decrease docker image size

Dockerfile

@@ -1,21 +1,57 @@
-FROM rustlang/rust:nightly-bullseye
-
-WORKDIR /app
-
-COPY ./. .
+####################################################################################################
+## Builder
+####################################################################################################
+FROM rustlang/rust:nightly-bullseye AS builder
+RUN apt update && apt install -y libssl-dev pkg-config libz-dev libcurl4 postgresql
+RUN update-ca-certificates
+
+# Create appuser
+ENV USER=bot
+ENV UID=10001
+
+RUN adduser \
+    --disabled-password \
+    --gecos "" \
+    --home "/nonexistent" \
+    --shell "/sbin/nologin" \
+    --no-create-home \
+    --uid "${UID}" \
+    "${USER}"
+
+WORKDIR /bot
+
+COPY ./ .
 
 RUN cargo install diesel_cli --no-default-features --features postgres
 
 RUN cargo build --release
 
-RUN cp ./target/release/cleaner ./cleaner
+####################################################################################################
+## Final image
+####################################################################################################
+FROM debian:bullseye-slim
+
+RUN apt update && apt install -y postgresql
+
+# Import from builder.
+COPY --from=builder /etc/passwd /etc/passwd
+COPY --from=builder /etc/group /etc/group
+
+WORKDIR /bot
+
+# Copy our build
+COPY --from=builder /bot/target/release/el_monitorro ./
+COPY --from=builder /bot/target/release/deliver ./
+COPY --from=builder /bot/target/release/sync ./
+COPY --from=builder /bot/target/release/cleaner ./
 
-RUN cp ./target/release/sync ./sync
+COPY --from=builder /bot/docker/start.sh ./
 
-RUN cp ./target/release/el_monitorro ./el_monitorro
+COPY --from=builder /usr/local/cargo/bin/diesel ./
+COPY --from=builder /bot/migrations/ ./migrations/
 
-RUN cp ./target/release/deliver ./deliver
 
-RUN rm -rf ./target
+# Use an unprivileged user.
+USER bot:bot
 
-CMD ["bash", "/app/docker/start.sh"]
+CMD ["bash", "/bot/start.sh"]

docker/start.sh

@@ -6,7 +6,7 @@ then
     echo "Proceeding without setting the database"
 else
     echo "Setting the database"
-    diesel database setup
+    ./diesel database setup
 fi