// Initialize creates default emitters and instruments the default HTTP
// transport.
//
// The DROPSONDE_ORIGIN environment variable is required and specifies the
// source name for all metrics emitted by this process. If it is not set, the
// program will run normally but will not emit metrics.
//
// The DROPSONDE_DESTINATION environment variable sets the host and port to
// which metrics are sent. It is optional, and defaults to DefaultDestination.
func Initialize() {
http.DefaultTransport = &http.Transport{Proxy: http.ProxyFromEnvironment}
autowiredEmitter = &nullEventEmitter{}
origin := os.Getenv("DROPSONDE_ORIGIN")
if len(origin) == 0 {
log.Println("Failed to auto-initialize dropsonde: DROPSONDE_ORIGIN environment variable not set")
return
}
destination = os.Getenv("DROPSONDE_DESTINATION")
if len(destination) == 0 {
log.Println("DROPSONDE_DESTINATION not set. Using " + DefaultDestination)
destination = DefaultDestination
}
udpEmitter, err := emitter.NewUdpEmitter(destination)
if err != nil {
log.Printf("Failed to auto-initialize dropsonde: %v\n", err)
return
}
hbEmitter, err := emitter.NewHeartbeatEmitter(udpEmitter, origin)
if err != nil {
log.Printf("Failed to auto-initialize dropsonde: %v\n", err)
return
}
autowiredEmitter = emitter.NewEventEmitter(hbEmitter, origin)
go runtime_stats.NewRuntimeStats(autowiredEmitter, runtimeStatsInterval).Run(nil)
http.DefaultTransport = InstrumentedRoundTripper(http.DefaultTransport)
}
func CreateDefaultEmitter() (emitter.EventEmitter, string) {
origin := os.Getenv("DROPSONDE_ORIGIN")
if len(origin) == 0 {
log.Println("Failed to auto-initialize dropsonde: DROPSONDE_ORIGIN environment variable not set")
return nil, ""
}
destination := os.Getenv("DROPSONDE_DESTINATION")
if len(destination) == 0 {
log.Println("DROPSONDE_DESTINATION not set. Using " + DefaultDestination)
destination = DefaultDestination
}
udpEmitter, err := emitter.NewUdpEmitter(destination)
if err != nil {
log.Printf("Failed to auto-initialize dropsonde: %v\n", err)
return nil, destination
}
hbEmitter, err := emitter.NewHeartbeatEmitter(udpEmitter, origin)
if err != nil {
log.Printf("Failed to auto-initialize dropsonde: %v\n", err)
return nil, destination
}
return emitter.NewEventEmitter(hbEmitter, origin), destination
}
)
var _ = Describe("HeartbeatEmitter", func() {
var (
wrappedEmitter *fake.FakeByteEmitter
origin = "testHeartbeatEmitter/0"
)
BeforeEach(func() {
emitter.HeartbeatInterval = 10 * time.Millisecond
wrappedEmitter = fake.NewFakeByteEmitter()
})
Describe("NewHeartbeatEmitter", func() {
It("requires non-nil args", func() {
hbEmitter, err := emitter.NewHeartbeatEmitter(nil, origin)
Expect(err).To(HaveOccurred())
Expect(err.Error()).To(Equal("wrappedEmitter is nil"))
Expect(hbEmitter).To(BeNil())
})
It("starts periodic heartbeat emission", func() {
hbEmitter, err := emitter.NewHeartbeatEmitter(wrappedEmitter, origin)
Expect(err).NotTo(HaveOccurred())
Expect(hbEmitter).NotTo(BeNil())
Eventually(func() int { return len(wrappedEmitter.GetMessages()) }).Should(BeNumerically(">=", 2))
})
It("logs an error when heartbeat emission fails", func() {
wrappedEmitter.ReturnError = errors.New("fake error")