Dockerfile

############################
# Multi-stage build for StackScout
# 1. Builder: compile static Go binary
# 2. Runner: minimal image with CA certificates
############################

# syntax=docker/dockerfile:1.7
ARG GO_VERSION=1.24.9
ARG ALPINE_VERSION=3.22

############################
# Builder Stage
############################
FROM golang:${GO_VERSION}-alpine${ALPINE_VERSION} AS builder
WORKDIR /src

RUN apk add --no-cache git ca-certificates build-base

COPY go.mod go.sum ./
RUN --mount=type=cache,target=/go/pkg/mod \
    go mod download

COPY . .

# Set environment for static build (CGO disabled)
ENV CGO_ENABLED=0 GOOS=linux GOARCH=amd64
RUN --mount=type=cache,target=/go/pkg/mod \
    --mount=type=cache,target=/root/.cache/go-build \
    go build -trimpath -ldflags "-s -w" -o /out/stackscout ./cmd/stackscout

############################
# Runtime Stage
############################
FROM gcr.io/distroless/static AS runtime
LABEL org.opencontainers.image.source="https://github.com/ItsEcholot/StackScout" \
      org.opencontainers.image.title="StackScout" \
      org.opencontainers.image.description="StackScout monitors your containerized services for available image updates and reports metrics to InfluxDB." \
      org.opencontainers.image.licenses="MIT"

WORKDIR /app
COPY --from=builder /out/stackscout /app/stackscout

# Expose no ports (service pushes metrics externally)
ENTRYPOINT ["/app/stackscout"]