session: remove Session Group Predicate method

This was used to check that all linked sessions are no longer
active before attempting to register an autopilot session. But this is
no longer needed since this is done within NewSession.

Author: ellemouton

session/interface.go

@@ -222,12 +222,6 @@ type Store interface {
 	// GetSessionByID fetches the session with the given ID.
 	GetSessionByID(id ID) (*Session, error)
 
-	// CheckSessionGroupPredicate iterates over all the sessions in a group
-	// and checks if each one passes the given predicate function. True is
-	// returned if each session passes.
-	CheckSessionGroupPredicate(groupID ID,
-		fn func(s *Session) bool) (bool, error)
-
 	// DeleteReservedSessions deletes all sessions that are in the
 	// StateReserved state.
 	DeleteReservedSessions() error

session/kvdb_store.go

@@ -250,7 +250,8 @@ func (db *BoltStore) NewSession(label string, typ Type, expiry time.Time,
 
 				// Ensure that the session is no longer active.
 				if sess.State == StateCreated ||
-					sess.State == StateInUse {
+					sess.State == StateInUse ||
+					sess.State == StateReserved {
 
 					return fmt.Errorf("session (id=%x) "+
 						"in group %x is still active",
@@ -721,65 +722,6 @@ func (db *BoltStore) GetSessionIDs(groupID ID) ([]ID, error) {
 	return sessionIDs, nil
 }
 
-// CheckSessionGroupPredicate iterates over all the sessions in a group and
-// checks if each one passes the given predicate function. True is returned if
-// each session passes.
-//
-// NOTE: this is part of the Store interface.
-func (db *BoltStore) CheckSessionGroupPredicate(groupID ID,
-	fn func(s *Session) bool) (bool, error) {
-
-	var (
-		pass          bool
-		errFailedPred = errors.New("session failed predicate")
-	)
-	err := db.View(func(tx *bbolt.Tx) error {
-		sessionBkt, err := getBucket(tx, sessionBucketKey)
-		if err != nil {
-			return err
-		}
-
-		sessionIDs, err := getSessionIDs(sessionBkt, groupID)
-		if err != nil {
-			return err
-		}
-
-		// Iterate over all the sessions.
-		for _, id := range sessionIDs {
-			key, err := getKeyForID(sessionBkt, id)
-			if err != nil {
-				return err
-			}
-
-			v := sessionBkt.Get(key)
-			if len(v) == 0 {
-				return ErrSessionNotFound
-			}
-
-			session, err := DeserializeSession(bytes.NewReader(v))
-			if err != nil {
-				return err
-			}
-
-			if !fn(session) {
-				return errFailedPred
-			}
-		}
-
-		pass = true
-
-		return nil
-	})
-	if errors.Is(err, errFailedPred) {
-		return pass, nil
-	}
-	if err != nil {
-		return pass, err
-	}
-
-	return pass, nil
-}
-
 // getSessionIDs returns all the session IDs associated with the given group ID.
 func getSessionIDs(sessionBkt *bbolt.Bucket, groupID ID) ([]ID, error) {
 	var sessionIDs []ID

session/store_test.go

@@ -1,7 +1,6 @@
 package session
 
 import (
-	"strings"
 	"testing"
 	"time"
 
@@ -292,97 +291,6 @@ func TestLinkedSessions(t *testing.T) {
 	require.EqualValues(t, []ID{s4.ID, s5.ID}, sIDs)
 }
 
-// TestCheckSessionGroupPredicate asserts that the CheckSessionGroupPredicate
-// method correctly checks if each session in a group passes a predicate.
-func TestCheckSessionGroupPredicate(t *testing.T) {
-	t.Parallel()
-
-	// Set up a new DB.
-	clock := clock.NewTestClock(testTime)
-	db, err := NewDB(t.TempDir(), "test.db", clock)
-	require.NoError(t, err)
-	t.Cleanup(func() {
-		_ = db.Close()
-	})
-
-	// We will use the Label of the Session to test that the predicate
-	// function is checked correctly.
-
-	// Add a new session to the DB.
-	s1 := createSession(t, db, "label 1")
-
-	// Check that the group passes against an appropriate predicate.
-	ok, err := db.CheckSessionGroupPredicate(
-		s1.GroupID, func(s *Session) bool {
-			return strings.Contains(s.Label, "label 1")
-		},
-	)
-	require.NoError(t, err)
-	require.True(t, ok)
-
-	// Check that the group fails against an appropriate predicate.
-	ok, err = db.CheckSessionGroupPredicate(
-		s1.GroupID, func(s *Session) bool {
-			return strings.Contains(s.Label, "label 2")
-		},
-	)
-	require.NoError(t, err)
-	require.False(t, ok)
-
-	// Revoke the first session.
-	require.NoError(t, db.ShiftState(s1.LocalPublicKey, StateRevoked))
-
-	// Add a new session to the same group as the first one.
-	_ = createSession(t, db, "label 2", withLinkedGroupID(&s1.GroupID))
-
-	// Check that the group passes against an appropriate predicate.
-	ok, err = db.CheckSessionGroupPredicate(
-		s1.GroupID, func(s *Session) bool {
-			return strings.Contains(s.Label, "label")
-		},
-	)
-	require.NoError(t, err)
-	require.True(t, ok)
-
-	// Check that the group fails against an appropriate predicate.
-	ok, err = db.CheckSessionGroupPredicate(
-		s1.GroupID, func(s *Session) bool {
-			return strings.Contains(s.Label, "label 1")
-		},
-	)
-	require.NoError(t, err)
-	require.False(t, ok)
-
-	// Add a new session that is not linked to the first one.
-	s3 := createSession(t, db, "completely different")
-
-	// Ensure that the first group is unaffected.
-	ok, err = db.CheckSessionGroupPredicate(
-		s1.GroupID, func(s *Session) bool {
-			return strings.Contains(s.Label, "label")
-		},
-	)
-	require.NoError(t, err)
-	require.True(t, ok)
-
-	// And that the new session is evaluated separately.
-	ok, err = db.CheckSessionGroupPredicate(
-		s3.GroupID, func(s *Session) bool {
-			return strings.Contains(s.Label, "label")
-		},
-	)
-	require.NoError(t, err)
-	require.False(t, ok)
-
-	ok, err = db.CheckSessionGroupPredicate(
-		s3.GroupID, func(s *Session) bool {
-			return strings.Contains(s.Label, "different")
-		},
-	)
-	require.NoError(t, err)
-	require.True(t, ok)
-}
-
 // TestStateShift tests that the ShiftState method works as expected.
 func TestStateShift(t *testing.T) {
 	// Set up a new DB.

session_rpcserver.go

@@ -859,23 +859,6 @@ func (s *sessionRpcServer) AddAutopilotSession(ctx context.Context,
 				"group %x", groupSess.ID, groupSess.GroupID)
 		}
 
-		// Now we need to check that all the sessions in the group are
-		// no longer active.
-		ok, err := s.cfg.db.CheckSessionGroupPredicate(
-			groupID, func(s *session.Session) bool {
-				return s.State == session.StateRevoked ||
-					s.State == session.StateExpired
-			},
-		)
-		if err != nil {
-			return nil, err
-		}
-
-		if !ok {
-			return nil, fmt.Errorf("a linked session in group "+
-				"%x is still active", groupID)
-		}
-
 		linkedGroupID = &groupID
 		linkedGroupSession = groupSess