forked from purpleidea/mgmt
/
svc.go
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/
svc.go
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// Mgmt
// Copyright (C) 2013-2016+ James Shubin and the project contributors
// Written by James Shubin <james@shubin.ca> and the project contributors
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
// DOCS: https://godoc.org/github.com/coreos/go-systemd/dbus
package resources
import (
"encoding/gob"
"errors"
"fmt"
"log"
"time"
"github.com/purpleidea/mgmt/event"
"github.com/purpleidea/mgmt/util"
systemd "github.com/coreos/go-systemd/dbus" // change namespace
systemdUtil "github.com/coreos/go-systemd/util"
"github.com/godbus/dbus" // namespace collides with systemd wrapper
)
func init() {
gob.Register(&SvcRes{})
}
// SvcRes is a service resource for systemd units.
type SvcRes struct {
BaseRes `yaml:",inline"`
State string `yaml:"state"` // state: running, stopped, undefined
Startup string `yaml:"startup"` // enabled, disabled, undefined
}
// NewSvcRes is a constructor for this resource. It also calls Init() for you.
func NewSvcRes(name, state, startup string) *SvcRes {
obj := &SvcRes{
BaseRes: BaseRes{
Name: name,
},
State: state,
Startup: startup,
}
obj.Init()
return obj
}
// Init runs some startup code for this resource.
func (obj *SvcRes) Init() error {
obj.BaseRes.kind = "Svc"
return obj.BaseRes.Init() // call base init, b/c we're overriding
}
// Validate checks if the resource data structure was populated correctly.
func (obj *SvcRes) Validate() error {
if obj.State != "running" && obj.State != "stopped" && obj.State != "" {
return fmt.Errorf("State must be either `running` or `stopped` or undefined.")
}
if obj.Startup != "enabled" && obj.Startup != "disabled" && obj.Startup != "" {
return fmt.Errorf("Startup must be either `enabled` or `disabled` or undefined.")
}
return nil
}
// Watch is the primary listener for this resource and it outputs events.
func (obj *SvcRes) Watch(processChan chan event.Event) error {
if obj.IsWatching() {
return nil
}
obj.SetWatching(true)
defer obj.SetWatching(false)
cuuid := obj.converger.Register()
defer cuuid.Unregister()
var startup bool
Startup := func(block bool) <-chan time.Time {
if block {
return nil // blocks forever
//return make(chan time.Time) // blocks forever
}
return time.After(time.Duration(500) * time.Millisecond) // 1/2 the resolution of converged timeout
}
// obj.Name: svc name
if !systemdUtil.IsRunningSystemd() {
return fmt.Errorf("Systemd is not running.")
}
conn, err := systemd.NewSystemdConnection() // needs root access
if err != nil {
return fmt.Errorf("Failed to connect to systemd: %s", err)
}
defer conn.Close()
// if we share the bus with others, we will get each others messages!!
bus, err := util.SystemBusPrivateUsable() // don't share the bus connection!
if err != nil {
return fmt.Errorf("Failed to connect to bus: %s", err)
}
// XXX: will this detect new units?
bus.BusObject().Call("org.freedesktop.DBus.AddMatch", 0,
"type='signal',interface='org.freedesktop.systemd1.Manager',member='Reloading'")
buschan := make(chan *dbus.Signal, 10)
bus.Signal(buschan)
var svc = fmt.Sprintf("%v.service", obj.Name) // systemd name
var send = false // send event?
var exit = false
var dirty = false
var invalid = false // does the svc exist or not?
var previous bool // previous invalid value
set := conn.NewSubscriptionSet() // no error should be returned
subChannel, subErrors := set.Subscribe()
var activeSet = false
for {
// XXX: watch for an event for new units...
// XXX: detect if startup enabled/disabled value changes...
previous = invalid
invalid = false
// firstly, does svc even exist or not?
loadstate, err := conn.GetUnitProperty(svc, "LoadState")
if err != nil {
log.Printf("Failed to get property: %v", err)
invalid = true
}
if !invalid {
var notFound = (loadstate.Value == dbus.MakeVariant("not-found"))
if notFound { // XXX: in the loop we'll handle changes better...
log.Printf("Failed to find svc: %v", svc)
invalid = true // XXX ?
}
}
if previous != invalid { // if invalid changed, send signal
send = true
dirty = true
}
if invalid {
log.Printf("Waiting for: %v", svc) // waiting for svc to appear...
if activeSet {
activeSet = false
set.Remove(svc) // no return value should ever occur
}
obj.SetState(ResStateWatching) // reset
select {
case <-buschan: // XXX wait for new units event to unstick
cuuid.SetConverged(false)
// loop so that we can see the changed invalid signal
log.Printf("Svc[%v]->DaemonReload()", svc)
case event := <-obj.events:
cuuid.SetConverged(false)
if exit, send = obj.ReadEvent(&event); exit {
return nil // exit
}
if event.GetActivity() {
dirty = true
}
case <-cuuid.ConvergedTimer():
cuuid.SetConverged(true) // converged!
continue
case <-Startup(startup):
cuuid.SetConverged(false)
send = true
dirty = true
}
} else {
if !activeSet {
activeSet = true
set.Add(svc) // no return value should ever occur
}
log.Printf("Watching: %v", svc) // attempting to watch...
obj.SetState(ResStateWatching) // reset
select {
case event := <-subChannel:
log.Printf("Svc event: %+v", event)
// NOTE: the value returned is a map for some reason...
if event[svc] != nil {
// event[svc].ActiveState is not nil
switch event[svc].ActiveState {
case "active":
log.Printf("Svc[%v]->Started", svc)
case "inactive":
log.Printf("Svc[%v]->Stopped", svc)
case "reloading":
log.Printf("Svc[%v]->Reloading", svc)
default:
log.Fatalf("Unknown svc state: %s", event[svc].ActiveState)
}
} else {
// svc stopped (and ActiveState is nil...)
log.Printf("Svc[%v]->Stopped", svc)
}
send = true
dirty = true
case err := <-subErrors:
cuuid.SetConverged(false)
return fmt.Errorf("Unknown %s[%s] error: %v", obj.Kind(), obj.GetName(), err)
case event := <-obj.events:
cuuid.SetConverged(false)
if exit, send = obj.ReadEvent(&event); exit {
return nil // exit
}
if event.GetActivity() {
dirty = true
}
case <-cuuid.ConvergedTimer():
cuuid.SetConverged(true) // converged!
continue
case <-Startup(startup):
cuuid.SetConverged(false)
send = true
dirty = true
}
}
if send {
startup = true // startup finished
send = false
if dirty {
dirty = false
obj.isStateOK = false // something made state dirty
}
if exit, err := obj.DoSend(processChan, ""); exit || err != nil {
return err // we exit or bubble up a NACK...
}
}
}
}
// CheckApply checks the resource state and applies the resource if the bool
// input is true. It returns error info and if the state check passed or not.
func (obj *SvcRes) CheckApply(apply bool) (checkok bool, err error) {
log.Printf("%v[%v]: CheckApply(%t)", obj.Kind(), obj.GetName(), apply)
if obj.isStateOK { // cache the state
return true, nil
}
if !systemdUtil.IsRunningSystemd() {
return false, errors.New("Systemd is not running.")
}
conn, err := systemd.NewSystemdConnection() // needs root access
if err != nil {
return false, fmt.Errorf("Failed to connect to systemd: %v", err)
}
defer conn.Close()
var svc = fmt.Sprintf("%v.service", obj.Name) // systemd name
loadstate, err := conn.GetUnitProperty(svc, "LoadState")
if err != nil {
return false, fmt.Errorf("Failed to get load state: %v", err)
}
// NOTE: we have to compare variants with other variants, they are really strings...
var notFound = (loadstate.Value == dbus.MakeVariant("not-found"))
if notFound {
return false, fmt.Errorf("Failed to find svc: %v", svc)
}
// XXX: check svc "enabled at boot" or not status...
//conn.GetUnitProperties(svc)
activestate, err := conn.GetUnitProperty(svc, "ActiveState")
if err != nil {
return false, fmt.Errorf("Failed to get active state: %v", err)
}
var running = (activestate.Value == dbus.MakeVariant("active"))
var stateOK = ((obj.State == "") || (obj.State == "running" && running) || (obj.State == "stopped" && !running))
var startupOK = true // XXX DETECT AND SET
if stateOK && startupOK {
return true, nil // we are in the correct state
}
// state is not okay, no work done, exit, but without error
if !apply {
return false, nil
}
// apply portion
log.Printf("%v[%v]: Apply", obj.Kind(), obj.GetName())
var files = []string{svc} // the svc represented in a list
if obj.Startup == "enabled" {
_, _, err = conn.EnableUnitFiles(files, false, true)
} else if obj.Startup == "disabled" {
_, err = conn.DisableUnitFiles(files, false)
}
if err != nil {
return false, fmt.Errorf("Unable to change startup status: %v", err)
}
// XXX: do we need to use a buffered channel here?
result := make(chan string, 1) // catch result information
if obj.State == "running" {
_, err = conn.StartUnit(svc, "fail", result)
if err != nil {
return false, fmt.Errorf("Failed to start unit: %v", err)
}
} else if obj.State == "stopped" {
_, err = conn.StopUnit(svc, "fail", result)
if err != nil {
return false, fmt.Errorf("Failed to stop unit: %v", err)
}
}
status := <-result
if &status == nil {
return false, errors.New("Systemd service action result is nil")
}
if status != "done" {
return false, fmt.Errorf("Unknown systemd return string: %v", status)
}
// XXX: also set enabled on boot
return false, nil // success
}
// SvcUUID is the UUID struct for SvcRes.
type SvcUUID struct {
// NOTE: there is also a name variable in the BaseUUID struct, this is
// information about where this UUID came from, and is unrelated to the
// information about the resource we're matching. That data which is
// used in the IFF function, is what you see in the struct fields here.
BaseUUID
name string // the svc name
}
// IFF aka if and only if they are equivalent, return true. If not, false.
func (obj *SvcUUID) IFF(uuid ResUUID) bool {
res, ok := uuid.(*SvcUUID)
if !ok {
return false
}
return obj.name == res.name
}
// SvcResAutoEdges holds the state of the auto edge generator.
type SvcResAutoEdges struct {
data []ResUUID
pointer int
found bool
}
// Next returns the next automatic edge.
func (obj *SvcResAutoEdges) Next() []ResUUID {
if obj.found {
log.Fatal("Shouldn't be called anymore!")
}
if len(obj.data) == 0 { // check length for rare scenarios
return nil
}
value := obj.data[obj.pointer]
obj.pointer++
return []ResUUID{value} // we return one, even though api supports N
}
// Test gets results of the earlier Next() call, & returns if we should continue!
func (obj *SvcResAutoEdges) Test(input []bool) bool {
// if there aren't any more remaining
if len(obj.data) <= obj.pointer {
return false
}
if obj.found { // already found, done!
return false
}
if len(input) != 1 { // in case we get given bad data
log.Fatal("Expecting a single value!")
}
if input[0] { // if a match is found, we're done!
obj.found = true // no more to find!
return false
}
return true // keep going
}
// AutoEdges returns the AutoEdge interface. In this case the systemd units.
func (obj *SvcRes) AutoEdges() AutoEdge {
var data []ResUUID
svcFiles := []string{
fmt.Sprintf("/etc/systemd/system/%s.service", obj.Name), // takes precedence
fmt.Sprintf("/usr/lib/systemd/system/%s.service", obj.Name), // pkg default
}
for _, x := range svcFiles {
var reversed = true
data = append(data, &FileUUID{
BaseUUID: BaseUUID{
name: obj.GetName(),
kind: obj.Kind(),
reversed: &reversed,
},
path: x, // what matters
})
}
return &FileResAutoEdges{
data: data,
pointer: 0,
found: false,
}
}
// GetUUIDs includes all params to make a unique identification of this object.
// Most resources only return one, although some resources can return multiple.
func (obj *SvcRes) GetUUIDs() []ResUUID {
x := &SvcUUID{
BaseUUID: BaseUUID{name: obj.GetName(), kind: obj.Kind()},
name: obj.Name, // svc name
}
return []ResUUID{x}
}
// GroupCmp returns whether two resources can be grouped together or not.
func (obj *SvcRes) GroupCmp(r Res) bool {
_, ok := r.(*SvcRes)
if !ok {
return false
}
// TODO: depending on if the systemd service api allows batching, we
// might be able to build this, although not sure how useful it is...
// it might just eliminate parallelism be bunching up the graph
return false // not possible atm
}
// Compare two resources and return if they are equivalent.
func (obj *SvcRes) Compare(res Res) bool {
switch res.(type) {
case *SvcRes:
res := res.(*SvcRes)
if !obj.BaseRes.Compare(res) { // call base Compare
return false
}
if obj.Name != res.Name {
return false
}
if obj.State != res.State {
return false
}
if obj.Startup != res.Startup {
return false
}
default:
return false
}
return true
}