Update Dockerfile

Dockerfile

@@ -1,19 +1,26 @@
-# Make sure RUST_VERSION matches the Rust version
+# Pin the Rust toolchain version used in the build stage.
 ARG RUST_VERSION=1.92
-ARG APP_NAME=docker-rust-hello
+
+# Name of the compiled binary produced by Cargo (must match Cargo.toml package name).
+ARG APP_NAME=paste
 
 ################################################################################
-# Create a stage for building the application.
+# Build stage (DOI Rust image)
+# This stage compiles the application.
 ################################################################################
 
-FROM dhi.io/rust:${RUST_VERSION}-alpine3.22-dev AS build
+FROM docker.io/library/rust:${RUST_VERSION}-alpine AS build
+
+# Re-declare args inside the stage if you want to use them here.
 ARG APP_NAME
+
+# All build steps happen inside /app.
 WORKDIR /app
 
-# Install host build dependencies.
+# Install build dependencies needed to compile Rust crates on Alpine
 RUN apk add --no-cache clang lld musl-dev git
 
-# Build the application.
+# Build the application 
 RUN --mount=type=bind,source=src,target=src \
     --mount=type=bind,source=Cargo.toml,target=Cargo.toml \
     --mount=type=bind,source=Cargo.lock,target=Cargo.lock \
@@ -24,13 +31,13 @@ RUN --mount=type=bind,source=src,target=src \
     cp ./target/release/$APP_NAME /bin/server
 
 ################################################################################
-# Create a new stage for running the application that contains the minimal
-# We use dhi.io/static for the final stage because it’s a minimal Docker Hardened Image runtime (basically “just # enough OS to run the binary”), which helps keep the image small and with a lower attack surface compared to a # # full Alpine/Debian runtime.
+# Runtime stage (DOI Alpine image)
+# This stage runs the already-compiled binary with minimal dependencies.
 ################################################################################
 
-FROM dhi.io/static:20250419 AS final
+FROM docker.io/library/alpine:3.18 AS final
 
-# Create a non-privileged user that the app will run under.
+# Create a non-privileged user (recommended best practice)
 ARG UID=10001
 RUN adduser \
     --disabled-password \
@@ -39,17 +46,19 @@ RUN adduser \
     --shell "/sbin/nologin" \
     --no-create-home \
     --uid "${UID}" \
-    appuser
-USER appuser
+    imnyang
 
-# Copy the executable from the "build" stage.
-COPY --from=build /bin/server /bin/
+# Drop privileges for runtime.
+USER imnyang
 
-# Configure rocket to listen on all interfaces.
+# Copy only the compiled binary from the build stage.
+COPY --from=build /bin/paste /app/
+
+# Rocket: listen on all interfaces inside the container.
 ENV ROCKET_ADDRESS=0.0.0.0
 
-# Expose the port that the application listens on.
+# Document the port your app listens on.
 EXPOSE 8000
 
-# What the container should run when it is started.
-CMD ["/bin/server"]
+# Start the application.
+CMD ["/app/paste"]