Add context to Call() signature

This allows to configure a timeout per call as opposed to a global
timeout that's currently supported. This is a breaking change.

soap/soap.go

@@ -2,6 +2,7 @@ package soap
 
 import (
 	"bytes"
+	"context"
 	"crypto/tls"
 	"encoding/xml"
 	"io/ioutil"
@@ -229,7 +230,7 @@ func (s *Client) AddHeader(header interface{}) {
 }
 
 // Call performs HTTP POST request
-func (s *Client) Call(soapAction string, request, response interface{}) error {
+func (s *Client) Call(ctx context.Context, soapAction string, request, response interface{}) error {
 	envelope := SOAPEnvelope{}
 
 	if s.headers != nil && len(s.headers) > 0 {
@@ -257,6 +258,7 @@ func (s *Client) Call(soapAction string, request, response interface{}) error {
 		req.SetBasicAuth(s.opts.auth.Login, s.opts.auth.Password)
 	}
 
+	req.WithContext(ctx)
 	req.Header.Add("Content-Type", "text/xml; charset=\"utf-8\"")
 	req.Header.Add("SOAPAction", soapAction)
 	req.Header.Set("User-Agent", "gowsdl/0.1")
@@ -269,8 +271,9 @@ func (s *Client) Call(soapAction string, request, response interface{}) error {
 
 	tr := &http.Transport{
 		TLSClientConfig: s.opts.tlsCfg,
-		Dial: func(network, addr string) (net.Conn, error) {
-			return net.DialTimeout(network, addr, s.opts.timeout)
+		DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
+			d := net.Dialer{Timeout: s.opts.timeout}
+			return d.DialContext(ctx, network, addr)
 		},
 		TLSHandshakeTimeout: s.opts.tlshshaketimeout,
 	}