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engine: DBus cleanup

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This commit is contained in:
Jonathan Gold
2018-05-05 10:26:29 -04:00
committed by James Shubin
parent a407771eaf
commit 299080f590
3 changed files with 78 additions and 32 deletions
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15
engine/resources/hostname.go
View File

@@ -37,6 +37,7 @@ func init() {
const (
hostname1Path = "/org/freedesktop/hostname1"
hostname1Iface = "org.freedesktop.hostname1"
dbusPropertiesIface = "org.freedesktop.DBus.Properties"
)
// ErrResourceInsufficientParameters is returned when the configuration of the
@@ -112,12 +113,16 @@ func (obj *HostnameRes) Watch() error {
return errwrap.Wrap(err, "Failed to connect to bus")
}
defer bus.Close()
callResult := bus.BusObject().Call(
engineUtil.DBusAddMatch, 0,
fmt.Sprintf("type='signal',path='%s',interface='org.freedesktop.DBus.Properties',member='PropertiesChanged'", hostname1Path))
if callResult.Err != nil {
return errwrap.Wrap(callResult.Err, "Failed to subscribe to DBus events for hostname1")
// watch the PropertiesChanged signal on the hostname1 dbus path
args := fmt.Sprintf(
"type='signal', path='%s', interface='%s', member='PropertiesChanged'",
hostname1Path,
dbusPropertiesIface,
)
if call := bus.BusObject().Call(engineUtil.DBusAddMatch, 0, args); call.Err != nil {
return errwrap.Wrap(call.Err, "Failed to subscribe to DBus events for hostname1")
}
defer bus.BusObject().Call(engineUtil.DBusRemoveMatch, 0, args) // ignore the error
signals := make(chan *dbus.Signal, 10) // closed by dbus package
bus.Signal(signals)

15
engine/resources/nspawn.go
View File

@@ -38,9 +38,9 @@ import (
const (
running = "running"
stopped = "stopped"
dbusInterface = "org.freedesktop.machine1.Manager"
machineNew = "org.freedesktop.machine1.Manager.MachineNew"
machineRemoved = "org.freedesktop.machine1.Manager.MachineRemoved"
dbusMachine1Iface = "org.freedesktop.machine1.Manager"
machineNew = dbusMachine1Iface + ".MachineNew"
machineRemoved = dbusMachine1Iface + ".MachineRemoved"
nspawnServiceTmpl = "systemd-nspawn@%s"
)
@@ -155,13 +155,12 @@ func (obj *NspawnRes) Watch() error {
defer bus.Close()
// add a match rule to match messages going through the message bus
call := bus.BusObject().Call(engineUtil.DBusAddMatch, 0,
fmt.Sprintf("type='signal',interface='%s',eavesdrop='true'",
dbusInterface))
// <-call.Done
if err := call.Err; err != nil {
args := fmt.Sprintf("type='signal',interface='%s',eavesdrop='true'", dbusMachine1Iface)
if call := bus.BusObject().Call(engineUtil.DBusAddMatch, 0, args); call.Err != nil {
return err
}
defer bus.BusObject().Call(engineUtil.DBusRemoveMatch, 0, args) // ignore the error
busChan := make(chan *dbus.Signal)
defer close(busChan)
bus.Signal(busChan)

74
engine/resources/packagekit/packagekit.go
View File

@@ -29,6 +29,7 @@ import (
"github.com/purpleidea/mgmt/util"
"github.com/godbus/dbus"
multierr "github.com/hashicorp/go-multierror"
errwrap "github.com/pkg/errors"
)
@@ -186,34 +187,50 @@ func (obj *Conn) Close() error {
}
// internal helper to add signal matches to the bus, should only be called once
func (obj *Conn) matchSignal(ch chan *dbus.Signal, path dbus.ObjectPath, iface string, signals []string) error {
func (obj *Conn) matchSignal(ch chan *dbus.Signal, path dbus.ObjectPath, iface string, signals []string) (func() error, error) {
if obj.Debug {
obj.Logf("matchSignal(%v, %v, %s, %v)", ch, path, iface, signals)
}
// eg: gdbus monitor --system --dest org.freedesktop.PackageKit --object-path /org/freedesktop/PackageKit | grep <signal>
var call *dbus.Call
bus := obj.GetBus().BusObject()
var argsList []string
// cleanup function should be called when done or when AddMatch errors
removeSignals := func() error {
var errList error
for i := len(argsList) - 1; i >= 0; i-- { // last in first out
if call := bus.Call(engineUtil.DBusRemoveMatch, 0, argsList[i]); call.Err != nil {
errList = multierr.Append(errList, call.Err)
}
}
return errList
}
// TODO: if we make this call many times, we seem to receive signals
// that many times... Maybe this should be an object singleton?
bus := obj.GetBus().BusObject()
var call *dbus.Call
pathStr := fmt.Sprintf("%s", path)
if len(signals) == 0 {
call = bus.Call(engineUtil.DBusAddMatch, 0, "type='signal',path='"+pathStr+"',interface='"+iface+"'")
args := fmt.Sprintf("type='signal', path='%s', interface='%s'", pathStr, iface)
argsList = append(argsList, args)
call = bus.Call(engineUtil.DBusAddMatch, 0, args)
} else {
for _, signal := range signals {
call = bus.Call(engineUtil.DBusAddMatch, 0, "type='signal',path='"+pathStr+"',interface='"+iface+"',member='"+signal+"'")
if call.Err != nil {
break
args := fmt.Sprintf("type='signal', path='%s', interface='%s', member'%s'", pathStr, iface, signal)
argsList = append(argsList, args)
if call = bus.Call(engineUtil.DBusAddMatch, 0, args); call.Err != nil {
break // fail if any one fails
}
}
}
if call.Err != nil {
return call.Err
defer removeSignals() // ignore the error
return nil, call.Err
}
// The caller has to make sure that ch is sufficiently buffered; if a
// message arrives when a write to c is not possible, it is discarded!
// This can be disastrous if we're waiting for a "Finished" signal!
obj.GetBus().Signal(ch)
return nil
return removeSignals, nil
}
// WatchChanges gets a signal anytime an event happens.
@@ -223,10 +240,11 @@ func (obj *Conn) WatchChanges() (chan *dbus.Signal, error) {
// but with much less specificity. If we're missing events, report the
// issue upstream! The UpdatesChanged signal is what hughsie suggested
var signal = "UpdatesChanged"
err := obj.matchSignal(ch, PkPath, PkIface, []string{signal})
removeSignals, err := obj.matchSignal(ch, PkPath, PkIface, []string{signal})
if err != nil {
return nil, err
}
defer removeSignals() // ignore the error
if Paranoid { // TODO: this filtering might not be necessary anymore...
// try to handle the filtering inside this function!
rch := make(chan *dbus.Signal)
@@ -286,7 +304,11 @@ func (obj *Conn) ResolvePackages(packages []string, filter uint64) ([]string, er
// add signal matches for Package and Finished which will always be last
var signals = []string{"Package", "Finished", "Error", "Destroy"}
obj.matchSignal(ch, interfacePath, PkIfaceTransaction, signals)
removeSignals, err := obj.matchSignal(ch, interfacePath, PkIfaceTransaction, signals)
if err != nil {
return nil, err
}
defer removeSignals()
if obj.Debug {
obj.Logf("ResolvePackages(): Object(%s, %v)", PkIface, interfacePath)
}
@@ -396,7 +418,11 @@ func (obj *Conn) InstallPackages(packageIDs []string, transactionFlags uint64) e
}
var signals = []string{"Package", "ErrorCode", "Finished", "Destroy"} // "ItemProgress", "Status" ?
obj.matchSignal(ch, interfacePath, PkIfaceTransaction, signals)
removeSignals, err := obj.matchSignal(ch, interfacePath, PkIfaceTransaction, signals)
if err != nil {
return err
}
defer removeSignals()
bus := obj.GetBus().Object(PkIface, interfacePath) // pass in found transaction path
call := bus.Call(FmtTransactionMethod("RefreshCache"), 0, false)
@@ -454,7 +480,11 @@ func (obj *Conn) RemovePackages(packageIDs []string, transactionFlags uint64) er
}
var signals = []string{"Package", "ErrorCode", "Finished", "Destroy"} // "ItemProgress", "Status" ?
obj.matchSignal(ch, interfacePath, PkIfaceTransaction, signals)
removeSignals, err := obj.matchSignal(ch, interfacePath, PkIfaceTransaction, signals)
if err != nil {
return err
}
defer removeSignals()
bus := obj.GetBus().Object(PkIface, interfacePath) // pass in found transaction path
call := bus.Call(FmtTransactionMethod("RemovePackages"), 0, transactionFlags, packageIDs, allowDeps, autoremove)
@@ -499,7 +529,11 @@ func (obj *Conn) UpdatePackages(packageIDs []string, transactionFlags uint64) er
}
var signals = []string{"Package", "ErrorCode", "Finished", "Destroy"} // "ItemProgress", "Status" ?
obj.matchSignal(ch, interfacePath, PkIfaceTransaction, signals)
removeSignals, err := obj.matchSignal(ch, interfacePath, PkIfaceTransaction, signals)
if err != nil {
return err
}
defer removeSignals()
bus := obj.GetBus().Object(PkIface, interfacePath) // pass in found transaction path
call := bus.Call(FmtTransactionMethod("UpdatePackages"), 0, transactionFlags, packageIDs)
@@ -544,7 +578,11 @@ func (obj *Conn) GetFilesByPackageID(packageIDs []string) (files map[string][]st
}
var signals = []string{"Files", "ErrorCode", "Finished", "Destroy"} // "ItemProgress", "Status" ?
obj.matchSignal(ch, interfacePath, PkIfaceTransaction, signals)
removeSignals, err := obj.matchSignal(ch, interfacePath, PkIfaceTransaction, signals)
if err != nil {
return
}
defer removeSignals()
bus := obj.GetBus().Object(PkIface, interfacePath) // pass in found transaction path
call := bus.Call(FmtTransactionMethod("GetFiles"), 0, packageIDs)
@@ -611,7 +649,11 @@ func (obj *Conn) GetUpdates(filter uint64) ([]string, error) {
}
var signals = []string{"Package", "ErrorCode", "Finished", "Destroy"} // "ItemProgress" ?
obj.matchSignal(ch, interfacePath, PkIfaceTransaction, signals)
removeSignals, err := obj.matchSignal(ch, interfacePath, PkIfaceTransaction, signals)
if err != nil {
return nil, err
}
defer removeSignals()
bus := obj.GetBus().Object(PkIface, interfacePath) // pass in found transaction path
call := bus.Call(FmtTransactionMethod("GetUpdates"), 0, filter)