Docker ctor

FROM golang:alpine as builder
# prepare go env
ENV GOPATH /go
ENV NAME cloud-torrent
ENV PACKAGE github.com/jpillora/$NAME
ENV PACKAGE_DIR $GOPATH/src/$PACKAGE
ENV PATH $GOPATH/bin:/usr/local/go/bin:$PATH
ENV CGO_ENABLED 0
ENV AUTH 'admin:admin'

RUN apk upgrade --update && apk add --no-cache ca-certificates bash gcc musl-dev openssl git go curl
RUN git clone https://$PACKAGE.git $PACKAGE_DIR
RUN cd $PACKAGE_DIR && go build -ldflags "-X main.VERSION=$(git describe --abbrev=0 --tags)" -o /usr/local/bin/$NAME

FROM alpine:latest
RUN apk upgrade --update && apk add --no-cache ca-certificates openssl curl
COPY --from=builder /usr/local/bin/$NAME /
WORKDIR downloads
RUN ls -a
ENTRYPOINT ["/bin/sh", "-c","cloud-torrent","--auth","$AUTH"]