Support for setting custom Transport in S3Client configuration

cmd/client-s3.go

@@ -137,50 +137,55 @@ func newFactory() func(config *Config) (Client, *probe.Error) {
 				creds = credentials.NewStaticV2(config.AccessKey, config.SecretKey, "")
 			}
 
-			tr := &http.Transport{
-				Proxy: http.ProxyFromEnvironment,
-				DialContext: (&net.Dialer{
-					Timeout:   10 * time.Second,
-					KeepAlive: 15 * time.Second,
-				}).DialContext,
-				MaxIdleConnsPerHost:   256,
-				IdleConnTimeout:       90 * time.Second,
-				TLSHandshakeTimeout:   10 * time.Second,
-				ExpectContinueTimeout: 10 * time.Second,
-				// Set this value so that the underlying transport round-tripper
-				// doesn't try to auto decode the body of objects with
-				// content-encoding set to `gzip`.
-				//
-				// Refer:
-				//    https://golang.org/src/net/http/transport.go?h=roundTrip#L1843
-				DisableCompression: true,
-			}
+			var transport http.RoundTripper
 
-			if useTLS {
-				// Keep TLS config.
-				tlsConfig := &tls.Config{
-					RootCAs: globalRootCAs,
-					// Can't use SSLv3 because of POODLE and BEAST
-					// Can't use TLSv1.0 because of POODLE and BEAST using CBC cipher
-					// Can't use TLSv1.1 because of RC4 cipher usage
-					MinVersion: tls.VersionTLS12,
+			if config.Transport != nil {
+				transport = config.Transport
+			} else {
+				tr := &http.Transport{
+					Proxy: http.ProxyFromEnvironment,
+					DialContext: (&net.Dialer{
+						Timeout:   10 * time.Second,
+						KeepAlive: 15 * time.Second,
+					}).DialContext,
+					MaxIdleConnsPerHost:   256,
+					IdleConnTimeout:       90 * time.Second,
+					TLSHandshakeTimeout:   10 * time.Second,
+					ExpectContinueTimeout: 10 * time.Second,
+					// Set this value so that the underlying transport round-tripper
+					// doesn't try to auto decode the body of objects with
+					// content-encoding set to `gzip`.
+					//
+					// Refer:
+					//    https://golang.org/src/net/http/transport.go?h=roundTrip#L1843
+					DisableCompression: true,
 				}
-				if config.Insecure {
-					tlsConfig.InsecureSkipVerify = true
+				if useTLS {
+					// Keep TLS config.
+					tlsConfig := &tls.Config{
+						RootCAs: globalRootCAs,
+						// Can't use SSLv3 because of POODLE and BEAST
+						// Can't use TLSv1.0 because of POODLE and BEAST using CBC cipher
+						// Can't use TLSv1.1 because of RC4 cipher usage
+						MinVersion: tls.VersionTLS12,
+					}
+					if config.Insecure {
+						tlsConfig.InsecureSkipVerify = true
+					}
+					tr.TLSClientConfig = tlsConfig
+
+					// Because we create a custom TLSClientConfig, we have to opt-in to HTTP/2.
+					// See https://github.com/golang/go/issues/14275
+					//
+					// TODO: Enable http2.0 when upstream issues related to HTTP/2 are fixed.
+					//
+					// if e = http2.ConfigureTransport(tr); e != nil {
+					// 	return nil, probe.NewError(e)
+					// }
 				}
-				tr.TLSClientConfig = tlsConfig
-
-				// Because we create a custom TLSClientConfig, we have to opt-in to HTTP/2.
-				// See https://github.com/golang/go/issues/14275
-				//
-				// TODO: Enable http2.0 when upstream issues related to HTTP/2 are fixed.
-				//
-				// if e = http2.ConfigureTransport(tr); e != nil {
-				// 	return nil, probe.NewError(e)
-				// }
+				transport = tr
 			}
 
-			var transport http.RoundTripper = tr
 			if config.Debug {
 				if strings.EqualFold(config.Signature, "S3v4") {
 					transport = httptracer.GetNewTraceTransport(newTraceV4(), transport)

cmd/client.go

@@ -19,6 +19,7 @@ package cmd
 import (
 	"context"
 	"io"
+	"net/http"
 	"os"
 	"time"
 
@@ -194,6 +195,7 @@ type Config struct {
 	Debug        bool
 	Insecure     bool
 	Lookup       minio.BucketLookupType
+	Transport    *http.Transport
 }
 
 // SelectObjectOpts - opts entered for select API