func main() {
// Create a recent in-memory store, evicting data after 20s.
//
// The store defines where information about traces (i.e. spans and
// annotations) will be stored during the lifetime of the application. This
// application uses a MemoryStore store wrapped by a RecentStore with an
// eviction time of 20s (i.e. all data after 20s is deleted from memory).
memStore := appdash.NewMemoryStore()
store := &appdash.RecentStore{
MinEvictAge: 20 * time.Second,
DeleteStore: memStore,
}
// Start the Appdash web UI on port 8700.
//
// This is the actual Appdash web UI -- usable as a Go package itself, We
// embed it directly into our application such that visiting the web server
// on HTTP port 8700 will bring us to the web UI, displaying information
// about this specific web-server (another alternative would be to connect
// to a centralized Appdash collection server).
url, err := url.Parse("http://localhost:8700")
if err != nil {
log.Fatal(err)
}
tapp, err := traceapp.New(nil, url)
if err != nil {
log.Fatal(err)
}
tapp.Store = store
tapp.Queryer = memStore
log.Println("Appdash web UI running on HTTP :8700")
go func() {
log.Fatal(http.ListenAndServe(":8700", tapp))
}()
// We will use a local collector (as we are running the Appdash web UI
// embedded within our app).
//
// A collector is responsible for collecting the information about traces
// (i.e. spans and annotations) and placing them into a store. In this app
// we use a local collector (we could also use a remote collector, sending
// the information to a remote Appdash collection server).
collector := appdash.NewLocalCollector(store)
// Here we use the local collector to create a new opentracing.Tracer
tracer := appdashtracer.NewTracer(collector)
opentracing.InitGlobalTracer(tracer)
// Setup our router (for information, see the gorilla/mux docs):
router := mux.NewRouter()
router.HandleFunc("/", Home)
router.HandleFunc("/endpoint", Endpoint)
// Setup Negroni for our app (for information, see the negroni docs):
n := negroni.Classic()
n.UseHandler(router)
n.Run(":8699")
}
func TestTracer(t *testing.T) {
log.SetFlags(0)
var tracer ot.Tracer
tracer = &Tracer{}
ot.InitGlobalTracer(tracer)
ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
serverSpan, err := tracer.Join(
"serverSpan",
ot.TextMap,
ot.HTTPHeaderTextMapCarrier(r.Header))
if err != nil {
panic(err)
}
time.Sleep(time.Second * 1)
serverSpan.Finish()
fmt.Fprintln(w, "Hello, client")
}))
defer ts.Close()
span, nctx := ot.StartSpanFromContext(context.TODO(), "main_test")
defer span.Finish()
foo(nctx, "bar", 0)
httpClient := &http.Client{}
httpReq, _ := http.NewRequest("GET", ts.URL, nil)
// Transmit the span's TraceContext as HTTP headers on our
// outbound request.
tracer.Inject(
span,
ot.TextMap,
ot.HTTPHeaderTextMapCarrier(httpReq.Header))
if _, err := httpClient.Do(httpReq); err != nil {
panic(err)
}
}