fix: improve the default dockerfile

Signed-off-by: Mateusz Urbanek <[email protected]>

Dockerfile

@@ -1,44 +1,47 @@
-ARG ALPINE_VERSION=edge
-
-FROM alpine:$ALPINE_VERSION AS builder
+# Stage 1: Build the application
+FROM docker.io/library/rust:1.80-alpine AS builder
 
+# Update Alpine packages and install build dependencies
 RUN apk update && apk add --no-cache --virtual .build-dependencies \
-  cargo \
-  cmake \
-  build-base \
-  file \
-  libgcc \
-  musl-dev \
-  protobuf \
-  protobuf-dev \
-  rust
-
-RUN apk add --no-cache llvm-libunwind \
-  pkgconfig
+    musl-dev \
+    protobuf \
+    protobuf-dev
 
+# Copy the source code into the image
 COPY . /usr/src/sozu
 WORKDIR /usr/src/sozu
 
+# Build the application in release mode with a frozen lockfile
 RUN cargo vendor --locked
 RUN cargo build --release --frozen
 
-FROM alpine:$ALPINE_VERSION AS bin
+# Stage 2: Create the runtime environment
+FROM docker.io/library/alpine:3.20 AS bin
 
+# Expose ports for the application
 EXPOSE 80
 EXPOSE 443
 
+# Define volumes for configuration and runtime state
 VOLUME /etc/sozu
 VOLUME /run/sozu
 
+# Create a directory for persistent state
 RUN mkdir -p /var/lib/sozu
 
+# Install runtime dependencies
 RUN apk update && apk add --no-cache \
   llvm-libunwind \
   libgcc \
   ca-certificates
 
+# Copy the built binary from the builder stage
 COPY --from=builder /usr/src/sozu/target/release/sozu /usr/local/bin/sozu
+
+# Copy the default configuration file
 COPY os-build/config.toml /etc/sozu/config.toml
 
+# Set the default entry point to the binary and provide default command
+# to start the application with a specific config
 ENTRYPOINT ["/usr/local/bin/sozu"]
 CMD ["start", "-c", "/etc/sozu/config.toml"]

doc/how_to_use.md

@@ -32,15 +32,12 @@ Check out the command line [documentation](./configure_cli.md) for more informat
 
 ## Run it with Docker
 
-The repository provides a multi-stage [Dockerfile][df] image based on `alpine:edge`.
+The repository provides a multi-stage [Dockerfile][df] image based on `alpine:3.20`.
 
 You can build the image by doing:
 
     docker build -t sozu .
 
-There's also the [clevercloud/sozu](https://hub.docker.com/r/clevercloud/sozu/) image
-following the master branch (outdated).
-
 Run it with the command:
 
 ```bash
@@ -55,10 +52,6 @@ docker run \
   sozu
 ```
 
-To build an image with a specific version of Alpine:
-
-    docker build --build-arg ALPINE_VERSION=3.14 -t sozu:main-alpine-3.14 .
-
 ### Using a custom `config.toml` configuration file
 
 The default configuration for sozu can be found in `../os-build/docker/config.toml`.