update docker sample

basics/docker_sample/.dockerignore

@@ -0,0 +1 @@
+Dockerfile

basics/docker_sample/Cargo.toml

@@ -6,3 +6,5 @@ edition = "2018"
 
 [dependencies]
 actix-web = "3"
+env_logger = "0.9"
+log = "0.4"

basics/docker_sample/Dockerfile

@@ -1,24 +1,38 @@
-FROM rust:1-slim-buster AS base
-
-ENV USER=root
+# NB: This is not a production-grade Dockerfile.
 
+#################
+## build stage ##
+#################
+FROM rust:1-slim-bullseye AS builder
 WORKDIR /code
-RUN cargo init
-COPY Cargo.toml /code/Cargo.toml
+
+# Download crates-io index and fetch dependency code.
+# This step avoids needing to spend time on every build downloading the index
+# which can take a long time within the docker context. Docker will cache it.
+RUN USER=root cargo init
+COPY Cargo.toml Cargo.toml
 RUN cargo fetch
 
-COPY src /code/src
+# copy app files
+COPY src src
 
-CMD [ "cargo", "test", "--offline" ]
+# compile app
+RUN cargo build --release
 
-FROM base AS builder
+###############
+## run stage ##
+###############
+FROM debian:bullseye-slim
+WORKDIR /app
 
-RUN cargo build --release --offline
+# copy server binary from build stage
+COPY --from=builder /code/target/release/docker_sample docker_sample
 
-FROM debian:buster-slim
+# set user to non-root unless root is required for your app
+USER 1001
 
-COPY --from=builder /code/target/release/docker_sample /usr/bin/docker_sample
+# indicate what port the server is running on
+EXPOSE 8080
 
-EXPOSE 5000
-
-ENTRYPOINT [ "/usr/bin/docker_sample" ]
+# run server
+CMD [ "/app/docker_sample" ]

basics/docker_sample/src/main.rs

@@ -1,26 +1,28 @@
-#[macro_use]
-extern crate actix_web;
-
-use actix_web::{App, HttpResponse, HttpServer, Responder};
+use actix_web::{get, middleware::Logger, App, HttpResponse, HttpServer, Responder};
 
 #[get("/")]
 async fn index() -> impl Responder {
-    println!("GET: /");
     HttpResponse::Ok().body("Hello world!")
 }
 
 #[get("/again")]
 async fn again() -> impl Responder {
-    println!("GET: /again");
     HttpResponse::Ok().body("Hello world again!")
 }
 
 #[actix_web::main]
 async fn main() -> std::io::Result<()> {
-    println!("Starting actix-web server");
+    env_logger::init_from_env(env_logger::Env::new().default_filter_or("info"));
 
-    HttpServer::new(|| App::new().service(index).service(again))
-        .bind("0.0.0.0:5000")?
-        .run()
-        .await
+    log::info!("Starting HTTP server: go to http://localhost:8080");
+
+    HttpServer::new(|| {
+        App::new()
+            .wrap(Logger::default())
+            .service(index)
+            .service(again)
+    })
+    .bind(("0.0.0.0", 8080))?
+    .run()
+    .await
 }