restic/repository/config.go

88 lines
2.0 KiB
Go

package repository
import (
"crypto/rand"
"crypto/sha256"
"encoding/hex"
"errors"
"io"
"github.com/restic/chunker"
"github.com/restic/restic/backend"
"github.com/restic/restic/debug"
)
// Config contains the configuration for a repository.
type Config struct {
Version uint `json:"version"`
ID string `json:"id"`
ChunkerPolynomial chunker.Pol `json:"chunker_polynomial"`
}
// repositoryIDSize is the length of the ID chosen at random for a new repository.
const repositoryIDSize = sha256.Size
// RepoVersion is the version that is written to the config when a repository
// is newly created with Init().
const RepoVersion = 1
// JSONUnpackedSaver saves unpacked JSON.
type JSONUnpackedSaver interface {
SaveJSONUnpacked(backend.Type, interface{}) (backend.ID, error)
}
// JSONUnpackedLoader loads unpacked JSON.
type JSONUnpackedLoader interface {
LoadJSONUnpacked(backend.Type, backend.ID, interface{}) error
}
// CreateConfig creates a config file with a randomly selected polynomial and
// ID and saves the config in the repository.
func CreateConfig(r JSONUnpackedSaver) (Config, error) {
var (
err error
cfg Config
)
cfg.ChunkerPolynomial, err = chunker.RandomPolynomial()
if err != nil {
return Config{}, err
}
newID := make([]byte, repositoryIDSize)
_, err = io.ReadFull(rand.Reader, newID)
if err != nil {
return Config{}, err
}
cfg.ID = hex.EncodeToString(newID)
cfg.Version = RepoVersion
debug.Log("Repo.CreateConfig", "New config: %#v", cfg)
_, err = r.SaveJSONUnpacked(backend.Config, cfg)
return cfg, err
}
// LoadConfig returns loads, checks and returns the config for a repository.
func LoadConfig(r JSONUnpackedLoader) (Config, error) {
var (
cfg Config
)
err := r.LoadJSONUnpacked(backend.Config, nil, &cfg)
if err != nil {
return Config{}, err
}
if cfg.Version != RepoVersion {
return Config{}, errors.New("unsupported repository version")
}
if !cfg.ChunkerPolynomial.Irreducible() {
return Config{}, errors.New("invalid chunker polynomial")
}
return cfg, nil
}