Merge pull request #7 from mailgun/thrawn/develop

Fix HTTPPoolOptions.Transport

CHANGELOG

@@ -4,18 +4,19 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [2.0.0-rc.2] - 2019-06-03
+## [2.0.0-rc.3] - 2019-06-03
 ### Changes
 * Now using golang standard `context.Context` instead of `groupcache.Context`.
 * HTTP requests made by `httpGetter` now respect `context.Context` done.
 * Moved `HTTPPool` config `Context` and `Transport` to `HTTPPoolOptions` for consist configuration.
-* Now Associating the transport with peer `httpGetter` so we take advantage of
-  connection reuse.  This lowers the impact on DNS and improves performance for
-  high request volume low latency applications.
+* Now Associating the transport with peer `httpGetter` so there is no need to
+  call `Transport` function for each request.
 * Now always populating the hotcache. A more complex algorithm is unnecessary
   when the LRU cache will ensure the most used values remain in the cache. The
   evict code ensures the hotcache does not overcrowd the maincache.
 * Changed import paths to /v2 in accordance with go modules rules
+* Fixed Issue where `DefaultTransport` was always used even if `Transport` was
+  specified by the user.
 
 ## [1.3.0] - 2019-05-23
 ### Added

http.go

@@ -124,7 +124,10 @@ func (p *HTTPPool) Set(peers ...string) {
 	p.peers.Add(peers...)
 	p.httpGetters = make(map[string]*httpGetter, len(peers))
 	for _, peer := range peers {
-		p.httpGetters[peer] = &httpGetter{getTransport: p.opts.Transport, baseURL: peer + p.opts.BasePath}
+		p.httpGetters[peer] = &httpGetter{
+			getTransport: p.opts.Transport,
+			baseURL:      peer + p.opts.BasePath,
+		}
 	}
 }
 
@@ -242,15 +245,14 @@ func (h *httpGetter) makeRequest(ctx context.Context, method string, in *pb.GetR
 	// Pass along the context to the RoundTripper
 	req = req.WithContext(ctx)
 
-	// Associate the transport with this peer so we take advantage of connection reuse.
+	// Associate the transport with this peer so we don't need to
+	// call getTransport() every time a request is made.
 	if h.transport == nil {
 		if h.getTransport != nil {
 			h.transport = h.getTransport(ctx)
+		} else {
+			h.transport = http.DefaultTransport
 		}
-		// Ensure we have a copy of the default transport and not just a reference.
-		tr := http.DefaultTransport.(*http.Transport)
-		trCopy := http.Transport(*tr)
-		h.transport = &trCopy
 	}
 
 	res, err := h.transport.RoundTrip(req)