# Build stage: compile a static binary so the runtime image can be minimal.
FROM golang:1.25-alpine AS build
WORKDIR /src
COPY go.mod go.sum ./
RUN go mod download
COPY . .
RUN CGO_ENABLED=0 go build -trimpath -o /ultrashorty .

# Runtime stage.
FROM alpine:3.20
RUN adduser -D -u 10001 ultrashorty
USER ultrashorty
COPY --from=build /ultrashorty /usr/local/bin/ultrashorty
# The redirects CSV is supplied at deploy time (bind mount / config), and
# --host must be set to 0.0.0.0 to accept connections from outside the
# container -- ultrashorty defaults to localhost. Example:
#   docker run -v ./redirects.csv:/redirects.csv <image> --host 0.0.0.0 /redirects.csv
EXPOSE 4000
ENTRYPOINT ["ultrashorty"]