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repository_client.go
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repository_client.go
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package image
import (
"context"
"crypto/tls"
"encoding/json"
"fmt"
"net/http"
"strings"
"time"
"github.com/distribution/distribution/v3"
"github.com/distribution/distribution/v3/manifest/manifestlist"
"github.com/distribution/distribution/v3/manifest/ocischema"
"github.com/distribution/distribution/v3/manifest/schema1" //nolint: staticcheck
"github.com/distribution/distribution/v3/manifest/schema2"
"github.com/distribution/distribution/v3/reference"
"github.com/distribution/distribution/v3/registry/client"
"github.com/distribution/distribution/v3/registry/client/auth"
"github.com/distribution/distribution/v3/registry/client/auth/challenge"
"github.com/distribution/distribution/v3/registry/client/transport"
"github.com/hashicorp/go-cleanhttp"
"github.com/opencontainers/go-digest"
ociv1 "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/patrickmn/go-cache"
"go.uber.org/ratelimit"
"golang.org/x/sync/semaphore"
"github.com/akuity/kargo/internal/logging"
)
const (
// maxMetadataConcurrency is the maximum number of concurrent goroutines that
// can be used to fetch metadata. Per Go's documentation, goroutines are very
// cheap (practical to spawn tens of thousands), AND we have a rate limiter in
// place for each registry, so there's no reason for this number not to be
// pretty large.
maxMetadataConcurrency = 1000
unknown = "unknown"
)
var metaSem = semaphore.NewWeighted(maxMetadataConcurrency)
// knownMediaTypes is the list of supported media types.
var knownMediaTypes = []string{
// V!
schema1.MediaTypeSignedManifest, //nolint: staticcheck
// V2
schema2.SchemaVersion.MediaType,
manifestlist.SchemaVersion.MediaType,
// OCI
ocischema.SchemaVersion.MediaType,
ociv1.MediaTypeImageIndex,
}
// repositoryClient is a client for retrieving information from a specific image
// container repository.
type repositoryClient struct {
registry *registry
image string
repo distribution.Repository
// The following behaviors are overridable for testing purposes:
getImageByTagFn func(
context.Context,
string,
*platformConstraint,
) (*Image, error)
getImageByDigestFn func(
context.Context,
digest.Digest,
*platformConstraint,
) (*Image, error)
getManifestByTagFn func(
context.Context,
string,
) (distribution.Manifest, error)
getManifestByDigestFn func(
context.Context,
digest.Digest,
) (distribution.Manifest, error)
extractImageFromManifestFn func(
context.Context,
distribution.Manifest,
*platformConstraint,
) (*Image, error)
extractImageFromV1ManifestFn func(
*schema1.SignedManifest, // nolint: staticcheck
*platformConstraint,
) (*Image, error)
extractImageFromV2ManifestFn func(
context.Context,
*schema2.DeserializedManifest,
*platformConstraint,
) (*Image, error)
extractImageFromOCIManifestFn func(
context.Context,
*ocischema.DeserializedManifest,
*platformConstraint,
) (*Image, error)
extractImageFromCollectionFn func(
context.Context,
distribution.Manifest,
*platformConstraint,
) (*Image, error)
getBlobFn func(context.Context, digest.Digest) ([]byte, error)
}
// newRepositoryClient parses the provided repository URL to infer registry
// information and image name. This information is used to initialize and
// return a new repository client.
func newRepositoryClient(
repoURL string,
insecureSkipTLSVerify bool,
creds *Credentials,
) (*repositoryClient, error) {
repoRef, err := reference.ParseNormalizedNamed(repoURL)
if err != nil {
return nil, fmt.Errorf("error parsing image repo URL %s: %w", repoURL, err)
}
registryURL := reference.Domain(repoRef)
reg := getRegistry(registryURL)
image := reg.normalizeImageName(reference.Path(repoRef))
apiAddress := strings.TrimSuffix(reg.apiAddress, "/")
httpTransport := cleanhttp.DefaultTransport()
if insecureSkipTLSVerify {
httpTransport.TLSClientConfig = &tls.Config{
InsecureSkipVerify: insecureSkipTLSVerify, // nolint: gosec
}
}
challengeManager, err := getChallengeManager(
apiAddress,
&rateLimitedRoundTripper{
limiter: reg.rateLimiter,
internalRoundTripper: httpTransport,
},
)
if err != nil {
return nil, fmt.Errorf("error getting challenge manager for %s: %w", apiAddress, err)
}
if creds == nil {
creds = &Credentials{}
}
rlt := &rateLimitedRoundTripper{
limiter: reg.rateLimiter,
internalRoundTripper: transport.NewTransport(
httpTransport,
auth.NewAuthorizer(
challengeManager,
auth.NewTokenHandler(
httpTransport,
creds,
image,
"pull",
),
auth.NewBasicHandler(creds),
),
),
}
imageRef, err := reference.WithName(image)
if err != nil {
return nil, fmt.Errorf("error getting reference for image %q: %w", image, err)
}
repo, err := client.NewRepository(imageRef, apiAddress, rlt)
if err != nil {
return nil, fmt.Errorf(
"error creating internal repository for image %q in registry %s: %w",
image,
apiAddress,
err,
)
}
r := &repositoryClient{
registry: reg,
image: image,
repo: repo,
}
r.getImageByTagFn = r.getImageByTag
r.getImageByDigestFn = r.getImageByDigest
r.getManifestByTagFn = r.getManifestByTag
r.getManifestByDigestFn = r.getManifestByDigest
r.extractImageFromManifestFn = r.extractImageFromManifest
r.extractImageFromV1ManifestFn = r.extractImageFromV1Manifest
r.extractImageFromV2ManifestFn = r.extractImageFromV2Manifest
r.extractImageFromOCIManifestFn = r.extractImageFromOCIManifest
r.extractImageFromCollectionFn = r.extractImageFromCollection
r.getBlobFn = r.getBlob
return r, nil
}
// getChallengeManager makes an initial request to a registry's API v2 endpoint.
// The response is used to configure a challenge manager, which is returned.
//
// Defining it this way makes it easy to override for testing purposes.
var getChallengeManager = func(
apiAddress string,
roundTripper http.RoundTripper,
) (challenge.Manager, error) {
httpClient := &http.Client{
Transport: roundTripper,
}
apiAddress = fmt.Sprintf("%s/v2/", apiAddress)
resp, err := httpClient.Get(apiAddress)
if err != nil {
return nil, fmt.Errorf("error requesting %s: %w", apiAddress, err)
}
defer resp.Body.Close()
// Consider only HTTP 200 and 401 to be valid responses
if resp.StatusCode != http.StatusOK &&
resp.StatusCode != http.StatusUnauthorized {
return nil, fmt.Errorf(
"GET %s returned an HTTP %d status code; this address may not "+
"be a valid v2 Registry endpoint",
apiAddress,
resp.StatusCode,
)
}
challengeManager := challenge.NewSimpleManager()
if err = challengeManager.AddResponse(resp); err != nil {
err = fmt.Errorf("error configuring challenge manager: %w", err)
}
return challengeManager, err
}
// getTags retrieves a list of all tags from the repository.
func (r *repositoryClient) getTags(ctx context.Context) ([]string, error) {
logger := logging.LoggerFromContext(ctx)
logger.Trace("retrieving tags for image")
tagSvc := r.repo.Tags(ctx)
tags, err := tagSvc.All(ctx)
if err != nil {
return nil, fmt.Errorf("error retrieving tags from repository: %w", err)
}
return tags, nil
}
// getImageByTag retrieves an Image by tag. This function uses no cache since
// tags can be mutable.
func (r *repositoryClient) getImageByTag(
ctx context.Context,
tag string,
platform *platformConstraint,
) (*Image, error) {
manifest, err := r.getManifestByTagFn(ctx, tag)
if err != nil {
return nil, fmt.Errorf("error retrieving manifest for tag %s: %w", tag, err)
}
image, err := r.extractImageFromManifestFn(ctx, manifest, platform)
if err != nil {
return nil, fmt.Errorf("error extracting image from manifest for tag %q: %w", tag, err)
}
if image != nil {
image.Tag = tag
}
return image, nil
}
// getImageByDigest retrieves an Image for a given digest. This function uses a
// cache since information retrieved by digest will never change.
func (r *repositoryClient) getImageByDigest(
ctx context.Context,
d digest.Digest,
platform *platformConstraint,
) (*Image, error) {
logger := logging.LoggerFromContext(ctx)
logger.Tracef("retrieving image for manifest %s", d)
if entry, exists := r.registry.imageCache.Get(d.String()); exists {
image := entry.(Image) // nolint: forcetypeassert
return &image, nil
}
logger.Tracef("image for manifest %s NOT found in cache", d)
manifest, err := r.getManifestByDigestFn(ctx, d)
if err != nil {
return nil, fmt.Errorf("error retrieving manifest %s: %w", d, err)
}
image, err := r.extractImageFromManifestFn(ctx, manifest, platform)
if err != nil {
return nil, fmt.Errorf("error extracting image from manifest %s: %w", d, err)
}
if image != nil {
// Cache the image
r.registry.imageCache.Set(d.String(), *image, cache.DefaultExpiration)
logger.Tracef("cached image for manifest %s", d)
}
return image, nil
}
// getManifestByTag retrieves a manifest for a given tag.
func (r *repositoryClient) getManifestByTag(
ctx context.Context,
tag string,
) (distribution.Manifest, error) {
logger := logging.LoggerFromContext(ctx)
logger.Tracef("retrieving manifest for tag %q from repository", tag)
manifestSvc, err := r.repo.Manifests(ctx)
if err != nil {
return nil, fmt.Errorf("error getting manifest service: %w", err)
}
manifest, err := manifestSvc.Get(
ctx,
digest.FromString(tag),
distribution.WithTag(tag),
distribution.WithManifestMediaTypes(knownMediaTypes),
)
if err != nil {
return nil, fmt.Errorf("error retrieving manifest for tag %q: %w", tag, err)
}
return manifest, nil
}
// getManifestByDigest retrieves a manifest for a given digest.
func (r *repositoryClient) getManifestByDigest(
ctx context.Context,
d digest.Digest,
) (distribution.Manifest, error) {
logger := logging.LoggerFromContext(ctx)
logger.Tracef("retrieving manifest for digest %q from repository", d.String())
manifestSvc, err := r.repo.Manifests(ctx)
if err != nil {
return nil, fmt.Errorf("error getting manifest service: %w", err)
}
manifest, err := manifestSvc.Get(
ctx,
d,
distribution.WithManifestMediaTypes(knownMediaTypes),
)
if err != nil {
return nil, fmt.Errorf("error retrieving manifest for digest %q: %w", d, err)
}
return manifest, nil
}
// extractImageFromManifest extracts an Image from a given manifest. V1
// (legacy), V2, and OCI manifests are supported as well as manifest lists and
// indices (e.g. for multi-arch images).
func (r *repositoryClient) extractImageFromManifest(
ctx context.Context,
manifest distribution.Manifest,
platform *platformConstraint,
) (*Image, error) {
switch m := manifest.(type) {
case *schema1.SignedManifest: //nolint: staticcheck
return r.extractImageFromV1ManifestFn(m, platform)
case *schema2.DeserializedManifest:
return r.extractImageFromV2ManifestFn(ctx, m, platform)
case *ocischema.DeserializedManifest:
return r.extractImageFromOCIManifestFn(ctx, m, platform)
case *manifestlist.DeserializedManifestList, *ocischema.DeserializedImageIndex:
return r.extractImageFromCollectionFn(ctx, manifest, platform)
default:
return nil, fmt.Errorf("invalid manifest type %T", manifest)
}
}
// manifestInfo is a struct used for unmarshaling manifest information.
type manifestInfo struct {
OS string `json:"os"`
Arch string `json:"architecture"`
Variant string `json:"variant"`
Created string `json:"created"`
}
// extractImageFromV1Manifest extracts an Image from a given V1 manifest. It is
// valid for this function to return nil if the manifest does not match the
// specified platform, if any.
func (r *repositoryClient) extractImageFromV1Manifest(
manifest *schema1.SignedManifest, // nolint: staticcheck
platform *platformConstraint,
) (*Image, error) {
// We need this to calculate the digest
_, manifestBytes, err := manifest.Payload() // nolint: staticcheck
if err != nil {
return nil, fmt.Errorf("error extracting payload from V1 manifest: %w", err)
}
digest := digest.FromBytes(manifestBytes)
logger := logging.LoggerFromContext(context.Background())
logger.Tracef("extracting image from V1 manifest %s", digest)
if len(manifest.History) == 0 {
return nil, fmt.Errorf("no history information found in V1 manifest %s", digest)
}
var info manifestInfo
if err = json.Unmarshal(
[]byte(manifest.History[0].V1Compatibility),
&info,
); err != nil {
return nil, fmt.Errorf("error unmarshaling V1 manifest %s: %w", digest, err)
}
if platform != nil &&
!platform.matches(info.OS, info.Arch, info.Variant) {
return nil, nil
}
createdAt, err := time.Parse(time.RFC3339Nano, info.Created)
if err != nil {
return nil, fmt.Errorf(
"error parsing createdAt timestamp from V1 manifest %s: %w",
digest,
err,
)
}
return &Image{
Digest: digest,
CreatedAt: &createdAt,
}, nil
}
// extractImageFromV2Manifest extracts an Image from a given V2 manifest. It is
// valid for this function to return nil if the manifest does not match the
// specified platform, if any.
func (r *repositoryClient) extractImageFromV2Manifest(
ctx context.Context,
manifest *schema2.DeserializedManifest,
platform *platformConstraint,
) (*Image, error) {
// We need this to calculate the digest
_, manifestBytes, err := manifest.Payload()
if err != nil {
return nil, fmt.Errorf("error extracting payload from V2 manifest: %w", err)
}
digest := digest.FromBytes(manifestBytes)
logger := logging.LoggerFromContext(ctx)
logger.Tracef("extracting image from V2 manifest %s", digest)
// This referenced config object has platform information and creation
// timestamp
blob, err := r.getBlobFn(ctx, manifest.Config.Digest)
if err != nil {
return nil, fmt.Errorf(
"error fetching blob %s referenced by V2 manifest %s: %w",
manifest.Config.Digest,
digest,
err,
)
}
var info manifestInfo
if err = json.Unmarshal(blob, &info); err != nil {
return nil, fmt.Errorf(
"error unmarshaling blob %s referenced by V2 manifest %s: %w",
manifest.Config.Digest,
digest,
err,
)
}
if platform != nil &&
!platform.matches(info.OS, info.Arch, info.Variant) {
return nil, nil
}
createdAt, err := time.Parse(time.RFC3339Nano, info.Created)
if err != nil {
return nil, fmt.Errorf(
"error parsing createdAt timestamp from blob %s referenced by V2 manifest %s: %w",
manifest.Config.Digest,
digest,
err,
)
}
return &Image{
Digest: digest,
CreatedAt: &createdAt,
}, nil
}
// extractImageFromOCIManifest extracts an Image from a given OCI manifest. It
// is valid for this function to return nil if the manifest does not match the
// specified platform, if any.
func (r *repositoryClient) extractImageFromOCIManifest(
ctx context.Context,
manifest *ocischema.DeserializedManifest,
platform *platformConstraint,
) (*Image, error) {
// We need this to calculate the digest
_, manifestBytes, err := manifest.Payload()
if err != nil {
return nil, fmt.Errorf("error extracting payload from OCI manifest: %w", err)
}
digest := digest.FromBytes(manifestBytes)
logger := logging.LoggerFromContext(ctx)
logger.Tracef("extracting image from OCI manifest %s", digest)
// This referenced config object has platform information and creation
// timestamp
blob, err := r.getBlobFn(ctx, manifest.Config.Digest)
if err != nil {
return nil, fmt.Errorf(
"error fetching blob %s referenced by OCI manifest %s: %w",
manifest.Config.Digest,
digest,
err,
)
}
var info manifestInfo
if err = json.Unmarshal(blob, &info); err != nil {
return nil, fmt.Errorf(
"error unmarshaling blob %s referenced by OCI manifest %s: %w",
manifest.Config.Digest,
digest,
err,
)
}
if info.OS == unknown || info.OS == "" || info.Arch == unknown || info.Arch == "" {
// This doesn't look like an image. It might be an attestation or something
// else. It's definitely not what we're looking for.
return nil, nil
}
if platform != nil &&
!platform.matches(info.OS, info.Arch, info.Variant) {
return nil, nil
}
createdAt, err := time.Parse(time.RFC3339Nano, info.Created)
if err != nil {
return nil, fmt.Errorf(
"error parsing createdAt timestamp from blob %s referenced by OCI manifest %s: %w",
manifest.Config.Digest,
digest,
err,
)
}
return &Image{
Digest: digest,
CreatedAt: &createdAt,
}, nil
}
// extractImageFromCollection extracts an Image from a V2 manifest list or OCI
// index. It is valid for this function to return nil if no manifest in the list
// or index matches the specified platform, if any. This function assumes it is
// only ever invoked with a manifest list or index.
func (r *repositoryClient) extractImageFromCollection(
ctx context.Context,
collection distribution.Manifest,
platform *platformConstraint,
) (*Image, error) {
// We need this to calculate the digest. Note that this is the digest of the
// list or index.
_, manifestBytes, err := collection.Payload()
if err != nil {
return nil, fmt.Errorf("error getting collection payload: %w", err)
}
digest := digest.FromBytes(manifestBytes)
logger := logging.LoggerFromContext(ctx)
logger.Tracef(
"extracting image from V2 manifest list or OCI index %s",
digest,
)
refs := make([]distribution.Descriptor, 0, len(collection.References()))
for _, ref := range collection.References() {
if ref.Platform == nil ||
ref.Platform.OS == unknown || ref.Platform.OS == "" ||
ref.Platform.Architecture == unknown || ref.Platform.Architecture == "" {
// This reference doesn't look like a reference to an image. It might
// be an attestation or something else. Skip it.
continue
}
refs = append(refs, ref)
}
if len(refs) == 0 {
return nil, fmt.Errorf(
"empty V2 manifest list or OCI index %s is not supported",
digest,
)
}
// If there's a platform constraint, find the ref that matches it and
// that's the information we're really after.
if platform != nil {
var matchedRefs []distribution.Descriptor
// Filter out references that don't match the platform
for _, ref := range refs {
if platform != nil && !platform.matches(
ref.Platform.OS,
ref.Platform.Architecture,
ref.Platform.Variant,
) {
continue
}
matchedRefs = append(matchedRefs, ref)
}
if len(matchedRefs) == 0 {
// No refs matched the platform
return nil, nil
}
if len(matchedRefs) > 1 {
// This really shouldn't happen.
return nil, fmt.Errorf(
"expected only one reference to match platform %q, but found %d",
platform.String(),
len(matchedRefs),
)
}
ref := matchedRefs[0]
image, err := r.getImageByDigestFn(ctx, ref.Digest, platform)
if err != nil {
return nil, fmt.Errorf(
"error getting image from manifest %s: %w",
ref.Digest,
err,
)
}
if image == nil {
// This really shouldn't happen.
return nil, fmt.Errorf(
"expected manifest for digest %v to match platform %q, but it did not",
ref.Digest,
platform.String(),
)
}
image.Digest = digest
return image, nil
}
// If we get to here there was no platform constraint.
// Manifest lists and indices don't have a createdAt timestamp, and we had no
// platform constraint, so we'll follow ALL the references to find the most
// recently pushed manifest's createdAt timestamp.
var createdAt *time.Time
for _, ref := range refs {
image, err := r.getImageByDigestFn(ctx, ref.Digest, platform)
if err != nil {
return nil, fmt.Errorf(
"error getting image from manifest %s: %w",
ref.Digest,
err,
)
}
if image == nil {
// This really shouldn't happen.
return nil, fmt.Errorf(
"found no image for manifest %s",
ref.Digest,
)
}
if createdAt == nil || image.CreatedAt.After(*createdAt) {
createdAt = image.CreatedAt
}
}
return &Image{
Digest: digest,
CreatedAt: createdAt,
}, nil
}
// getBlob retrieves a blob from the repository.
func (r *repositoryClient) getBlob(
ctx context.Context,
digest digest.Digest,
) ([]byte, error) {
logger := logging.LoggerFromContext(ctx)
logger.Tracef("retrieving blob for digest %q", digest.String())
return r.repo.Blobs(ctx).Get(ctx, digest)
}
// rateLimitedRoundTripper is a rate limited implementation of
// http.RoundTripper.
type rateLimitedRoundTripper struct {
limiter ratelimit.Limiter
internalRoundTripper http.RoundTripper
}
// RoundTrip implements the http.RoundTripper interface.
func (r *rateLimitedRoundTripper) RoundTrip(
req *http.Request,
) (*http.Response, error) {
r.limiter.Take()
return r.internalRoundTripper.RoundTrip(req)
}