Method removeDaggerSession

engine/server/session.go:390–507

requires that sess.stateMu is held

(ctx context.Context, sess *daggerSession)

// requires that sess.stateMu is held
func (srv *Server) removeDaggerSession(ctx context.Context, sess *daggerSession) error {
	slog := slog.With("session", sess.sessionID)

	slog.Info("removing session; stopping client services and flushing")
	defer slog.Debug("session removed")

	// check if the local cache needs pruning after session is removed, prune if so
	defer func() {
		if srv.isShuttingDown() {
			return
		}
		time.AfterFunc(time.Second, srv.throttledGC)
	}()

	srv.daggerSessionsMu.Lock()
	delete(srv.daggerSessions, sess.sessionID)
	srv.daggerSessionsMu.Unlock()

	sess.state = sessionStateRemoved
	sess.beginClosing()

	var errs error

	// in theory none of this should block very long, but add a safeguard just in case
	ctx, cancel := context.WithTimeout(context.WithoutCancel(ctx), 60*time.Second)
	defer cancel()

	if err := sess.services.StopSessionServices(ctx, sess.sessionID); err != nil {
		slog.Warn("error stopping services", "error", err)
		errs = errors.Join(errs, fmt.Errorf("stop client services: %w", err))
	}

	slog.Debug("stopped services")

	if sess.resolver != nil {
		errs = errors.Join(errs, sess.resolver.Close())
		sess.resolver = nil
	}

	// release containers + buildkit solver/session state in parallel

	var releaseGroup errgroup.Group
	sess.containersMu.Lock()
	defer sess.containersMu.Unlock()
	for ctr := range sess.containers {
		if ctr != nil {
			releaseGroup.Go(func() error {
				return ctr.Release(ctx)
			})
		}
	}

	// clients may be mutated under clientMu alone (e.g. getOrInitClient's
	// failure cleanup deletes entries without holding stateMu), so snapshot
	// under clientMu rather than iterating the live map below.
	sess.clientMu.RLock()
	clients := make([]*daggerClient, 0, len(sess.clients))
	for _, client := range sess.clients {