func (s *watcherSuite) TestStringsWatcherStopsWithPendingSend(c *gc.C) {
// Call the Deployer facade's WatchUnits for machine-0.
var results params.StringsWatchResults
args := params.Entities{Entities: []params.Entity{{Tag: s.rawMachine.Tag()}}}
err := s.stateAPI.Call("Deployer", "", "WatchUnits", args, &results)
c.Assert(err, gc.IsNil)
c.Assert(results.Results, gc.HasLen, 1)
result := results.Results[0]
c.Assert(result.Error, gc.IsNil)
// Start a StringsWatcher and check the initial event.
w := watcher.NewStringsWatcher(s.stateAPI, result)
wc := statetesting.NewStringsWatcherC(c, s.State, w)
// Create a service, deploy a unit of it on the machine.
mysql, err := s.State.AddService("mysql", s.AddTestingCharm(c, "mysql"))
c.Assert(err, gc.IsNil)
principal, err := mysql.AddUnit()
c.Assert(err, gc.IsNil)
err = principal.AssignToMachine(s.rawMachine)
c.Assert(err, gc.IsNil)
// Ensure the initial event is delivered. Then test the watcher
// can be stopped cleanly without reading the pending change.
s.BackingState.Sync()
statetesting.AssertCanStopWhenSending(c, w)
wc.AssertClosed()
}
func (s *watcherSuite) TestWatchUnitsKeepsEvents(c *gc.C) {
// Create two services, relate them, and add one unit to each - a
// principal and a subordinate.
mysql, err := s.State.AddService("mysql", s.AddTestingCharm(c, "mysql"))
c.Assert(err, gc.IsNil)
logging, err := s.State.AddService("logging", s.AddTestingCharm(c, "logging"))
c.Assert(err, gc.IsNil)
eps, err := s.State.InferEndpoints([]string{"mysql", "logging"})
c.Assert(err, gc.IsNil)
rel, err := s.State.AddRelation(eps...)
c.Assert(err, gc.IsNil)
principal, err := mysql.AddUnit()
c.Assert(err, gc.IsNil)
err = principal.AssignToMachine(s.rawMachine)
c.Assert(err, gc.IsNil)
relUnit, err := rel.Unit(principal)
c.Assert(err, gc.IsNil)
err = relUnit.EnterScope(nil)
c.Assert(err, gc.IsNil)
subordinate, err := logging.Unit("logging/0")
c.Assert(err, gc.IsNil)
// Call the Deployer facade's WatchUnits for machine-0.
var results params.StringsWatchResults
args := params.Entities{Entities: []params.Entity{{Tag: s.rawMachine.Tag()}}}
err = s.stateAPI.Call("Deployer", "", "WatchUnits", args, &results)
c.Assert(err, gc.IsNil)
c.Assert(results.Results, gc.HasLen, 1)
result := results.Results[0]
c.Assert(result.Error, gc.IsNil)
// Start a StringsWatcher and check the initial event.
w := watcher.NewStringsWatcher(s.stateAPI, result)
wc := statetesting.NewStringsWatcherC(c, s.State, w)
wc.AssertChange("mysql/0", "logging/0")
wc.AssertNoChange()
// Now, without reading any changes advance the lifecycle of both
// units, inducing an update server-side after each two changes to
// ensure they're reported as separate events over the API.
err = subordinate.EnsureDead()
c.Assert(err, gc.IsNil)
s.BackingState.Sync()
err = subordinate.Remove()
c.Assert(err, gc.IsNil)
err = principal.EnsureDead()
c.Assert(err, gc.IsNil)
s.BackingState.Sync()
// Expect these changes as 2 separate events, so that
// nothing gets lost.
wc.AssertChange("logging/0")
wc.AssertChange("mysql/0")
wc.AssertNoChange()
statetesting.AssertStop(c, w)
wc.AssertClosed()
}
// WatchUnits starts a StringsWatcher to watch all units deployed to
// the machine, in order to track which ones should be deployed or
// recalled.
func (m *Machine) WatchUnits() (*watcher.StringsWatcher, error) {
var results params.StringsWatchResults
args := params.Entities{
Entities: []params.Entity{{Tag: m.tag}},
}
err := m.dstate.caller.Call("Deployer", "", "WatchUnits", args, &results)
if err != nil {
return nil, err
}
if len(results.Results) != 1 {
return nil, fmt.Errorf("expected one result, got %d", len(results.Results))
}
result := results.Results[0]
if result.Error != nil {
return nil, result.Error
}
w := watcher.NewStringsWatcher(m.dstate.caller, result)
return w, nil
}