github.com/rigado/snapd@v2.42.5-go-mod+incompatible/overlord/devicestate/devicectx.go (about)

     1  // -*- Mode: Go; indent-tabs-mode: t -*-
     2  
     3  /*
     4   * Copyright (C) 2018-2019 Canonical Ltd
     5   *
     6   * This program is free software: you can redistribute it and/or modify
     7   * it under the terms of the GNU General Public License version 3 as
     8   * published by the Free Software Foundation.
     9   *
    10   * This program is distributed in the hope that it will be useful,
    11   * but WITHOUT ANY WARRANTY; without even the implied warranty of
    12   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    13   * GNU General Public License for more details.
    14   *
    15   * You should have received a copy of the GNU General Public License
    16   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
    17   *
    18   */
    19  
    20  package devicestate
    21  
    22  import (
    23  	"github.com/snapcore/snapd/asserts"
    24  	"github.com/snapcore/snapd/overlord/snapstate"
    25  	"github.com/snapcore/snapd/overlord/state"
    26  )
    27  
    28  // DeviceCtx picks a device context from state, optional task or an
    29  // optionally pre-provided one. Returns ErrNoState if a model
    30  // assertion is not yet known.
    31  // In particular if task belongs to a remodeling change this will find
    32  // the appropriate remodel context.
    33  func DeviceCtx(st *state.State, task *state.Task, providedDeviceCtx snapstate.DeviceContext) (snapstate.DeviceContext, error) {
    34  	if providedDeviceCtx != nil {
    35  		return providedDeviceCtx, nil
    36  	}
    37  	// use the remodelContext if the task is part of a remodel change
    38  	remodCtx, err := remodelCtxFromTask(task)
    39  	if err == nil {
    40  		return remodCtx, nil
    41  	}
    42  	if err != nil && err != state.ErrNoState {
    43  		return nil, err
    44  	}
    45  	modelAs, err := findModel(st)
    46  	if err != nil {
    47  		return nil, err
    48  	}
    49  	return modelDeviceContext{model: modelAs}, nil
    50  }
    51  
    52  type modelDeviceContext struct {
    53  	model *asserts.Model
    54  }
    55  
    56  // sanity
    57  var _ snapstate.DeviceContext = modelDeviceContext{}
    58  
    59  func (dc modelDeviceContext) Model() *asserts.Model {
    60  	return dc.model
    61  }
    62  
    63  func (dc modelDeviceContext) Store() snapstate.StoreService {
    64  	return nil
    65  }
    66  
    67  func (dc modelDeviceContext) ForRemodeling() bool {
    68  	return false
    69  }