49 lines
1.5 KiB
Go
49 lines
1.5 KiB
Go
package updater
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import (
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"context"
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"fmt"
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"github.com/docker/docker/api/types/registry"
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"github.com/shcizo/package-updater/internal/imageref"
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)
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// DistributionClient is the subset of the Docker SDK the Resolver needs.
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// *client.Client satisfies it.
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type DistributionClient interface {
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DistributionInspect(ctx context.Context, imageRef, encodedRegistryAuth string) (registry.DistributionInspect, error)
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}
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// Resolver turns "repo:tag" into "repo:tag@digest" by asking the local
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// daemon, which contacts the registry.
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type Resolver struct {
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cli DistributionClient
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auth *RegistryAuth
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}
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// NewResolver returns a Resolver. auth may be nil (anonymous access).
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func NewResolver(cli DistributionClient, auth *RegistryAuth) *Resolver {
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return &Resolver{cli: cli, auth: auth}
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}
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// Resolve returns ref pinned to the digest its tag currently points at. It
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// fails for a ref without a tag or with a digest already.
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func (r *Resolver) Resolve(ctx context.Context, ref string) (string, error) {
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p := imageref.Parse(ref)
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switch {
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case p.Digest != "":
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return "", fmt.Errorf("image %q already has a digest", ref)
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case p.Tag == "":
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return "", fmt.Errorf("image %q has no tag to resolve", ref)
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}
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info, err := r.cli.DistributionInspect(ctx, ref, r.auth.For(p.Repo))
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if err != nil {
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return "", fmt.Errorf("resolve %s: %w", ref, err)
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}
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if info.Descriptor.Digest == "" {
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return "", fmt.Errorf("resolve %s: registry returned no digest", ref)
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}
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return ref + "@" + info.Descriptor.Digest.String(), nil
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}
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