forked from TrueCloudLab/distribution
9c88801a12
Back in the before time, the best practices surrounding usage of Context weren't quite worked out. We defined our own type to make usage easier. As this packaged was used elsewhere, it make it more and more challenging to integrate with the forked `Context` type. Now that it is available in the standard library, we can just use that one directly. To make usage more consistent, we now use `dcontext` when referring to the distribution context package. Signed-off-by: Stephen J Day <stephen.day@docker.com>
85 lines
2.5 KiB
Go
85 lines
2.5 KiB
Go
package schema2
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import (
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"context"
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"github.com/docker/distribution"
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"github.com/opencontainers/go-digest"
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)
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// builder is a type for constructing manifests.
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type builder struct {
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// bs is a BlobService used to publish the configuration blob.
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bs distribution.BlobService
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// configMediaType is media type used to describe configuration
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configMediaType string
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// configJSON references
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configJSON []byte
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// dependencies is a list of descriptors that gets built by successive
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// calls to AppendReference. In case of image configuration these are layers.
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dependencies []distribution.Descriptor
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}
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// NewManifestBuilder is used to build new manifests for the current schema
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// version. It takes a BlobService so it can publish the configuration blob
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// as part of the Build process.
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func NewManifestBuilder(bs distribution.BlobService, configMediaType string, configJSON []byte) distribution.ManifestBuilder {
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mb := &builder{
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bs: bs,
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configMediaType: configMediaType,
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configJSON: make([]byte, len(configJSON)),
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}
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copy(mb.configJSON, configJSON)
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return mb
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}
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// Build produces a final manifest from the given references.
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func (mb *builder) Build(ctx context.Context) (distribution.Manifest, error) {
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m := Manifest{
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Versioned: SchemaVersion,
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Layers: make([]distribution.Descriptor, len(mb.dependencies)),
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}
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copy(m.Layers, mb.dependencies)
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configDigest := digest.FromBytes(mb.configJSON)
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var err error
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m.Config, err = mb.bs.Stat(ctx, configDigest)
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switch err {
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case nil:
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// Override MediaType, since Put always replaces the specified media
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// type with application/octet-stream in the descriptor it returns.
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m.Config.MediaType = mb.configMediaType
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return FromStruct(m)
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case distribution.ErrBlobUnknown:
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// nop
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default:
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return nil, err
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}
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// Add config to the blob store
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m.Config, err = mb.bs.Put(ctx, mb.configMediaType, mb.configJSON)
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// Override MediaType, since Put always replaces the specified media
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// type with application/octet-stream in the descriptor it returns.
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m.Config.MediaType = mb.configMediaType
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if err != nil {
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return nil, err
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}
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return FromStruct(m)
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}
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// AppendReference adds a reference to the current ManifestBuilder.
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func (mb *builder) AppendReference(d distribution.Describable) error {
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mb.dependencies = append(mb.dependencies, d.Descriptor())
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return nil
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}
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// References returns the current references added to this builder.
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func (mb *builder) References() []distribution.Descriptor {
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return mb.dependencies
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}
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