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Conceptually the backend configuration should be validated when creating or opening the backend, but not when filling in information from environment variables into the configuration.
87 lines
2.8 KiB
Go
87 lines
2.8 KiB
Go
package restic
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import (
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"context"
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"hash"
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"io"
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)
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// Backend is used to store and access data.
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//
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// Backend operations that return an error will be retried when a Backend is
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// wrapped in a RetryBackend. To prevent that from happening, the operations
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// should return a github.com/cenkalti/backoff/v4.PermanentError. Errors from
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// the context package need not be wrapped, as context cancellation is checked
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// separately by the retrying logic.
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type Backend interface {
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// Location returns a string that describes the type and location of the
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// repository.
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Location() string
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// Connections returns the maxmimum number of concurrent backend operations.
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Connections() uint
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// Hasher may return a hash function for calculating a content hash for the backend
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Hasher() hash.Hash
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// HasAtomicReplace returns whether Save() can atomically replace files
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HasAtomicReplace() bool
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// Remove removes a File described by h.
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Remove(ctx context.Context, h Handle) error
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// Close the backend
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Close() error
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// Save stores the data from rd under the given handle.
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Save(ctx context.Context, h Handle, rd RewindReader) error
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// Load runs fn with a reader that yields the contents of the file at h at the
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// given offset. If length is larger than zero, only a portion of the file
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// is read.
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//
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// The function fn may be called multiple times during the same Load invocation
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// and therefore must be idempotent.
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//
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// Implementations are encouraged to use backend.DefaultLoad
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Load(ctx context.Context, h Handle, length int, offset int64, fn func(rd io.Reader) error) error
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// Stat returns information about the File identified by h.
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Stat(ctx context.Context, h Handle) (FileInfo, error)
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// List runs fn for each file in the backend which has the type t. When an
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// error occurs (or fn returns an error), List stops and returns it.
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//
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// The function fn is called exactly once for each file during successful
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// execution and at most once in case of an error.
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//
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// The function fn is called in the same Goroutine that List() is called
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// from.
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List(ctx context.Context, t FileType, fn func(FileInfo) error) error
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// IsNotExist returns true if the error was caused by a non-existing file
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// in the backend.
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//
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// The argument may be a wrapped error. The implementation is responsible
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// for unwrapping it.
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IsNotExist(err error) bool
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// Delete removes all data in the backend.
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Delete(ctx context.Context) error
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}
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type BackendUnwrapper interface {
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// Unwrap returns the underlying backend or nil if there is none.
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Unwrap() Backend
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}
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// FileInfo is contains information about a file in the backend.
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type FileInfo struct {
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Size int64
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Name string
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}
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// ApplyEnvironmenter fills in a backend configuration from the environment
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type ApplyEnvironmenter interface {
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ApplyEnvironment(prefix string)
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}
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