package state import ( "bytes" "encoding/json" "fmt" "io" "io/ioutil" "os" "path/filepath" "time" "github.com/hashicorp/terraform/terraform" ) // lock metadata structure for local locks type LockInfo struct { // Path to the state file Path string // The time the lock was taken Created time.Time // Extra info passed to State.Lock Info string } // return the lock info formatted in an error func (l *LockInfo) Err() error { return fmt.Errorf("state locked. path:%q, created:%s, info:%q", l.Path, l.Created, l.Info) } func (l *LockInfo) String() string { js, err := json.Marshal(l) if err != nil { panic(err) } return string(js) } // LocalState manages a state storage that is local to the filesystem. type LocalState struct { // Path is the path to read the state from. PathOut is the path to // write the state to. If PathOut is not specified, Path will be used. // If PathOut already exists, it will be overwritten. Path string PathOut string // the file handle corresponding to PathOut stateFileOut *os.File // created is set to tru if stateFileOut didn't exist before we created it. // This is mostly so we can clean up emtpy files during tests, but doesn't // hurt to remove file we never wrote to. created bool state *terraform.State readState *terraform.State written bool } // SetState will force a specific state in-memory for this local state. func (s *LocalState) SetState(state *terraform.State) { s.state = state s.readState = state } // StateReader impl. func (s *LocalState) State() *terraform.State { return s.state.DeepCopy() } // Lock implements a local filesystem state.Locker. func (s *LocalState) Lock(reason string) error { if s.stateFileOut == nil { if err := s.createStateFiles(); err != nil { return err } } if err := s.lock(); err != nil { if info, err := s.lockInfo(); err == nil { return info.Err() } return fmt.Errorf("state file %q locked: %s", s.Path, err) } return s.writeLockInfo(reason) } func (s *LocalState) Unlock() error { // we can't be locked if we don't have a file if s.stateFileOut == nil { return nil } os.Remove(s.lockInfoPath()) fileName := s.stateFileOut.Name() unlockErr := s.unlock() s.stateFileOut.Close() s.stateFileOut = nil // clean up the state file if we created it an never wrote to it stat, err := os.Stat(fileName) if err == nil && stat.Size() == 0 && s.created { os.Remove(fileName) } return unlockErr } // Open the state file, creating the directories and file as needed. func (s *LocalState) createStateFiles() error { if s.PathOut == "" { s.PathOut = s.Path } // yes this could race, but we only use it to clean up empty files if _, err := os.Stat(s.PathOut); os.IsNotExist(err) { s.created = true } // Create all the directories if err := os.MkdirAll(filepath.Dir(s.PathOut), 0755); err != nil { return err } f, err := os.OpenFile(s.PathOut, os.O_RDWR|os.O_CREATE, 0666) if err != nil { return err } s.stateFileOut = f return nil } // WriteState for LocalState always persists the state as well. // TODO: this should use a more robust method of writing state, by first // writing to a temp file on the same filesystem, and renaming the file over // the original. // // StateWriter impl. func (s *LocalState) WriteState(state *terraform.State) error { if s.stateFileOut == nil { if err := s.createStateFiles(); err != nil { return nil } } defer s.stateFileOut.Sync() s.state = state if _, err := s.stateFileOut.Seek(0, os.SEEK_SET); err != nil { return err } if err := s.stateFileOut.Truncate(0); err != nil { return err } if state == nil { // if we have no state, don't write anything else. return nil } s.state.IncrementSerialMaybe(s.readState) s.readState = s.state if err := terraform.WriteState(s.state, s.stateFileOut); err != nil { return err } s.written = true return nil } // PersistState for LocalState is a no-op since WriteState always persists. // // StatePersister impl. func (s *LocalState) PersistState() error { return nil } // StateRefresher impl. func (s *LocalState) RefreshState() error { var reader io.Reader if !s.written { // we haven't written a state file yet, so load from Path f, err := os.Open(s.Path) if err != nil { // It is okay if the file doesn't exist, we treat that as a nil state if !os.IsNotExist(err) { return err } // we need a non-nil reader for ReadState and an empty buffer works // to return EOF immediately reader = bytes.NewBuffer(nil) } else { defer f.Close() reader = f } } else { // no state to refresh if s.stateFileOut == nil { return nil } // we have a state file, make sure we're at the start s.stateFileOut.Seek(0, os.SEEK_SET) reader = s.stateFileOut } state, err := terraform.ReadState(reader) // if there's no state we just assign the nil return value if err != nil && err != terraform.ErrNoState { return err } s.state = state s.readState = state return nil } // return the path for the lockInfo metadata. func (s *LocalState) lockInfoPath() string { stateDir, stateName := filepath.Split(s.Path) if stateName == "" { panic("empty state file path") } if stateName[0] == '.' { stateName = stateName[1:] } return filepath.Join(stateDir, fmt.Sprintf(".%s.lock.info", stateName)) } // lockInfo returns the data in a lock info file func (s *LocalState) lockInfo() (*LockInfo, error) { path := s.lockInfoPath() infoData, err := ioutil.ReadFile(path) if err != nil { return nil, err } info := LockInfo{} err = json.Unmarshal(infoData, &info) if err != nil { return nil, fmt.Errorf("state file %q locked, but could not unmarshal lock info: %s", s.Path, err) } return &info, nil } // write a new lock info file func (s *LocalState) writeLockInfo(info string) error { path := s.lockInfoPath() lockInfo := &LockInfo{ Path: s.Path, Created: time.Now().UTC(), Info: info, } infoData, err := json.Marshal(lockInfo) if err != nil { panic(fmt.Sprintf("could not marshal lock info: %#v", lockInfo)) } err = ioutil.WriteFile(path, infoData, 0600) if err != nil { return fmt.Errorf("could not write lock info for %q: %s", s.Path, err) } return nil }