# syntax=docker/dockerfile:experimental

############################

# STEP 1 build executable binary

############################

# FROM golang:alpine AS builder

FROM --platform=$BUILDPLATFORM golang:1.17 as builder

ARG VERSION

ARG COMMIT_HASH

ARG BUILD_DATE

ARG TARGETOS

ARG TARGETARCH

RUN update-ca-certificates

# RUN apk update && apk add --no-cache git

# Create appuser.

ENV USER=appuser

ENV UID=10001

# See https://stackoverflow.com/a/55757473/12429735RUN

RUN adduser \

--disabled-password \

--gecos "" \

--home "/nonexistent" \

--shell "/sbin/nologin" \

--no-create-home \

--uid "${UID}" \

"${USER}"

WORKDIR $GOPATH/src/github.com/zinclabs/zinc/

COPY . .

# Fetch dependencies.

# Using go get.

RUN go get -d -v

# Using go mod.

# RUN go mod download

# RUN go mod verify

# Build the binary.

# to tackle error standard_init_linux.go:207: exec user process caused "no such file or directory" set CGO_ENABLED=0.

# CGO_ENABLED=0 builds a statically linked binary.

# docs for -ldflags at https://pkg.go.dev/cmd/link

# -w : Omit the DWARF symbol table.

# -s : Omit the symbol table and debug information.

# Omit the symbol table and debug information will reduce the binary size.

# RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -ldflags="-w -s" -o zinc cmd/zinc/main.go

ENV VERSION=$VERSION

ENV COMMIT_HASH=$COMMIT_HASH

ENV BUILD_DATE=$BUILD_DATE

RUN CGO_ENABLED=0 GOOS=$TARGETOS GOARCH=$TARGETARCH go build -ldflags="-s -w -X github.com/zinclabs/zinc/pkg/meta/v1.Version=${VERSION} -X github.com/zinclabs/zinc/pkg/meta/v1.CommitHash=${COMMIT_HASH} -X github.com/zinclabs/zinc/pkg/meta/v1.BuildDate=${BUILD_DATE}" -o zinc cmd/zinc/main.go

############################

# STEP 2 build a small image

############################

# FROM public.ecr.aws/lts/ubuntu:latest

FROM scratch

# Import the user and group files from the builder.

COPY --from=builder /etc/passwd /etc/passwd

COPY --from=builder /etc/group /etc/group

# Copy the ssl certificates

COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/ca-certificates.crt

# Copy our static executable.

COPY --from=builder /go/src/github.com/zinclabs/zinc/zinc /go/bin/zinc

# Use an unprivileged user.

USER appuser:appuser

# Port on which the service will be exposed.

EXPOSE 4080

# Run the zinc binary.

ENTRYPOINT ["/go/bin/zinc"]