81 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			Go
		
	
	
			
		
		
	
	
			81 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			Go
		
	
	
package schema2
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import (
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	"github.com/docker/distribution"
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	"github.com/docker/distribution/context"
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	"github.com/docker/distribution/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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	// configJSON references
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	configJSON []byte
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	// layers is a list of layer descriptors that gets built by successive
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	// calls to AppendReference.
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	layers []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, configJSON []byte) distribution.ManifestBuilder {
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	mb := &builder{
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		bs:         bs,
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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.layers)),
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	}
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	copy(m.Layers, mb.layers)
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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 = MediaTypeConfig
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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, MediaTypeConfig, 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 = MediaTypeConfig
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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.layers = append(mb.layers, 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.layers
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}
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