Skip http proxy localhost for docker env

cmd/minikube/cmd/start.go

@@ -688,6 +688,12 @@ func generateCfgFromFlags(cmd *cobra.Command, k8sVersion string) (cfg.Config, er
 					// convert https_proxy to HTTPS_PROXY for linux
 					// TODO (@medyagh): if user has both http_proxy & HTTPS_PROXY set merge them.
 					k = strings.ToUpper(k)
+					if k == "HTTP_PROXY" || k == "HTTPS_PROXY" {
+						if strings.HasPrefix(v, "localhost") || strings.HasPrefix(v, "127.0") {
+							out.WarningT("Not passing {{.name}}={{.value}} to docker env.", out.V{"name": k, "value": v})
+							continue
+						}
+					}
 					dockerEnv = append(dockerEnv, fmt.Sprintf("%s=%s", k, v))
 				}
 			}

cmd/minikube/cmd/start_test.go

@@ -17,7 +17,12 @@ limitations under the License.
 package cmd
 
 import (
+	"os"
 	"testing"
+
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+	"k8s.io/minikube/pkg/minikube/constants"
 )
 
 func Test_extractVMDriverVersion(t *testing.T) {
@@ -43,3 +48,58 @@ func Test_extractVMDriverVersion(t *testing.T) {
 		t.Errorf("Expected version: %s, got: %s", expectedVersion, v)
 	}
 }
+
+func TestGenerateCfgFromFlagsHTTPProxyHandling(t *testing.T) {
+	viper.SetDefault(memory, constants.DefaultMemorySize)
+	viper.SetDefault(humanReadableDiskSize, constants.DefaultDiskSize)
+	originalEnv := os.Getenv("HTTP_PROXY")
+	defer func() {
+		err := os.Setenv("HTTP_PROXY", originalEnv)
+		if err != nil {
+			t.Fatalf("Error reverting env HTTP_PROXY to it's original value. Got err: %s", err)
+		}
+	}()
+	k8sVersion := constants.NewestKubernetesVersion
+	var tests = []struct {
+		description  string
+		proxy        string
+		proxyIgnored bool
+	}{
+
+		{
+			description:  "http_proxy=127.0.0.1:3128",
+			proxy:        "127.0.0.1:3128",
+			proxyIgnored: true,
+		},
+		{
+			description:  "http_proxy=localhost:3128",
+			proxy:        "localhost:3128",
+			proxyIgnored: true,
+		},
+		{
+			description: "http_proxy=1.2.3.4:3128",
+			proxy:       "1.2.3.4:3128",
+		},
+		{
+			description: "no http_proxy",
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.description, func(t *testing.T) {
+			cmd := &cobra.Command{}
+			if err := os.Setenv("HTTP_PROXY", test.proxy); err != nil {
+				t.Fatalf("Unexpected error setting HTTP_PROXY: %v", err)
+			}
+			config, err := generateCfgFromFlags(cmd, k8sVersion)
+			if err != nil {
+				t.Fatalf("Got unexpected error %v during config generation", err)
+			}
+			// ignored proxy should not be in config
+			for _, v := range config.MachineConfig.DockerEnv {
+				if v == test.proxy && test.proxyIgnored {
+					t.Fatalf("Value %v not expected in dockerEnv but occurred", v)
+				}
+			}
+		})
+	}
+}