chore: delete unused image digest resolver

pkg/client/deploy/resolver.go

@@ -1,24 +1,17 @@
 package deploy
 
 import (
-	"context"
-	"errors"
 	"fmt"
 	"strings"
-	"time"
 
 	"github.com/distribution/reference"
-	"github.com/docker/docker/api/types"
-	"github.com/opencontainers/go-digest"
 	"github.com/psviderski/uncloud/internal/secret"
 	"github.com/psviderski/uncloud/pkg/api"
-	"google.golang.org/grpc/codes"
 )
 
 // ServiceSpecResolver transforms user-provided service specs into deployment-ready form.
 type ServiceSpecResolver struct {
 	ClusterDomain string
-	ImageResolver *ImageDigestResolver
 }
 
 // Resolve transforms a service spec into its fully resolved form ready for deployment.
@@ -33,7 +26,6 @@ func (r *ServiceSpecResolver) Resolve(spec api.ServiceSpec) (api.ServiceSpec, er
 		r.applyDefaults,
 		r.resolveServiceName,
 		r.expandIngressPorts,
-		r.resolveImageDigest,
 	}
 
 	for _, step := range steps {
@@ -111,21 +103,6 @@ func (r *ServiceSpecResolver) expandIngressPorts(spec *api.ServiceSpec) error {
 	return nil
 }
 
-func (r *ServiceSpecResolver) resolveImageDigest(spec *api.ServiceSpec) error {
-	if r.ImageResolver == nil {
-		// Skip digest resolution when no resolver is provided.
-		return nil
-	}
-
-	image, err := r.ImageResolver.Resolve(spec.Container.Image, spec.Container.PullPolicy)
-	if err != nil {
-		return fmt.Errorf("resolve image digest: %w", err)
-	}
-	spec.Container.Image = image
-
-	return nil
-}
-
 func GenerateServiceName(image string) (string, error) {
 	img, err := reference.ParseDockerRef(image)
 	if err != nil {
@@ -144,181 +121,3 @@ func GenerateServiceName(image string) (string, error) {
 	}
 	return fmt.Sprintf("%s-%s", imageName, suffix), nil
 }
-
-type ImageResolverClient interface {
-	api.ImageClient
-	api.MachineClient
-}
-
-// TODO(lhf): as of April 2025, ImageDigestResolver is not used in the codebase and considered more harmful
-// than helpful. It's safe to remove it.
-type ImageDigestResolver struct {
-	Ctx    context.Context
-	Client ImageResolverClient
-}
-
-// Resolve resolves the image to the image with the digest according to the pull policy:
-//   - always: Fetch the latest digest for the image tag in the registry.
-//   - missing: Find the latest image matching the tag on any machine and use its digest, if it exists.
-//     When there is no matching image on any machine, it behaves like 'always'.
-//   - never: !Not implemented! Similar to 'missing' but when there is no matching image on any machine,
-//     it returns an error.
-//
-// If the image is already pinned to a digest, it is returned as is.
-func (r *ImageDigestResolver) Resolve(image, policy string) (string, error) {
-	if r.Ctx == nil {
-		r.Ctx = context.Background()
-	}
-
-	ref, err := reference.ParseNormalizedNamed(image)
-	if err != nil {
-		return "", fmt.Errorf("parse image: %w", err)
-	}
-	if _, ok := ref.(reference.Canonical); ok {
-		// The image is already pinned to a digest.
-		return image, nil
-	}
-
-	switch policy {
-	case api.PullPolicyAlways:
-		return r.resolveAlways(image)
-	case api.PullPolicyMissing:
-		return r.resolveMissing(image)
-	case api.PullPolicyNever:
-		return "", fmt.Errorf("pull policy '%s' is not supported yet", policy)
-	}
-	return image, nil
-}
-
-// resolveAlways resolves the image to the image with the digest by querying the registry from all machines.
-func (r *ImageDigestResolver) resolveAlways(image string) (string, error) {
-	// TODO: broadcast to a subset of machines in large clusters to avoid being rate-limited by the registry.
-	ctx, _, err := api.ProxyMachinesContext(r.Ctx, r.Client, nil)
-	if err != nil {
-		return "", fmt.Errorf("create request context to broadcast to all machines: %w", err)
-	}
-
-	remoteImages, err := r.Client.InspectRemoteImage(ctx, image)
-	if err != nil {
-		return "", fmt.Errorf("inspect image '%s' in registry from all machines: %w", image, err)
-	}
-	if len(remoteImages) == 0 {
-		return "", fmt.Errorf("inspect image '%s' in registry from all machines: unexpected empty response", image)
-	}
-
-	for _, ri := range remoteImages {
-		if ri.Metadata != nil && ri.Metadata.Error != "" {
-			// Save the last error to return it if all machines fail to inspect the image.
-			err = fmt.Errorf("inspect image '%s' in registry on machine '%s': %s",
-				image, ri.Metadata.Machine, ri.Metadata.Error)
-			continue
-		}
-
-		return reference.FamiliarString(ri.Image.Reference), nil
-	}
-
-	return "", err
-}
-
-func (r *ImageDigestResolver) resolveMissing(image string) (string, error) {
-	ctx, _, err := api.ProxyMachinesContext(r.Ctx, r.Client, nil)
-	if err != nil {
-		return "", fmt.Errorf("create request context to broadcast to all machines: %w", err)
-	}
-
-	machineImages, err := r.Client.InspectImage(ctx, image)
-	if err != nil {
-		if errors.Is(err, api.ErrNotFound) {
-			// If the image is missing on all machines, the 'missing' policy is equivalent to 'always'.
-			return r.resolveAlways(image)
-		}
-		return "", fmt.Errorf("inspect image '%s' on all machines: %w", image, err)
-	}
-
-	var availableImages []types.ImageInspect
-	for _, mi := range machineImages {
-		// Metadata can be nil if the request was proxied to only one machine.
-		if mi.Metadata != nil && mi.Metadata.Error != "" {
-			if codes.Code(mi.Metadata.Status.Code) != codes.NotFound {
-				fmt.Printf("WARNING: failed to inspect image '%s' on machine '%s': %s\n",
-					image, mi.Metadata.Machine, mi.Metadata.Error)
-			}
-			continue
-		}
-
-		availableImages = append(availableImages, mi.Image)
-	}
-
-	if len(availableImages) == 0 {
-		// If the image is missing on all machines, the 'missing' policy is equivalent to 'always'.
-		return r.resolveAlways(image)
-	}
-
-	// Find the latest image with a RepoDigest.
-	var latestDigest digest.Digest
-	var latestCreated time.Time
-	for _, img := range availableImages {
-		if len(img.RepoDigests) == 0 {
-			continue
-		}
-
-		// TODO: handle multiple RepoDigests. This could happen for example if the same image was pulled twice using
-		// 	both its index (multi-arch) digest and manifest (platform-specific) digest:
-		//  {
-		//    "Id": "sha256:6fee7566e4273ee6078f08e167e36434b35f72152232a5e6f1446288817dabe5",
-		//    "RepoTags": [
-		//        "traefik/whoami:latest"
-		//    ],
-		//    "RepoDigests": [
-		//        "traefik/whoami@sha256:200689790a0a0ea48ca45992e0450bc26ccab5307375b41c84dfc4f2475937ab",
-		//        "traefik/whoami@sha256:4f90b33ddca9c4d4f06527070d6e503b16d71016edea036842be2a84e60c91cb"
-		//    ],
-		//    ...
-		//  }
-		//  Should the registry be queried to find out which digest to use?
-		repoDigest := img.RepoDigests[0]
-		created, err := time.Parse(time.RFC3339Nano, img.Created)
-		if err != nil {
-			continue
-		}
-
-		if created.After(latestCreated) {
-			ref, err := reference.ParseNormalizedNamed(repoDigest)
-			if err != nil {
-				continue
-			}
-			if c, ok := ref.(reference.Canonical); ok {
-				latestDigest = c.Digest()
-				latestCreated = created
-			}
-		}
-	}
-
-	if latestDigest != "" {
-		return imageWithDigest(image, latestDigest)
-	}
-
-	// Don't pin the digest if no RepoDigests were found. This means the available images were not pulled from
-	// a registry but built locally or loaded from an archive. In this case, the available images (could be multiple
-	// for different platforms) should be copied to other machines to be able to run service containers on them.
-	return image, nil
-}
-
-// imageWithDigest adds a digest to an image string if it doesn't already contain one.
-func imageWithDigest(image string, dig digest.Digest) (string, error) {
-	ref, err := reference.ParseNormalizedNamed(image)
-	if err != nil {
-		return "", fmt.Errorf("parse image: %w", err)
-	}
-
-	if _, ok := ref.(reference.Canonical); !ok {
-		// Preserves the original tag if present.
-		img, err := reference.WithDigest(ref, dig)
-		if err != nil {
-			return "", fmt.Errorf("add digest to image: %w", err)
-		}
-		return reference.FamiliarString(img), nil
-	}
-
-	return image, nil
-}