Task fixing slim dockerfile (#1750)

* fixing our slim image dockerfile to be built with modules and use the golang proxy

* simplifying env expressions

* moving to use GOPROXY by default

* enabling proxy for the tests

Dockerfile

@@ -1,4 +1,5 @@
 FROM gobuffalo/buffalo:latest
+ENV GOPROXY=https://proxy.golang.org
 
 ARG CODECOV_TOKEN
 

Dockerfile.build

@@ -1,6 +1,8 @@
 FROM golang:latest
 EXPOSE 3000
 ENV BP=$GOPATH/src/github.com/gobuffalo/buffalo
+ENV GOPROXY=https://proxy.golang.org
+
 RUN go version
 
 RUN curl -sL https://deb.nodesource.com/setup_8.x | bash \

Dockerfile.slim.build

@@ -1,6 +1,8 @@
 FROM golang:alpine
 EXPOSE 3000
 ENV BP=$GOPATH/src/github.com/gobuffalo/buffalo
+ENV GOPROXY=https://proxy.golang.org 
+
 RUN apk add --no-cache --upgrade apk-tools \
 && apk add --no-cache bash curl openssl git build-base nodejs npm postgresql libpq postgresql-contrib sqlite sqlite-dev mysql-client vim
 
@@ -34,7 +36,9 @@ RUN rm -rfv $BP && mkdir -p $BP
 WORKDIR $BP
 
 COPY . .
+ENV GO111MODULE=on
 RUN make deps && make install
+ENV GO111MODULE=
 
 RUN buffalo version
 

azure-pipelines.yml

@@ -1,6 +1,7 @@
 variables:
   GOBIN:  "$(GOPATH)/bin" # Go binaries path
   GOPATH: "$(system.defaultWorkingDirectory)/gopath" # Go workspace path
+  GOPROXY: "https://proxy.golang.org"
   modulePath: "$(GOPATH)/src/github.com/$(build.repository.name)" # Path to the module"s code
 
 jobs: