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

     1  // -*- Mode: Go; indent-tabs-mode: t -*-
     2  
     3  /*
     4   * Copyright (C) 2015-2016 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  	"time"
    25  
    26  	"github.com/snapcore/snapd/client"
    27  	"github.com/snapcore/snapd/overlord/cmdstate"
    28  	"github.com/snapcore/snapd/overlord/hookstate"
    29  	"github.com/snapcore/snapd/overlord/snapstate"
    30  	"github.com/snapcore/snapd/overlord/state"
    31  	"github.com/snapcore/snapd/snap"
    32  )
    33  
    34  type Instruction struct {
    35  	Action string   `json:"action"`
    36  	Names  []string `json:"names"`
    37  	client.StartOptions
    38  	client.StopOptions
    39  	client.RestartOptions
    40  }
    41  
    42  type ServiceActionConflictError struct{ error }
    43  
    44  // Control creates a taskset for starting/stopping/restarting services via systemctl.
    45  // The appInfos and inst define the services and the command to execute.
    46  // Context is used to determine change conflicts - we will not conflict with
    47  // tasks from same change as that of context's.
    48  func Control(st *state.State, appInfos []*snap.AppInfo, inst *Instruction, context *hookstate.Context) ([]*state.TaskSet, error) {
    49  	var tts []*state.TaskSet
    50  
    51  	var ctlcmds []string
    52  	switch {
    53  	case inst.Action == "start":
    54  		if inst.Enable {
    55  			ctlcmds = []string{"enable"}
    56  		}
    57  		ctlcmds = append(ctlcmds, "start")
    58  	case inst.Action == "stop":
    59  		if inst.Disable {
    60  			ctlcmds = []string{"disable"}
    61  		}
    62  		ctlcmds = append(ctlcmds, "stop")
    63  	case inst.Action == "restart":
    64  		if inst.Reload {
    65  			ctlcmds = []string{"reload-or-restart"}
    66  		} else {
    67  			ctlcmds = []string{"restart"}
    68  		}
    69  	default:
    70  		return nil, fmt.Errorf("unknown action %q", inst.Action)
    71  	}
    72  
    73  	st.Lock()
    74  	defer st.Unlock()
    75  
    76  	svcs := make([]string, 0, len(appInfos))
    77  	snapNames := make([]string, 0, len(appInfos))
    78  	lastName := ""
    79  	names := make([]string, len(appInfos))
    80  	for i, svc := range appInfos {
    81  		svcs = append(svcs, svc.ServiceName())
    82  		snapName := svc.Snap.InstanceName()
    83  		names[i] = snapName + "." + svc.Name
    84  		if snapName != lastName {
    85  			snapNames = append(snapNames, snapName)
    86  			lastName = snapName
    87  		}
    88  	}
    89  
    90  	var ignoreChangeID string
    91  	if context != nil && !context.IsEphemeral() {
    92  		if task, ok := context.Task(); ok {
    93  			if chg := task.Change(); chg != nil {
    94  				ignoreChangeID = chg.ID()
    95  			}
    96  		}
    97  	}
    98  
    99  	if err := snapstate.CheckChangeConflictMany(st, snapNames, ignoreChangeID); err != nil {
   100  		return nil, &ServiceActionConflictError{err}
   101  	}
   102  
   103  	for _, cmd := range ctlcmds {
   104  		argv := append([]string{"systemctl", cmd}, svcs...)
   105  		desc := fmt.Sprintf("%s of %v", cmd, names)
   106  		// Give the systemctl a maximum time of 61 for now.
   107  		//
   108  		// Longer term we need to refactor this code and
   109  		// reuse the snapd/systemd and snapd/wrapper packages
   110  		// to control the timeout in a single place.
   111  		ts := cmdstate.ExecWithTimeout(st, desc, argv, 61*time.Second)
   112  		tts = append(tts, ts)
   113  	}
   114  
   115  	// make a taskset wait for its predecessor
   116  	for i := 1; i < len(tts); i++ {
   117  		tts[i].WaitAll(tts[i-1])
   118  	}
   119  
   120  	return tts, nil
   121  }