pndFilesystemStore.go

package nucleus

import (
	"encoding/json"
	"os"
	"sync"

	cpb "code.fbi.h-da.de/danet/gosdn/api/go/gosdn/csbi"
	"code.fbi.h-da.de/danet/gosdn/controller/customerrs"
	"code.fbi.h-da.de/danet/gosdn/controller/interfaces/networkdomain"
	"code.fbi.h-da.de/danet/gosdn/controller/interfaces/networkelement"
	"code.fbi.h-da.de/danet/gosdn/controller/store"
	"github.com/google/uuid"
	log "github.com/sirupsen/logrus"
	"github.com/spf13/viper"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"
)

// FilesystemPndStore provides a filesystem implementation for a pnd store.
type FilesystemPndStore struct {
	pendingChannels map[uuid.UUID]chan networkelement.Details
	csbiClient      cpb.CsbiServiceClient
	pathToPndFile   string
	fileMutex       sync.Mutex
}

// NewFilesystemPndStore returns a filesystem implementation for a pnd store.
func NewFilesystemPndStore() FilesystemPndStore {
	if err := store.EnsureFilesystemStorePathExists(store.PndFilename); err != nil {
		log.Error(err)
	}

	return FilesystemPndStore{
		pendingChannels: make(map[uuid.UUID]chan networkelement.Details),
		pathToPndFile:   store.GetCompletePathToFileStore(store.PndFilename),
		fileMutex:       sync.Mutex{},
	}
}

func (t *FilesystemPndStore) readAllPndsFromFile() ([]networkdomain.NetworkDomain, error) {
	var loadedPnds []LoadedPnd

	content, err := os.ReadFile(t.pathToPndFile)
	if err != nil {
		return nil, err
	}

	err = json.Unmarshal(content, &loadedPnds)
	if err != nil {
		return nil, err
	}

	pnds := make([]networkdomain.NetworkDomain, len(loadedPnds))

	csbiClient, err := t.getCsbiClient()
	if err != nil {
		return nil, err
	}

	for i, loadedPND := range loadedPnds {
		newPnd, err := NewPND(
			loadedPND.Name,
			loadedPND.Description,
			uuid.MustParse(loadedPND.ID),
			csbiClient,
			t.callback,
		)
		if err != nil {
			return nil, err
		}

		pnds[i] = newPnd
	}
	return pnds, nil
}

func (t *FilesystemPndStore) writeAllPndsToFile(pnds []networkdomain.NetworkDomain) error {
	serializedData, err := json.Marshal(pnds)
	if err != nil {
		return err
	}

	err = os.WriteFile(t.pathToPndFile, serializedData, 0600)
	if err != nil {
		return err
	}

	return nil
}

// Add a pnd to the store.
func (t *FilesystemPndStore) Add(pndToAdd networkdomain.NetworkDomain) error {
	t.fileMutex.Lock()
	defer t.fileMutex.Unlock()

	pnds, err := t.readAllPndsFromFile()
	if err != nil {
		return err
	}

	pnds = append(pnds, pndToAdd)

	err = t.writeAllPndsToFile(pnds)
	if err != nil {
		return err
	}

	return nil
}

// Delete deletes a pnd from the store.
func (t *FilesystemPndStore) Delete(pndToDelete networkdomain.NetworkDomain) error {
	t.fileMutex.Lock()
	defer t.fileMutex.Unlock()

	pnds, err := t.readAllPndsFromFile()
	if err != nil {
		return err
	}

	for i, pnd := range pnds {
		if pnd.ID() == pndToDelete.ID() {
			//remove item from slice
			pnds[i] = pnds[len(pnds)-1]
			pnds = pnds[:len(pnds)-1]

			err = t.writeAllPndsToFile(pnds)
			if err != nil {
				return err
			}

			return nil
		}
	}

	return &customerrs.CouldNotDeleteError{Identifier: pndToDelete.ID(), Type: pndToDelete, Err: err}
}

// Get provides a the query interface to find a stored pnd.
func (t *FilesystemPndStore) Get(query store.Query) (networkdomain.NetworkDomain, error) {
	t.fileMutex.Lock()
	defer t.fileMutex.Unlock()

	pnds, err := t.readAllPndsFromFile()
	if err != nil {
		return nil, err
	}

	for _, pnd := range pnds {
		if pnd.ID() == query.ID || pnd.GetName() == query.Name {
			return pnd, nil
		}
	}

	return nil, &customerrs.CouldNotFindError{ID: query.ID, Name: query.Name}
}

// GetAll returns all pnds currently on the store.
func (t *FilesystemPndStore) GetAll() ([]networkdomain.NetworkDomain, error) {
	t.fileMutex.Lock()
	defer t.fileMutex.Unlock()

	pnds, err := t.readAllPndsFromFile()

	return pnds, err
}

// PendingChannels holds channels used communicate with pending
// cSBI deployments.
func (t *FilesystemPndStore) PendingChannels(id uuid.UUID, parseErrors ...error) (chan networkelement.Details, error) {
	ch, ok := t.pendingChannels[id]
	if !ok {
		return nil, &customerrs.CouldNotFindError{ID: id}
	}
	return ch, nil
}

// AddPendingChannel adds a pending channel to the map.
func (t *FilesystemPndStore) AddPendingChannel(id uuid.UUID, ch chan networkelement.Details) {
	t.pendingChannels[id] = ch
}

// RemovePendingChannel removes a pending channel from the map.
func (t *FilesystemPndStore) RemovePendingChannel(id uuid.UUID) {
	delete(t.pendingChannels, id)
}

func (t *FilesystemPndStore) callback(id uuid.UUID, ch chan networkelement.Details) {
	if ch != nil {
		t.AddPendingChannel(id, ch)
		log.Infof("pending channel %v added", id)
	} else {
		t.RemovePendingChannel(id)
		log.Infof("pending channel %v removed", id)
	}
}

func (t *FilesystemPndStore) getCsbiClient() (cpb.CsbiServiceClient, error) {
	if t.csbiClient == nil {
		orchestrator := viper.GetString("csbi-orchestrator")
		conn, err := grpc.Dial(orchestrator, grpc.WithTransportCredentials(insecure.NewCredentials()))
		if err != nil {
			return nil, err
		}

		t.csbiClient = cpb.NewCsbiServiceClient(conn)
	}

	return t.csbiClient, nil
}