github.com/bugraaydogar/snapd@v0.0.0-20210315170335-8c70bb858939/overlord/servicestate/service_control.go (about)

     1  // -*- Mode: Go; indent-tabs-mode: t -*-
     2  
     3  /*
     4   * Copyright (C) 2020 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 servicestate
    21  
    22  import (
    23  	"fmt"
    24  
    25  	"github.com/snapcore/snapd/overlord/snapstate"
    26  	"github.com/snapcore/snapd/overlord/state"
    27  	"github.com/snapcore/snapd/snap"
    28  	"github.com/snapcore/snapd/wrappers"
    29  
    30  	tomb "gopkg.in/tomb.v2"
    31  )
    32  
    33  // ServiceAction encapsulates a single service-related action (such as starting,
    34  // stopping or restarting) run against services of a given snap. The action is
    35  // run for services listed in services attribute, or for all services of the
    36  // snap if services list is empty.
    37  // The names of services are app names (as defined in snap yaml).
    38  type ServiceAction struct {
    39  	SnapName       string   `json:"snap-name"`
    40  	Action         string   `json:"action"`
    41  	ActionModifier string   `json:"action-modifier,omitempty"`
    42  	Services       []string `json:"services,omitempty"`
    43  }
    44  
    45  func (m *ServiceManager) doServiceControl(t *state.Task, _ *tomb.Tomb) error {
    46  	st := t.State()
    47  	st.Lock()
    48  	defer st.Unlock()
    49  
    50  	perfTimings := state.TimingsForTask(t)
    51  	defer perfTimings.Save(st)
    52  
    53  	var sc ServiceAction
    54  	err := t.Get("service-action", &sc)
    55  	if err != nil {
    56  		return fmt.Errorf("internal error: cannot get service-action: %v", err)
    57  	}
    58  
    59  	var snapst snapstate.SnapState
    60  	if err := snapstate.Get(st, sc.SnapName, &snapst); err != nil {
    61  		return err
    62  	}
    63  	info, err := snapst.CurrentInfo()
    64  	if err != nil {
    65  		return err
    66  	}
    67  
    68  	svcs := info.Services()
    69  	if len(svcs) == 0 {
    70  		return nil
    71  	}
    72  
    73  	var services []*snap.AppInfo
    74  	if len(sc.Services) == 0 {
    75  		// no services specified, take all services of the snap
    76  		services = info.Services()
    77  	} else {
    78  		for _, svc := range sc.Services {
    79  			app := info.Apps[svc]
    80  			if app == nil {
    81  				return fmt.Errorf("no such service: %s", svc)
    82  			}
    83  			if !app.IsService() {
    84  				return fmt.Errorf("%s is not a service", svc)
    85  			}
    86  			services = append(services, app)
    87  		}
    88  	}
    89  
    90  	meter := snapstate.NewTaskProgressAdapterUnlocked(t)
    91  
    92  	var startupOrdered []*snap.AppInfo
    93  	if sc.Action != "stop" {
    94  		startupOrdered, err = snap.SortServices(services)
    95  		if err != nil {
    96  			return err
    97  		}
    98  	}
    99  
   100  	// Note - state must be unlocked when calling wrappers below.
   101  	switch sc.Action {
   102  	case "stop":
   103  		disable := sc.ActionModifier == "disable"
   104  		flags := &wrappers.StopServicesFlags{
   105  			Disable: disable,
   106  		}
   107  		st.Unlock()
   108  		err := wrappers.StopServices(services, flags, snap.StopReasonOther, meter, perfTimings)
   109  		st.Lock()
   110  		if err != nil {
   111  			return err
   112  		}
   113  		if disable {
   114  			// re-read snapst after reacquiring the lock as it could have changed.
   115  			if err := snapstate.Get(st, sc.SnapName, &snapst); err != nil {
   116  				return err
   117  			}
   118  			changed, err := updateSnapstateServices(&snapst, nil, services)
   119  			if err != nil {
   120  				return err
   121  			}
   122  			if changed {
   123  				snapstate.Set(st, sc.SnapName, &snapst)
   124  			}
   125  		}
   126  	case "start":
   127  		enable := sc.ActionModifier == "enable"
   128  		flags := &wrappers.StartServicesFlags{
   129  			Enable: enable,
   130  		}
   131  		st.Unlock()
   132  		err = wrappers.StartServices(startupOrdered, nil, flags, meter, perfTimings)
   133  		st.Lock()
   134  		if err != nil {
   135  			return err
   136  		}
   137  		if enable {
   138  			// re-read snapst after reacquiring the lock as it could have changed.
   139  			if err := snapstate.Get(st, sc.SnapName, &snapst); err != nil {
   140  				return err
   141  			}
   142  			changed, err := updateSnapstateServices(&snapst, startupOrdered, nil)
   143  			if err != nil {
   144  				return err
   145  			}
   146  			if changed {
   147  				snapstate.Set(st, sc.SnapName, &snapst)
   148  			}
   149  		}
   150  	case "restart":
   151  		st.Unlock()
   152  		err := wrappers.RestartServices(startupOrdered, nil, meter, perfTimings)
   153  		st.Lock()
   154  		return err
   155  	case "reload-or-restart":
   156  		flags := &wrappers.RestartServicesFlags{Reload: true}
   157  		st.Unlock()
   158  		err := wrappers.RestartServices(startupOrdered, flags, meter, perfTimings)
   159  		st.Lock()
   160  		return err
   161  	default:
   162  		return fmt.Errorf("unhandled service action: %q", sc.Action)
   163  	}
   164  	return nil
   165  }