forked from TrueCloudLab/distribution
87 lines
3.1 KiB
Go
87 lines
3.1 KiB
Go
package storagedriver
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import (
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"fmt"
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"io"
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"strconv"
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"strings"
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)
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// Version is a string representing the storage driver version, of the form Major.Minor.
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// The registry must accept storage drivers with equal major version and greater minor version,
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// but may not be compatible with older storage driver versions.
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type Version string
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// Major returns the major (primary) component of a version
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func (version Version) Major() uint {
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majorPart := strings.Split(string(version), ".")[0]
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major, _ := strconv.ParseUint(majorPart, 10, 0)
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return uint(major)
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}
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// Minor returns the minor (secondary) component of a version
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func (version Version) Minor() uint {
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minorPart := strings.Split(string(version), ".")[1]
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minor, _ := strconv.ParseUint(minorPart, 10, 0)
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return uint(minor)
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}
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// CurrentVersion is the current storage driver Version
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const CurrentVersion Version = "0.1"
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// StorageDriver defines methods that a Storage Driver must implement for a filesystem-like
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// key/value object storage
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type StorageDriver interface {
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// GetContent retrieves the content stored at "path" as a []byte
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// Should primarily be used for small objects
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GetContent(path string) ([]byte, error)
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// PutContent stores the []byte content at a location designated by "path"
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// Should primarily be used for small objects
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PutContent(path string, content []byte) error
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// ReadStream retrieves an io.ReadCloser for the content stored at "path" with a given byte
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// offset
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// May be used to resume reading a stream by providing a nonzero offset
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ReadStream(path string, offset uint64) (io.ReadCloser, error)
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// WriteStream stores the contents of the provided io.ReadCloser at a location designated by
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// the given path
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// The driver will know it has received the full contents when it has read "size" bytes
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// May be used to resume writing a stream by providing a nonzero offset
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// The offset must be no larger than the CurrentSize for this path
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WriteStream(path string, offset, size uint64, readCloser io.ReadCloser) error
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// CurrentSize retrieves the curernt size in bytes of the object at the given path
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// It should be safe to read or write anywhere up to this point
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CurrentSize(path string) (uint64, error)
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// List returns a list of the objects that are direct descendants of the given path
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List(path string) ([]string, error)
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// Move moves an object stored at sourcePath to destPath, removing the original object
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// Note: This may be no more efficient than a copy followed by a delete for many implementations
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Move(sourcePath string, destPath string) error
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// Delete recursively deletes all objects stored at "path" and its subpaths
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Delete(path string) error
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}
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// PathNotFoundError is returned when operating on a nonexistent path
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type PathNotFoundError struct {
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Path string
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}
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func (err PathNotFoundError) Error() string {
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return fmt.Sprintf("Path not found: %s", err.Path)
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}
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// InvalidOffsetError is returned when attempting to read or write from an invalid offset
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type InvalidOffsetError struct {
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Path string
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Offset uint64
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}
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func (err InvalidOffsetError) Error() string {
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return fmt.Sprintf("Invalid offset: %d for path: %s", err.Offset, err.Path)
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}
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