// runTriggers executes the triggers for each
// monitored resource if it's state has changed
func (c *Catalog) runTriggers(r resource.Resource) error {
c.status.Lock()
defer c.status.Unlock()
for subscribed, trigger := range r.SubscribedTo() {
item := c.status.Items[subscribed]
if !item.StateChanged {
continue
}
c.config.Logger.Printf("%s running trigger, because %s has changed\n", r.ID(), subscribed)
c.config.L.Push(trigger)
if err := c.config.L.PCall(0, 0, nil); err != nil {
c.config.Logger.Printf("%s trigger exited with an error: %s\n", r.ID(), err)
return err
}
}
return nil
}
// execute processes a single resource
func (c *Catalog) execute(r resource.Resource) *StatusItem {
if err := c.hasFailedDependencies(r); err != nil {
return &StatusItem{Err: err}
}
if err := r.Validate(); err != nil {
return &StatusItem{Err: err}
}
if err := r.Initialize(); err != nil {
return &StatusItem{Err: err}
}
defer r.Close()
state, err := r.Evaluate()
if err != nil {
return &StatusItem{Err: err}
}
if c.config.DryRun {
return &StatusItem{}
}
// Current and wanted states for the resource
want := utils.NewString(state.Want)
current := utils.NewString(state.Current)
// The list of present and absent states for the resource
present := utils.NewList(r.PresentStates()...)
absent := utils.NewList(r.AbsentStates()...)
// Process resource
id := r.ID()
var action func() error
switch {
case want.IsInList(present) && current.IsInList(absent):
action = r.Create
c.config.Logger.Printf("%s is %s, should be %s\n", id, current, want)
case want.IsInList(absent) && current.IsInList(present):
action = r.Delete
c.config.Logger.Printf("%s is %s, should be %s\n", id, current, want)
default:
// No-op: resource is in sync
}
stateChanged := false
if action != nil {
stateChanged = true
if err := action(); err != nil {
return &StatusItem{StateChanged: true, Err: err}
}
}
// Process resource properties
for _, p := range r.Properties() {
synced, err := p.IsSynced()
if err != nil {
// Some properties make no sense if the resource is absent, e.g.
// setting up file permissions requires that the file managed by the
// resource is present, therefore we ignore errors for properties
// which make no sense if the resource is absent.
if err == resource.ErrResourceAbsent {
continue
}
e := fmt.Errorf("unable to evaluate property %s: %s\n", p.Name, err)
return &StatusItem{StateChanged: true, Err: e}
}
if !synced {
stateChanged = true
c.config.Logger.Printf("%s property '%s' is out of date\n", id, p.Name())
if err := p.Set(); err != nil {
e := fmt.Errorf("unable to set property %s: %s\n", p.Name, err)
return &StatusItem{StateChanged: true, Err: e}
}
}
}
if err := c.runTriggers(r); err != nil {
return &StatusItem{StateChanged: stateChanged, Err: err}
}
return &StatusItem{StateChanged: stateChanged, Err: nil}
}