func sampleData(c appdash.Collector) error {
const numTraces = 60
log.Printf("Adding sample data (%d traces)", numTraces)
for i := appdash.ID(1); i <= numTraces; i++ {
traceID := appdash.NewRootSpanID()
traceRec := appdash.NewRecorder(traceID, c)
traceRec.Name(fakeHosts[rand.Intn(len(fakeHosts))])
// A random length for the trace.
length := time.Duration(rand.Intn(1000)) * time.Millisecond
startTime := time.Now().Add(-time.Duration(rand.Intn(100)) * time.Minute)
traceRec.Event(&sqltrace.SQLEvent{
ClientSend: startTime,
ClientRecv: startTime.Add(length),
SQL: "SELECT * FROM table_name;",
Tag: fmt.Sprintf("fakeTag%d", rand.Intn(10)),
})
// We'll split the trace into N (3-7) spans (i.e. "N operations") each with
// a random duration of time adding up to the length of the trace.
numSpans := rand.Intn(7-3) + 3
times := randomSplit(int(length/time.Millisecond), numSpans)
lastSpanID := traceID
for j := 1; j <= numSpans; j++ {
// The parent span is the predecessor.
spanID := appdash.NewSpanID(lastSpanID)
rec := appdash.NewRecorder(spanID, c)
rec.Name(fakeNames[(j+int(i))%len(fakeNames)])
if j%3 == 0 {
rec.Log("hello")
}
if j%5 == 0 {
rec.Msg("hi")
}
// Generate a span event.
spanDuration := time.Duration(times[j-1]) * time.Millisecond
rec.Event(&sqltrace.SQLEvent{
ClientSend: startTime,
ClientRecv: startTime.Add(spanDuration),
SQL: "SELECT * FROM table_name;",
Tag: fmt.Sprintf("fakeTag%d", rand.Intn(10)),
})
// Shift the start time forward.
startTime = startTime.Add(spanDuration)
// Check for any recorder errors.
if errs := rec.Errors(); len(errs) > 0 {
return fmt.Errorf("recorder errors: %v", errs)
}
lastSpanID = spanID
}
}
return nil
}
func getSpanID(h http.Header) (spanID *appdash.SpanID, fromHeader string, err error) {
// Check for Span-ID.
fromHeader = HeaderSpanID
spanID, err = getSpanIDHeader(h, HeaderSpanID)
if err != nil {
return nil, fromHeader, err
}
// Check for Parent-Span-ID.
if spanID == nil {
fromHeader = HeaderParentSpanID
spanID, err = getSpanIDHeader(h, HeaderParentSpanID)
if err != nil {
return nil, fromHeader, err
}
if spanID != nil {
newSpanID := appdash.NewSpanID(*spanID)
spanID = &newSpanID
}
}
// Create a new root span ID.
if spanID == nil {
fromHeader = ""
newSpanID := appdash.NewRootSpanID()
spanID = &newSpanID
}
return spanID, fromHeader, nil
}
// RoundTrip implements the RoundTripper interface.
func (t *Transport) RoundTrip(original *http.Request) (*http.Response, error) {
// To set extra querystring params, we must make a copy of the Request so
// that we don't modify the Request we were given. This is required by the
// specification of http.RoundTripper.
req := cloneRequest(original)
t.setCloneRequest(original, req)
defer t.setCloneRequest(original, nil)
child := t.Recorder.Child()
if t.SetName {
child.Name("Request " + req.URL.Host)
}
// New child span is created and set as HTTP header instead of using `child`
// in order to have a single span recording operation per httptrace event
// (HTTPClient or HTTPServer).
span := appdash.NewSpanID(t.Recorder.SpanID)
SetSpanIDHeader(req.Header, span)
e := NewClientEvent(req)
e.ClientSend = time.Now()
// Make the HTTP request.
transport := t.getTransport()
resp, err := transport.RoundTrip(req)
e.ClientRecv = time.Now()
if err == nil {
e.Response = responseInfo(resp)
} else {
e.Response.StatusCode = -1
}
child.Event(e)
child.Finish()
return resp, err
}