libgit2: Improve HTTP redirection observability

Git repositories may be redirected to different URLs
when they are accessed via HTTP. The two most obvious
scenarios are from HTTP to HTTPS and when the .git suffix
is missing.
By improving the logging on this process users can identify
changes required to their GitRepository objects.

Signed-off-by: Paulo Gomes <paulo.gomes@weave.works>

pkg/git/libgit2/managed/http.go

@@ -165,7 +165,7 @@ func (t *httpSmartSubtransport) Action(transportOptionsURL string, action git2go
 		// Therefore, on the initial GET operation we update the target URL to include the
 		// new target, so the subsequent actions include the correct target URL.
 		// Example of this is trying to access a Git repository without the .git suffix.
-		if req.Response != nil && req.Response.StatusCode == http.StatusMovedPermanently {
+		if req.Response != nil {
 			if newURL, err := req.Response.Location(); err == nil && newURL != nil {
 				if strings.EqualFold(newURL.Host, req.URL.Host) && strings.EqualFold(newURL.Port(), req.URL.Port()) {
 					opts, _ := getTransportOptions(transportOptionsURL)
@@ -175,6 +175,9 @@ func (t *httpSmartSubtransport) Action(transportOptionsURL string, action git2go
 
 					opts.TargetURL = trimActionSuffix(newURL.String())
 					AddTransportOptions(transportOptionsURL, *opts)
+
+					debugLog.Info("[http]: server responded with redirect",
+						"newURL", opts.TargetURL, "StatusCode", req.Response.StatusCode)
 				}
 			}
 		}
@@ -419,7 +422,6 @@ func (self *httpSmartSubtransportStream) sendRequest() error {
 				return err
 			}
 
-			traceLog.Info("[http]: POST redirect", "URL", self.req.URL)
 			continue
 		}
 
@@ -435,7 +437,7 @@ func (self *httpSmartSubtransportStream) sendRequest() error {
 			return err
 		}
 
-		return fmt.Errorf("Unhandled HTTP error %s", resp.Status)
+		return fmt.Errorf("unhandled HTTP error %s", resp.Status)
 	}
 
 	self.resp = resp