I am trying to get value TTFB and Connect value
c := exec.Command( "curl", "-w", "Connect: %{time_connect} TTFB: %{time_starttransfer} Total time: %{time_total}", "-o", "/dev/null", "http://my.domain/favicon.ico") cID, err := c.Run() fmt.Printf("%s", cID)
It prints a sting like
Connect: 0.205 TTFB: 0.353 Total time: 0.354
However, I need only the value of TTFB , Connect, Total time value in golang variable.
Also, Is there any way I can get the values without specifically using curl?
There's builtin support for this since Go 1.7. Go 1.7 added HTTP Tracing, read blog post: Introducing HTTP Tracing
You can specify callback functions which get called at the appropriate phases / points when making an HTTP(S) request. You can specify your callback functions by creating a value of httptrace.ClientTrace, and "arm" it using httptrace.WithClientTrace().
Here's an example function which gets a URL param, and prints the timing of getting it:
func timeGet(url string) { req, _ := http.NewRequest("GET", url, nil) var start, connect, dns, tlsHandshake time.Time trace := &httptrace.ClientTrace{ DNSStart: func(dsi httptrace.DNSStartInfo) { dns = time.Now() }, DNSDone: func(ddi httptrace.DNSDoneInfo) { fmt.Printf("DNS Done: %v\n", time.Since(dns)) }, TLSHandshakeStart: func() { tlsHandshake = time.Now() }, TLSHandshakeDone: func(cs tls.ConnectionState, err error) { fmt.Printf("TLS Handshake: %v\n", time.Since(tlsHandshake)) }, ConnectStart: func(network, addr string) { connect = time.Now() }, ConnectDone: func(network, addr string, err error) { fmt.Printf("Connect time: %v\n", time.Since(connect)) }, GotFirstResponseByte: func() { fmt.Printf("Time from start to first byte: %v\n", time.Since(start)) }, } req = req.WithContext(httptrace.WithClientTrace(req.Context(), trace)) start = time.Now() if _, err := http.DefaultTransport.RoundTrip(req); err != nil { log.Fatal(err) } fmt.Printf("Total time: %v\n", time.Since(start)) }
Example calling it:
timeGet("https://google.com")
Example output:
DNS Done: 7.998465ms Connect time: 12.677085ms TLS Handshake: 128.65394ms Time from start to first byte: 176.461087ms Total time: 176.723402ms
Also be sure to check out github.com/davecheney/httpstat which gives you a CLI utility that also uses the httptracing package under the hood.
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