func WithClientTrace(ctxcontext.Context, trace *ClientTrace)context.Context

type ClientTrace struct {// GetConn is called before a connection is created or// retrieved from an idle pool. The hostPort is the// "host:port" of the target or proxy. GetConn is called even// if there's already an idle cached connection available.GetConn func(hostPortstring)// GotConn is called after a successful connection is// obtained. There is no hook for failure to obtain a// connection; instead, use the error from// Transport.RoundTrip.GotConn func(GotConnInfo)// PutIdleConn is called when the connection is returned to// the idle pool. If err is nil, the connection was// successfully returned to the idle pool. If err is non-nil,// it describes why not. PutIdleConn is not called if// connection reuse is disabled via Transport.DisableKeepAlives.// PutIdleConn is called before the caller's Response.Body.Close// call returns.// For HTTP/2, this hook is not currently used.PutIdleConn func(errerror)// GotFirstResponseByte is called when the first byte of the response// headers is available.GotFirstResponseByte func()// Got100Continue is called if the server replies with a "100// Continue" response.Got100Continue func()// Got1xxResponse is called for each 1xx informational response header// returned before the final non-1xx response. Got1xxResponse is called// for "100 Continue" responses, even if Got100Continue is also defined.// If it returns an error, the client request is aborted with that error value.Got1xxResponse func(codeint, headertextproto.MIMEHeader)error// DNSStart is called when a DNS lookup begins.DNSStart func(DNSStartInfo)// DNSDone is called when a DNS lookup ends.DNSDone func(DNSDoneInfo)// ConnectStart is called when a new connection's Dial begins.// If net.Dialer.DualStack (IPv6 "Happy Eyeballs") support is// enabled, this may be called multiple times.ConnectStart func(network, addrstring)// ConnectDone is called when a new connection's Dial// completes. The provided err indicates whether the// connection completed successfully.// If net.Dialer.DualStack ("Happy Eyeballs") support is// enabled, this may be called multiple times.ConnectDone func(network, addrstring, errerror)// TLSHandshakeStart is called when the TLS handshake is started. When// connecting to an HTTPS site via an HTTP proxy, the handshake happens// after the CONNECT request is processed by the proxy.TLSHandshakeStart func()// TLSHandshakeDone is called after the TLS handshake with either the// successful handshake's connection state, or a non-nil error on handshake// failure.TLSHandshakeDone func(tls.ConnectionState,error)// WroteHeaderField is called after the Transport has written// each request header. At the time of this call the values// might be buffered and not yet written to the network.WroteHeaderField func(keystring, value []string)// WroteHeaders is called after the Transport has written// all request headers.WroteHeaders func()// Wait100Continue is called if the Request specified// "Expect: 100-continue" and the Transport has written the// request headers but is waiting for "100 Continue" from the// server before writing the request body.Wait100Continue func()// WroteRequest is called with the result of writing the// request and any body. It may be called multiple times// in the case of retried requests.WroteRequest func(WroteRequestInfo)}

funcContextClientTrace¶

func ContextClientTrace(ctxcontext.Context) *ClientTrace

ContextClientTrace returns theClientTrace associated with theprovided context. If none, it returns nil.

type DNSDoneInfo struct {// Addrs are the IPv4 and/or IPv6 addresses found in the DNS// lookup. The contents of the slice should not be mutated.Addrs []net.IPAddr// Err is any error that occurred during the DNS lookup.Errerror// Coalesced is whether the Addrs were shared with another// caller who was doing the same DNS lookup concurrently.Coalescedbool}

type DNSStartInfo struct {Hoststring}

type GotConnInfo struct {// Conn is the connection that was obtained. It is owned by// the http.Transport and should not be read, written or// closed by users of ClientTrace.Connnet.Conn// Reused is whether this connection has been previously// used for another HTTP request.Reusedbool// WasIdle is whether this connection was obtained from an// idle pool.WasIdlebool// IdleTime reports how long the connection was previously// idle, if WasIdle is true.IdleTimetime.Duration}

type WroteRequestInfo struct {// Err is any error encountered while writing the Request.Errerror}