdStreams,
   440  			Tail:    tail,
   441  			Since:   sinceProto,
   442  		},
   443  	})
   444  	if err != nil {
   445  		return nil, err
   446  	}
   447  
   448  	messageChan := make(chan *backend.LogMessage, 1)
   449  	go func() {
   450  		defer close(messageChan)
   451  		for {
   452  			// Check the context before doing anything.
   453  			select {
   454  			case <-ctx.Done():
   455  				return
   456  			default:
   457  			}
   458  			subscribeMsg, err := stream.Recv()
   459  			if err == io.EOF {
   460  				return
   461  			}
   462  			// if we're not io.EOF, push the message in and return
   463  			if err != nil {
   464  				select {
   465  				case <-ctx.Done():
   466  				case messageChan <- &backend.LogMessage{Err: err}:
   467  				}
   468  				return
   469  			}
   470  
   471  			for _, msg := range subscribeMsg.Messages {
   472  				// make a new message
   473  				m := new(backend.LogMessage)
   474  				m.Attrs = make([]backend.LogAttr, 0, len(msg.Attrs)+3)
   475  				// add the timestamp, adding the error if it fails
   476  				m.Timestamp, err = gogotypes.TimestampFromProto(msg.Timestamp)
   477  				if err != nil {
   478  					m.Err = err
   479  				}
   480  
   481  				nodeKey := contextPrefix + ".node.id"
   482  				serviceKey := contextPrefix + ".service.id"
   483  				taskKey := contextPrefix + ".task.id"
   484  
   485  				// copy over all of the details
   486  				for _, d := range msg.Attrs {
   487  					switch d.Key {
   488  					case nodeKey, serviceKey, taskKey:
   489  						// we have the final say over context details (in case there
   490  						// is a conflict (if the user added a detail with a context's
   491  						// key for some reason))
   492  					default:
   493  						m.Attrs = append(m.Attrs, backend.LogAttr{Key: d.Key, Value: d.Value})
   494  					}
   495  				}
   496  				m.Attrs = append(m.Attrs,
   497  					backend.LogAttr{Key: nodeKey, Value: msg.Context.NodeID},
   498  					backend.LogAttr{Key: serviceKey, Value: msg.Context.ServiceID},
   499  					backend.LogAttr{Key: taskKey, Value: msg.Context.TaskID},
   500  				)
   501  
   502  				switch msg.Stream {
   503  				case swarmapi.LogStreamStdout:
   504  					m.Source = "stdout"
   505  				case swarmapi.LogStreamStderr:
   506  					m.Source = "stderr"
   507  				}
   508  				m.Line = msg.Data
   509  
   510  				// there could be a case where the reader stops accepting
   511  				// messages and the context is canceled. we need to check that
   512  				// here, or otherwise we risk blocking forever on the message
   513  				// send.
   514  				select {
   515  				case <-ctx.Done():
   516  					return
   517  				case messageChan <- m:
   518  				}
   519  			}
   520  		}
   521  	}()
   522  	return messageChan, nil
   523  }
   524  
   525  // convertSelector takes a backend.LogSelector, which contains raw names that
   526  // may or may not be valid, and converts them to an api.LogSelector proto. It
   527  // returns an error if something fails
   528  func convertSelector(ctx context.Context, cc swarmapi.ControlClient, selector *backend.LogSelector) (*swarmapi.LogSelector, error) {
   529  	// don't rely on swarmkit to resolve IDs, do it ourselves
   530  	swarmSelector := &swarmapi.LogSelector{}
   531  	for _, s := range selector.Services {
   532  		service, err := getService(ctx, cc, s, false)
   533  		if err != nil {
   534  			return nil, err
   535  		}
   536  		c := service.Spec.Task.GetContainer()
   537  		if c == nil {
   538  			return nil, errors.New("logs only supported on container tasks")
   539  		}
   540  		swarmSelector.ServiceIDs = append(swarmSelector.ServiceIDs, service.ID)
   541  	}
   542  	for _, t := range selector.Tasks {
   543  		task, err := getTask(ctx, cc, t)
   544  		if err != nil {
   545  			return nil, err
   546  		}
   547  		c := task.Spec.GetContainer()
   548  		if c == nil {
   549  			return nil, errors.New("logs only supported on container tasks")
   550  		}
   551  		swarmSelector.TaskIDs = append(swarmSelector.TaskIDs, task.ID)
   552  	}
   553  	return swarmSelector, nil
   554  }
   555  
   556  // imageWithDigestString takes an image such as name or name:tag
   557  // and returns the image pinned to a digest, such as name@sha256:34234
   558  func (c *Cluster) imageWithDigestString(ctx context.Context, image string, authConfig *apitypes.AuthConfig) (string, error) {
   559  	ref, err := reference.ParseAnyReference(image)
   560  	if err != nil {
   561  		return "", err
   562  	}
   563  	namedRef, ok := ref.(reference.Named)
   564  	if !ok {
   565  		if _, ok := ref.(reference.Digested); ok {
   566  			return image, nil
   567  		}
   568  		return "", errors.Errorf("unknown image reference format: %s", image)
   569  	}
   570  	// only query registry if not a canonical reference (i.e. with digest)
   571  	if _, ok := namedRef.(reference.Canonical); !ok {
   572  		namedRef = reference.TagNameOnly(namedRef)
   573  
   574  		taggedRef, ok := namedRef.(reference.NamedTagged)
   575  		if !ok {
   576  			return "", errors.Errorf("image reference not tagged: %s", image)
   577  		}
   578  
   579  		repo, _, err := c.config.ImageBackend.GetRepository(ctx, taggedRef, authConfig)
   580  		if err != nil {
   581  			return "", err
   582  		}
   583  		dscrptr, err := repo.Tags(ctx).Get(ctx, taggedRef.Tag())
   584  		if err != nil {
   585  			return "", err
   586  		}
   587  
   588  		namedDigestedRef, err := reference.WithDigest(taggedRef, dscrptr.Digest)
   589  		if err != nil {
   590  			return "", err
   591  		}
   592  		// return familiar form until interface updated to return type
   593  		return reference.FamiliarString(namedDigestedRef), nil
   594  	}
   595  	// reference already contains a digest, so just return it
   596  	return reference.FamiliarString(ref), nil
   597  }
   598  
   599  // digestWarning constructs a formatted warning string
   600  // using the image name that could not be pinned by digest. The
   601  // formatting is hardcoded, but could me made smarter in the future
   602  func digestWarning(image string) string {
   603  	return fmt.Sprintf("image %s could not be accessed on a registry to record\nits digest. Each node will access %s independently,\npossibly leading to different nodes running different\nversions of the image.\n", image, image)
   604  }