feat: improve dockerfile, better stages

Dockerfile

@@ -1,45 +1,70 @@
 # Build Stage
-FROM rust:1.81.0 as builder
+FROM rust:1.81.0-alpine as builder
 
+# Install build dependencies
+RUN apk add --no-cache \
+    musl-dev \
+    pkgconfig \
+    openssl-dev
+
+WORKDIR /usr/src
 RUN USER=root cargo new --bin time-banner
-WORKDIR ./time-banner
-ENV CARGO_REGISTRIES_CRATES_IO_PROTOCOL=sparse
-COPY ./Cargo.toml ./Cargo.toml
+WORKDIR /usr/src/time-banner
+
+# Copy dependency files for better layer caching
+COPY ./Cargo.toml ./Cargo.lock* ./build.rs ./
+# Copy the timezone data file needed by build.rs
+COPY ./src/abbr_tz ./src/abbr_tz
+
 # Build empty app with downloaded dependencies to produce a stable image layer for next build
 RUN cargo build --release
 
 # Build web app with own code
 RUN rm src/*.rs
-ADD . ./
+COPY ./src ./src
 RUN rm ./target/release/deps/time_banner*
 RUN cargo build --release
 
+# Strip the binary to reduce size
+RUN strip target/release/time-banner
 
-FROM debian:bullseye-slim
+# Runtime Stage - Alpine for smaller size and musl compatibility
+FROM alpine:3.19
 ARG APP=/usr/src/app
+ARG APP_USER=appuser
+ARG UID=1000
+ARG GID=1000
 
-RUN apt-get update \
-    && apt-get install -y ca-certificates tzdata \
-    && rm -rf /var/lib/apt/lists/*
+# Install runtime dependencies
+RUN apk add --no-cache \
+    ca-certificates \
+    tzdata
 
-ENV TZ=Etc/UTC \
-    APP_USER=appuser
+ENV TZ=Etc/UTC
 
-RUN groupadd $APP_USER \
-    && useradd -g $APP_USER $APP_USER \
+# Create user with specific UID/GID
+RUN addgroup -g $GID -S $APP_USER \
+    && adduser -u $UID -D -S -G $APP_USER $APP_USER \
     && mkdir -p ${APP}
 
-COPY --from=builder /time-banner/target/release/time-banner ${APP}/time-banner
-COPY --from=builder /time-banner/src/fonts ${APP}/fonts
-COPY --from=builder /time-banner/src/templates ${APP}/templates
+# Copy application files
+COPY --from=builder --chown=$APP_USER:$APP_USER /usr/src/time-banner/target/release/time-banner ${APP}/time-banner
+COPY --from=builder --chown=$APP_USER:$APP_USER /usr/src/time-banner/src/fonts ${APP}/fonts
+COPY --from=builder --chown=$APP_USER:$APP_USER /usr/src/time-banner/src/templates ${APP}/templates
 
-RUN chown -R $APP_USER:$APP_USER ${APP}
+# Set proper permissions
+RUN chmod +x ${APP}/time-banner
 
 USER $APP_USER
 WORKDIR ${APP}
 
-EXPOSE 3000
-ENV PORT 3000
+# Use ARG for build-time configuration, ENV for runtime
+ARG PORT=3000
+ENV PORT=${PORT}
+EXPOSE ${PORT}
 
+# Add health check (using wget since curl isn't in Alpine by default)
+HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
+    CMD wget --quiet --tries=1 --spider http://localhost:${PORT}/health || exit 1
 
 CMD ["./time-banner"]