Golang State.Get方法代码示例

// NewUser tracks a new authenticated user and saves its details in the state
func NewUser(st *state.State, username, macaroon string, discharges []string) (*UserState, error) {
	var authStateData AuthState

	err := st.Get("auth", &authStateData)
	if err == state.ErrNoState {
		authStateData = AuthState{}
	} else if err != nil {
		return nil, err
	}

	sort.Strings(discharges)
	authStateData.LastID++
	authenticatedUser := UserState{
		ID:              authStateData.LastID,
		Username:        username,
		Macaroon:        macaroon,
		Discharges:      discharges,
		StoreMacaroon:   macaroon,
		StoreDischarges: discharges,
	}
	authStateData.Users = append(authStateData.Users, authenticatedUser)

	st.Set("auth", authStateData)

	return &authenticatedUser, nil
}

func checkAliasConflict(st *state.State, snapName, alias string) error {
	// check against snaps
	var snapNames map[string]*json.RawMessage
	err := st.Get("snaps", &snapNames)
	if err != nil && err != state.ErrNoState {
		return err
	}
	for name := range snapNames {
		if name == alias || strings.HasPrefix(alias, name+".") {
			return &aliasConflictError{
				Alias:  alias,
				Snap:   snapName,
				Reason: fmt.Sprintf("it conflicts with the command namespace of installed snap %q", name),
			}
		}
	}

	// check against aliases
	return checkAgainstEnabledAliases(st, func(otherAlias, otherSnap string) error {
		if otherAlias == alias {
			return &aliasConflictError{
				Alias:  alias,
				Snap:   snapName,
				Reason: fmt.Sprintf("already enabled for %q", otherSnap),
			}
		}
		return nil
	})
}

// Apply applies any necessary patches to update the provided state to
// conventions required by the current patch level of the system.
func Apply(s *state.State) error {
	var stateLevel int
	s.Lock()
	err := s.Get("patch-level", &stateLevel)
	s.Unlock()
	if err != nil && err != state.ErrNoState {
		return err
	}
	if stateLevel == Level {
		// already at right level, nothing to do
		return nil
	}
	if stateLevel > Level {
		return fmt.Errorf("cannot downgrade: snapd is too old for the current system state (patch level %d)", stateLevel)
	}

	level := stateLevel
	for level < Level {
		logger.Noticef("Patching system state from level %d to %d", level, level+1)
		patch := patches[level+1]
		if patch == nil {
			return fmt.Errorf("cannot upgrade: snapd is too new for the current system state (patch level %d)", level)
		}
		err := applyOne(patch, s, level)
		if err != nil {
			logger.Noticef("Cannnot patch: %v", err)
			return fmt.Errorf("cannot patch system state from level %d to %d: %v", level, level+1, err)
		}
		level++
	}

	return nil
}

// CheckMacaroon returns the UserState for the given macaroon/discharges credentials
func CheckMacaroon(st *state.State, macaroon string, discharges []string) (*UserState, error) {
	var authStateData AuthState
	err := st.Get("auth", &authStateData)
	if err != nil {
		return nil, ErrInvalidAuth
	}

NextUser:
	for _, user := range authStateData.Users {
		if user.Macaroon != macaroon {
			continue
		}
		if len(user.Discharges) != len(discharges) {
			continue
		}
		// sort discharges (stored users' discharges are already sorted)
		sort.Strings(discharges)
		for i, d := range user.Discharges {
			if d != discharges[i] {
				continue NextUser
			}
		}
		return &user, nil
	}
	return nil, ErrInvalidAuth
}

// patch1 adds the snap type and the current revision to the snap state.
func patch1(s *state.State) error {
	var stateMap map[string]*snapstate.SnapState

	err := s.Get("snaps", &stateMap)
	if err == state.ErrNoState {
		return nil
	}
	if err != nil {
		return err
	}

	for snapName, snapState := range stateMap {
		seq := snapState.Sequence
		if len(seq) == 0 {
			continue
		}
		typ := snap.TypeApp
		snapInfo, err := readInfo(snapName, seq[len(seq)-1])
		if err != nil {
			logger.Noticef("Recording type for snap %q: cannot retrieve info, assuming it's a app: %v", snapName, err)
		} else {
			logger.Noticef("Recording type for snap %q: setting to %q", snapName, snapInfo.Type)
			typ = snapInfo.Type
		}
		snapState.SetType(typ)
		snapState.Current = seq[len(seq)-1].Revision
	}

	s.Set("snaps", stateMap)
	return nil
}

// Init initializes an empty state to the current implemented patch level.
func Init(s *state.State) {
	s.Lock()
	defer s.Unlock()
	if s.Get("patch-level", new(int)) != state.ErrNoState {
		panic("internal error: expected empty state, attempting to override patch-level without actual patching")
	}
	s.Set("patch-level", Level)
}

// patch2:
// - migrates SnapSetup.Name to SnapSetup.SideInfo.RealName
// - backfills SnapState.{Sequence,Candidate}.RealName if its missing
func patch2(s *state.State) error {

	var stateMap map[string]*OldSnapState
	err := s.Get("snaps", &stateMap)
	if err == state.ErrNoState {
		return nil
	}
	if err != nil {
		return err
	}

	// migrate SnapSetup in all tasks:
	//  - the new SnapSetup uses SideInfo, backfil from Candidate
	//  - also move SnapSetup.{Name,Revision} into SnapSetup.SideInfo.{RealName,Revision}
	var oldSS OldSnapSetup
	var newSS snapstate.SnapSetup
	for _, t := range s.Tasks() {
		err := t.Get("snap-setup", &oldSS)
		if err == state.ErrNoState {
			continue
		}
		if err != nil && err != state.ErrNoState {
			return err
		}
		// some things stay the same
		newSS.Channel = oldSS.Channel
		newSS.Flags = oldSS.Flags
		newSS.SnapPath = oldSS.SnapPath
		newSS.DownloadInfo = oldSS.DownloadInfo
		newSS.SideInfo = oldSS.SideInfo
		// ... and some change
		if newSS.SideInfo == nil {
			newSS.SideInfo = &snap.SideInfo{}
			if snapst, ok := stateMap[oldSS.Name]; ok && snapst.Candidate != nil {
				newSS.SideInfo = snapst.Candidate
			}
		}
		if newSS.SideInfo.RealName == "" {
			newSS.SideInfo.RealName = oldSS.Name
		}
		if newSS.SideInfo.Revision.Unset() {
			newSS.SideInfo.Revision = oldSS.Revision
		}
		t.Set("snap-setup", &newSS)
	}

	// backfill snapstate.SnapState.{Sequence,Candidate} with RealName
	// (if that is missing, was missing for e.g. sideloaded snaps)
	for snapName, snapState := range stateMap {
		for _, si := range snapState.Sequence {
			setRealName(si, snapName)
		}
	}
	s.Set("snaps", stateMap)

	return nil
}

// CheckMacaroon returns the UserState for the given macaroon/discharges credentials
func CheckMacaroon(st *state.State, macaroon string, discharges []string) (*UserState, error) {
	var authStateData AuthState
	err := st.Get("auth", &authStateData)
	if err != nil {
		return nil, ErrInvalidAuth
	}

	snapdMacaroon, err := MacaroonDeserialize(macaroon)
	if err != nil {
		return nil, ErrInvalidAuth
	}
	// attempt snapd macaroon verification
	if snapdMacaroon.Location() == snapdMacaroonLocation {
		// no caveats to check so far
		check := func(caveat string) error { return nil }
		// ignoring discharges, unused for snapd macaroons atm
		err = snapdMacaroon.Verify(authStateData.MacaroonKey, check, nil)
		if err != nil {
			return nil, ErrInvalidAuth
		}
		macaroonID := snapdMacaroon.Id()
		userID, err := strconv.Atoi(macaroonID)
		if err != nil {
			return nil, ErrInvalidAuth
		}
		user, err := User(st, userID)
		if err != nil {
			return nil, ErrInvalidAuth
		}
		if macaroon != user.Macaroon {
			return nil, ErrInvalidAuth
		}
		return user, nil
	}

	// if macaroon is not a snapd macaroon, fallback to previous token-style check
NextUser:
	for _, user := range authStateData.Users {
		if user.Macaroon != macaroon {
			continue
		}
		if len(user.Discharges) != len(discharges) {
			continue
		}
		// sort discharges (stored users' discharges are already sorted)
		sort.Strings(discharges)
		for i, d := range user.Discharges {
			if d != discharges[i] {
				continue NextUser
			}
		}
		return &user, nil
	}
	return nil, ErrInvalidAuth
}

func getConns(st *state.State) (map[string]connState, error) {
	// Get information about connections from the state
	var conns map[string]connState
	err := st.Get("conns", &conns)
	if err != nil && err != state.ErrNoState {
		return nil, fmt.Errorf("cannot obtain data about existing connections: %s", err)
	}
	if conns == nil {
		conns = make(map[string]connState)
	}
	return conns, nil
}

// patch2:
// - migrates SnapSetup.Name to SnapSetup.SideInfo.RealName
// - backfills SnapState.{Sequence,Candidate}.RealName if its missing
func patch2(s *state.State) error {

	var oldStateMap map[string]*patch1SnapState
	err := s.Get("snaps", &oldStateMap)
	if err == state.ErrNoState {
		return nil
	}
	if err != nil {
		return err
	}
	newStateMap := make(map[string]*patch2SnapState, len(oldStateMap))

	for key, oldSnapState := range oldStateMap {
		newStateMap[key] = patch2SnapStateFromPatch1(oldSnapState, key)
	}

	// migrate SnapSetup in all tasks:
	//  - the new SnapSetup uses SideInfo, backfil from Candidate
	//  - also move SnapSetup.{Name,Revision} into SnapSetup.SideInfo.{RealName,Revision}
	var oldSS patch1SnapSetup
	for _, t := range s.Tasks() {
		var newSS patch2SnapSetup
		err := t.Get("snap-setup", &oldSS)
		if err == state.ErrNoState {
			continue
		}
		if err != nil && err != state.ErrNoState {
			return err
		}
		// some things stay the same
		newSS.Channel = oldSS.Channel
		newSS.Flags = patch2Flags(oldSS.Flags)
		newSS.SnapPath = oldSS.SnapPath
		// ... and some change
		newSS.SideInfo = &patch2SideInfo{}
		if snapst, ok := oldStateMap[oldSS.Name]; ok && snapst.Candidate != nil {
			newSS.SideInfo = patch2SideInfoFromPatch1(snapst.Candidate, oldSS.Name)
		}
		if newSS.SideInfo.RealName == "" {
			newSS.SideInfo.RealName = oldSS.Name
		}
		if newSS.SideInfo.Revision.Unset() {
			newSS.SideInfo.Revision = oldSS.Revision
		}
		t.Set("snap-setup", &newSS)
	}

	s.Set("snaps", newStateMap)

	return nil
}

// NewTransaction creates a new configuration transaction initialized with the given state.
//
// The provided state must be locked by the caller.
func NewTransaction(st *state.State) *Transaction {
	transaction := &Transaction{state: st}
	transaction.changes = make(map[string]map[string]interface{})

	// Record the current state of the map containing the config of every snap
	// in the system. We'll use it for this transaction.
	err := st.Get("config", &transaction.pristine)
	if err == state.ErrNoState {
		transaction.pristine = make(map[string]map[string]*json.RawMessage)
	} else if err != nil {
		panic(fmt.Errorf("internal error: cannot unmarshal configuration: %v", err))
	}
	return transaction
}

// SetDevice updates the device details in the state.
func SetDevice(st *state.State, device *DeviceState) error {
	var authStateData AuthState

	err := st.Get("auth", &authStateData)
	if err == state.ErrNoState {
		authStateData = AuthState{}
	} else if err != nil {
		return err
	}

	authStateData.Device = device
	st.Set("auth", authStateData)

	return nil
}

// User returns a user from the state given its ID
func User(st *state.State, id int) (*UserState, error) {
	var authStateData AuthState

	err := st.Get("auth", &authStateData)
	if err != nil {
		return nil, err
	}

	for _, user := range authStateData.Users {
		if user.ID == id {
			return &user, nil
		}
	}
	return nil, fmt.Errorf("invalid user")
}

// All retrieves return a map from name to SnapState for all current snaps in the system state.
func All(s *state.State) (map[string]*SnapState, error) {
	// XXX: result is a map because sideloaded snaps carry no name
	// atm in their sideinfos
	var stateMap map[string]*SnapState
	if err := s.Get("snaps", &stateMap); err != nil && err != state.ErrNoState {
		return nil, err
	}
	curStates := make(map[string]*SnapState, len(stateMap))
	for snapName, snapState := range stateMap {
		if snapState.HasCurrent() {
			curStates[snapName] = snapState
		}
	}
	return curStates, nil
}

// Device returns the device details from the state.
func Device(st *state.State) (*DeviceState, error) {
	var authStateData AuthState

	err := st.Get("auth", &authStateData)
	if err == state.ErrNoState {
		return &DeviceState{}, nil
	} else if err != nil {
		return nil, err
	}

	if authStateData.Device == nil {
		return &DeviceState{}, nil
	}

	return authStateData.Device, nil
}