Dockerfile

# syntax=docker/dockerfile:1

################################################################################
# Create a stage for building the application.

ARG RUST_VERSION=latest
ARG APP_NAME=rsomhap

FROM rust:${RUST_VERSION} AS builder
ARG APP_NAME

WORKDIR /usr/src/app

# Build the application.
# Leverage a cache mount to /usr/local/cargo/registry/
# for downloaded dependencies and a cache mount to /app/target/ for 
# compiled dependencies which will speed up subsequent builds.
# Leverage a bind mount to the src directory to avoid having to copy the
# source code into the container. Once built, copy the executable to an
# output directory before the cache mounted /app/target is unmounted.
RUN --mount=type=bind,source=src,target=src \
    --mount=type=bind,source=Cargo.toml,target=Cargo.toml \
    --mount=type=cache,target=/app/target/ \
    --mount=type=cache,target=/usr/local/cargo/registry/ \
    <<EOF
set -e
cargo build --release
EOF

################################################################################
# Create a new stage for running the application that contains the minimal
# runtime dependencies for the application. This often uses a different base
# image from the build stage where the necessary files are copied from the build
# stage.
FROM debian:bookworm-slim AS final
ARG APP_NAME

WORKDIR /usr/src/app

# Create a non-privileged user that the app will run under.
# See https://docs.docker.com/develop/develop-images/dockerfile_best-practices/#user
ARG UID=10001
RUN adduser \
    --disabled-password \
    --gecos "" \
    --home "/nonexistent" \
    --shell "/sbin/nologin" \
    --no-create-home \
    --uid "${UID}" \
    appuser
USER appuser

# Copy the executable from the "build" stage.
COPY --from=builder /usr/src/app/target/release/${APP_NAME} .

# Copy the necessary files.
COPY templates ./templates
COPY static ./static
COPY config.toml ./

# Expose the port that the application listens on.
EXPOSE 5299

# What the container should run when it is started.
CMD ["./rsomhap"]