forked from TrueCloudLab/distribution
51 lines
1.7 KiB
Go
51 lines
1.7 KiB
Go
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package storage
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import (
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"fmt"
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"net/http"
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"github.com/docker/distribution/storagedriver"
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)
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// LayerHandler provides middleware for serving the contents of a Layer.
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type LayerHandler interface {
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// Resolve returns an http.Handler which can serve the contents of a given
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// Layer if possible, or nil and an error when unsupported. This may
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// directly serve the contents of the layer or issue a redirect to another
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// URL hosting the content.
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Resolve(layer Layer) (http.Handler, error)
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}
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// LayerHandlerInitFunc is the type of a LayerHandler factory function and is
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// used to register the contsructor for different LayerHandler backends.
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type LayerHandlerInitFunc func(storageDriver storagedriver.StorageDriver, options map[string]interface{}) (LayerHandler, error)
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var layerHandlers map[string]LayerHandlerInitFunc
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// RegisterLayerHandler is used to register an LayerHandlerInitFunc for
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// a LayerHandler backend with the given name.
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func RegisterLayerHandler(name string, initFunc LayerHandlerInitFunc) error {
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if layerHandlers == nil {
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layerHandlers = make(map[string]LayerHandlerInitFunc)
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}
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if _, exists := layerHandlers[name]; exists {
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return fmt.Errorf("name already registered: %s", name)
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}
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layerHandlers[name] = initFunc
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return nil
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}
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// GetLayerHandler constructs a LayerHandler
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// with the given options using the named backend.
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func GetLayerHandler(name string, options map[string]interface{}, storageDriver storagedriver.StorageDriver) (LayerHandler, error) {
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if layerHandlers != nil {
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if initFunc, exists := layerHandlers[name]; exists {
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return initFunc(storageDriver, options)
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}
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}
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return nil, fmt.Errorf("no layer handler registered with name: %s", name)
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}
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