package netmap import ( "errors" "fmt" "strings" "git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/refs" ) // prefix of keys to subnet attributes. const attrSubnetPrefix = "__NEOFS__SUBNET_" const ( // subnet attribute's value denoting subnet entry attrSubnetValEntry = "True" // subnet attribute's value denoting subnet exit attrSubnetValExit = "False" ) // NodeSubnetInfo groups information about subnet which can be written to NodeInfo. // // Zero value represents entry to zero subnet. type NodeSubnetInfo struct { exit bool id *refs.SubnetID } // Enabled returns true iff subnet membership is enabled for the node. func (x NodeSubnetInfo) Enabled() bool { return !x.exit } // SetEntryFlag sets the subnet entry flag. func (x *NodeSubnetInfo) SetEntryFlag(enters bool) { x.exit = !enters } // ID returns identifier of the subnet. func (x NodeSubnetInfo) ID() *refs.SubnetID { return x.id } // SetID sets identifier of the subnet. func (x *NodeSubnetInfo) SetID(id *refs.SubnetID) { x.id = id } func subnetAttributeKey(id *refs.SubnetID) string { txt, _ := id.MarshalText() // never returns an error return attrSubnetPrefix + string(txt) } // WriteSubnetInfo writes NodeSubnetInfo to NodeInfo via attributes. NodeInfo must not be nil. // // Existing subnet attributes are expected to be key-unique, otherwise undefined behavior. // // Does not add (removes existing) attribute if node: // - disables non-zero subnet; // - enables zero subnet. // // Attribute key is calculated from ID using format `__NEOFS__SUBNET_%s`. // Attribute Value is: // - `True` if node enters the subnet; // - `False`, otherwise. func WriteSubnetInfo(node *NodeInfo, info NodeSubnetInfo) { attrs := node.GetAttributes() id := info.ID() enters := info.Enabled() // calculate attribute key key := subnetAttributeKey(id) if refs.IsZeroSubnet(id) == enters { for i := range attrs { if attrs[i].GetKey() == key { attrs = append(attrs[:i], attrs[i+1:]...) break // attributes are expected to be key-unique } } } else { var val string if enters { val = attrSubnetValEntry } else { val = attrSubnetValExit } presented := false for i := range attrs { if attrs[i].GetKey() == key { attrs[i].SetValue(val) presented = true } } if !presented { index := len(attrs) attrs = append(attrs, Attribute{}) attrs[index].SetKey(key) attrs[index].SetValue(val) } } node.SetAttributes(attrs) } // ErrRemoveSubnet is returned when a node needs to leave the subnet. var ErrRemoveSubnet = errors.New("remove subnet") var errNoSubnets = errors.New("no subnets") // IterateSubnets iterates over all subnets the node belongs to and passes the IDs to f. // Handler must not be nil. // // Subnet attributes are expected to be key-unique, otherwise undefined behavior. // // If f returns ErrRemoveSubnet, then removes subnet entry. Note that this leads to an instant mutation of NodeInfo. // Breaks on any other non-nil error and returns it. // // Returns an error if any subnet attribute has wrong format. // Returns an error if the node is not included in any subnet by the end of the loop. func IterateSubnets(node *NodeInfo, f func(refs.SubnetID) error) error { attrs := node.GetAttributes() var ( err error id refs.SubnetID entries uint zeroEntry = true ) for i := 0; i < len(attrs); i++ { // range must not be used because of attrs mutation in body key := attrs[i].GetKey() // cut subnet ID string idTxt := strings.TrimPrefix(key, attrSubnetPrefix) if len(idTxt) == len(key) { // not a subnet attribute continue } // check value val := attrs[i].GetValue() if val != attrSubnetValExit && val != attrSubnetValEntry { return fmt.Errorf("invalid attribute value: %s", val) } // decode subnet ID if err = id.UnmarshalText([]byte(idTxt)); err != nil { return fmt.Errorf("invalid ID text: %w", err) } // update status of zero subnet isZero := refs.IsZeroSubnet(&id) if isZero { zeroEntry = val == attrSubnetValEntry } // continue to process only the subnets to which the node belongs if val == attrSubnetValExit { continue } // pass ID to the handler err = f(id) isRemoveErr := errors.Is(err, ErrRemoveSubnet) if err != nil && !isRemoveErr { return err } if isRemoveErr { if isZero { // we can't remove attribute of zero subnet because it means entry attrs[i].SetValue(attrSubnetValExit) } else { // we can set False or remove attribute, latter is more memory/network efficient. attrs = append(attrs[:i], attrs[i+1:]...) i-- } continue } entries++ } if zeroEntry { // missing attribute of zero subnet equivalent to entry refs.MakeZeroSubnet(&id) err = f(id) if err != nil { if !errors.Is(err, ErrRemoveSubnet) { return err } // zero subnet should be clearly removed with False value index := len(attrs) attrs = append(attrs, Attribute{}) attrs[index].SetKey(subnetAttributeKey(&id)) attrs[index].SetValue(attrSubnetValExit) } else { entries++ } } if entries <= 0 { return errNoSubnets } node.SetAttributes(attrs) return nil }