Dockerfile.scratch

# syntax=docker/dockerfile:1@sha256:b6afd42430b15f2d2a4c5a02b919e98a525b785b1aaff16747d2f623364e39b6
##### Stage 1: Build (pinned & minimal, multi-arch) #####
FROM --platform=$BUILDPLATFORM golang@sha256:c2a1f7b2095d046ae14b286b18413a05bb82c9bca9b25fe7ff5efef0f0826166 AS build
#1.26.2-alpine

WORKDIR /src

ENV GOFLAGS="-mod=readonly" \
    GOMODCACHE=/go/pkg/mod \
    GOCACHE=/root/.cache/go-build \
    CGO_ENABLED=0

RUN apk add --no-cache ca-certificates tzdata

COPY go.mod go.sum ./
RUN go mod download

COPY . .

ARG TARGETOS
ARG TARGETARCH
ARG TARGETVARIANT
ARG VERSION=0.0.0
ARG BUILD_DATE="2025-01-01T00:00:00Z"
ARG GIT_REVISION="0000000000000000000000000000000000000000"

# Build the main controller binary
RUN --mount=type=cache,target=/go/pkg/mod \
    --mount=type=cache,target=/root/.cache/go-build \
    set -eux; \
    export GOOS="${TARGETOS:-linux}"; \
    export GOARCH="${TARGETARCH}"; \
    if [ -n "${TARGETVARIANT:-}" ]; then export GOARM="${TARGETVARIANT#v}"; fi; \
    go build \
      -trimpath \
      -ldflags="-s -w \
        -X 'pangolin-kube-controller/internal/version.Version=${VERSION}' \
        -X 'pangolin-kube-controller/internal/version.Commit=${GIT_REVISION}' \
        -X 'pangolin-kube-controller/internal/version.Date=${BUILD_DATE}'" \
      -o /out/pangolin-kube-controller \
      ./cmd/controller; \
    go build \
      -trimpath \
      -o /out/healthcheck \
      ./cmd/healthcheck

##### Stage 2: Scratch Runtime #####
FROM scratch

ARG VERSION=0.0.0
ARG BUILD_DATE="2025-01-01T00:00:00Z"
ARG GIT_REVISION="0000000000000000000000000000000000000000"

LABEL org.opencontainers.image.title="Pangolin Kubernetes Controller" \
    org.opencontainers.image.description="Synchronises Pangolin Traefik configuration into K8S Traefik CRDs" \
    org.opencontainers.image.vendor="fosrl" \
    org.opencontainers.image.version="${VERSION}" \
    org.opencontainers.image.source="https://github.com/fosrl/pangolin-kube-controller" \
    org.opencontainers.image.licenses="AGPL-3.0-only" \
    org.opencontainers.image.revision="${GIT_REVISION}" \
    org.opencontainers.image.created="${BUILD_DATE}" \
    org.opencontainers.image.documentation="https://github.com/fosrl/pangolin-kube-controller" \
    org.opencontainers.image.authors="fosrl"

WORKDIR /

# Copy runtime dependencies
COPY --from=build /etc/ssl/certs/ /etc/ssl/certs/
COPY --from=build /usr/share/zoneinfo/ /usr/share/zoneinfo/
COPY --from=build /out/pangolin-kube-controller /controller
COPY --from=build /out/healthcheck /healthcheck

# Make healthcheck port and path configurable, with defaults
ENV HEALTHCHECK_PORT=9090 \
    HEALTHCHECK_PATH=/health/ready

USER 65532:65532

HEALTHCHECK --interval=30s --timeout=3s --start-period=10s --retries=3 \
    CMD ["/healthcheck"]

ENTRYPOINT ["/controller"]