It depends on how far down the connection process it reached before timing
out...
What is the timeout setting your http client?
Try this example:
func main() {
req, _ := http.NewRequest("GET",
"https://deelay.me/300/https://google.com";, nil)
trace := &httptrace.ClientTrace{
GetConn: func(hostPort string) {
fmt.Printf("Get Conn: %s\n", hostPort)
},
GotConn: func(connInfo httptrace.GotConnInfo) {
fmt.Printf("Got Conn: %s\n", connInfo.Conn.LocalAddr().String())
},
ConnectStart: func(network, addr string) {
fmt.Printf("Conn start: %s %s\n", network, addr)
},
ConnectDone: func(network, addr string, err error) {
fmt.Printf("Conn done: %s %s\n", network, addr)
},
}
req = req.WithContext(httptrace.WithClientTrace(req.Context(), trace))
client := http.Client{
Timeout: time.Millisecond * 250,
}
if _, err := client.Do(req); err != nil {
log.Fatal(err)
}
}
-----------------------
Output:
Get Conn: deelay.me:443
Conn start: tcp 167.99.174.142:443
Conn done: tcp 167.99.174.142:443
*Got Conn: 192.168.0.103:52450*
2020/10/14 14:11:04 Get "https://deelay.me/300/https://google.com": context
deadline exceeded (Client.Timeout exceeded while awaiting headers)
--------------------
If you play with the timeout value and set the timeout on the client to be
too small, GotConn is not hit because the timeout triggers before acquiring
a connection for example due to a TLS handshake delay etc.
>>> I'm not seeing anything in the httptrace library for for a
"FailedConnInfo" equivalent to "GotConnInfo." Am I overlooking something?
the GotConn documentation says that for errors look for the error returned
by the roundtrip call
On Tuesday, October 13, 2020 at 12:18:01 PM UTC-7 [email protected] wrote:
> One problem came up. Sorry for the false positive.
>
> How can I capture this information for a request which failed to connect?
>
> If a connection times out with, say "context deadline exceeded
> (Client.Timeout exceeded while awaiting headers)", the local outgoing port
> is not captured.
>
> I'm not seeing anything in the httptrace library for for a
> "FailedConnInfo" equivalent to "GotConnInfo." Am I overlooking something?
>
> On Thursday, October 8, 2020 at 1:12:39 PM UTC-5 [email protected] wrote:
>
>> Hi Ryan,
>>
>> You can get it via httptrace (https://blog.golang.org/http-tracing)
>>
>> Example:
>> req, _ := http.NewRequest("GET", "http://example.com";, nil)
>> trace := &httptrace.ClientTrace{
>> GotConn: func(connInfo httptrace.GotConnInfo) {
>> fmt.Printf("Got Conn: %s\n",
>> connInfo.Conn.LocalAddr().String()) <------------------------- This has the
>> local outgoing port
>> },
>> }
>> req = req.WithContext(httptrace.WithClientTrace(req.Context(), trace))
>> if _, err := http.DefaultTransport.RoundTrip(req); err != nil {
>> log.Fatal(err)
>> }
>>
>>
>> On Wednesday, October 7, 2020 at 9:09:54 AM UTC-7 [email protected]
>> wrote:
>>
>>> Is it possible to capture the outgoing port for a given HTTP request?
>>>
>>> I'm using a knockoff of ab that I wrote in go to send repeated requests
>>> to a given web service. Sometimes we get an error and I want to look at a
>>> packet trace of it. The problem is it's really hard to find one failed
>>> request in 1,000 in a tcp dump. If I can see the source port, that would
>>> help me narrow it down.
>>>
>>> The code I'm doing is effectively this (forgive any typos, this is a
>>> quick & dirty recopy, not a cut & paste):
>>>
>>> tlsConfig := &tls.Config{
>>> InsecureSkipVerify: true,
>>> }
>>>
>>> transport := &http.Transport{
>>> DisableKeepAlives: true,
>>> TLSClientCOnfig: tlsCOnfig,
>>> ResponseHeaderTimeout: time.Duration(headerTimeout) * time.Second,
>>> }
>>>
>>> client := &http.Client{
>>> Timeout: time.Duration(timeOut) * time.second,
>>> Transport: transport,
>>> }
>>>
>>> response, err :=client.Get(*targetURL) // How can I capture the
>>> outgoing port from this?
>>>
>>
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