Function getContentCacheOrNil

repo/open.go:139–178

(ctx context.Context, si *APIServerInfo, opt *content.CachingOptions, password string, mr *metrics.Registry, timeNow func() time.Time)

}

func getContentCacheOrNil(ctx context.Context, si *APIServerInfo, opt *content.CachingOptions, password string, mr *metrics.Registry, timeNow func() time.Time) (*cache.PersistentCache, error) {
	opt = opt.CloneOrDefault()

	cs, err := cache.NewStorageOrNil(ctx, opt.CacheDirectory, opt.ContentCacheSizeBytes, "server-contents")
	if cs == nil {
		// this may be (nil, nil) or (nil, err)
		return nil, errors.Wrap(err, "error opening storage")
	}

	// derive content cache key from the password & HMAC secret
	saltWithPurpose := append([]byte("content-cache-protection"), opt.HMACSecret...)

	const cacheEncryptionKeySize = 32

	keyAlgo := si.LocalCacheKeyDerivationAlgorithm
	if keyAlgo == "" {
		keyAlgo = DefaultServerRepoCacheKeyDerivationAlgorithm
	}

	cacheEncryptionKey, err := crypto.DeriveKeyFromPassword(password, saltWithPurpose, cacheEncryptionKeySize, keyAlgo)
	if err != nil {
		return nil, errors.Wrap(err, "unable to derive cache encryption key from password")
	}

	prot, err := cacheprot.AuthenticatedEncryptionProtection(cacheEncryptionKey)
	if err != nil {
		return nil, errors.Wrap(err, "unable to initialize protection")
	}

	pc, err := cache.NewPersistentCache(ctx, "cache-storage", cs, prot, cache.SweepSettings{
		MaxSizeBytes: opt.ContentCacheSizeBytes,
		LimitBytes:   opt.ContentCacheSizeLimitBytes,
		MinSweepAge:  opt.MinContentSweepAge.DurationOrDefault(content.DefaultDataCacheSweepAge),
	}, mr, timeNow)
	if err != nil {
		return nil, errors.Wrap(err, "unable to open persistent cache")
	}

	return pc, nil
}

// openAPIServer connects remote repository over Kopia API.
func openAPIServer(ctx context.Context, si *APIServerInfo, cliOpts ClientOptions, cachingOptions *content.CachingOptions, password string, options *Options) (Repository, error) {