allowing proxy-settings to be passed in for Docker

This changes will allow proxy settings to be passed in for docker
as well as Env variable in Dockerfile.

simply invoke 'make image HTTP_PROXY=http://whateverhost:port'.

Change-Id: I4264b2a96d86a6feedee1b21a9f1bac8e74c8fc5

Dockerfile

@@ -2,6 +2,8 @@ FROM centos:centos7
 
 ADD . /usr/src/sriov-network-device-plugin
 
+ENV HTTP_PROXY $http_proxy
+ENV HTTPS_PROXY $https_proxy
 ENV INSTALL_PKGS "git golang make"
 RUN yum install -y $INSTALL_PKGS && \
     rpm -V $INSTALL_PKGS && \

Makefile

@@ -16,10 +16,19 @@ TESTPKGS = $(shell env GOPATH=$(GOPATH) $(GO) list -f '{{ if or .TestGoFiles .XT
 
 export GOPATH
 export GOBIN
+
 # Docker
 IMAGEDIR=$(BASE)/images
 DOCKERFILE=$(CURDIR)/Dockerfile
 TAG=nfvpe/sriov-device-plugin
+# Accept proxy settings for docker 
+DOCKERARGS=
+ifdef HTTP_PROXY
+	DOCKERARGS += --build-arg http_proxy=$(HTTP_PROXY)
+endif
+ifdef HTTPS_PROXY
+	DOCKERARGS += --build-arg https_proxy=$(HTTPS_PROXY)
+endif
 
 # Go tools
 GO      = go
@@ -137,11 +146,7 @@ vendor: glide.lock | $(BASE) ; $(info  retrieving dependencies...)
 # To pass proxy for Docker invoke it as 'make image HTTP_POXY=http://192.168.0.1:8080'
 .PHONY: image
 image: | $(BASE) ; $(info Building Docker image...)
-ifdef HTTP_PROXY
-	@docker build -t $(TAG) -f $(DOCKERFILE)  $(CURDIR) --build-arg http_proxy=$(HTTP_PROXY)
-else
-	@docker build -t $(TAG) -f $(DOCKERFILE)  $(CURDIR) 
-endif
+	@docker build -t $(TAG) -f $(DOCKERFILE)  $(CURDIR) $(DOCKERARGS)
 
 # Misc