# Built following https://medium.com/@chemidy/create-the-smallest-and-secured-golang-docker-image-based-on-scratch-4752223b7324

# STEP 1 build executable binary
FROM golang:alpine as builder

# BUILD_DATE and VCS_REF are immaterial, since this is a 2-stage build, but our build
# hook won't work unless we specify the args
ARG BUILD_DATE
ARG VCS_REF

# Install SSL ca certificates
RUN apk update && apk add git && apk add ca-certificates
# Create appuser
RUN adduser -D -g '' appuser
COPY . $GOPATH/src/mypackage/myapp/
WORKDIR $GOPATH/src/mypackage/myapp/
#get dependancies
RUN go get -d -v
#build the binary
RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -a -installsuffix cgo -ldflags="-w -s" -o /go/bin/alertmanager-discord


# STEP 2 build a small image
# start from scratch
FROM scratch
# Now we DO need these, for the auto-labeling of the image
ARG BUILD_DATE
ARG VCS_REF

# Good docker practice, plus we get microbadger badges
LABEL org.label-schema.build-date=$BUILD_DATE \
      org.label-schema.vcs-url="https://github.com/funkypenguin/alertmanager-discord.git" \
      org.label-schema.vcs-ref=$VCS_REF \
      org.label-schema.schema-version="2.2-r1"
      
COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
COPY --from=builder /etc/passwd /etc/passwd
# Copy our static executable
COPY --from=builder /go/bin/alertmanager-discord /go/bin/alertmanager-discord

EXPOSE 9094
USER appuser
ENTRYPOINT ["/go/bin/alertmanager-discord"]