Add logs, add Dockerfile

problem_01/Cargo.toml

@@ -3,7 +3,7 @@ name = "problem_01"
 version = "0.1.0"
 edition = "2021"
 
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
 [dependencies]
+env_logger = "^0.10"
+log = "^0.4"
 tokio = { version = "1.27.0", features = ["full"] }

problem_01/Dockerfile

@@ -0,0 +1,22 @@
+FROM rust:latest as builder
+
+WORKDIR /usr/src/app
+COPY . .
+# Will build and cache the binary and dependent crates in release mode
+RUN --mount=type=cache,target=/usr/local/cargo,from=rust:latest,source=/usr/local/cargo \
+    --mount=type=cache,target=target \
+    cargo build --release && mv ./target/release/problem_01 ./problem_01
+
+# Runtime image
+FROM debian:bullseye-slim
+
+# Run as "app" user
+RUN useradd -ms /bin/bash app
+
+USER app
+WORKDIR /app
+
+# Get compiled binaries from builder's cargo install directory
+COPY --from=builder /usr/src/app/problem_01 /app/problem_01
+
+# No CMD or ENTRYPOINT, see fly.toml with `cmd` override.

problem_01/src/main.rs

@@ -17,13 +17,13 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
                     Ok(n) if n == 0 => return,
                     Ok(n) => n,
                     Err(e) => {
-                        eprintln!("failed to read from socket; err = {:?}", e);
+                        log::error!("failed to read from socket; err = {:?}", e);
                         return;
                     }
                 };
 
                 if let Err(e) = socket.write_all(&buf[0..n]).await {
-                    eprintln!("failed to write to socket; err = {:?}", e);
+                    log::error!("failed to write to socket; err = {:?}", e);
                     return;
                 }
             }