Documentation
¶
Overview ¶
Package nameq is an application support library for using the information exported by the nameq service.
Index ¶
Constants ¶
const ( // The directory used when an empty string is given to SetFeature or RemoveFeature. DefaultFeatureDir = "/etc/nameq/features" // The directory used when an empty string is given to NewFeatureMonitor. DefaultStateDir = "/run/nameq/state" )
Variables ¶
This section is empty.
Functions ¶
func FeatureBuffer ¶
FeatureBuffer is an unbounded buffering adapter for Feature channels. The supplied channel doesn't need to be buffered.
func RemoveFeature ¶
RemoveFeature removes a local feature. DefaultFeatureDir is used if an empty string is given. Redundant calls are ok.
func SetFeature ¶
SetFeature adds or updates a local feature. data must be a valid JSON document. DefaultFeatureDir is used if an empty string is given. Redundant calls are ok.
Types ¶
type Feature ¶
type Feature struct {
Name string // Name of the feature.
Host net.IP // IPv4 or IPv6 address of the host where the feature exists.
Data []byte // JSON value if feature added or updated, or nil if removed.
}
Feature represents a momentary state of a feature on a host.
type FeatureDemux ¶
FeatureDemux can be used to forward Features from FeatureMonitor to multiple subscribers based on the Name field.
Example:
monitor, err := nameq.NewFeatureMonitor("", nil)
if err != nil {
return
}
defer monitor.Close()
foo := make(chan *nameq.Feature)
bar1 := make(chan *nameq.Feature)
bar2 := make(chan *nameq.Feature)
nameq.FeatureDemux{
"foo": {
nameq.FeatureBuffer(foo),
},
"bar": {
nameq.FeatureBuffer(bar1),
nameq.FeatureBuffer(bar2),
},
}.Start(monitor.C)
go consume(foo)
go consume(bar1)
go consume(bar2)
func (FeatureDemux) Add ¶
func (queues FeatureDemux) Add(name string, output chan<- *Feature)
Add a subscriber. The supplied channel should be buffered.
func (FeatureDemux) AddBuffer ¶
func (queues FeatureDemux) AddBuffer(name string, output chan<- *Feature)
AddBuffer adds a subscriber with unbounded buffering. The supplied channel doesn't need to be buffered.
func (FeatureDemux) Start ¶
func (outputs FeatureDemux) Start(input <-chan *Feature)
Start after adding all subscribers. Supply the FeatureMonitor's channel as the argument.
type FeatureMonitor ¶
type FeatureMonitor struct {
// Produces current information, followed by updates in real time. There
// may be seemingly redundant entries when a feature is updated rapidly.
C <-chan *Feature
// Boot is closed after all existing features have been delivered via C.
// Client code is free to set this member to nil after it has been closed.
Boot <-chan struct{}
// contains filtered or unexported fields
}
FeatureMonitor watches the nameq runtime state for changes.
func NewFeatureMonitor ¶
func NewFeatureMonitor(stateDir string, logger Logger) (m *FeatureMonitor, err error)
NewFeatureMonitor watches the specified state directory, or the default state directory if an empty string is given. The directory must exist. The logger is used for I/O errors, unless nil.
func (*FeatureMonitor) Close ¶
func (m *FeatureMonitor) Close()
Close stops watching immediately and closes the channel.
Source Files